TECTONIC SETTING, STRATIGRAPHY AND HYDROCARBON POTENTIAL OF THE BEDOUT SUB-BASIN, NORTH WEST SHELF

1993 ◽  
Vol 33 (1) ◽  
pp. 138
Author(s):  
Paul Lipski
Keyword(s):  
Late Jurassic ◽  
Oil And Gas ◽  
Tectonic Setting ◽  
Tectonic Activity ◽  
Hydrocarbon Generation ◽  
Considerable Potential ◽  
North West ◽  
Canning Basin ◽  
Carbonate Deposition ◽  
Migration Pathways

The tectonic and depositional histories of the Bedout Sub-basin are closely related to more widely explored areas of the southern North West Shelf, i.e. the Barrow and Dampier Sub-basins. The Mesozoic Bedout Sub-basin onlaps and overlies the Palaeozoic offshore Canning Basin sequence. Four distinct tectonic regimes characterised the Triassic, Early to Late Jurassic, Late Jurassic to Late Cretaceous, and Tertiary to present:During the Triassic, the Bedout Sub-basin was part of a broad intracratonic downwarp that also encompassed the Barrow, Dampier and Beagle Sub-basins. A thick sequence of Locker Shale and Upper and Lower Keraudren Formations (Mungaroo Formation equivalent) was deposited.During the Jurassic rifting phase, the Bedout Sub-basin was a subsiding rim basin, landward of the uplifted rift margin. Sedimentation was dominated by a thick sequence of fluviodeltaic to marginal marine deposits.In the post-break-up phase from the Callovian to latest Cretaceous, a transgressive regime resulted in deep open marine conditions with widespread claystone and minor carbonate deposition over the southern North West Shelf.Through the Tertiary to the present, shallow shelf conditions prevailed and sedimentation was dominated by a thick prograding carbonate wedge.Hydrocarbon source is provided by a thick sequence of Triassic Locker Shale and Lower Keraudren Formation. The Locker Shale is presently mature for hydrocarbon generation over most of the Bedout Sub-basin and has the potential to generate both oil and gas. The Lower Keraudren Formation is a mature source mainly for gas/condensate in deeper sections of the sub-basin. Jurassic marine claystones, which represent a prolific source in the Barrow and Dampier Sub-basins, are not present in the Bedout Sub-basin.Reservoir rocks exist in the Triassic and Jurassic sections. However, gentle Jurassic rim basin tectonic activity has resulted in minor faulting compared to the adjacent rift. This has limited migration pathways from Triassic source to Jurassic reservoirs. The primary reservoir objectives are sandstones of the Triassic Upper and Lower Keraudren Formations.Although large structural traps are uncommon, there is considerable potential to host large hydrocarbon accumulations in stratigraphic traps. A giant prospect involving the onlap of the Triassic sequence has been identified in the eastern Bedout Sub-basin. Pursuit of this play should accelerate exploration in this sparsely drilled area.

scholarly journals Structure and Composition of Basement and Sedimentary Cover in the Southwestern Part of the Siljan Ring, Central Sweden: New Data from the C-C-1 Drill Core

2021 ◽  
Author(s):  
Olga Sivalneva ◽  
Alexandr Postnikov ◽  
Vladimir Kutcherov ◽  
Marianna Tuchkova ◽  
Alexandr Buzilov ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Sedimentary Cover ◽  
Tectonic Setting ◽  
Sedimentary Rocks ◽  
Black Shales ◽  
Tectonic Activity ◽  
Drill Core ◽  
Rock Fracturing ◽  
Southwestern Part ◽  
Basement Rocks

Results of geological and geophysical investigations of the Siljan Ring impact structure (central Sweden) revealed complicated relationships between Paleozoic sedimentary succession and the Precambrian basement. Tectonic and depositional evolution caused complex geology. Studies of a new drill core from the C-C-1 well provide information necessary for the reconstruction of the geological setting in the southwestern part of Siljan Ring. The whole interval of the core section is from 32.60 to 634.90 m with almost no breaks. The sedimentary cover is 373.55 m thick in total. The sedimentary sequences are predominantly composed of wackestones, mudstones, and shales. In the lower part of the sedimentary section, limestone layers intercalate with black shales. In a result of the investigations, it has been suggested that sedimentary layers represent Late Ordovician and Silurian deposits and have disturbed stratigraphic relations. The basement section is composed of Precambrian meta-volcanic and meta-sedimentary rocks. The contact between the basement and the sedimentary cover is tectonic, not normal sedimentary, in origin. Tectonic processes caused intensive rock fracturing. Four generations of fractures were identified with analysis of fracture relations and mineralization sequence. Only two of them occur in sedimentary rocks that probably belong to the latest stages of tectonic activity. Highly fractured basement rocks in some cases contain open vugs developed along the fractures. Rock matrix is tight either in sedimentary and basement rocks and only micro-porosity space is recognized in cataclastic zones. Single evidence of bituminous filling of micro-porosity zone and partly cemented vug is established in limestone from the lower part of the sedimentary section. These findings are particularly valuable for stratigraphy refinement and tectonic setting reconstructions as well as oil and gas reservoir forecasts.

The petroleum prospectivity of the Oobagooma Sub-basin and adjacent Leveque Platform, North West Shelf, Australia

2016 ◽  
Vol 56 (2) ◽  
pp. 563
Author(s):  
Paul Harrison ◽  
Chris Swarbrick ◽  
Jim Winterhalder ◽  
Mark Ballesteros
Keyword(s):  
Oil And Gas ◽  
Long Distance ◽  
The West ◽  
North West ◽  
Canning Basin ◽  
The Past ◽  
The North ◽  
Late Tertiary ◽  
Exploration Drilling ◽  
Hydrocarbon Charge

The Oobagooma Sub-basin of the Roebuck Basin includes the offshore extension of the onshore Fitzroy Trough of the Canning Basin. Together with the Leveque Platform, it covers an area of approximately 50,000 km2, yet only 14 exploration wells have been drilled in the area to date, five of which were drilled in the past 30 years. The sub-basin contains sediments ranging in age from Ordovician to Recent. This study examines the petroleum prospectivity of a region that is one of the least explored on Australia’s North West Shelf. Recent exploration drilling has revived interest in the area, with the 2014 Phoenix South–1 oil discovery in the offshore Bedout Sub-basin and the 2015 Ungani Far West–1 oil discovery in the onshore Fitzroy Trough. The two most significant source rock sequences relevant to the Oobagooma Sub-basin are the Carboniferous Laurel Formation and the Jurassic section. The former interval is part of a proven petroleum system onshore and is the source of the gas discovered at Yulleroo and oil at Ungani and Ungani Far West. A thick Jurassic trough to the north of the Oobagooma Sub-basin is believed to be the source of the oil and gas in Arquebus–1A and gas in Psepotus–1. Hydrocarbon charge modelling indicates significant expulsion occurred during both the Cretaceous and Tertiary from both source intervals. Trap timing is generally favourable given that inversion structures formed in several episodes during the Late Jurassic to Late Tertiary. The Early Triassic, now proven to be oil prone in the Phoenix South area (Molyneux et al, 2015), provides an additional (albeit less likely) source for the Oobagooma Sub-basin. These rocks are thin to absent within the Oobagooma Sub-basin, so long-distance migration would be required from deep troughs to the west.

THE EROMANGA BASIN

1989 ◽  
Vol 29 (1) ◽  
pp. 379
Author(s):  
H.R.B. Wecker
Keyword(s):  
Middle Triassic ◽  
Significant Proportion ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Structural Deformation ◽  
Tectonic Activity ◽  
Hydrocarbon Generation ◽  
Basin Region ◽  
Migration Pathways ◽  
Eromanga Basin

The Eromanga Basin, encompassing an area of approximately 1 million km2 in Central Australia, is a broad intracratonic downwarp containing up to 3000 m of Middle Triassic to Late Cretaceous sediments.Syndepositional tectonic activity within the basin was minimal and the main depocentres largely coincide with those of the preceding Permo- Triassic basins. Several Tertiary structuring phases, particularly in the Early Tertiary, have resulted in uplift and erosion of the Eromanga Basin section along its eastern margin, and the development of broad, northwesterly- to northeasterly- trending anticlines within the basin. In some instances, high angle faults are associated with these features. This structural deformation occurred in an extensional regime and was strongly influenced by the underlying Palaeozoic structural grain.The Eromanga Basin section is composed of a basal, dominantly non- marine, fluvial and lacustrine sequence overlain by shallow marine deposits which are in turn overlain by another fluvial, lacustrine and coal- swamp sequence. The basal sequence is the principal zone of interest to petroleum exploration. It contains the main reservoirs and potential source rocks and hosts all commercial hydrocarbon accumulations found to date. While the bulk of discovered reserves are in structural traps, a significant stratigraphic influence has been noted in a number of commercially significant hydrocarbon accumulations.All major discoveries have been in the central Eromanga Basin region overlying and adjacent to the hydrocarbon- productive, Permo- Triassic Cooper Basin. The mature Permian section is believed to have contributed a significant proportion of the Eromanga- reservoired hydrocarbons. Accordingly, structural timing and migration pathways within the Permian and Middle Triassic- Jurassic sections are important factors for exploration in the central Eromanga Basin region. Elsewhere, in less thermally- mature areas, hydrocarbon generation post- dates Tertiary structuring and thus exploration success will relate primarily to source- rock quality, maturity and drainage factors.Although exploration in the basin has proceeded spasmodically for over 50 years, it has only been in the last decade that significant exploration activity has occurred. Over this recent period, some 450 exploration wells and 140 000 km of seismic acquisition have been completed in the pursuit of Eromanga Basin oil accumulations. This has resulted in the discovery of 227 oil and gas pools totalling an original in- place proved and probable (OOIP) resource of 360 MMSTB oil and 140 BCF gas.Though pool sizes are generally small, up to 5 MMSTB OOIP, the attractiveness of Eromanga exploration lies in the propensity for stacked pools at relatively shallow depths, moderate to high reservoir productivity, and established infrastructure with pipelines to coastal centres. Coupled with improved exploration techniques and increasing knowledge of the basinal geology, these attributes will undoubtedly ensure the Eromanga Basin continues to be a prime onshore area for future petroleum exploration in Australia.

Comprehensive basin-wide 3D petroleum systems modelling providing new insights into proven petroleum systems and remaining prospectivity in the Exmouth Sub-basin, Australia

2020 ◽  
Vol 60 (2) ◽  
pp. 753
Author(s):  
Oliver Schenk ◽  
Craig Dempsey ◽  
Robbie Benson ◽  
Michael Cheng ◽  
Sugandha Tewari ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Oil And Gas ◽  
Hydrocarbon Exploration ◽  
Source Rocks ◽  
Long Distance ◽  
North West ◽  
Petroleum Systems ◽  
Northern Carnarvon Basin ◽  
Hydrocarbon Expulsion

The Exmouth Sub-basin is part of the Northern Carnarvon Basin, offshore north-west Australia, and has undergone a complex tectonic history. Hydrocarbon exploration resulted in the discovery of a variety of oil and gas accumulations; however, their distribution and charge history from different petroleum systems is still poorly understood due to limited knowledge of the deeper basin architecture. The basin-wide, long-offset, broadband 2017 Exmouth 3D multiclient seismic dataset allowed a seamless interpretation into this deeper section. This work revealed new insights on the tectono-stratigraphic evolution of the Exmouth Sub-basin. Mesozoic extension, that was restricted to the latest Triassic, was followed by a sag phase with homogeneous, shale-dominated deposition, resulting in source rock potential for the entire Jurassic section. These findings, together with potential field modelling, were integrated into this first basin-wide 3D petroleum system model to better constrain the thermal history and petroleum systems. The model improved our understanding of the complex charge history of hydrocarbon fields. It predicts that hydrocarbon expulsion from Late Jurassic source rocks continued into the Late Cretaceous, a period when the regional Early Cretaceous Muderong Formation was an efficient seal rock. This implies that, in addition to long-distance, sub-Muderong migration, vertical, short-distance migration may have contributed significant petroleum charge to the discovered accumulations in the southern Exmouth Sub-basin. The model also predicts additional prospective areas: fault-seal structures within Early Cretaceous intervals north of the Novara Arch, intra-formational Late Jurassic sandstones north of the current fields (with low biodegradation risk) and Triassic reservoirs along the basin margins and north of the Jurassic depocentre.

scholarly journals Subsurface structure of the Netherlands - results of recent onshore and offshore mapping

2006 ◽  
Vol 85 (4) ◽  
pp. 245-276 ◽  
Author(s):  
E.J.T. Duin ◽  
J.C. Doornenbal ◽  
R.H.B. Rijkers ◽  
J.W. Verbeek ◽  
Th.E. Wong
Keyword(s):  
The Netherlands ◽  
Cross Sections ◽  
Late Jurassic ◽  
Tectonic Setting ◽  
Tectonic Activity ◽  
Late Permian ◽  
Structural Elements ◽  
Depth Maps ◽  
Tectonically Active ◽  
Roer Valley Graben

AbstractThis paper presents depth maps for eight key horizons and seven thickness maps covering the onshore and offshore areas for the Late Permian to recent sedimentary section of the Netherlands. These maps, prepared in the context of a TNO regional mapping project, are supported by nine regional structural cross sections and a table summarizing the timing of tectonic activity from Carboniferous to recent. These new regional maps enable the delineation of various structural elements but also reveal the development of these elements through time with improved detail. Since the latest Carboniferous the tectonic setting of the Netherlands changed repeatedly. During successive tectonic phases several pre-existing structural elements were reactivated and new elements appeared. The various identified regional structural elements are grouped into six tectonically active periods: Late Carboniferous, Permian, Triassic, Late Jurassic, Late Cretaceous and Cenozoic. This study demonstrates that many structural elements and fault systems were repeatedly reactivated and that a clear distinction exists between long-lived elements, such as the Roer Valley Graben, and short-lived structural elements, such as the Terschelling Basin.

Geothermal condition and outlook for oil and gas deposits in the north-west Black Sea shelf

2002 ◽  
Vol 8 (2-3) ◽  
pp. 206-208
Author(s):  
V.G. Osadchyi ◽  
◽  
O.A. Prykhod'ko ◽  
I.I. Hrytsyk ◽  
◽  
...  
Keyword(s):  
Black Sea ◽  
Oil And Gas ◽  
North West ◽  
The North ◽  
West Black Sea

Depositional Environment Drive as Overpressure Generation: Study Case in “Gap” Field, North West Java Basin

2020 ◽  
Author(s):  
A., C. Prasetyo
Keyword(s):  
Clay Mineral ◽  
Depositional Environment ◽  
Mineral Content ◽  
Hydrocarbon Generation ◽  
Well Test ◽  
Burial History ◽  
The South ◽  
North West ◽  
The North ◽  
Geological Processes

Overpressure existence represents a geological hazard; therefore, an accurate pore pressure prediction is critical for well planning and drilling procedures, etc. Overpressure is a geological phenomenon usually generated by two mechanisms, loading (disequilibrium compaction) and unloading mechanisms (diagenesis and hydrocarbon generation) and they are all geological processes. This research was conducted based on analytical and descriptive methods integrated with well data including wireline log, laboratory test and well test data. This research was conducted based on quantitative estimate of pore pressures using the Eaton Method. The stages are determining shale intervals with GR logs, calculating vertical stress/overburden stress values, determining normal compaction trends, making cross plots of sonic logs against density logs, calculating geothermal gradients, analyzing hydrocarbon maturity, and calculating sedimentation rates with burial history. The research conducted an analysis method on the distribution of clay mineral composition to determine depositional environment and its relationship to overpressure. The wells include GAP-01, GAP-02, GAP-03, and GAP-04 which has an overpressure zone range at depth 8501-10988 ft. The pressure value within the 4 wells has a range between 4358-7451 Psi. Overpressure mechanism in the GAP field is caused by non-loading mechanism (clay mineral diagenesis and hydrocarbon maturation). Overpressure distribution is controlled by its stratigraphy. Therefore, it is possible overpressure is spread quite broadly, especially in the low morphology of the “GAP” Field. This relates to the delta depositional environment with thick shale. Based on clay minerals distribution, the northern part (GAP 02 & 03) has more clay mineral content compared to the south and this can be interpreted increasingly towards sea (low energy regime) and facies turned into pro-delta. Overpressure might be found shallower in the north than the south due to higher clay mineral content present to the north.

Stratigraphy, structure and geochemistry of Archaean supracrustal rocks from Oqaatsut and Naajaat Qaqqaat, north-east Disko Bugt, West Greenland

1999 ◽  
pp. 65-78
Author(s):  
Henrik Rasmussen ◽  
Lars Frimodt Pedersen
Keyword(s):  
Tectonic Setting ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
West Greenland ◽  
North West ◽  
North East ◽  
Metavolcanic Rocks ◽  
Arc Setting ◽  
Area North ◽  
Back Arc

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Rasmussen, H., & Frimodt Pedersen, L. (1999). Stratigraphy, structure and geochemistry of Archaean supracrustal rocks from Oqaatsut and Naajaat Qaqqaat, north-east Disko Bugt, West Greenland. Geology of Greenland Survey Bulletin, 181, 65-78. https://doi.org/10.34194/ggub.v181.5114 _______________ Two Archaean supracrustal sequences in the area north-east of Disko Bugt, c. 1950 and c. 800 m in thickness, are dominated by pelitic and semipelitic mica schists, interlayered with basic metavolcanic rocks. A polymict conglomerate occurs locally at the base of one of the sequences. One of the supracrustal sequences has undergone four phases of deformation; the other three phases. In both sequences an early phase, now represented by isoclinal folds, was followed by north-west-directed thrusting. A penetrative deformation represented by upright to steeply inclined folds is only recognised in one of the sequences. Steep, brittle N–S and NW–SE striking faults transect all rock units including late stage dolerites and lamprophyres. Investigation of major- and trace-element geochemistry based on discrimination diagrams for tectonic setting suggests that both metasediments and metavolcanic rocks were deposited in an environment similar to a modern back-arc setting.

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