Aberdeen Conference in 1999 on the Lower Cretaceous of the North Sea. This talk (abstract) discussed the Lower Cretaceous plays in a sequnce stratigraphy framework. This includes HST and LST and discusses the known hydrocarbon fields in this context.
Structures and hydrocarbon prospects in emi field, offshore niger deltaeSAT Journals
Abstract The Niger Delta is ranked among the world’s major hydrocarbon provinces in the world. Oil and gas in the Niger Delta are mainly trapped in sandstones and unconsolidated sands in the Agbada formation and the structural traps are not easy to map precisely because they are very slight, not obvious and very complicated. The main aim was to determine the structures and hydrocarbon prospects in Emi-field, off shore Niger Delta using seismic data integrated with well logs. Four (4) horizons namely L1, L2, L3 and L4 were selected and structural maps drawn for each of the horizons. Fault closures of high quality hydrocarbon prospects were identified and delineated. The integration of seismic data with well logs greatly improved the extent of accuracy and exactness of structural maps in hydrocarbon prospects and its development in Emi Field. Key words: Structures, hydrocarbon prospects, Emi Field, Niger Delta
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
A REVIEW OF GROWTH FAULTS AND ROLLOVER ANTICLINES (A CASE STUDY OF NIGER DELTA) James Opemipo OLOMO
Growth faults and its associated rollover anticlines are generally syndepositional sedimentary structures that result from diastrophism which was contemporaneous with sedimentation. They are special structures which occur abundantly in the Niger Delta & constitute one of the most important hydrocarbon traps in the region .
Despite this abundance, their occurrence is however restricted to the extensional zone of the Niger delta. These structures can be identified from outcrops, seismic data , structure contour maps and well logs. While their propagation history can be constrained by the use of key kinematic tools, such as t-z, d-l and expansion index plots. Although, it has been identified that these structures are target structures in the accumulation of oil and gas, they can also be destructive, especially if they are reactivated after hydrocarbon accumulation.
Hence, it is important for the petroleum explorationist to identify, map their extent and constrain the propagation history of these structures, in order to minimise exploration risk.
From the Arctic to the Tropics: The U.S. UNCLOS Bathymetric Mapping ProgramLarry Mayer
Since CHC2006, the University of New Hampshire’s Center for Coastal & Ocean Mapping/Joint Hydrographic Center has mapped with multibeam, the bathymetry of an additional ~220,000 km2 of seafloor in areas as diverse as the Arctic, the Northern Marianas of the western Pacific and the Gulf of Mexico. The mapping supports any potential U.S. submission for of extended continental shelves under Article 76 of the United Nations Convention of the Law of the Sea. Consequently, the mapping has concentrated on capturing the complete extent of the 2500-m isobath and the zone where the Article 76-defined foot of the slope exists. In practice, the complete area between ~1500 and ~4500 m water depths is mapped in each region (with the exception of the Arctic Ocean). The data have been collected in conditions that range from harsh Arctic sea ice to the calms of the Philippine Sea tropics. Although, some of the conditions have limited the quality of some of the data, the data quality is generally quite good and geological surprises have been uncovered on each of the cruises.
Structures and hydrocarbon prospects in emi field, offshore niger deltaeSAT Journals
Abstract The Niger Delta is ranked among the world’s major hydrocarbon provinces in the world. Oil and gas in the Niger Delta are mainly trapped in sandstones and unconsolidated sands in the Agbada formation and the structural traps are not easy to map precisely because they are very slight, not obvious and very complicated. The main aim was to determine the structures and hydrocarbon prospects in Emi-field, off shore Niger Delta using seismic data integrated with well logs. Four (4) horizons namely L1, L2, L3 and L4 were selected and structural maps drawn for each of the horizons. Fault closures of high quality hydrocarbon prospects were identified and delineated. The integration of seismic data with well logs greatly improved the extent of accuracy and exactness of structural maps in hydrocarbon prospects and its development in Emi Field. Key words: Structures, hydrocarbon prospects, Emi Field, Niger Delta
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
A REVIEW OF GROWTH FAULTS AND ROLLOVER ANTICLINES (A CASE STUDY OF NIGER DELTA) James Opemipo OLOMO
Growth faults and its associated rollover anticlines are generally syndepositional sedimentary structures that result from diastrophism which was contemporaneous with sedimentation. They are special structures which occur abundantly in the Niger Delta & constitute one of the most important hydrocarbon traps in the region .
Despite this abundance, their occurrence is however restricted to the extensional zone of the Niger delta. These structures can be identified from outcrops, seismic data , structure contour maps and well logs. While their propagation history can be constrained by the use of key kinematic tools, such as t-z, d-l and expansion index plots. Although, it has been identified that these structures are target structures in the accumulation of oil and gas, they can also be destructive, especially if they are reactivated after hydrocarbon accumulation.
Hence, it is important for the petroleum explorationist to identify, map their extent and constrain the propagation history of these structures, in order to minimise exploration risk.
From the Arctic to the Tropics: The U.S. UNCLOS Bathymetric Mapping ProgramLarry Mayer
Since CHC2006, the University of New Hampshire’s Center for Coastal & Ocean Mapping/Joint Hydrographic Center has mapped with multibeam, the bathymetry of an additional ~220,000 km2 of seafloor in areas as diverse as the Arctic, the Northern Marianas of the western Pacific and the Gulf of Mexico. The mapping supports any potential U.S. submission for of extended continental shelves under Article 76 of the United Nations Convention of the Law of the Sea. Consequently, the mapping has concentrated on capturing the complete extent of the 2500-m isobath and the zone where the Article 76-defined foot of the slope exists. In practice, the complete area between ~1500 and ~4500 m water depths is mapped in each region (with the exception of the Arctic Ocean). The data have been collected in conditions that range from harsh Arctic sea ice to the calms of the Philippine Sea tropics. Although, some of the conditions have limited the quality of some of the data, the data quality is generally quite good and geological surprises have been uncovered on each of the cruises.
Exploration history of Oil and Gas in GhanaElorm Obenechi
This is a document that Oil and Gas students will find useful. it talks in brief about Oil and Gas exploration in Ghana and current state (as at 2008).
It is a good read.
sedimentary basin may be defined as an area of depression in the earth’s crust in which sediments accumulate during a particular time span at a significantly greater rate, and so to a significantly greater thickness.
In this slide, the Framework of Petroleum Geology is discussed with the Pure Science such as Physics, Chemistry, and Biology.
Moreover, the composite relation is detailed with the initiative way to abandonment of the well.
Most Important factor, The Jobs crises is discussed !
Scientific and economical aspect of seabed exploration and miningSomnathKamble6
Scientific & Economical Aspect of Seabed exploration & Mining
SEABED – The floor of a sea or ocean is known as seabed(also known as the sea floor, or ocean floor or the bottom of the ocean)
STRUCTURE - tectonic movement, and sediment from various sources.
SEDIMENTS –
Terrigenous
Biogenous
Hydrogenous
Cosmogenous
HISTORY OF SCIENTIFIC ASPECTS
SCIENTIFIC ASPECT
ECONOMICAL ASPECT OF SEABED EXPLORATION
MINING OF SEABED
Journal Petroleum Geology. Northern and Central North Sea Aptian sands, lowstand systems tract. Sequence stratigraphy development, Logs and micropapaeontology. prospectivity
The broad overview of the Oil and Gas Industry contained in this PowerPoint presentation contains more technical detail than the “Broad Overview for Non-technical Staff”. It is intended for executive staff who lack a background in Geoscience and/or Engineering and/or for new employees to the industry.
Exploration history of Oil and Gas in GhanaElorm Obenechi
This is a document that Oil and Gas students will find useful. it talks in brief about Oil and Gas exploration in Ghana and current state (as at 2008).
It is a good read.
sedimentary basin may be defined as an area of depression in the earth’s crust in which sediments accumulate during a particular time span at a significantly greater rate, and so to a significantly greater thickness.
In this slide, the Framework of Petroleum Geology is discussed with the Pure Science such as Physics, Chemistry, and Biology.
Moreover, the composite relation is detailed with the initiative way to abandonment of the well.
Most Important factor, The Jobs crises is discussed !
Scientific and economical aspect of seabed exploration and miningSomnathKamble6
Scientific & Economical Aspect of Seabed exploration & Mining
SEABED – The floor of a sea or ocean is known as seabed(also known as the sea floor, or ocean floor or the bottom of the ocean)
STRUCTURE - tectonic movement, and sediment from various sources.
SEDIMENTS –
Terrigenous
Biogenous
Hydrogenous
Cosmogenous
HISTORY OF SCIENTIFIC ASPECTS
SCIENTIFIC ASPECT
ECONOMICAL ASPECT OF SEABED EXPLORATION
MINING OF SEABED
Journal Petroleum Geology. Northern and Central North Sea Aptian sands, lowstand systems tract. Sequence stratigraphy development, Logs and micropapaeontology. prospectivity
The broad overview of the Oil and Gas Industry contained in this PowerPoint presentation contains more technical detail than the “Broad Overview for Non-technical Staff”. It is intended for executive staff who lack a background in Geoscience and/or Engineering and/or for new employees to the industry.
pp395 414 Journal Petroleum Geology10 1987 The Albian transgression in the so...Stephen Crittenden
description of the regional Albian transgression as identified by wireline log, lithostratigraphy and biostratigraphy correlation - England, North Sea, Holland and Germany
Newsletter on Stratigraphy volume 15_number_3_p163-171_Planktonic_foraminifer...Stephen Crittenden
Planktonic foraminifera from drill cuttings through the Early Tertiary interval of a borehole in the southern North Sea. Discusion of the recovered fauna and comparison with other records from the North Sea basin
Goban Spur Presentation: the Early Cretaceous (Barremian -?Aptian) foraminife...Stephen Crittenden
Stephen Crittenden. Chapter 13 of Ph D Thesis written in 1981/1982 when a postgraduate student, using DSDP samples provided kindly by Dr Jacques Sigal and Dr Francoise Magniez. Foraminfera and Ostracoda were described from the "Urgonian" facies of the Early Cretaceous.
Template of Cretaceous lithostratigraphy in the North Sea. Preliminary status in 2007. An example of procedure process. Mike Charnock & Stephen Crittenden
Historical and early exploration records of hydrocarbon seeps in Kuwait and the surrounding area that led to the discovery of the super giant oilfield - Burgan. A tale of political intrigue and geology.
A sequence of slides detailing a preliminary study for age dating (biostrat) the Enjefa Beach succession in Kuwait. The sedimentology of the cliff section is that of Dr Saifullah Khan Tanoli and acts as the framework. The description of the modern day Beach Rock is by S Crittenden
The foraminiferid Osangularia schloenbachi (Reuss) the erection of a neotype....Stephen Crittenden
Erection of a neotype for the loss of the original specimen of the foraminiferid Osanglaria schloenbachi Crittenden and Price conducted an extensive search with no success. But....since this erection of the neotype the original type specimens have been found in Vienna
Crittenden 1984-jm3-1-1[1] A note on the Early Cretaceous biostratigraphy (f...Stephen Crittenden
foraminifera and lithostratigraphy of the Early cretaceous interval of a borehole in the Southern North Sea. Correlated with the onshore UK and to the Dutch sector
foraminifera from the Atherfield Clay of the Idle of Wight. Lithosection description, illustration of the foraminifera. Lower Cretaceous marine sediments
North sea marl våle – maureen nomenclature linkedin versionStephen Crittenden
Lithostratigraphy and biostratigraphy of the lower Tertiary of the southern North Sea - UK, Danish and Norwegian sectors. Brief notes and comments as a basis for further discussion
Spe 163367-ms-p Modelling of regional aquifer.....Burgan Field Minagish Reser...Stephen Crittenden
Bergan Field Kuwait. The Minagish Reservoir comprising oolite shoals, is aquifer pressure connected to other fields in the region which interact with each other.
Eage poster 53, copenhagen, steve crittenden & adi kadar et al, 2012finalStephen Crittenden
Biofacies and palaeoenvironment & stratigraphy of the ratawi, Minagish and Makhul formations Kuwait, reservoir, source rocks, conventional and unconventional expl plays.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
1. 1
This is the unedited abstract of a talk presented in 1999 in Aberdeen. The accompanying OHP /
Power point illustrations for the talk will be available on a different upload. These include my
original constructed creaming curves, and descriptions of some of the fields etc for the Lower
Cretaceous in NW Europe presented at the conference. Some of these were then utilized by
Academics, who were at the conference, in a subsequent Conference themed publication. There is
also a poster on my slide share and an abstract posted on my Linkedin profile.
CONFERENCE: LOWER CRETACEOUS OF THE CENTRAL NORTH SEA:
REGIONAL SETTING AND DEPOSITIONAL ARCHITECTURE; CONFERENCE
ABSTRACTS VOLUME; ABERDEEN, MAY 18th – 19th , 1999. pp 41 – 44
ORAL PRESENTATION
THE LOWER CRETACEOUS OF THE AGAT FIELD AREA; COMPARISONS WITH
THE UK CENTRAL NORTH SEA AND IMPLICATIONS FOR EXPLORATION ON THE
NORWEGIAN CONTINENTAL SHELF
STEPHEN CRITTENDEN1
, BRIT E. SAUAR2
, FRODI HJALTASON2
1
Independent Geological Consultant, Waye Cottage, Chagford, Devon, UK, TQ13 8HN.
2 Norsk Hydro Exploration and Production, PO Box 200, N-1321, Stabekk, Norway.
Exploration on the continental shelf offshore north west Europe has over the last three decades
progressed from the initial search for large obvious structural traps to the search for more subtle
stratigraphic plays. Within such a strategy the pursuit of the subtle plays, usually stratigraphical
traps, relies upon a thorough understanding of the vast amount of data generated in the preceeding
structural phase of exploration. In other words exploration progresses from the simple to the
complex.
Conventional exploration wisdom indicates empirically that the initial phase of exploration in a
virgin basin/province usually yields the greatest rewards in terms of the volume of hydrocarbons
discovered. Initially, usually after a slow start as a geological / geophysical data-base is developed,
the wells drilled result in the discovery of large volumes of hydrocarbons (either a few large fields
or a number of smaller fields). As time and exploration progresses the size and number of new
discoveries tends to decrease. This concept can be illustrated graphically by a ‘discovery curve’
(colloquially termed a ‘creaming curve’) - volumes of hydrocarbons discovered against time / wells
drilled - which shows that the largest fields are discovered in the initial phases of exploration when
the large structures are drilled and that the subsequent discovered fields size become smaller as the
structures left to drill are smaller. The overall ‘discovery curve’ for the North Sea is now (1999)
considered to indicate a mature petroleum province.
However, other factors which affect the shape of the overall ‘discovery curve’ have to be considered
and include, the division of the exploration region into license areas, technology changes such as
capability of drilling in deeper and deeper water, the progressive increase in infra-structure as fields
are discovered and the development of sophisticated geological models based on sequence
stratigraphy concepts. These factors tend to create a sub-pattern or sub-trend within the overall
‘discovery curve’. The overall discovery curve indicating the ‘maturity’ of the North Sea can
however, be misleading as will be explained.
In the North Sea and adjacent onshore areas there is a great deal of information available from over
30 years of exploration effort which can be examined and evaluated. Soon after exploration has
begun and well data and discovered fields data becomes available the search for prospects becomes
2. 2
more refined and the play models more subtle. Large structures are still the usual target (for
economic reasons) but discoveries can be grouped / delineated by either stratigraphic age or play-
type or location (by sub-dividing the region into provinces and sub-basins). These groupings allow,
from a re-evaluation of the data generated to date, the erection of a number of ‘discovery sub-
curves’ for , for example, the Late Jurassic, the Middle Jurassic and the Tertiary, each with its own
initial steep rise and subsequent flattening (Brennand & van Hoorn, 1986; Bain, 1993; Cordey,
1993) as they become mature.
In the Central North Sea the discovery of the large Tertiary play / structure of the Forties Field
provided the impetus for intense exploration of the Tertiary of the Central Graben of the North Sea
by numerous competing oil companies all eager to gain a share of the rewards. The risk had been
reduced by showing that the Early Tertiary was host to giant accumulations of oil and hence oil
companies concentrated their search using a proven play.
Similarly, in the Northern North Sea the Middle Jurassic Brent tilted fault block play epitomised by
the Ninian, Brent and Statfjord fields, became established in the East Shetland Basin.
The proven plays therefore, understandably concentrated the exploration efforts of the oil companies
to, in most cases, the positive disregard in investigating or considering other un-proven plays.
Occasionally other plays which have been developed in other parts of the basin / region, such as the
Upper Jurassic Brae Sands play of the South Viking Graben, prompted some investigation
elsewhere such as, for example, the East Shetland Basin.
The erection of ‘discovery sub-curves’ is important as they reveal that prospects using the tried and
tested plays, such as the rotated and tilted Jurassic Brent fault blocks, are sought and drilled long
after the ‘big ones’ have been found and the onset of the economic law of diminishing returns (see
Cordey, 1993). The ‘discovery sub-curve’ indicates a diminishing return (the curve flattens out) and
that time and effort may have been better employed in the search for large fields (or numerous
smaller fields) of a new play concept: ie in the generation of a steep upward part of a new
‘discovery sub-curve’ where the rewards are greatest. In other words some ‘sleeping giants’ have
been ignored. However, what and where are these ‘sleeping giants’? The new plays, which lead to
the discovery of ‘sleeping giants’, are often found by luck while drilling a prospect of one of the
established plays. This is the case for the Lower Cretaceous as illustrated by, the giant Britannia
Field (1975), the North Glenn accumulation (1975), the Captain Field (1977) and the Agat Field
(1976). These discoveries were ‘concealed’ in the overall ‘discovery curve’ and were found while
pursuing the Jurassic plays, hence the Lower Cretaceous Aptian play was not pursued with vigour
(Crittenden, 1991, 1992, 1993, 1994).
If an objective analysis of the components of the overall ‘discovery curve’ is undertaken the
start of a new Lower Cretaceous ‘discovery sub-curve’ can be seen and which was not pursued.
This is a classic case of exploration effort being concentrated on established plays, particularly the
Jurassic as it represents a perceived reduced risk, which thus suppressed / delayed the innovation of
a riskier new play despite the stimulus of the presence of large discoveries.
It is innovation and free-thinking that results in the generation of new leads and prospects defined
by new play models in a basin. The basin after all has a reduced risk because it has become a proven
hydrocarbon province with an established infrastructure. The innovation of sequence stratigraphy
has helped in the reduction of geological risk. Such sequence stratigraphy modelling has allowed,
for example, an in-depth understanding of the stratigraphical development of the Middle Jurassic
and the distribution of the Brent Sands. These highstand systems tract sands form prolific reservoirs
but the traps are structural. However, where are the coeval lowstand system tract sands which would
have been deposited in the basin lows? Are they in the northern parts of the North Sea and Atlantic
margin in the marine depositional area off the Brent delta front? The Upper Jurassic highstand sands
are the Fulmar Formation and the Piper sands of the Central North Sea graben margin areas while
the coeval lowstand sand fans, the Brae Formation, are found in the grabens.
3. 3
Such a sequence stratigraphy classification of play types can be applied to the Lower
Cretaceous discovery data set for the whole of the North Sea and north west Europe and can
be superimposed upon the overall structural trap to subtle trap exploration concept.
The Lower to Middle Cretaceous has been a proven hydrocarbon bearing interval in the North Sea
since the discovery of oil/gas in sandstones in the Moray Firth (1975), offshore the Netherlands
(1978 - Helm Field) and onshore the Netherlands (1938 - De Mient-1 well) and in carbonates
offshore Denmark. In the Saxony basin of the eastern Netherlands and Germany, the Lower
Cretaceous has been exploited for hydrocarbons since the end of the 19th century and is host to the
Schoonebeek Field (in the Dutch section of the Saxony Basin) a giant accumulation of oil (STOIIP
1 billion barrels). Lower to Middle Cretaceous oil and gas accumulations have been discovered in
areas such as, for example, the West of Shetland (Victory Field), the Celtic Sea Basin (Kinsale Head
and Ballycotton gas fields), the Central North Sea of the UK sector (eg. Britannia, Captain,
Goldeneye, Hannay and Scapa fields), the Northern North Sea of the Norwegian sector (Agat Field)
and the Danish sector (Valdemar and Adda fields).
If these discoveries are analysed in detail it is apparent that a number of categories of discovery,
within an overall sequence stratigraphy model, can be recognised which can then be plotted as an
associated set of ‘discovery sub-curves’. These are related both to stratigraphical age within the
Cretaceous and genesis (highstand systems tracts, transgressive systems tracts and lowstand systems
tracts) and can be regionally stratigraphically mapped to generate prospectivity / lead / play models
(see Crittenden, 1982, 1987, 1995 and Crittenden et al., 1991, 1997, 1998).
The Agat Field is a prime example of a deepwater, clastic reservoir - lowstand systems tract - of
Late Aptian-Albian age (Gulbrandsen, 1987; Crittenden et al., 1997, 1998) in the Norwegian sector.
Canyons, initiated in the Jurassic, have provided in the Lower Cretaceous a transportation pathway
feeder system for the reservoir sands which have controlled for example the location of the
Aptian/Albian and Cenomanian Agat Formation sands accumulation (slope-fan channels with up-
dip pinch-out or detached basin-floor fans).
The Lower to Middle Cretaceous stratigraphy of the Agat area is remarkably similar to the UK
sector of the North Sea both in terms of lithologies, log shapes and biostratigraphy. For example, the
same regional Mid/Late Aptian regression is associated with the development of lowstand sytems
tracts in the North Sea region, particularly the Moray Firth ‘Bosun/Kopervik Sands’ fairway (eg.
Captain, Britannia, Hannay and Goldeneye fields) and the West of Shetland exploration area. The
discoveries in the Moray Firth area and the Agat discovery thus provide very useful exploration
analogues for comparison and contrast and for risking purposes for Lower to Middle Cretaceous
exploration in the Norwegian sector of the North Sea.
In conclusion such sequence stratigraphy modelling of the Agat Field and the Lower to Middle
Cretaceous fields in the Moray Firth, West of Shetland exploration area and the fields in other areas
of north west Europe allows similar geological play models to be applied in exploration strategies.
For example, similar structural lineaments / canyon relationships seen in the Agat area can be
sought elsewhere offshore Norway, both North Sea and Norwegian Sea, and west of Britain and
which may be associated with regional Mid-Aptian regression sand development.
The deeper undrilled parts of the North Sea, such as the Viking Graben, the Moere Basin and deeper
parts of the basins of the north east Atlantic frontier margin, particularly offshore Mid Norway are
considered in the light of a sequence stratigraphy model to be favourable sites for Lower to Middle
Cretaceous sand development (as well as in the Late Cretaceous, see Crittenden et al., 1998) and
thus may host ‘sleeping giants’.
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