Download as PDF, PPTX
Uploaded byElsayed Amer
4- Geophysics and exploration
The document discusses the framework and processes involved in oil and gas exploration, covering aspects from field development to geophysical methods such as seismic, magnetic, and gravity surveys. It outlines the roles and responsibilities of geophysicists in environmentally sensitive areas and emphasizes the importance of interpreting geological data to locate hydrocarbons. The document also highlights the strengths and limitations of seismic data in identifying potential reservoirs and understanding subsurface geology.
More Related Content
Similar to 4- Geophysics and exploration
4- Geophysics and exploration
- 1.
- 2. Oi l fi e l d f r am e wo r k
- 3.
- 4. Field development Exploration AbandonmentDevelopmentproduction Oil field development
- 5. Oil field development 03020104 AbandonmentProductionDevelopmentExploration • Seismic Activities • Drilling services • Construction • Hook up wells • Engineering • Operations • Optimization • Commissioning • Well plugging • Decommissioning machinery and equipment
- 6. Remember last lectures PetroleumSystem Traps structure Rock types
- 7. Hydrocarbon System Reservoir • HydrocarbonGeneration • Migration Kitchen Accumulation Trap • Reservoir rock ( pours & Permeable). • Sealing Container ( impermeable).
- 8. 8 24803 Source RockSource Rock TopSeal RockTop Seal Rock Reservoir RockReservoir Rock Anticlinal TrapAnticlinal Trap (Organic Rich)(Organic Rich)
- 9. Hydrocarbon Generation vsDepth Depth range km .5 2 3.5 5 2 4 6 8 Minimum Maximum AverageDepth(km) 0 1 2 3 4 5 6 Generation Intensity Biogenic Methane Wet Gas Methane 300 250 200 150 100 50 0 600 500 400 300 200 100 Cano- zoic MesozoicPaleozoic Immature Oil Generation Gas Generation PresentFormationTemperature(oC) Time (millions of years from present) Oil
- 10. Common Hydrocarbo nTraps Unconformity Trap Anticlinal Trap Fault Trap Buried Reef Pinch Out Grading Trap Sand Lens Salt Dome Traps Unconformity Surface Sub-Salt Sediment Truncation Anhydrite
- 11. Common Hydrocarbo nTraps Salt Dome Fault Unconformity Pinchout Anticline
- 12. Some people thinkthat oil is in big pools underground. Actually, most oil is trapped in the tiny pore spaces between grains of rock or sand. Most of these pores are too small to be seen with the naked eye.
- 13.
- 14. The study oftectonic plates and earthquakes The study of Earth’s composition Geophysics What is it? The study of natural hazards Explores for oil and gas The application of physics principles to the study of the subsurface of earth, to search of hydrocarbon. Geophysical investigations of the earth interior involves taking measurements at earth’s surface that are influenced by the internal distribution of physical properties. The objective of any exploration venture is to find new volumes of hydrocarbons at a low cost and in a short period of time.
- 16. What does aGeophysicist do? responsibilities Laying out geophones In old days used to have wide, high-impact cut lines Today, in environmentally sensitive areas we use hand cut, low-impact cut lines; supported by helicopters, not as much heavy equipment * As a geophysicist, your responsibility to ensure that work is done in environmentally sensitive manner Remote locations Moving into tougher areas to explore since easier areas have been evaluated
- 17. What does aGeophysicist do? responsibilities data processing Acquired data is processed at data processing centers in the office Geophysicist at top right is building a velocity model to get better data to analyze technologists often process as well Interpreter analyzes Interpreter analyzes the finished processed data to get an image of the subsurface.
- 18. What does aGeophysicist do? responsibilities Remote sensing Remote sensing used to understand the earth helpful in evaluating large areas aeromag data can be used in exploring for minerals Interpreter analyzes Interpreter analyzes the finished processed data to get an image of the subsurface.
- 22. 1 2 3 4 Magnetic Method Methods Gravity Method ElectroMagnetic Method Seismic Method
- 23. 1. Magnetic Method Sedimentary rocks : •Lime stone 10 – 25.000 • Sandstone 0 - 21.000 • Shale 60 – 18.600 Igneous Rock • Granite 10- 65 • Peridolite 95.500 – 196.000 Minerals • Quartz -15 • Magnetite 70.000-2 x 10^7 Measuring the strength and Intensity of earth’s magnetic field. The unit of measurem ent is Tesla
- 24.
- 25.
- 28.
- 29. 2. Gravity Method Measuring the variationin earths gravitational field caused by differences in the density of subsurface rocks Interpretation of gravity maps presents many problems, the simplest of which are caused by different subsurface bodies producing the same anomaly on the surface. Example: distinguishing between a small sphere of large density and a large sphere of low density at similar depths is impossible. In some circumstances gravity maps may indicate drillable prospect by locating salt domes and reefs (because of their low density.
- 30. Clay Sp.Gr. 2.3 LimestoneSp.Gr. 2.7 Sand Clay Sp.Gr. 2.4 5 6 7 94 81 2 3 5 6 7 94 81 2 3 Measured Force of Gravity Zero Line Grav.Min. Gravity Meter Gravimetric CurveGrav. Max.
- 31. -3 -2 -1 +1 Salt 2.1 gm/cm3 Corrected Gravity (BouguerAnomaly) Uncorrected Gravity Clastics 2.4 gm/cm3 Meter Gravity Value (mgal) Principles of Gravity Surveys
- 37.
- 38. History Seismic activities 1900 theoryof reflected and refracted waves. 1914-1918 (WW1) locating heavy guns by recording arrival times
- 39. 1919 Mintrop: patenton the refraction method (salt dome discovery, Texas) 1920’s reflection method (Oklahoma) 1953 magnetic tape: analog recording 1956 patent on CDP method
- 40. 1975 first 3Dsurveys 1980’s development of seismic workstation software
- 42. Seismic What is it? The seismic methods are the most widely used of all geophysical methods used in petroleum exploration. Seismic Reflection is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. Seismic methods measure seismic velocity of rock layers to detect both lateral and depth variations and the objective is to determine the lithology and geometry of the layers. A seismic wave can be thought of as shock wave (elastic wave) or vibration traveling through the ground. The rate of travel, or velocity, of the wave is related to the density of the rock.
- 43. Seismicconcepts Medium earth consistsof several layers of rock, which is between the layers of rock with another rock layers can be different density and wave speed response. According to Snell's law, can seismic waves change direction when passing through the boundary between the layers because of refraction and reflection.
- 44. Ideal Seismogram • Theseismic data recorded should give us the earth’s reflectivity sequence: Surface Depth Time Reflection Coefficient
- 45. Sea bed Boat Cable withhydrophones Sea Surface Source (Airguns) Sedimentary Layers Incident waves Reflected waves Marine Acquisition System
- 46. 3D Acquisition Techniques Seasurface Sea bed • 2 source, 6 streamer configuration • 12 lines shot in 1 boat pass
- 47.
- 48. SeismicResponse Causes of seismicresponse 1. Changes in bulk-rock velocity or density • Lithology (e.g., sandstone, shale, limestone, salt) Limestone Shale
- 49. SeismicResponse Causes of seismicresponse 1. Changes in bulk-rock velocity or density • Porosity (e.g., intrinsic, compaction, diagenesis) Fast Slow
- 50. SeismicResponse Causes of seismicresponse 1. Changes in bulk-rock velocity or density • Mineralogy (e.g., calcite vs. dolomite, carbonaceous shales) • Fluid type and saturation (water, oil, gas) Pore Fluid Density Salt Water 2.164 Fresh Water 2.155 Oil 2.095 Gas 1.856 Sandstone with 30% Porosity:
- 51. interface shot receivers shotreceivers Wave fronts How waves actually travel Surface of equal travel time Surface of equal phase
- 52. Determining location: seismic sources: seismicdetector 01 02 03
- 53. Petroleum exploration andproduction are concerned with the geological interpretation of geophysical data, especially in offshore areas. The location can be : Marine environment Land environment
- 58.
- 59. Vibrator Truck (Energy Source)RecordingTruck Geophone (Receivers) Returning Sound Waves
- 60. seismic source is adevice that generates controlled seismic energy used to perform both reflection and refraction seismic surveys. This is a sample text. You can replace this text. Enter your text here. This is a sample text. You can replace this text. Enter your text here. source
- 61. seismic source Natural SourceArtificial Source Earthquakes Marine Land Air Gun • Hammers • Weight drops • Explosive dynamite • Vibrators
- 62. 01 02 0304 05 Seismic Interpretation geophysicist petro physicist Reservoir Engineer Geologist Structural Geologist
- 73. Development Geoscience StudyPath Seismic Survey Sections Time Map Seismic Depth Map Isochore Map Structure Map Sediment Model Regional Geology Pressure Data Well Performance Logs Cores Well Correlation Description Analysis Petrophysics Evaluation Pal Data Log Shape Output Reservoir Geological Model Interpretation Data Sources
- 74. Test Results Fluid Properties Pressures Core Lithology Porosity Permeability Mudlogs Measurement WhileDrilling Indications Resistivity Wireline Logs Resistivity Radioactivity Density Sonic Velocity Hydrogen Content Geology Lithology Stratigraphy Petrophysics Lithology Porosity Hydrocarbon Saturation Net Reservoir Thickness Permeability Oil In-Place Petrophysics
- 75. Seismic Image ofAnticline - example 1000 2000 3000 Milliseconds 1 km
- 76. Seismic Image ofAnticline - interpretation 1000 2000 3000 Milliseconds 1 km Structure can be identified from seismic data
- 77. Seismic Image ofthe field – 3D example Faults Salt Dome Faults source Hydrophones - streamers
- 78. RIFTING ERA TIME UNIT GROUP ROCK UNIT FORMATION LITHOLOGY TYPESECTION THICKNESS(m) SOURCE RESERVOIR SEAL Conglomerate PRE-CAMBRIAN BASEMENT POST RIFT PLEISTOC. PLEIOCENE ZAAFARANA WARDAN ZEIT SOUTH GHARIB BELAYIM SYNRIFT CENOZOIC MIOCENE RASMAALABGHARANDAL KAREEM RUDEIS NUKHUL THAYIBA BED/ ABU ZENIMA Belayim 112-12 well THEBES ESNA SUDR DUWI (BROWN LIMESTONE MATULLA WATA ABU QADA RAHA MALHA QISEIB ROD EL HAMAL MESOZOIC PRERIFT PALEOZOIC OLIGOCENE EOCENE PALEOCENE CRETACEOUS LATEEARLY NEZZAZATELTIHELEGMA NUBIAN-ANUBIAN-B ABU DURBA JURASSIC TRIASSIC PERMIAN ATAQA LATEEARLY UMM BOGMA CARBONIFEROUS NAQUS ARABA NUBIAN-CNUBIAN-D CAMBRIAN- ORDOVICIAN QEBLIAT 81 5 South Gharib-2 North Gharib-2 Abu Zenima-1 Rudeis-2 Zeit Bay-1 Zeit Bay-1 Luxor Esna Wadi Sudr Gebel Duwi Wadi Matulla Wadi Wata Wadi Gharandal Raha Scarp Wadi Malha Wadi Qiseib Wadi Rod El Hamal Gebel Abu Durba Gebel Nukhul Gebel Naqus Gebel Qabllat 112 940 700 320 461 780 427 90 120 423 60 37 170 64 25 120 149 4 4 274 122 45 410 133 )( )( )( )( )( )( )( )( )( LEGEND Sandstone Coarse Sandstone Limestone Dolomite Anhydrite Salt Shale Cherty Limestone Basement Primary source rock Secondary source rock Reservoir rock Seal rock Gebel Zeit-2 HYDROCARBON GULF OF SUEZ STRATIGRAPHIC COLUMN 105
- 81. Well data Basin fill history HC systems • Able to image major depositional units SeismicStrength & Limitations • Able to identify potential source, reservoir, and seal units • Provides a stratigraphic framework within which other data can be understood The Limitations of Seismic Data • Good areal coverage The Strength of Seismic Data • Limited vertical and lateral resolution: can’t resolve “small” features • Stratigraphic interpretation is limited by the quality of the seismic data/imaging • Seismic responses are non-unique – e.g., low amplitude could be a massive sand or a thick shale • Typically we can’t “see” hydrocarbons