Petgeo1 6
Upcoming SlideShare
Loading in...5
×
 

Petgeo1 6

on

  • 1,025 views

 

Statistics

Views

Total Views
1,025
Views on SlideShare
1,025
Embed Views
0

Actions

Likes
0
Downloads
62
Comments
0

0 Embeds 0

No embeds

Accessibility

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Petgeo1 6 Petgeo1 6 Document Transcript

  • F -X C h a n ge F -X C h a n ge c u-tr a c k N y bu to k lic PETROLEUM GEOLOGY "Petroleum prospecting is an art." -E. DeGolyer Assoc. Prof. Dr. Volkan . Ediger .d o o .c m C m w o .d o w w w w w C lic k to bu y N O W ! PD O W ! PD c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic A STORY OF AN OILMAN "By the time Mark 'took a package' in early 1999, we had become good friends. For 17 years Mark and his wife traipsed around the world in the employ of Schlumberger, with stops in Egypt, Pakistan, and Venezuela (twice). As natives of North Dakota, they welcomed their first domestic assignment, a transfer to Houston, in early 1998. If nothing else, it would be a good thing for their three young daughters. Being laid off was a twist they hadn't expected. A highly competent and high-quality character in his early 40s, Mark was completely unphased by the event (after all, oil had dropped to $ 10 a barrel), and even welcomed the change of pace. As it turned out, he decided on a whole new career-in the funeral business. In just three months with a major funeral-home chain, Mark moved from an entry-level sales position to mid-management. This is not surprising if you know Mark, but consider some of the details. Early in his new job and just getting his feet on the ground, Mark pulled together and charted some local sales and growth figures in Excel. He presented them to his workgroup in PowerPoint using a computer projector. On the basis of his presentation, he was dubbed the resident 'computer techie.' I know Mark pretty well, and frankly, I'd rate him at the lower end of the techie ladder. The whole event struck Mark as weird, as it did me. The thought flashed to my brain. I'd spent the past six years developing research programs at Texas A&M University and the University of Houston, all the while sounding the alarm that the oil industry is under-researched and not nearly as high-tech as it claims. How did I reconcile my claims with this story? Then it occurred to me. The strength of the oil industry is not research or technology development, per se; it is that we innovate-relentlessly-on the basis of technological advances, no matter where the advances come from. If Bill Gates can make a better computer program, my thinking goes, we in the oil business probably can put it in use faster and better than any other industry. Mark relays another interesting story. It seems the funeral home's tracking system has a small breakdown, with the result that one of their (deceased) clients was misplaced. This upset the relatives tremendously. Mark had only overheard the incident (the shouting of an angry relative, I think), but nonetheless took the initiative to raise the issue at the next staff meeting. His question was obvious and simple: What are we doing to ensure this does not happen again? The response? Blank stares. No one had any intention of doing anything. A small change in the standard work flow did the trick. For people in the oil industry, isolating and solving problems competently is so natural, like drinking water, that we don't even realize we are doing it." From; Economides, M.J. and Oligney, R.E., 1999, The color of oil-Part V: Primary Colors: Hart's E&P, October 1999, p 156-162. 2 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic SYLLABUS I. INTRODUCTION Logistics, Energy Resources, Petroleum Industry, Upstream Business (Exploration & Production), Megatrends, Synergistic Teams. II. HISTORY AND GLOBAL PETROLEUM SYSTEM Petroleum History of Turkey, Global Oil System, Reserves & Resources, Hubbert's Curve, World Reserves, Productions & Consumptions. Exercise: Past, Present, and Future of Oil. III. COMPOSITION ORGANIC MATTER OF HYDROCARBONS AND SEDIMENTARY Main Compounds in Crude Oils, Plant Kingdom, Main Contributors of Organic Matter in Sediments, Color of Sedimentary Rocks, Sedimentary Organic Matter, Transportation & Deposition of Kerogen, Physico-chemical Conditions, Depositional Environments. Exercise: Palynofacies Analysis. IV. SOURCE ROCKS & PETROLEUM GENERATION Source Rocks of the World, World Petroleum Realms, Source Rock Analysis, Van Krevelen Diagram, Oil Generative Capacity, Diagenesis, Catagenesis & Metagenesis of Organic Matter, Petroleum Generation & Expulsion Exercise: Source Rock Evaluation. V. RESERVOIR ROCKS AND MIGRATION & ENTRAPMENT Giant Fields, Migration and Entrapment, Reservoir Rocks, Cap Rocks, Trap Formation, Geological Framework of Migration & Accumulation, Oil Half-life Model, Oil-Oil and Oil-Source Rock Correlations, Preservation-Degradation-Destruction of Trapped Oil. Exercise: Oil-Source Rock Correlation Exercise: Oil Half-life Model VI. PETROLEUM SYSTEM Petroleum System (Classification, Subsystems, Factors, Styles) Sedimentary Basins, Plays & Prospects, Petroleum System Name, Characteristics & Limits. Exercise: Deer-Boar (.) Petroleum System. Exercise: Partial or Complete Petroleum Systems. MIDTERM EXAMINATION 3 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic (Mid-semester Assignment: Literature Survey on Petroleum Geology) VII. GEOLOGICAL INVESTIGATION Petroleum Investigation, Petroleum System Logic, Petroleum Geology, Laws of Geology, Topographic & Geologic Maps. Exercise: Surface Geologic Mapping VIII. STRATIGRAPHY Stratigraphic Classification, Lithostratigraphy, Biostratigraphy, Chronostratigraphy. Exercise: Age Interpretation Exercise: Biozonation of a well. IX. WELL LOGGING & GEOPHYSICAL METHODS Dipmeter and Gammaray Logs, Spontaneous Potential (SP) and Resistivity Curves. Exercise: Gamma Ray and Dipmeter Logs. X. CORRELATIONS Correlation, Lithostratigraphic Correlation, Correlation of Electric Logs. Exercise: Correlation of Intertonguing Deposits. Exercise: Regional Correlation of Electric Logs. Exercise: Local Detail Correlation of Electric Logs. XI. SUBSURFACE GEOLOGY Subsurface Maps, Lithofacies Mapping, Structural Contour Maps, Isopach Maps, Paleogeologic Maps, Facies Maps, Block (Panel, Fence) Diagrams. Exercise: Regional Lithofacies Mapping. Exercise X: Structure, Isopach, and Lithofacies Mapping. Exercise XI: Preparation of Block Diagram. XII. PETROLEUM GEOLOGY OF TURKEY Exercise: Petroleum Geology of Thrace Basin. Exercise: Petroleum Geology of Southeastern Anatolia. XIII. PETROLEUM ECONOMICS Economic Evaluation of International Petroleum Projects. TERM PROJECT & PRESENTATIONS “ Teamwork on Petroleum Geology of Turkey” FINAL EXAMINATION Schedule Time: Wednesday 8:40-9:30, 9:40-10:30, 10:40-11:30, 11:40-12:30 Place: Prof. Dr. Ayhan Erler Room (Deceased October 13, 1998). 4 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Major Text Books (In chronological order) Levorsen, A. I., 1969, Geology of Petroleum: W.H. Freeman & Company. LeRoy, L.W., LeRoy, D.O., and Raese, J.W., 1977, Subsurface Geology: Colorado School of Mines. Brooks, J., 1981, Organic Maturation Studies and Fossil Fuel Exploration: Academic Press. Waples, D., 1981, Organic Geochemistry for Exploration Geologists: Burgess Publishing Company. Tissot, B.P. and Welte, D.H., 1984, Petroleum Formation and Occurrences: Springer and Verlag, Second Edition. Tearpock, D.J. and Bischke, R.E., 1991, Applied Subsurface Geological Mapping: Prentice Hall. Lerche, I., 1992, Oil Exploration: Basin Analysis and Economics: Academic Press. Magoon, L.B. and Dow, W.G., 1994, The Petroleum System: AAPG Memoir No. 60. Hunt, J., 1995, Petroleum Geochemistry and Geology: W. H. Freeman, Second Edition. Tyson, R.V., 1995, Sedimentary Organic Matter: Chapman and Hall, London. Selley, R.C., 1997, Elements of Petroleum Geology: Academic Press, Second Edition. Kearey, P., Brooks, and M., Hill, I., 2002, An Introduction to geophysical Exploration: Blackwell Publishing, United Kingdom, Third Edition. Gluyas J. and Swarbrick, R., 2004, Petroleum Geosciences: Blackwell Publishing, United Kingdom. Major Periodicals (In alphabetical order) American Association of Petroleum Geologists Bulletin Journal of Petroleum Geology Journal of Petroleum Technology Oil and Gas Journal OPEC Review Petroleum Engineer Petroleum Geology Petroleum Geoscience World Oil World Petroleum Congress Proceedings Grading Attendance and Participation Mid-semester Assignment Midterm Term Paper and Presentation Final 10 % 10 % 25 % 25 % 30 % Required Course Material Lecture Notes Colored Pencils (At least six colors), Ruler and Protractor. 5 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic MID-SEMESTER ASSIGNMENT "Literature Survey on Petroleum Geology" Procedure 1) Search for an article written on one of the subjects that will be discussed during this course (see the syllabus). METU, TPAO, MTA, and ULAKBIM libraries are the best places to look for such articles. 2) The article should be published in one of the recent journals dated between 2000-2003. 3) Write only a half-page summary of the article and return it together with the xerox copy of the article. (Please summarize it with your own words, do not copy! ). 4) The reference of the article should be given on top of the page, following AAPG’ s standard format, of which the examples are given below: A) A published book written by one or more authors: Flavin, C. and N. Lenssen, 1994, Power surge: Guide to the coming energy revolution: New York, Mc Graw Hill, 382 p. B) A published book written by a company or an organization: Worl Energy Council, 1993, Energy for tomorrow’ world: World Energy Council, London, Nichols s Publishing, 320 p. World Energy Outlook, 1994, International Energy Agency: Paris, France, Organization for Economic Cooperation and development, 305 p. C) An Article (or paper) written by one or more authors in a periodical (or journal): Weeks, L. G., 1958, Fuel reserves of the future: AAPG Bulletin, v. 42, no. 4, p. 24-31. Ivanhoe, L. F., 1995, Future world oil supplies: there is a finite limit: World Oil, October 1995, v. 216, p. 77-88. D) An anonymous article (or a paper) published in a periodical (or a journal): The Economist, 1994, A survey of energy: The Economist, v. 331, p. 60-77. E) An article (or a paper) written by one or more authors in a published proceeding: Masters, C. D., 1985, Distribution and quantitative assessment of world crude oil reserves: Proceedings of the 11th World Petroleum Congress, v. 2, p. 229-237. F) An article (or a paper) written by one or more authors as a chapter (or a section) in a book (or in any kind of publication) edited by one or more authors: Roodman, K. N., 1997, A cas history of oil-shortage scares, in L. Starke and B. Supple, eds., Our oil resource: New York, McGraw-Hill, p. 306-406. Dolton, G., D. L. Gautier, and H. Root, 1993, Natural gas resources, in D. G. Howell, ed., The future of energy in U.S.: U.S. Geological Survey Professional Paper 1570, p. 495-576. G) An unpublished report by a company, a survey, or an organization etc.: Lewin and Associates, 1976, The potential and economics of enhanced oil recovery: Final report proposed for the Federal Energy Administration under contract No. 60-44-5874-998. Merritt, D. R., 1986, Map of Alaska’ coal resources: Alaska Division of geological and Geophysical s Survey Open-file Report 84-24, 64 p. Meyer, F. L., 1995, Geology of Pennsylvanian rocks in the southeast New Mexico: New Mexico Institute of Mining and Technology Memoir 17, 123 p. H) An article (or paper) written in a different language: 6 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Muslimov, R. K. and G. Akhmedzova, 1975, Outlining and preparation of small petroleum fields for production: Geologiya Neft i Gaza, no. 1, p. 23-34. (In Russian). TERM PROJECT AND PRESENTATION "Teamwork on Petroleum Geology of Turkey” Term project is designed to improve students’ability to apply the principles of geology to the petroleum industry of Turkey. Students are expected to design and develop new exploration strategies to improve exploitation of the domestic petroleum resources in Turkey. For this, the already known petroleum systems and the present exploration activities should be evaluated thoroughly to be able to propose possible applications of modern information, theory, technique, and process. Examination of the modern international literature will enable students to investigate the most recent improvements in the world’ petroleum industry. s Building a Synergistic Teams Synergy simply means the action of discreet agencies so that the total effect is greater than the sum of the effects taken independently. In petroleum exploration and production business synergistic teams mean that geologists, geophysicists, petroleum engineers, and others work together on a project more effectively and efficiently as a team than working as individuals. It has almost been proven that the old style line organization cannot compete with the new teams. Therefore, you should either choose not to play or you integrate into a team system so that you can play. A team consists of a project manager (team leader) and team members (in our case, data-gathering, data-evaluation, report-writing, presentation etc.). Each individual of the team should always keep in mind that he or she will be rewarded if the team is successful. The critical individual in the team is the project manager who plans, organizes, reviews project performance, and communicates results. He also identifies and eliminates barriers between individuals and between other teams. Team members do independent thinking but share their experience and talents with the other members by feeling responsible for all the results. Term Paper and Presentations Each team is expected to return a term paper, which is written in standard AAPG article format. The articles should include an introduction (statement, purpose, and scope), a main section (presentation and evaluation of data and discussion), and a conclusion. The reference list, which includes the cited literature, is to be given at the end of the article. The team members may write and also present the term paper 7 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic together or one member may be assigned for each of these purposes. The presentations will last only 15 minutes sharp! and overhead projector transparencies should be used during presentations. I. INTRODUCTION References Cavoulacos, P. and Deffarges, E., 1997, Achieving profitable growth in E &P: New strategies, business model: Oil and Gas Journal, May 26, 1997, p. 42-48. Hart's Petroleum Engineer International, 1997, Megatrends of 1997-An industry perspective, v. 70, no. 1, p. 25-37. Ivanhoe, F.F., 1995, Future world oil supplies: There is a finite limit: World Oil, v. 216, no. 10, p. 77-90. Masters, J.A., 1990, Teamwork: p. 336-340. Oil and Gas Journal, 1996,, State-owned companies top reserves ranking outside U.S.: Oil and Gas Journal, v. 94, no. 36, p. 68-74. Sneider, R.M., 1993, The economic values of a synergistic organization, p. 328-331. Megatrends World E & P Business Hart's Petroleum Engineer International reviewed the opinions of H. Carlsen, M. Mes, L. Robinson, M. Simmons, J. Thorogood on the megatrends in the petroleum industry in 1997. The experts commonly believed that the megatrends in the industry towards the 21th century will be; 1) from status quo to flexibility, 2) from vogue to value added, 3) from nation state to business state, 4) from vulnerability to self preservation, 5) from nationalism to globalism, 6) from passivity to interactivity, 7) from competition to cooperation, 8) from human power to automation, 9) from homogeneity to diversity, 10) from mass marketing to micromarketing. A variety of activities is involved in the course of oil and gas industry, from upstream (exploration, development, and production) to downstream (refining and marketing). Transportation with pipelines and tankers is usually considered as at the middle. State-owned oil companies continued to dominate the OGJ100 list of the world's biggest oil and gas companies outside the US for many years. For instance, Saudi Arabian Oil Company and National Iranian Oil Company were listed in both reserves and production list of the top five stateowned companies outside the US in 1996 (Table I. 1). 8 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Table I. 1. Reserve and production leaders (Oil and Gas Journal, 1996). R A N K R A N K COMPANY PRODUCTION million bbl 1 Saudi Arabian Oil Co. 2,944.5 1 Saudi Arabian Oil Co. 1,318.4 1,119.0 1,097.6 962.3 2 3 4 5 2 3 4 5 National Iranian Oil Co. Petroleos Maxicanos China National Petroleum Co. Petroleos de Venezuela SA COMPANY Iraq National Oil Co. Kuwait Petroleum Corp. Abu Dhabi National Oil Co. National Iranian Oil Co. RESERVE million bbl 258,703.0 100,000.0 94,000.0 92,200.0 88,200.0 The leading nongovernmental company in both reserves and production is Royal Dutch/Shell: No. 6 in liquids production and No. 12 in liquids reserves. British Petroleum is the next largest nongovernmental company, ranking 12th in liquids production and 17th in liquids reserves. Elf Aquitaine of France ranked 14th in liquids production, Total of France 19th in the same category. Several major oil companies such as Exxon, Chevron, Mobile, and Texaco would rank in the OGJ100 top 20. However, the lists have changed after the merging of the major oil companies all around the world. Major changes in the oil and gas industry during the last decade and a half have necessitated significant changes in upstream business strategies (Cavoulacos and Deffarges, 1997). Successful upstream players have changed their strategies-from frontier exploration to development/production new ventures and on to gas and power plays-and built the capabilities necessary to achieve profitable growth. Moreover, these companies have adopted a new business model, an organisation paradigm based on process-driven networks of business units, accountability and pay-for-performance, empowered multidisciplinary teams, and best practice sharing. Synergistic Teams The synergistic team approach (Figure I. 1) has been tried by several large and small oil companies in the late 1970's and 1980's in order to compete more effectively and profitably with fewer staff and managers (Sneider, 1993). Synergy is defined as the action of discreet agencies so that the total effect is greater than the sum of the effects taken independently. Within the context of the petroleum exploration and production business, synergy means that geologists, geophysicists, petroleum engineers and others work together on a project more effectively and efficiently as a team than working as a group of individuals. 9 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Masters (1990) who considered team building a social activity, tribal, and attitude reviewed what is needed: 1) Recognition that many complex problems require the integrated brain power of numerous specialists (team), 2) Commitment and support from the top for the team concept (receptive environment), 3) Consistently high-quality people, 4) Trust, from the management and amongst themselves, 5) Friendship, 6) Freedom to contribute, 7) Freedom to communicate, 8) Job satisfaction by achievement rather than title, 9) Supportive, enabling management style, 10) Flexible, fluid organisation. No planners, 11) Once committed, anyone who doesn't participate is out, 12) The incontrovertible ethic (We pull together!), 13) The guts to stand behind this and make it work. This is not a system for pussycats. Exploration Milestones Ivanhoe (1995) has noted that petroleum exploration is an efficient technical procedure. However, he also noted that the largest oil and gas fields in any basin or oil province were also the biggest targets and the easiest to find with any given technology and thus they were normally found in any exploration phase. There are today virtually no areas where petroleum exploration cannot be successfully carried out if preliminary geological studies indicate a good chance of finding major oil fields. The exploration and drilling techniques routinely used by large oil companies and the dates of first applications are as follows: 1) Surface geology (1900), 2) Rotary drilling (1920), 3) Refraction seismic (1925), 4) Electric well logs (1930), 5) Analog reflection seismic (1935), 6) Mud logging (1940), 7) Offshore drilling barges (1950), 8) Deepwater drill ship (1956), 9) Semi-submersible rigs (1964), 10) Digital reflection seismic (1965), 11) 3-D digital reflection seismic (1978), 12) Horizontal drilling (1985). 10 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Energy Resources The simplest definition of energy is the capacity to do work (to do things or to get things done). Since work is done when a force is used to move an object some distance, it can easily be calculated by using the formula; Work=ForcexDistance. It is a hard work to push an automobile but hard studying does not fit into the mechanical work concept. When we work we get hungry, then we eat and gain energy. If we don't eat enough, we loose weight. Energy is found in different forms, such as; work, heat, electrical, chemical, nuclear, kinetic, potential, light, magnetic, sun, mass etc. Some forms of energy are nonspontaneous which takes place only as a result of an external stimulus; others are spontaneous which has a natural tendency to occur of its own accord. Energy is obtained from energy resources of which some are renewable and others are nonrenewable. The use of renewable resources is limited by the rate of renewal, the use of nonrenewable resources is limited by the reserves. Fossil fuels, including oil, natural gas, hard coal, and lignite and radioactive minerals are nonrenewables whereas the renewable are sun, wind, hydrothermal, tides, hydrogen etc. According to the first and second laws of thermodynamics although the universe never loses any energy, less and less of that energy can be converted into work as times go on. This is mainly because every spontaneous change is accompanied by an increase in entropy, which is a measure of randomness, disorder, or chaos. Shortage of energy and environmental problems are the major causes of energy crises or energy dilemma. Shortage of energy is the result of some natural causes such as limited reserves, increasing population and thus consumption. Artificial causes, on the other hand, result from some political and economical reasons. The ultimate goal is the efficient use of clean energy but we are going up the down escalator on energy. Figure I. 1. Synergistic organization in a small company which has from four to six teams of exploration and production technical staff. 11 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic II. HISTORY AND GLOBAL PETROLEUM SYSTEM References BP Amoco, Statistical Review of World Energy, 2002. Hubbert, M.K., 1956, Nuclear energy and the fossil fuels: American Petroleum Institute Drilling and Production Practices, p. 7-25. Ivanhoe, L.F., 1984, World crude output, reserves by region: Oil & Gas Journal Dec. 24, 1984. Ivanhoe, L.F., 1995, Future world oil supplies: there is a finite limit: World Oil, v. 216, no. 10,p. 77-90. PIGM (Petroleum Directorate of Turkey), Petroleum Activities in 1998. Turkish Petroleum Company, Annual Report, 1998. World Energy Yearbook, 1996. Petroleum History of Turkey 1859 1860 1876 1887 1888 1889 1897 1898 1890-1900 1901 1901 1908 COLONEL EDWIN L. DRAKE ’ WELL IN OIL CREEK, PA, USA. S PRODUCTION IN USA REACHED TO 650,000 BBL. PRICES DROPPED FROM 20 $ TO 2$. 34-YEARS-OLD SULTAN ABDULHAMID ASCENDED THE THRONE ON 31 AUGUST. HE RULED THE EMPIRE FOR 33 YEARS BETWEEN 1876-1908. CHEMICAL ANALYSES OF THE SKENDERUN OIL SAMPLE BY CHEMIST MOREAU IN STANBUL ON 17 JULY. MOUSUL & SURROUNDINGS WERE INCLUDED IN THE SULTAN’ S HAZ NE- HASSA (PRIVATE ASSET) ON 13 JANUARY. FIRST LICENCE TO AHMED NECAT EFEND ON 23 JUNE. FOR THE ÇENGEN OIL & GAS IN SKENDERUN. MÜREFTE LICENCES GRANTED TO HAL L R FAT PA A OPENNING A SQUARE WELL (108 M) BY THE ROMANIAN WORKERS IN GANOS. SOME OIL AND GAS SHOWS. GREAT BRITAN'S ARCHEOLOGICAL STUDIES. GERMANY'S BAGDAT RAILROAD PROJECT. FOLLOWING THE ESTABLISHMENT OF THE OTTOMAN BANK, EUROPEAN PETROLEUM CO. DRILLED THE HORADERE-1 WELL TURKEY’ FIRST PRODUCTION: 47 TONS OF OIL. S D’ ARCY CONCESSION: ANTOINE KITABJI KHAN MARKETTED IRAN TO WILLIAM KNOX D’ ARCY. FOC-FIRST OIL COMPANY (CHANGED TO APOC IN 1909, LATER TO BP) DRILLED IN MESC D- SÜLEYMAN IN IRAN. DISCOVERY OF OIL IN THE MIDDLE EAST. 12 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 1912 1912 1914-1918 1918 1920 1925 1926 1922 1923 1925 1925 1927 1929-1932 1929 1930 1931 1933 1934 1935 1937-38 1938-1945 1940 1940 1940 MÜ R FUAT PA A GRANTED A LICENCE IN KÜRZOT, VAN. KALTUZ GULBENKIAN ESTABLISHED THE TURKISH PETROLEUM COMPANY WITH BRITISH, GERMAN, AND DUTCH INVESTORS. WORLD WAR I (GREAT WAR!). CHANGE FROM BRITISH+GERMAN TO BRITISH+FRENCH ALLIANCES. MONDROS CEASE FIRE AGREEMENT ON 30 OCTOBER. TURKISH GRAND NATIONAL ASSEMBLY MEETING ON 23 APRIL. OIL PANIC IN USA REVISION OF LAW NO. 608: MAAD N N ZAMNAMES ON 12 APRIL. ACCEPTANCE OF LAW NO. 792: PETROLEUM LAW ON 12 MARCH. NEGOTIATIONS IN LAUSANNE. CURZON- NÖNÜ (HASAN BEY VE RIZA NUR BEY) DISCUSSIONS ENDED ON 23 JANUARY. APPLICATION TO COUNCIL OF THE LEAUGE OF NATIONS. TBMM’ CONTRACT WITH M. LUCIUS FROM LUXEMBURG S TBMM ACCEPTED THE COUNCIL’ REPORT ON 16 DECEMBER. S MUSUL AND KERKÜK IN IRAQ. IRAQ PETROLEUM COMPANY DISCOVERED BABA GURGUR OIL FIELD IN IRAQ ON 15 OCTOBER. 95,000 BBL/DAY !... WORLD ECONOMIC DEPRESSION. LUCIUS’ FIELD TRIPS WITH KEMAL LOKMAN WHO EDUCATED S IN FRANCE, CEVAT EYUP WHO EDUCATED IN USA, AND GERMAN KURT SCHMIDT. SHIRLEY L. MASON’ PAPER AT AAPG NEW ORLEANS MEETING: S “ NOT ENOUGH OIL IN TURKEY” LOKMAN’ ANSWER. CEVAT EYUP’ PAPER AT AAPG SAN S ANTONIO MEETING: “ PLENTY OF OIL IN TURKEY” ACCEPTANCE OF LAW NO. 2189 (PIGM: PETROLEUM DIRECTORATE OF TURKEY; MINISTRY OF ECONOMY) ON 20 MAY. CEVAT EYÜP: GENERAL DIRECTOR. BASBIRIN-1 STARTED BEFORE THE MINISTER OF ECONOMY CELAL BAYAR ON 13 OCTOBER. LAW NO. 2804: MTAE (MINERAL RESEARCH AND EXPLORATION INSTITUTE OF TURKEY) ON 22 JUNE. HERM S-1, KERBENT-1, HERM S-2 WELLS WORLD WAR II. DISCOVERY OF OIL IN RAMANDA -1 ON 24 APRIL. FIRST FALSE OIL DISCOVERY IN TURKEY. PRIME MINISTER REFIK SAYDAM, MINISTER OF ECONOMY HÜSNÜ ÇAKIR VISITED RAMANDA -1 ON 24 APRIL. KEMAL LOKMAN: LK TÜRK PETROLÜNÜN BULUNU TAR N, BÜYÜK M LLET MECL N KÜ AD LE TÜRKÜN M LL VE S YAS HAK YET EL NE ALDI I GÜNÜN AR FES NE TESADÜF ETMES B R FAL HAYRA ALAMETT R. BUGÜN, AYNI ZAMANDA PETROL ARA TIRMA VE BULMA TAR ZDE BÜYÜK B R BA LANGIÇ, B R DÖNÜM GÜNÜ OLUP KALACAKTIR” 13 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 1946 MULTI-PARTY ELECTIONS: DEMOCRATIC PARTY (DP) AND REPUBLICAN POEOPLE’ PARTY (CHP) S 1948 DECLERATION OF RAMANDA AS ECONOMICAL FIELD AND PRESIDENT NÖNÜ & PRIME MINISTER GÜNALTAY VISITED THE AREA IN MARCH. DISCOVERY OF THE GARZAN OIL FIELD. ACCENTANCE OF LAW NO. 6326 (PETROLEUM LAW) AND LAW NO. 6327 (TPAO'S ESTABLISHMENT LAW) ON 7 MARCH. ESTABLISHMENT OF THE GENERAL DIRECTORATE OF PETROLEUM AFFAIRS. ACCEPTANCE OF LAW NO 2929 ON 20 MAY. TPAO CHANGED INTO TPA . REFINARY (TO TÜPRA CHANGED FROM PRA ), PIPE-LINES (TO BOTA ), MARKETTING (ATA CHANGED TO POA ), SHARES IN GSA AND PETK M TO TÜRK YE K MYA SANAY KURUMU, POA , D TA , AND PETKUR. ON 18 JUNE, AGAIN TPAO (SUBSIDIARIES: TÜPRA , POA , BOTA ,D TA ; ASSOCITED COMPANIES: PRAGAZ, TÜMA , BYA-TÜRK) PRAGAZ’ (D TA IN 1993) SHARES TO TOPLU KONUT ON 28 S MAY. KAMU DARES BA KANLI I. PRIVITIZATION PROGRAM. 88/13180 GOVERNMENTAL DECISION SIGNED BY THE COUNCIL OF MINISTERS ON 21 AUGUST. TPAO'S AUTHORIZATION FOR PETROLEUM ACTIVITIES ABROAD. TPIC ESTABLISHED IN JERSEY CHANNEL ISLANDS (ENGLAND) ON 7 DECEMBER. OIL ACTIVITIES IN EGYPT. TPAO’ AUTHORIZATION FOR ACTIVITIES IN KAZAKHSTAN ON S 20 JUNE. 4 FEBRUARY KAZAKTURKMUNAY LTD ESTABLISHED AIOC (AZERBAIJAN INTERNATIONAL OPERATING COMPANY). TURKISH SHARES INREASED TO 6.75 % COUNCIL OF MINISTER’ DECISION NO: 95/6526 ON 8 FEBRUARY. S BOTA REORGANIZED. BOTINT, TURKGAS IN 1997. 700 PRODUCTION WELLS IN ABOUT 100 OIL FIELDS. AROUND 3,2 M TONS DOMESTIC (TPAO: 2,4 M TONS, SHELL: 598,5 M TONS, MOBIL AND DORCHESTER: 85,1 M TONS, ERSAN: 3,7 M TONS, OTHERS: 76,9 M TONS). DOMESTIC PRODUCTION IS AROUND 12%. 53 WELLS A YEAR (TPAO: 38 WELLS, OTHERS: 15 WELLS). 1951 1954 1983 1984 1986 1988 1988 1993 1993 1995 1998 Global expelled oil system (=Global oil resources) includes all the expelled oil that existed before human intervention. Resources are defined as the reserves and currently uneconomic deposits. The Global Oil System The most widely accepted definitions of the oil and gas accumulations in the pools are as follows: 14 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic present in an area. Conservative bankers will not loan money on resources. Explorationists must first find -and then petroleum engineers convert-theoretical resources into producible reserves. An example of resources that will never become a reserve is gold in seawater. The term "reserve" includes the amount of proven petroleum, which exists in identifiable fields. Therefore, reservoired oil system can be defined as the total original oil-in-place in all fields, known and yet-to-be-found oil which would be included in global oil reserves using current economic criteria. Oil-in-place is the total amount of oil in situ and yet-to-befound oil is the quantity of economically extractable oil, which remains to be discovered. Ivanhoe (1995) has emphasized that oil companies are in business to make money- not to find oil per se. He proposed the terms active and inactive reserves. Active reserves are those producible within the foreseeable future (20 years or less), whereas inactive reserves are existence known but not considered producible within 20 years, ie. inaccessible or producible only with as-yet non-commercial methods like enhanced oil recovery, etc. Conservative bankers will not loan money on inactive reserves and some inactive reserves are called inferred reserves. Reserves can not be extracted totally and some will remain in place depending on the available technology. The amount that can be extracted from the reservoirs is called recoverable reserve. Ultimate global recoverable oil reserves, therefore, depend upon a global recovery factor for the reservoired oil system. R/P ratio is the recoverable reserves (bbl or tons of oil) divided by present-day yearly production (bbl/year or tons/year). It gives an idea about how many years will your reserves last if you continue producing them with the present-day rate. Some reserves are called political reserves. Government petroleum ministries have an inherent interest in announcing the "good news" of large national hydrocarbon reserves inasmuch as large political reserves are useful for national prestige and in negotiations for OPEC production quotas, World Bank loans and grants, etc. Sudden unsubstantiated reserve increases announced by any government should, therefore, be viewed with considerable scepticism. Reserves and Resources Ivanhoe (1995) considers that oil reserves are by definition economic, or profitable while resources, conversely, are less tangible. Reserves are engineers' (conservative) opinions of how much oil is known to be producible, within a known time, with known techniques, at known costs and in known fields. Conservative bankers will loan money on reserves. Resources are geologists' (optimistic) opinions of all oil theoretically Hubbert's Curve M. King Hubbert was among the first scientists who noticed that petroleum industry shows a unidirectional evolution, including a period of beginning, period of ascent, a 15 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic that there is strong evidence that the restricted Hubbert curve for the world's total EUR (estimated ultimate reserve) of oil may first peak about the year 2000. It may then fluctuate along a horizontal production line (restricted by Saudi Arabia/OPEC) before inevitable decline towards a low baseline after year 2050. At an annual global production of 20 billion bbl/year, an ultimate difference of global EUR of 300 billion bbl will defer the inevitable doomsday by only 15 years, ie. 300/20. period of decline, and an end (Figure II. 1). He made the only scientifically valid projection of future oil production in 1956. He correctly forecasted- on the basis of statistical projections of past U.S. (onshore and offshore lower48 states without Alaska)- that oil production would peak in 1969. Since then, the US oil production has declined within 5% of Hubbert's 1956 prediction. Ivanhoe (1995) concluded Figure II. 1. Hubbert's curve (Ivanhoe, 1984) petroleum industry and the history of Exercise: Past, Present, and petroleum in Turkey. Future of Oil 2) Try to establish the common points among the collapses of the Ottoman Empire and the Soviet Union with respect to their petroleum resources. 1) Try to determine the most possible reasons for the collapse of the Ottoman Empire during First World War by studying the history of the world's 16 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 3) Study the world's oil (Tables II. 1-2) and gas (Tables II. 3-4) reserves, productions, and R/P ratios. 4) Study the world oil production history and future production curve based on future reserve life by area (Figure II). 5) Write a scenario for the future of the Turkish petroleum industry by examining Figure II. 17 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2005 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge c u-tr a c k N y bu to k lic Volkan . Ediger, Petroleum Geology'2003 Figure II. 2. World oil production history and future production curve based on future reserve life by area (Ivanhoe, 1995). 18 .d o o .c m C m w o .d o w w w w w C lic k to bu y N O W ! PD O W ! PD c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Table II. 1. Distribution of world oil reserves in 2004 (Bp Amoco, 2005) 19 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Table II. 2. World oil production (Bp Amoco, 2005) Table II. 3. Distribution of world natural gas reserves in 2004 (Bp Amoco, 2005) 20 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Table II. 4. World natural gas production (Bp Amoco, 2002) 21 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 22 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic III. COMPOSITION OF HYDROCARBONS AND SEDIMENTARY ORGANIC MATTER References Braiser, M.D., 1980, Microfossils: George Allen & Unwin Ltd., London, 193 p. Burgess, J.D., 1974, Microscopic examination of kerogen (dispersed organic matter) in petroleum exploration: Geological Society of America Special Paper, No. 153, p. 19-30. Duran, B., 1980, Sedimentary organic matter and kerogen. Definition and quantitative importance of kerogen, in: B. Durand (Ed.), Kerogen: Organic matter from sedimentary rocks: Editions Technip, Paris, p. 13-34. Hunt, J.M., 1979, Petroleum geochemistry and geology: Freeman, San Francisco, 617 p. Krumbein, W.C. and Garrels, R.M., 1952, Origin and classification of chemical sediments in terms of pH and oxidation-reduction potential: Journal of Geology, v. 60, no. 1, p. 1-33. Potter, Maynard, and Pryor, 1980, Sedimentology of shales: Springer-Verlag, New York-Heidelberg-Berlin. Staplin, F.L. et al., 1982, How to assess maturation and paleotemperatures: Society of Economic Paleontologists and Mineralogists, Short course No. 7, 289 p. Tschudy, R.H. and Scott, R.A., 1969, Aspects of palynology: John Wiley and Sons, Inc., New York, 510 p. Tissot, B.P. and Welte, D.H., 1984, Petroleum formations and occurrences: Springer and Verlag, Berlin, Second Edition, 699 p. Traverse, A. (Ed.), 1994, Sedimentation of organic particles: Cambridge University Press, Cambridge, 544 p. Tyson, R.V. 1995, Sedimentary organic matter: Chapman and Hall, U.K., 615 p. Whittaker, R.H., 1969, New concepts of kingdoms of organisms: Science, vol. 163, p. 150-160. 23 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic their further subdivisions. Furthermore, the concentration of several hydrocarbon types or N, S, O compounds show a high degree of covariance, as a result of a common origin, or common chemical affinities. Saturated hydrocarbons comprise normal and branched alkanes (paraffins). Aromatic hydrocarbons include pure aromatics, cycloalkanoaromatics (naphthenoaromatics) molecules, and usually cyclic sulfur compounds, which are most frequently benzothiophene derivatives and their total abundance of aromatic hydrocarbons, can be roughly evaluated through the sulfur content of the aromatic fraction. Main Compounds in Crude Oils Crude oil is basically composed of hydrocarbons and heteroatoms Tissot and Welte (1984). Some of the hydrocarbons are saturated (paraffins, alkanes) and others are unsaturated. Saturated hydrocarbons are in the form of straight chains (normal alkenes), branched, or cyclic (naptehenes: cyclo-alkanes or cycloparaffins). Unsaturated hydrocarbons are alkenes (olefine), alkynes (acetylene), and arenes (aromatics). The gross composition of a crude oil can be defined by the contents of saturated hydrocarbons, aramotic hydrocarbons, and resins and asphaltenes (Table III. 1). These parameters are not independent, as all crude oils consist of these three groups of components. If one of these groups is missing, the other two groups amount to 100 %, as saturates plus aromatics plus resins and asphaltenes are unity. Resins and asphaltenes are made of the higher molecular weight polycyclic fraction of crude oils comprising N, S, and O atoms. Aspaltenes are insoluble in light alkanes and thus precipitate with n-hexane. Resins are more soluble, but are likewise very polar and are retained on alumina when performing liquid choromatography. This fact automatically introduces a certain degree of correlation between these groups and Table III. 1. Gross composition of crude oils (Wt. % of the fraction boiling above 210 0 C) (Tissot and Welte, 1978). NORMAL PRODUCIBLE OIL (AVER. OF 517) ALL CRUDE OILS INCLUDING TARS (AVER. OF 636) DISSEMINATED BITUMEN (AVER. OF 1057) SATURATED HC 57.2 53.3 29.2 AROMATIC HC 28.6 28.2 19.7 RESIN+ASPHALTS 14.2 18.5 51.1 2.07 (230 samples) - 1.85 (88 samples) AROMATIC SULFUR 24 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic III. 1). The main precursor of hydrocarbons is Protista which are motile unicellular organisms with rather varied morphology. Some have whiplike flagella for locomotion (dinoflagellates of Division Pyrrhophyta) and photosyntehetic pigments. Some engulf their food with the aid of mobile pseudopodia (foraminifers and radiolarians of Phylum Sarcodina), whilst some others have a coat of bristle-like cilia and ingest their food through a mount surrounded by 'tentacles' (tintinnids of Phylum Ciliophora). Therefore, some resemble the true Plantae and are probably close to the ancestral line of that group, others are more akin to animals than plants. Plant Kingdom In the nineteen century it was usual to recognise only the two kingdoms: Plantae and Animalae (Braiser, 1980). Plants were considered to be non-motile and photosynthetic whereas animals were considered to be motile and feeding by ingestion of preformed organic matter. Although these distinctions are evident amongst macroscopic organisms living on land, the largely aqueous world of microscopic life abounds with organisms that appear to straddle the plant/animal boundary. Whittaker (1969) overcame these anomalies by recognising five kingdoms: the Monera, Protista, Plantae, Fungi, and Animalia (Figure Figure III. 1. The kingdoms of life (Braiser, 1980). 25 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Main Contributors of Organic Matter in Sediments consists of cellulose and lignin. Most algae are usually devoid of cellulose. Bacteria, phytoplankton, zooplankton, and higher plants are the main contributors of organic matter in sediments (Tissot and Welte, 1984). Lipids and lipid-like fractions of organisms play a dominant role in the formation of petroleum. Lignin and tannin are aromatic (phenolic) structures which are not synthesized by animals but very common in plant tissues. Lignin occurs as a three-dimensional network located between the cellulose miscelles of supporting tissues of plants. Tannins, although widespread, are quantitatively less important than lignins. They are intermediate between cellulose and lignin in composition and in behaviour. Lignin and tannin are typically found in higher plants but also in fungi and algae. Lipids encompass fat substances such as animal fat, vegetable oil, and waxes. Fats are used as energy storage in plants and animals since they have high energy content. Waxes are designed for protective function (bee's wax, leaf coating etc.). Seeds, spores, fruits especially of higher plants are rich in lipids. Algae growing under nitrogen-deficient conditions and in cold water have high lipid. For instance, diatoms have up to 70 % on a dry weight basis lipid. Oil-soluble pigments, terpenoids, steroids, and complex waxes (suberin and cutin) are called lipid-like compounds. Physico-Chemico-Biological Conditions Physico-chemico-biological conditions of both transportation media and depositional environments are significant for the organic matter preservation. The major agencies causing decomposition of plant tissues are oxidation, aerobic and anaerobic bacteria, fungi, hydrolysis, enzymes, and insect attack. While protoplasm, chlorophyll, oil and starch disappear quickly, cuticle, spore-pollen exine, waxes, and resins are very resistant. Proteins are highly ordered polymers, made from individual amino acids. They account for most of the nitrogen compounds in organisms. They catalyse biochemical reactions in the form of enzymes. Carbohydrate is collective name used for individual sugars and their polymers. They include mono-, di, tri-, and polysaccharides. Carbohydrates are among the most abundant constitutes of plants and animals. They are sources of energy and form the supporting tissues of plants and certain animals. Cellulose and chitin are among the most prominent palysaccharides occurring in nature. Wood tissue in higher plants Eh-pH conditions of the media play an important role in organic matter preservation (Figure III. 2). The oxidation-reduction potential (Eh) of sediments is intimately related to and perhaps more important than hydrogen-ion concentration (pH) for the preservation of organic matter in sediments (Tschudy and Scott, 1969). Acidic (pH is less than 7) and reducing (Eh is negative) environments are the 26 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic best for the organic matter preservation. Figure III. 2. Sedimentary chemical end-member association in their relations to 27 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic environmental limitations imposed by selected Eh and pH values. Associations in brackets refer to hypersaline solutions (Krumbein and Garrels, 1952) Fe3+/Fe2+ ratio. High ratios are associated with red colors, low with greens. However, the removal of iron is not necessary to develop green colors, only reduction of the Fe3+ to Fe2+. Color of Sedimentary Rocks Potter et al. (1980) showed that color is by far the most important feature of a shale and is controlled by two rock variables that are directly measurable, Fe3+ and organic carbon (Figure III. 3). It is valuable for stratigraphic correlation and seems to have possible environmental significance. The amount of organic carbon present is another important, and partly independent, control of color. Therefore, the dark-coloured and finegrained sedimentary rocks usually consist of enough organic matter for petroleum generation. The color of mudrocks is independent of the total amount of iron present but strongly controlled by the Figure III. 3. Suggested relationship of shale color to carbon content and oxidation state of iron. The mole fraction is used to indicate the proportion of the total iron that is in the +2 state and m represents the number of moles of iron per gram of rock. Finer subdivisions of color are possible, but are difficult to reproduce. Colors determined on wet samples in natural light (Potter et al., 1980). 28 .d o m w o .c C m o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic different preparation and observation techniques. Basically three environmental variables are important in controlling the amount of organic matter: Durand (1980) uses the definition sedimentary organic matter insoluble in the usual organic solvents. Tissot and Welte (1984) prefer to define kerogen as the organic constituents of sedimentary rocks that are insoluble in both aqueous alkaline and common organic solvents. Burgess (1974) defines kerogen in a specifically optical way as finely disseminated organic material freed from a sedimentary rock after acid treatment. Hunt (1979) broadened this definition to disseminated organic matter of sedimentary rocks in non-oxidizing acids, bases, and organic solvents. 1) The rate of production of organic matter in surface waters of the basin, or in some cases its introduction by rivers. 2) The rate of sedimentation of other components, such as terrigenous particles or the shells of pelagic organisms, which serve to "dilute" the organic matter. 3) The rate of decomposition of the organic matter in the upper few centimeters of sediments. Sedimentary Organic Matter Kerogen is not a single variable substance but nearly always a complex and heterogeneous mixture whose composition reflects widely varying proportions of a large number of differing precursor materials (Tyson, 1995). These materials may also have varied widely in their preservation state (and thus composition) at the time they became fossilized in the host sediment. The original organic matter is transformed into kerogen by a variety of geochemical reactions that takes place during diagenesis and burial. However, some workers have refused to accept any redefinition of the term kerogen (Tyson, 1995). Sedimentary rocks commonly contain minerals and organic matter with the pore spaces filled with primarily by water, bitumen, oil and/or gas. The most common term used to describe the fossil organic matter in sedimentary rocks is kerogen and In the absence of migrant hydrocarbons, kerogen is usually 95% or more of the total organic matter in sedimentary rocks (Tyson, 1995). Kerogen is a mixture of macerals and other degraded plant and/or animal remains. Bitumen is that fraction of organic matter that is soluble in organic solvents Sedimentary organic matter, dispersed organic debris, organic debris, palynodebris, organoclaste, palynoclast, clast, palynological organic matter, particulate organic matter-POM, dispersed organic matter-DOM are some of the synonyms proposed by various authors. The kerogen classification, which is commonly used in oil industry, is given in Table III. The most comprehensive discussion on sedimentary organic matter and kerogen can be found in Tyson (1995). He noted that there is no absolute and precise correspondence between the organic matter recognized by geochemists, palynologists, and organic petrologists, because each uses 29 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Table III. 2. The commonly used kerogen classification (FOR COAL) KEROGEN Alginite LIPTINITE GROUP VITRINITE GROUP INERTINITE GROUP ORIGIN PROTISTA Highly Oil Prone Algal (FOR OIL) Type I MACERAL (Algae, including dinoflagellates, Botryococcus etc.) Sporinite Cutinite Resinite (?Type I) Herbaceous (?Amorphous) Type II Oil Prone (Spores, Pollen, Resin, Leaf, Bark etc.) Vitrinite Woody Type III PLANTA Gas Prone (Wood Tissue, Cortex Tisuue) Fusinite Sclerotinite (Microforam linings) PLANTA Coaly Type IV Inert PLANTA FUNGI PROTISTA Exercise: Palynofacies Analysis Table II. 2 for kerogen classification. 1) Prepare a kerogen distribution chart (x-axis: 0-100 %, y-axis: depth) in Figure III. 4 to illustrate variation of palynofacies percentages with depth (time) by using data given in Table III. 3) Try to interpret the paleoenvironment where deposition took place. 4) Discuss the source rock potential of sedimentary organic matter recorded throughout the well. 2. Draw type I kerogen first, then type II, type III, and type IV kerogens. Use 30 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Table III. 3. Palynofacies data for the Ankara-1 well. Wood Tissues % Dinoflagellate % Spores Pollen % Fusinite % Various Algae % Leaf Tissue % Resins % TOTAL % 1000 19.0 36.1 4.2 5.4 28.0 6.2 1.1 100.0 1200 18.1 54.0 1.3 2.1 18.3 4.1 2.1 100.0 1500 16.2 50.1 6.2 4.3 21.0 1.0 1.2 100.0 1750 14.1 42.3 2.2 10.1 23.1 5.0 3.2 100.0 2000 14.4 48.1 1.0 6.2 26.2 2.1 2.0 100.0 2300 10.5 64.0 3.3 - 19.1 3.1 - 100.0 2700 9.2 47.1 8.2 6.1 28.3 1.1 - 100.0 3000 18.4 46.1 3.4 7.1 22.0 2.0 1.0 100.0 3500 23.2 41.1 4.1 7.4 21.1 1.0 2.1 100.0 3600 39.6 21.2 1.0 11.1 27.1 - - 100.0 3800 42.1 18.2 - 13.1 24.4 1.1 1.1 100.0 4000 28.3 18.3 2.1 12.2 34.1 2.0 3.0 - 100.0 4500 41.3 13.1 1.1 13.4 31.1 - 4600 45.0 9.2 1.5 14.1 28.2 1.0 1.0 100.0 4800 - - - 100.0 - - - 100.0 5000 - - - 100.0 - - - 100.0 Depth M 31 100.0 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure III. 4. Palynofacies distribution chart of the Ankara-1 well. 32 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic IV. SOURCE ROCKS & PETROLEUM GENERATION References Klemme, H.D. and Ulmishek, G.F., 1991, Effective petroleum source rocks of the World: stratigraphic distribution and controlling depositional factors: AAPG Bulletin, v. 75, No. 12, p. 1809-1851. Peters, K.E. and Cassa, M.R., 1994, Applied source rock geochemistry, in: L.B. Magoon and W.G. Dows (Eds.), The petroleum system-from source to trap: AAPG Memoir No. 60, p. 93-120. Tissot, B.P., Durand, B., Espitalie, J., and Combaz, A., 1974, Influence of the nature and diagenesis of organic matter in formation of petroleum: AAPG Bulletin, v. 58, p. 499-506. Ulmishek, G.F. and Klemme, H.D., 1992, Areal and spatial distribution and effectiveness of the world's petroleum source rocks: Proceedings of the Thirteenth World Petroleum Congress, v. 2, John Wiley and Sons, U.K., p. 121-136. Waples, D., 1980, Organic geochemistry for exploration geologists: Burgess Publishing Co., USA, 151 p. Welte, D.H., 1965. Relation between petroleum and source rock: AAPG Bull., 49: 2249-2267. and quality of reservoir rocks and seals, their juxtaposition with source rocks, and maturation and migration history. Source Rocks of the World The uneven distribution of world's oil and gas reserves is widely believed to have resulted from variations in conditions of generation, maturation, entrapment, and preservation of petroleum. However, Ulmishek and Klemme (1992) (also Klemme and Ulmishek, 1991) have noted that one of the most important factors is the uneven areal and stratigraphic distribution of hydrocarbon source rocks and other important factors are the availability They have also noted that several primary factors controlled the areal distribution of source rocks, their geochemical type, and their effectiveness which means the amounts of discovered original conventionally recoverable reserves of oil and gas generated by these rocks. These factors are; 1) geologic age, 33 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 2) paleolatitude of the depositional areas, 3) structural forms in which the deposition of source rocks occurred, 4) the evolution of biota. favourable for source rock deposition. Two-third of the source rocks of the six principal stratigraphic intervals were deposited between the paleoequator and 450 paleolatitudes. Geologic Age: Six stratigraphic intervals, representing one-third of Phanerozoic time, contain petroleum source rocks that have provided more than 90 % of the world's discovered original reserves of oil and gas (in barrels of oil equivalent). Structural Forms: Structural forms reflecting tectonic stages in basin development significantly affected source rock deposition. Source rocks deposited in platforms, circular sags, and linear sags provided more than three-quarters of original reserves generated from the six principal intervals. The maturation time of these source rocks demonstrates that the majority of discovered oil and gas is very young. Almost 70% of the world's original reserves of oil and gas has been generated since the Coniacian, and nearly 50% of the world's petroleum has been generated and trapped since the Oligocene (Figure IV. 1). They are: Biologic Evolution: The significance of biologic evolution for oil and gas genesis is poorly understood. The effect of biologic evolution of source rock deposition during the Phanerozoic was principally expressed as two opposing developmental trends: 1) Silurian (generated 9% of world's reserves), 2) Upper Devonian-Tournaisian (8% of reserves), 3) Pennsylvanian-Lower Permian (8% of reserves), 4) Upper Jurassic (25 % of reserves), 5) middle Cretaceous (AptianTuronian) (29 % of reserves), 6) Oligocene-Miocene (12.5 % of reserves). Paleolatitude: A warm and moist climate, characteristic of low to middle paleolatitudes is believed to be 1) Diversification and expansion of producers increased the areas of bioproduction and widened the range of organic matter types, 2) the evolution of consumers and decomposers was directed to more complete use of organic matter. These developments resulted in a change of environments suitable for deposition and preservation of organic matter in sediments. 34 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure IV. 1. Petroleum source rocks of the World (Klemme and Ulmishek, 1991) 35 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic World Petroleum Realms Ulmishek, 1991; Ulmishek Klemme, 1992; Figure IV.2). The distribution of oil and gas reserves in the world, relation of the reserves to specific source rocks, and maturation history of the source rocks as related to the plate tectonic evolution, suggest that the world may be divided into four main petroleum regions (petroleum realms) which are characterised by different richness in hydrocarbon reserves and variation in the formation and occurrences of petroleum basins (Klemme and In the Tethyan Realm (17% of the total area; 68 % of the petroleum reserves), favourable tectonic and palegeographic development resulted in rich hydrocarbon reserves. The realm occupies only one-sixth of the continental (including shelves) area of the globe; yet, it contains two-thirds of original discovered hydrocarbon reserves of the world. Figure IV. 2. Petroleum realms of the world (Klemme and Ulmishek, 1991). 36 and .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic matter to oil, wet gas, and finally to dry gas and pyrobitumen as a result of temperature-time driven reactions. Thermal alteration of organic matter occurs in three stages, namely diagenesis (immature), catagenesis (early, peak, late mature), and metagenesis (postmature or overmature) (Figure IV. 3). Boreal Realm (28% of the total area; 23 % of the petroleum reserves) is the second in petroleum richness. It occupies Precambrian cratonic blocks of the Laurasian continents and accreted terranes formed in the course of their collisions. During the Paleozoic, the continents were located in low paleolatitudes and moved to the north in the Mesozoic. Diagenesis refers to all chemical, biological, and physical changes to organic matter during and after deposition of sediments but prior to the reaching burial temperatures greater than about 60o-80o C. Pacific Realm (17 % of the total area; 5 % of the petroleum reserves) is areally equal to the Tethyan realm; however, it contains only 5% of the world's oil and gas reserves. The realm includes the late Mesozoic and Tertiary basins of the Pacific rim and back-arc and foredeep basins of North and South America which are genetically related to the Pacific tectonics. Catagenesis can be divided into the oil zone (or oil window), where liquid oil generation is accompanied by gas formation, and the wet gas zone, where light hydrocarbons are generated through cracking. South Gondwana Realm (38 % of the total area; 4% of the petroleum reserves) is the largest in area and poorest in hydrocarbons reserves. The realm includes the Gondwana continents outside the area of the Tethyan and Pacific diastrophism. Metagenesis corresponds to the dry gas zone where dry gas is generated. Dry gas consists of 98% or more of methane. Thermally immature source rocks have been affected by diagenesis without a pronounced effect of temperature and microbial gas is produced in this stage. Thermally mature source rock is in the oil window and has affected by thermal processes. Thermally overmature (or postmature) source rock is in the wet and dry gas zones (gas window). Source Rock Analysis The application of organic geochemical techniques to petroleum exploration has only recently achieved widespread acceptance among exploration geologists. Source-rock evaluations, oil-oil correlations, and oilsource rock correlations are the organic geochemists’ common applications of organic geochemistry in petroleum industry. Source-rock evaluations involve reasonably good semi-quantitative predictions of the probability of sedimentary rocks containing oil. It has long been known that sedimentary organic matter in the source rocks should satisfy four independent conditions for petroleum generation and expulsion. Thermal maturity is the conversion of sedimentary organic 37 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic met only partially, oil generation will be severely reduced. Welte (1965) has noted that a minimum organic carbon content (0.5 %) in a source bed is necessary before bitumen expulsion can occur, even though small amounts of bitumen is adsorbed on kerogen and clay surfaces, and no bitumen can be expelled from the source rock until these adsorption sites are filled. These are the amount of organic matter in the rock (Quantity), the oil-generating capability of that organic matter (Quality), the maturity of the kerogen (Maturity), and the expulsion efficiency of the bitumen from the rock. If any one of these conditions is not met, no migratable oil can be generated and if one condition is Figure IV. 3. Evolution of hydrocarbons from Kerogen (Brooks, 1981 after Durand,1980). 38 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic developed to characterize coals by Van Krevelen (1961). Tissot et al. (1974) extended the use of the Van Krevelen diagram from coals to include kerogen dispersed in sedimentary rocks. Modified Van Krevelen diagram (Figure IV. 4) consists of hydrogen index (HI) versus oxygen index (OI) plots generated from Rock-Eval pyrolysis and TOC analysis of Whole rock (Peters and Cassa, 1994). Van Krevelen Diagram Peters and Cassa (1994) listed all of the geochemical parameters related to the quantity, quality, and maturation for any sedimentary rock to be a good source rock (Table IV.1). Kerogen types are distinguished using the atomic H/C versus O/C or Van Krevelen diagram, originally Table IV.1. Geochemical parameters describing quantity, quality, and maturation of sedimentary organic matter (Peters and Cassa, 1994). 39 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure IV. 4. Combined use of organic petrography, elemental analysis, and Rock-Eval pyrolysis and TOC improves confidence in assessment of the quality and maturity of kerogen in rock samples. A sample anaylzed by Rock-Eval pyrolysis was characterized as being marginally mature (Tmax= 435 oC) and gas prone (HI=150 mg HC/g TOC). Organic petrography shows a TAI of 2.5, and Ro of 0.5 % (supporting the maturity assessment from pyrolysis), and the following maceral composition: type II 20 %, type III 60 %, and type IV 20 %. The calculated atomic H/C (0.90) corresponds with that determined by elemental analysis, supporting a dominantly gas-prone character (Peter and Cassa, 1994). Oil Generative Capacity 40 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Following the determination of a source rock rock in an exploration area, geochemists are interested in total oil that is the amount of oil which could be generated from a given volume of source bed if generation went to completion. Q2, Scaled for quality (If Type I+II Kerogen is 100 %, Q2=2.0, if it is 50 % Q2=1) Oil already generated is the oil which has already been generated from a given volume of source bed. Both aspects are important but in a given geologic setting one may be much more relevant than the other. E, The expulsion efficiency of the source sequences. E is not quantifiable at the present time, so it is preferable to omit it. M, Percentage generation factor corresponding to the thermal maturity of the kerogen (Ro %) Because the quantity and quality factors of an average rock are normalised to 1.0, a Total Oil of 1.0 represents an average shale. An average shale generates 80 million barrels of oil (or bitumen) per cubic mile of rock. There are basically two methods of calculating total oil and oil already generated. In the direct approach, the rock is actually subjected to catagenetic conditions in order to measure directly how much bitumen is produced. The Rock-Eval and other pyrolysis techniques are among such methods. Exercises: Evaluation The indirect approaches involve measuring quantity, quality, and maturity of the organic matter independently, and then combining these data to predict what the oil generative capacity should be. These methods rely on the assumption that it is possible to predict bitumen generative capacity from the chemical and physical properties of a kerogen. The following formulas can be used for calculations in indirect methods: Source Rock 1) Perform a typical source rock analysis by using data on quantity, quality, and maturity of organic matter in the rock samples taken from the Ankara-1 well (Table IV.2) in Figure IV. 5. Use the parameter ranges given in Table IV.1 to determine the source rock capacity of the samples (TOC > 0.5 %, HI > 1, Type I+II > 50 %, TAI: 2.6-3.3). 2) To use the atomic H/C data, you must first convert the measured, present-day H/C ratios to the ones that the kerogens had when they were thermally immature. This can easily be done by plotting atomic H/C versus TAI for each sample on Van Krevelen diagram (Figure IV. 6) and then tracing the H/C ratios back to its immature value to find the calculated immature H/C ratios. The immature values are given in Table IV. 3. Total Oil= Q1 Q2 Oil Already Generated= Q1 Q2 M Oil Expelled= Q1 Q2 M E Where; Q1, Scaled for quantity. If TOC= 1.0 %, Q1 = 1.0 41 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 7) Draw the total oil and oil already generated profiles for the Ankara-1 well in Figure IV. 8. The amount of oil generated can be calculated, assuming that total oil of 1.0 corresponds 80 million bbls of oil per cubic mile of rock (Note that the volume of reservoir should be known for this calculation). 3) The immature H/C ratios data need to be scaled by converting atomic H/C ratios of immature kerogen to quality factor (Q2 from H/C data) in Figure IV. 7. Quality factors are given in Table IV. 3. 4) Maceral analysis data also need to be scaled (Q2 from maceral analysis) Quality factor is equal to 1 if alginite+exinite is 50% and the quality factor is equal to 2 if alginite+exinite is 100%. Complete the empty column in Table IV. 3. 8) Discuss the possible causes of the discrepancies between the H/C and maceral analysis results for several samples (Samples 1000, 1500, 1750, 2000, 2300, 4000, 4500). Should these discrepancies be taken seriously by the interpreter or just be overlooked or swept under the rug? 5) Calculate M values by converting TAI to Ro using the conversion factors in Table IV. 4. 9) Discuss also the reason for the discrepancies in total oil profiles. 6) Calculate total oil for H/C ratio and for maceral analysis, and also oil already generated for H/C ration and for maceral analysis and complete the columns in Table IV.5. Note that Q1 is equal to Corg. 10) Discuss the reason why no maceral analysis was possible in the lowermost two samples? Table IV.2. Source rock data for the Ankara-1 well. Depth m Type of Sample C org % Atomic H/C TAI Type I+II % 1000 1200 1500 1750 2000 2300 2700 3000 3500 3600 3800 4000 4500 4600 4800 5000 Sidewall Cores " " " " " " Core Cuttings " " " " " " " 0.6 0.8 0.5 0.3 1.3 0.7 1.6 2.5 0.5 1.2 1.0 0.7 1.5 1.7 2.1 2.2 1.07 1.22 1.05 0.65 0.77 0.81 1.33 1.27 1.15 0.98 0.86 0.75 0.72 0.66 0.41 0.38 2.0-2.5 2.0-2.5 2.0-2.5 2.0-2.5 2.2 2.6 2.5 2.5 2.6 2.7 2.9 3.0 3.1 3.2 3.7 3.8 75 80 80 75 80 90 85 75 70 50 45 60 45 40 ? ? 42 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure IV. 5. Source rock evaluation of the Ankara-1 well. 43 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure IV. 6. H/C versus TAI for the Ankara-1 well samples (An example is given for the sample taken from 4000 m). Figure IV. 7. Kerogen quality factor as a function of H/C ratio of the immature kerogen (An example is given for the sample taken from 4000 m). Table IV. 3. Quality factors from H/C and macerals Depth Measured Immature Quality Factor Quality Factor m H/C H/C (From H/C) (From macerals) 1.07 1.07 1.05 1000 1.22 1.22 1.50 1200 1.05 1.05 1.00 1500 0.65 0.65 0.17 1750 44 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 0.77 0.81 1.33 1.27 1.15 0.98 0.86 0.75 0.72 0.66 0.41 0.38 2000 2300 2700 3000 3500 3600 3800 4000 4500 4600 4800 5000 0.77 0.81 1.35 1.30 1.20 1.05 1.05 0.90 0.90 0.90 ? ? 0.35 0.43 1.85 1.70 1.35 0.90 0.90 0.60 0.60 0.60 ? ? Table IV. 4. Conversion between Thermal Alteration Index (TAI) and Vitrinite Reflectance Index (Ro). Ro TAI Ro TAI 0.30 2.0 1.26 3.15 0.34 2.1 1.30 3.2 0.38 2.2 1.33 3.25 0.40 2.25 1.36 3.3 0.42 2.3 1.39 3.35 0.44 2.35 1.42 3.4 0.46 2.4 1.46 3.45 0.48 2.45 1.50 3.5 0.50 2.5 1.62 3.55 0.55 2.55 1.75 3.6 0.60 2.6 1.87 3.65 0.65 2.65 2.0 3.7 0.70 2.7 2.25 3.75 0.77 2.75 2.5 3.8 0.85 2.8 2.75 3.85 0.93 2.85 3.0 3.9 1.00 2.9 3.25 3.95 1.07 2.95 3.5 4.0 1.15 3.0 4.0 4.0 1.19 3.05 4.5 4.0 1.22 3.1 5.0 4.0 Table IV. 5. Calculation of total oil and oil already generated. Depth M 1000 1200 1500 1750 Q1 Q2 (H/C) Q2 (Mac.) M 0.6 0.8 0.5 0.3 45 Total Oil (H/C) Total Oil (Mac.) Oil Al. Gen. (H/C) Oil Al.Gen. (Mac.) .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 2000 2300 2700 3000 3500 3600 3800 4000 4500 4600 4800 5000 1.3 0.7 1.6 2.5 0.5 1.2 1.0 0.7 1.5 1.7 2.1 2.2 Figure IV. 8. Total oil and oil already generated profiles for the Ankara-1 well. 46 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic V. RESERVOIR ROCKS AND MIGRATION & ENTRAPMENT References Biddle, K.T. and Wielchowsky, C.C., 1994, Hydrocarbon traps, in: L.B. Magoon and W.G. Dows (Eds.), The petroleum system-from source to trap: AAPG Memoir No. 60, p. 219-235. Carmalt, S.W. and St. John, B., 1986, Giant oil and Gas fields, in: Halbouty, M.T. (Ed.), Future petroleum provinces of the world: Proceedings of the Wallace E. Pratt Memorial Conference, Phoenix, December 1984: AAPG Memoir No. 40, p. 11-53. Demaison, G. and Huizinga, B.J., 1991, Genetic classification of petroleum systems: AAPG Bulletin, v. 75, no. 10, p. 1626-1643. Levorsen, A.I., 1969, Geology of petroleum: W.H. Freeman and Company, p.538-550. Waples, D., 1980, Organic geochemistry for exploration geologists: Burgess Publishing Co., USA, 151 p. Magoon, L.B. and Dow, W.G., 1994, The petroleum system, in: L.B. Magoon and W.G. Dows (Eds.), The petroleum system-from source to trap: AAPG Memoir No. 60, p. 3-24. 47 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic in these provinces are found across a wide range of geographic area, many of which remain only moderately or lightly explored. The basins offer, therefore, significant geologic scope for future exploration. In more than 350 basins which contain a giant field, anticlines are the main trap type. Reefs, faults, saltrelated, and stratigraphic traps are less than 50 each Majority of the giant field's reservoir rocks are of Cretaceous-Tertiary age. The Jurassic and Permian reservoir rocks are in the second the Triassic, Carboniferous and Devonian reservoir rocks are in the third place. Around 300 of the reservoir rocks are sandstones and the number of carbonates (limestone and dolomite) reservoirs are close to 200. Giant Fields Carmalt and St. John (1986) defined giant field as the one which the estimate of ultimate recoverable oil is 500 million bbl of oil or gas equivalent. Although the giant fields are few in numbers, they contain about two-thirds of the discovered recoverable reserves (Table V.1). The 509 giant fields contain a total of 868,115 million bbl of oil and 3,193 tcf of natural gas. Converting gas to oil equivalent (6,000 cu ft/bbl) results in the giants containing 1,400,343 million bbl of oil equivalent (boe). Geologically, giants are found most commonly in provinces that can be classified as having formed in continental crust and having been associated with a plate collision. Basins Table V.1. Ten biggest Giant Oil and Gas Fields (Carmalt and St. John, 1986) Field Name (Discovery Date) 1. Ghawer (1948) 2. Burgan (1938) 3. Urengoy (1966) 4. Safaniya (1951) 5. Bolivar Coastal (1917) 6. Yamburg (1969) 7. Bovanenkovo (1971) 8.Cantarell Complex (1976) 9. Zakum Country Recoverable Equival. Oil Reserves Billion bbl Depth m Trap Type Geologic Age Lithology Saudi Arabia Kuwait 87.500 2,200 Anticline Jurassic Carbonate 87.083 1,400 Anticline Cretaceous Sandstone Russian Federation Saudi Arabia Venezuela 47.602 1,200 Anticline Cretaceous Sandstone 38.066 1,600 Anticline Cretaceous Sandstone 30.100 900 Stratigraphic Miocene Sandstone Russian Federation Russian Federattion Mexico 27.983 1,000 Broad Arch Cretaceous Sandstone 24.416 1,200 Anticline Cretaceous Sandstone 20.000 1,500 Anticline Cretaceous Carbonate Abu Dhabi 18.400 2,700 Anticline Jurassic Carbonate 48 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic (1964) 10. Manifa (1957) Saudi Arabia 17.800 2,300 Anticline Cretaceous Sandstone Migration and Entrapment Trap Formation Petroleum System consists of two subsystem: 1) Generative Subsystem and 2) Migration and Entrapment Subsystem (Demaison and Huizinga, 1991). The generative subsystem includes the biochemical transformation from organic matter to kerogen and thermo-chemical kinetics from kerogen to petroleum, while the migration and entrapment subsystem includes only the physical processes leading to the entrapment of petroleum into the traps. Trap identification is the first step in prospect evaluation and an important part of any exploration or assessment program (Biddle and Wielchowsky, 1994). Future success in exploration will depend increasingly on an improved understanding of how traps are formed and an appreciaiton of the numerous varieties of trap types that exist. Investigations of plays describe a series of present-day traps, and of prospects, an individual trap, and determine whether they have economic value and are exploitable with available technology and tools (Magoon and Dow, 1994). A series of related prospects is a play. A play is defined as a continuous portion of sedimentary volume which contains pools (or many traps). Plays should have; 1) same productive sequence, 2) similar chemical composition of petroleum, and 3) coeval traps. By the time diagenesis was complete at the end of the oil window, most of the oil-prone organic matter were in the form of petroleum. During and after diagenesis, water was squeezed out of the source rock into the reservoir rock and a fraction of petroleum and some kerogen was entrained in the water (expulsion). Expulsion may continue after diagenesis. Petroleum expelled from an active source rock can migrate along a fault plane or a permeable carrier bed to porous reservoir rocks (primary migration) and further migrates into a trap which is the part of the reservoir rock capped or surrounded by a comparatively impermeable seal or cap rock (secondary migration). A trap is a subsurface loci where petroleum can no longer continue its migration towards the surfaces because its buoyant movement has been arrested (Magoon and Dow, 1994). To be a viable trap, subsurface feature must be capable of receving hydrocarbons and storing them for some significant length of time (Biddle and Wielchowsky, 1994). This requires two fundamental components: a reservoir rock in which to store the hydrocarbons, and a seal (or set of seals) to keep the hydrocarbo ns from migrating out of the trap. Once petroleum has reached the reservoir rock, it must be concentrated into pools if it is to be commercially available. Petroleum was also deposited in the nonreservoir shales or carbonates as disseminated hydrocarbon particles (bitumen) associated with the nonsoluble organic matter (kerogen). 49 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Traps are either structural, stratigraphic, or a combination of both. (Figures V. 1-3) Structural traps are created by the syn- to postdepositional deformation of strata into a geometry (a structure) that permits the accumulation of hydrocarbons in the subsurface. In 1936, Levorsen proposed th term stratigraphic traps for features "in which a variaiton in stratigraphy is the chief confining element in the reservoir which traps the oil." Today, we would define a stratigraphic trap as one in which the requisite geometry and reservoir-seal(s) combination were formed by any variaiton in the stratigraphy that is independent of stratuctural deformation, except for regional tilting time (Biddle and Wielchowsky, 1994). Combination trap is any trap that has both structural and stratigraphic elements, regardless of whether both are required for the trap to be viable (Biddle and Wielchowsky, 1994). 50 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure V. 1. Major catagories of structural traps: (A) fold, (B) fault, (C) piercement, (D) combination faold-fault, (E) and (F) subunconformities. The situation in (E) is commonly excluded from the structural category (Biddle and Wielchowsky, 1994). 51 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure V. 2. Primary or depositional stratigraphic traps. (A) Traps created by lateral changes in sedimentary rock type during deposition. Top: juxtaposition of reservoir and seal caused by lateral facies changes. Bottom: reservoir termination due to the depositional pinchout of porous and permeable rock units. (B) Traps formed by buried depositional relief. In each example, sedimentary processes form a potential trapping geometry, but require burial by younger impermeable section to create the required top seal (Biddle and Wielchowsky, 1994). 52 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure V. 3. Combination traps. (A) Intersection of a fault with an updip depositional edge of porous and permeable section. (B) Folding of an updip depositional pinchout of reservoir section. In these examples, both the structural and stratigraphic elements are required to form a viable trap (Biddle and Wielchowsky, 1994). 53 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 8) The fluid pressure within the reservoir rock may flactuate between 11,000 atm. They may very many times during the geological history of the region. Geological Framework of Migration and Accumulation (Levorsen, 1969) 1) Nearly all petroleum pools exist within an environment of water-free, interstitial (in fractures or cracks), edge and bottom water. This means that migration is intimately related to hydrology, fluid pressure, and water movement (hydrodynamic). 9) The geological history of the traps may vary widely from a single geological episode to a combination of several phenomena. Reservoir Rocks 2) The gas and oil are chiefly immiscible in the water and both are of lower density then the surrounding water. Reservoir rocks are any rock that contains connected pores (Levorsen, 1969). Nearly all reservoir rocks are unmetamorphosed sedimentary rocks. Reservoir rocks are classified as silisiclastics (clastic, fragmental, or detrital) or chemicalbiochemicals (carbonates, precipitated sedimentary rocks). 3) Reservoir rocks that contain petroleum differ from one another in various ways; in geological age (from Precambrian to Pliocene), in composition (from siliciclastics to carbonates), in origin (from sedimentary to igneous), in pororsity (from 1 to 40 %), and in permeability (from 1 md to many md). Pore spaces may either be primary (original or interconnected porosity) or secondary (intermediate, induced, or limestone porosity). The primary porosity is mainly determined by: 4) There is a wide variation in the character of the trap or barrier that retains the pool. The traps may be stratigraphical, structural or combination of these. 1) arrangement and form of pores (packing, uniformity of grain size, and shape of grains). 5) Size and shape of pores (porosity), paths between the pores (permeability) and the chemical character of the reservoir rocks may vary widely. 2) degree to interconnected. 6) The minimum time for oil and gas to generate, migrate and accumulate into pools is probably less than 1 my. which they are 3) their distribution in the sedimentary rocks. While some diagenetic processes such as solutions, recrystallization and dolomitization, and fractures and joints contribute others such as cementation and compaction reduces the secondary porosity. Clays usually create significant problems by decreasing the porosity and permeability and by negatively 7) The temperatures of the reservoir rock may flactuate, generally between 50-100 0 C (122-212 0 F). The maximum temperature observed is 163 0 C (325 0 F). 54 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic radioactive decay. The third assumption processes are uniform and filling rates are constant. Although individual oil fields do not have a uniform half-life, the global population does. Reservoired conventional oil has a well-defined half-life of 29 million years derived from the distribution of oil generation. influencing the drilling and production activities. Sedimentary rocks consist of grains of solid matter with varying shapes which are more or less cemented, and between which there are empty spaces called porosity. It is these pores which are able to contain fluids such as water or liquid or gaseous hydrocarbons and to allow them to circulate (porous and permeable). Oil-oil and Oil-source rock Correlations Porosity is the ratio of pore volume to total volume. The effective porosity is the ratio of the volume of interconnected pores to the total volume of the sample. Porosity is classified as negligible (0-5 %), poor (5-10 %), fair (10-15 %), good (15-20 %), and very good (20-25 %). Shows of petroleum are proof of a petroleum system and when encountered during drilling are useful exploration clues, particularly when they can be quantified and regionally mapped. Cutting or cores that bubble or bleed oil and gas during removal from the well are called live shows, in contrast to the asphaltic staining of dead shows. The quality of shows can be evaluated by their fluorescence under ultraviolet light, by colour of organic solvent extracts, or by geochemical screening methods. Permeability characterizes the ability of rocks to allow the circulation of fluids contained in their pores. It is the coeeficient k in Darcy's formula and is measured in md (milidarcy). Permeability depends upon pore dimensions and configuration. Permeability is classified as fair (1-10 md), good (10-100 md, and very good (100-1000 md). Oil-oil and oil-source rock correlations are of great importance to exploration. Oil-oil correlations are simpler, because one is comparing the same kind of organic material. Two oil samples having common origin may differ substantially in chemical composition because of changes which have occurred during migration or storage in the reservoir rocks. These changes can include loss of heavy, light, or polar components; biodegradation and water washing; and thermal disproportination. In order to attempt oil-oil correlations, it is necessary to know how each of the above transformations will affect an oil's chemical properties. Oil Half -life Model Miller (1992) who proposed the oil half-life model made three major geological assumptions. One of them is that the global rate of oil generation and expulsion equals the are of natural loss. This means oil is continually being generated in which an equilibrium situation will balance the loss. The second assumption that the oil loss can be described by a natural decay law. On a global basis, oil is destroyed exponentially with time in analogy with 55 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic choromatography. Most of the migrationally induced changes in oil composition probably occur as the bitumen makes its way out of the finegrained source rock (primary migration). Secondary migration generally causes smaller changes. Table V.2 shows the effects of five types of alteration processes on crude oil composition. During migration, the heavier and more polar components are left behind, much as the polar compounds and asphaltenes are left behind during column Table V. 2. Effects of alteration processes on crude oil composition (Waples, 1981). Migration Water Washing Biodegradation Gas Deasphalting Thermal Maturation API Gravity INCREASES DECREASES DECREASES INCREASES INCREASES % Sulfur DECREASES INCREASES INCREASES DECREASES DECREASES C15 + Fraction (% of crude) DECREASES INCREASES INCREASES DECREASES DECREASES DECREASES INCREASES INCREASES DECREASES Gasoline (C4-C7) Fraction (% of crude) INCREASES DECREASES DECREASES INCREASES INCREASES Paraffinicity INCREASES INCREASES DECREASES INCREASES INCREASES Porphyrin content DECREASES ? INCREASES INCREASES DECREASES n-paraffins (% of crude) INCREASES GENERALLY INCREASES DECREASES INCREASES INCREASES SLIGHTLY DECREASES INCREASES INCREASING OR NO EFFECT NO EFFECT DECREASES NO EFFECT DECREASES OR NO EFFECT NO EFFECT DECREASES INCREASES DECREASES INCREASES IF GAS IS NOT LOST Asphaltenes (% of crude) n-paraffins Maximum in distribution curve n-paraffins CPI δ13C NO SIGNIFICANT EFFECT DECREASES DEPENDS ON COMPOSITION INCREASES UNLESS DEASPHALTING OCCURS degree of water washing. During water washing, the more soluble components of petroleum are simply removed in solution. Light hydrocarbons, Water washing and biodegradation often go together. Water washing can occur without biodegradation, but biodegradation will always be accompanies by at least some 56 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic particularly aromatics, and the smaller polar molecules become depleted. Exercise: Oil-source correlation Microorganisms are very selective in which compounds they metabolize. Anaeorobic bacteria are not thought to be important in biodegradation of hydrocarbons. Compounds containing heteroatoms are often consumed relatively rapidly, and n-alkanes are generally severely depleted or totally in extensively degraded oils. Occasionally, the isoprenoid hydrocarbons are also noticeably depleted. rock 1) The following exercise involves oilsource rock correlation in the stanbul1 well. Source rock data for which are given in Table V.3. Apparent oil show was detected in a sandstone core taken at 7927 feet in this well. 2) Evaluate the oil-source history of the well by performing a typical source rock evaluation in Figure V. 4. Since the TAI data show some scatter, particularly in the oil-generative zone (TAI= 2.6-3.3), it would be wise to obtain the best fit of the maturity curve to the all the data. For this plot the TAI data against depth and then obtain the best fit curve. Oil inherit biomarker distributions similar to those in the bitumen from the source rock, thus allowing oil-oil and oil-source rock correlation or fingerprinting and paleoreconstruction of source rock depositional conditions. An advantage of biomarkers is their resistance to biodegradation by aerobic bacteria in the reservoir. For heavily biodegraded oils where biomarkers have been partially altered, correlation sometimes requires sealed tube pyrolysis of asphaltenes, followed by biomarker analysis of the generated bitumen. Biomarker and other correlation techniques, such as stable carbon isotope analysis and pyrolysis-gas chromatography are among the most powerful tools for mapping petroleum systems to reduce exploration risks. 3) Compare your interpretation with the total oil and oil already generated curves for the complete section which is given in Figure V. 5. 4) Discuss the nature and origin of the oil show of which the analytical data is given in Table V. 4. Is it possible that upward migration could have occurred ? Note that the geochemical data of 9,000 ft, 9,500 ft, 10000 ft, and 10,500 ft samples are also given in the same table. Table V.3. Source-Rock Data for the stanbul-1 Well 57 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Depth (ft) TOC % Alginite + Exinite % TAI 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 6,500 7,000 7,500 7,927 8,000 8,500 9,000 9,500 10,000 10,500 11,000 11,500 12,000 12,500 1.2 1.5 1.8 0.9 1.3 2.6 2.1 1.5 1.2 1.3 1.9 1.0 0.5 0.8 Core 1.3 1.4 1.1 3.7 3.2 1.3 0.1 0.2 0.1 0.4 60 70 60 50 70 80 80 75 50 35 50 25 10 10 (Oil show) 60 80 70 90 80 60 100 95 95 90 1.5-2 2.0 2.0 2.2 2.3 2.2 2.5 2.5 2.5 2.6 2.5 2.6 2.7 2.7 2.9 2.8 3.0 2.7 3.0 3-3.5 3.5 3.5 3.5 3.5 Table V. 4. Analytical Data for Oil Stain and Bitumens from Postulated Source-Rock Intervals, stanbul-1 Well. Depth (ft) 7,927 9,000 9,500 10,000 10,500 Porphyrins Ni V 1.21 0.55 0.88 0.15 1.52 0.59 1.37 0.65 1.91 1.02 a δ13C (‰ PDB) Kerogen Bitumen -26.0 -30.2 -30.7 -26.1 -27.2 -25.3 -25.7 -28.3 -25.5 obtained from gas chromatograms. 58 Pristanea Phytane 0.57 0.92 0.48 0.66 0.51 CPIa 23-31 1.09 1.02 1.18 1.29 1.28 maximum n-parafin C25 C17 C27 C27 C27 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure V. 4. Source rock evaluation of the stanbul-1 well. 59 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure V. 5. Total oil and oil already generated for the stanbul-1 well. 1) Assuming there is only one source rock of 250 Ma in age, oil is generated 145 million years ago and migrated Exercise: Oil half-life Model 60 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic 2) Draw a typical "degree of system filling" (y-axis) versus "time in halflives" (x-axis) diagram in Figure V. 6. immediately after generation, the accumulation of oil in the system with constant generation and exponential decay as it is progressively created and destroyed, 3) Calculate the total amount of oil that existed in the reservoir rock 100 million years ago, assuming 500,000 bbl of oil exist today in the present reservoir. Figure V. 6. Degree of system filling versus time in half-lives diagram. 61 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic VI. PETROLEUM SYSTEM Reference Magoon, L.B. and Dow, W.G., 1994, The petroleum system, in: Magoon, L.B. and Dow, W.G. (Eds.), The Petroleum System-From Source to Trap: AAPG Memoir 60, p. 3-24. phase at the surface, but either way it is considered petroleum, as are solid petroleum materials such as natural bitumen and asphalt, and bituminous sands (=unconventional oil). Definition A petroleum system is defined as a natural system that encompasses a pod of active source rock and all related oil and gas and which includes all the geological elements and processes that are essential if a hydrocarbon accumulation is to exist . System describes the interdependent elements and processes that form the functional unit that creates hydrocarbon accumulations. Petroleum includes high concentrations of; 1) thermal or biogenic gas found in conventional reservoirs or in gas hydrate, tight reservoirs, fractured shale, and coal; or 2) condensates, crude oils, and asphalts found in nature. A pod of active source rock indicates that a contiguous volume of organic matter is creating petroleum, either through biological activity (biologically) or temperature (thermally), at a specified time. The volume or pod of active source rock is determined by mapping the organic facies (quantity, quality, and thermal maturation) considered to be the presently active, inactive, or spent source rock using organic geochemical data displayed as geochemical logs. A source rock is active when it is generating this petroleum, whereas an inactive or spent (depleted) source was at some time in the past an active source rock. From the time a petroleum phase is created a petroleum system The terms petroleum, hydrocarbon, and oil and gas are synonyms. The term conventional oil is used for the petroleum other than gas and unconventional oil which are heavy oil, tar sand, and oil shale. Petroleum originally referred to crude oil, but its definition was broadened later to include all naturally occurring hydrocarbons, whether gaseous, liquid, or solid. Condensate is in a gas phase in the accumulation and in a liquid 62 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic exists and a petroleum system exists wherever the essential elements and processes occur. The active time can be present day or any time in the past. The essential elements include a petroleum source rock, reservoir rock, seal rock, and overburden rock, whereas the processes are trap formation and generation-migrationaccumulation of petroleum. These essential elements and processes must occur in time and space so that organic matter included in a source rock can be converted to a petroleum accumulation. Petroleum System Name The name of a petroleum system includes the source rock, followed by the name of the major reservoir rock, and then the symbol expressing the level of certainty. A petroleum system can be identified at three levels of certainty: known, hypothetical, or speculative. The level of certainty indicates the confidence for which a particular pod of active source rock has generated the hydrocarbons in an accumulation. In a known (!) petroleum system, a good geochemical match exists between the active source rock and the oil or gas accumulations. In a hypothetical (.) petroleum system, geochemical information identifies a source rock, but no geochemical match exists between the source rock and the petroleum accumulation. In a speculative (?) petroleum system, the existence of either a source rock or petroleum is postulated entirely on the basis of geologic or geophysical evidence The essential elements are a petroleum source rock, reservoir rock, seal rock, and overburden rock at the critical moment. The functions of the first three rock units are obvious. However, the function of the overburden rock is more subtle because, in addition to providing the overburden necessary to thermally mature the source rock, it can also have considerable impact on the geometry of the underlying migration path and trap. The generation-migrationaccumulation of hydrocarbons, or age of the petroleum system, is based on stratigraphic and petroleum geochemical studies and on the burial history chart. These processes are followed by the preservation time, which takes place after the generationmigration-accumulation of hydrocarbons occur, and is time when hydrocarbons within the petroleum system are preserved, modified, or destroyed. For example, the Deer-Boar (.) is a hypothetical petroleum system consisting of the Devonian Deer Shale as the oil source rock and the Boar Sandstone as the major reservoir rock. Characteristics and Limits The geographic, stratigraphic, and temporal extent of the petroleum system is specific and is best depicted using a table which includes field name, discovery date, reservoir rock, API gravity (0 API), cumulative oil production (million bbl), and When the generation-migrationaccumulation of the petroleum system extends to the present day, there is no preservation time, and it would be expected that most of the petroleum is preserved and that comparatively little has been biodegraded or destroyed. 63 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic remaining reserves (million bbl) and following four figures: geographic extent or known extent of the petroleum system. 1) A burial history chart depicting the critical moment, age, and essential elements at a specified location; The burial history chart shows that time when most of the petroleum in the system is generated and accumulating in its primary trap. 2) A map and 3) A cross section drawn at the critical moment depicting the spatial relationship of the essential elements; and The petroleum system event chart shows eight different events. The top dour events record the time of deposition from stratigraphic studies of the essential elements, and the next two events record the time the petroleum system processes took place. The formation of traps is investigated using geophysical data and structural geologic analysis. 4) A petroleum system events chart showing the temporal relationship of the essential elements and processes and the preservation time and critical moment for the system. The critical moment is that point in time selected by the investigator that best depicts the generation-migration-accumulation of most hydrocarbons in a petroleum system. Geologically, generation, migration, and accumulation of petroleum at one location usually occur over a short time span. Exercise: Deer-Boar Petroleum System (.) 1) Examine the plan map showing the geographic extent of the fictitious Deer-Boar (.) petroleum system at the critical moment (250 Ma) which is given in Figure VI. 1. Thermally immature source rock is outside the oil window. The pod of active source rock lies within the oil and gas windows. A map or cross section drawn at the critical moment best shows the geographic and stratigraphic extent of the system. The geographic extent of the petroleum system at the critical moment is define by a line that circumscribes the pod of active source rock and includes all the discovered petroleum shows, seeps, and accumulations that originated form that pool. The cross section shows the geometry of the essential elements at the time of hydrocarbon accumulation and best depicts the stratigraphic extend of the system. A plan map, drawn at the critical time, includes a line that circumscribes the pod of active source rock and all related discovered hydrocarbons. This map depicts the 2) Examine the geologic cross section showing the stratigraphic extent of the same petroleum system at the critical point which is given in Figure VI. 2. Thermally mature source rock lies updip of the oil window. The pod of active source rock is downdip of the oil window. 3) Examine the burial history chart showing the critical moment (250 Ma) and the time of oil generation (260-240 Ma) for the same petroleum system, which is given in Figure VI. 3. Neogene (N) includes the Quaternary (Q) here. 64 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Boar (.) petroleum system. Neogene (N) also includes the Quaternary (Q). 5) Describe briefly the geological history of the region. 4) Prepare the events chart (Figure VI. 4) showing the relationship between the essential elements and processes as well as the preservation time and critical moment for the fictitious Deer- 6) Write a brief report about the petroleum geology of the area. Figure VI. 1. Plan map showing the geographic extent of the fictitious Deer-Boar (.) petroleum system at the critical moment (250 Ma) (Magoon and Dow, 1994). 65 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure VI. 2. Geologic cross section showing the stratigraphic extent of the fictitious Deer-Boar (.) petroleum system at the critical point (Magoon and Dow, 1994) Figure VI. 3. Burial history chart showing the critical moment (250 Ma) and the time of oil generation (260-240 Ma) for the fictitious Deer-Boar (.) petroleum system (magoon and Dow, 1992). 66 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure VI. 4. The events chart showing the relationship between the essential elements and processes as well as the preservation time and critical moment for the fictitious Deer-Boar (.) petroleum system (Magoon and Dow, 1994) 2) The number of petroleum systems is determined by the number of pods of active source, as shown by the three examples in Figure VI.6. Complete the cross sections in A and C. Note that petroleum accumulation is charged by a single pod of active source rock (A and C) and by two pods of active source rock (B). Exercise: Partial or Complete Petroleum Systems 1) Three examples of partial or complete petroleum systems at the critical moment are given in Figure VI. 5. Complete the cross sections in B and C. Note that petroleum accumulation is charged by a single pod of active source rock (one petroleum system). 3) Discuss the differences between one petroleum system and two petroleum systems. 67 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure VI. 5. Three examples of partial or complete petroleum systems at the critical moment are given in Figure II.5. (A) The essential elements are present, but the system is incomplete (thus no petroleum system); (B) one petroleum system; and (C) two petroleum systems. Notice that the overburden rocks creates the geometry of the most recent sedimentary basin and that the source rock was deposited in a larger, older sedimentary basin (Magoon and Dow, 1994). 68 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c
  • F -X C h a n ge F -X C h a n ge N y bu bu y N O W ! PD O W ! PD c u-tr a c k to k lic Figure VI. 6. Petroleum accumulation is charged by (A) a single pod of active source rock, or one petroleum system; (B) two pods, or two petroleum systems; and (C) one pod, or one petroleum system (Magoon and Dow, 1994). 69 .d o o .c m C m w o .d o w w w w w C lic k to Volkan . Ediger, Petroleum Geology'2003 c u-tr a c k .c