APPLICATION OF THE DETACHMENT MODEL FOR CONTINENTAL EXTENSION TO HYDROCARBON EXPLORATION IN EXTENSIONAL BASINS

1988 ◽  
Vol 28 (1) ◽  
pp. 167 ◽  
Author(s):  
M.A. Etheridge ◽  
P.A. Symonds ◽  
T.G. Powell

The extension of the continental lithosphere that gives rise to continental rifts and eventually to passive continental margins and their basins is considered generally to involve shear on one or more major, shallow dipping normal faults (detachments). The operation of these detachments induces a basic asymmetry into the extensional terrane that is analogous to that in thrust terranes. As a result, the two sides of a continental rift and conjugate passive margin segments are predicted to have contrasting structure, facies development, subsidence history and thermal evolution.The major structural consequence of the detachment model is that half-graben rather than full graben geometry is expected in rift basins, consistent with recent interpretations in a wide range of continental rifts and passive margins. Half-graben geometry dominates in the Bass Strait basins, the Canning Basin and in a number of Proterozoic rifts, and has been observed on most parts of the Australian continental margin. Variations in the along-strike geometry of extensional basins are accommodated by transfer faults or fault zones. Transfer faults are as important and widespread in rifts as the classical normal faults, and they have important consequences for hydrocarbon exploration (e.g. design of seismic surveys, structural interpretation of seismic data, play and leav development).The fundam* nal asymmetry of extensional basins, and their compartmentalisation by transfer faults also control to a large extent the distribution of both source and reservoir facies. A model for facies distribution in a typical rift basin is presented, together with its implications for the prime locations of juxtaposed sources and reservoirs. Maturation of synrift source rocks depends on both the regional heat flow history and the amount of post-rift subsidence (and therefore burial). Both of these factors are influenced, and are partly predictable by the detachment model. In particular, there may be substantial horizontal offset of both the maximum thermal anomaly and the locus of post-rift subsidence from the rift basin. Analysis of deep crustal geophysical data may aid in the interpretation of detachment geometry and, therefore, of the gross distribution of thermal and subsidence histories.

1989 ◽  
Vol 29 (2) ◽  
pp. 99
Author(s):  
M. A. Etheridge ◽  
P. A. Symonds ◽  
T. G. Powell

The extension of the continental lithosphere that gives rise to continental rifts and eventually to passive continental margins and their basins is considered generally to involve shear on one or more major, shallow dipping normal faults (detachments). The operation of these detachments induces a basic asymmetry into the extensional terrane that is analogous to that in thrust terranes. As a result, the two sides of a continental rift and conjugate passive margin segments are predicted to have contrasting structure, facies development, subsidence history and thermal evolution.The major structural consequence of the detachment model is that half- graben rather than full graben geometry is expected in rift basins, consistent with recent interpretations in a wide range of continental rifts and passive margins. Half- graben geometry dominates in the Bass Strait basins, the Canning Basin and in a number of Proterozoic rifts, and has been observed on most parts of the Australian continental margin. Variations in the along- strike geometry of extensional basins are accommodated by transfer faults or fault zones. Transfer faults are as important and widespread in rifts as the classical normal faults, and they have important consequences for hydrocarbon exploration (e.g. design of seismic surveys, structural interpretation of seismic data, play and lead development).The fundamental asymmetry of extensional basins, and their compartmentalisation by transfer faults also control to a large extent the distribution of both source and reservoir facies. A model for facies distribution in a typical rift basin is presented, together with its implications for the prime locations of juxtaposed sources and reservoirs. Maturation of syn- rift source rocks depends on both the regional heat flow history and the amount of post- rift subsidence (and therefore burial). Both of these factors are influenced, and are partly predictable by the detachment model. In particular, there may be substantial horizontal offset of both the maximum thermal anomaly and the locus of post- rift subsidence from the rift basin. Analysis of deep crustal geophysical data may aid in the interpretation of detachment geometry and, therefore, of the gross distribution of thermal and subsidence histories.


1988 ◽  
Vol 28 (1) ◽  
pp. 76 ◽  
Author(s):  
B.J. Drummond ◽  
M.A. Etheridge ◽  
P.J. Davies ◽  
M.F. Middleton

The Fitzroy Trough is a north-west/south-east trending rift along the north-east margin of the Canning Basin. The major crustal extension in the trough occurred in the Middle Devonian to Early Carboniferous. Most idealised cross-sections show down-to-trough normal faults bounding both sides of the trough. In contrast, we show the trough to have a half- graben style, with one side a hinge zone or flexure, and the other side bounded by normal faults. Thus, the basin has marked structural asymmetry. The sense of asymmetry switches several times along strike with the hinged margin on the north-eastern margin in some places and the south-west margin in others. The switching in asymmetry occurs at transfer faults. This structural style is expected in extensional tectonic models where the extension occurs on a detachment surface and is typical of many continental and passive margin rifts. The asymmetry of the Palaeozoic structure has implications for resource exploration because of its influence on facies development in and subsequent structural evolution of the trough. Quite different syn-rift clastic and carbonate facies are expected on faulted and hinged margins of a half-graben. Post-rift subsidence will also be somewhat asymmetric, influencing the carbonate reef geometry in particular. Mesozoic deformation in the basin reactivated many of the Palaeozoic normal and transfer faults, and induced reverse slip up basement surfaces on the hinged margin segments.


2021 ◽  
Author(s):  
Wajdi Belkhiria ◽  
Haifa Boussiga ◽  
Imen Hamdi Nasr ◽  
Adnen Amiri ◽  
Mohamed Hédi Inoubli

<p>The Sahel basin in eastern Tunisia has been subject for hydrocarbon exploration since the early fifties. Despite the presence of a working petroleum system in the area, most of the drilled wells were dry or encountered oil shows that failed to give commercial flow rates. A better understanding of the tectono-sedimentary evolution of the Sahel basin is of great importance for future hydrocarbon prospectivity. In this contribution, we present integration of 2D seismic reflection profiles, exploration wells and new acquired gravity data. These subsurface data reveal that the Sahel basin developed as a passive margin during Jurassic-Early Cretaceous times and was later inverted during the Cenozoic Alpine orogeny. The occurrence of Triassic age evaporites and shales deposited during the Pangea breakup played a fundamental role in the structural style and tectono-sedimentary evolution of the study area. Seismic and gravity data revealed jointly important deep-seated extensional faults, almost along E-W and few along NNE–SSW and NW-SE directions, delimiting horsts and grabens structures. These syn-rift extensional faults controlled deposition, facies distribution and thicknesses of the Jurassic and Early cretaceous series. Most of these inherited deep-seated normal and transform faults are ornamented by different types of salt-related structures. The first phase of salt rising was initiated mainly along these syn-extensional faults in the Late Jurassic forming salt domes and continued into the Early and Late Cretaceous leading to salt-related diapir structures. During this period, the salt diapirism was accompanied by the development of salt withdrawal minibasins, characterized important growth strata due the differential subsidence. These areas represent important immediate kitchen areas to the salt-related structures. The later Late Cretaceous - Cenozoic shortening phases induced preferential rejuvenation of the diapiric structures and led to the inversion of former graben/half-graben structures and ultimately to vertical salt welds along salt ridges. These salt structures represent key elements that remains largely undrilled in the Sahel basin. Our results improve the understanding of salt growth in eastern Tunisia and consequently greatly impact the hydrocarbon prospectivity in the area.</p>


2009 ◽  
Vol 49 (2) ◽  
pp. 600
Author(s):  
Brad Field ◽  
Jan Baur ◽  
Kyle Bland ◽  
Greg Browne ◽  
Angela Griffin ◽  
...  

Hydrocarbon exploration on the East Coast of the North Island has not yet yielded significant commercial reserves, even though the elements of a working petroleum system are all present (Field et al, 1997). Exploration has focussed on the shallow, Neogene part of the succession, built up during plate margin convergence over the last ∼24 million years. Convergent margins are generally characterised by low-total organic carbon (TOC) source rocks and poor clastic reservoir quality due to poor sorting and labile grains. However, the obliquely-convergent Hikurangi subduction margin of the East Coast has high TOC source rocks that pre-date the subduction phase, and its reservoir potential, though variable, has several aspects in its favour, namely: deep-water rocks of high porosity and permeability; preservation of pore space by overpressure; the presence of fractured reservoirs and hybrid reservoirs, where low clastic permeability is enhanced by fractures. The East Coast North Island is a Neogene oblique subduction margin, with Neogene shelf and slope basins that developed on Late Cretaceous-Paleogene passive margin marine successions. The main hydrocarbon source rocks are Late Cretaceous and Paleocene and the main reservoir potential is in the Neogene (Field et al, 2005). Miocene mudstones with good seal potential are common, as is significant over-pressuring. Neogene deformation controlled basin development and accommodation space and strongly-influenced lateral facies development and fractured reservoirs. Early to Middle Miocene thrusting was followed by later Neogene extension (e.g. Barnes et al 2002), with a return to thrusting in the Pliocene. Local wells have flow-tested gas shows.


1985 ◽  
Vol 25 (1) ◽  
pp. 362 ◽  
Author(s):  
P.E. Williamson ◽  
C.J. Pigram ◽  
J.B. Colwell ◽  
A.S. Scherl ◽  
K.L. Lockwood ◽  
...  

Exploration in the Bass Basin has mainly concentrated on the Eocene part of the Eastern View Coal Measures with the pre-Eocene stratigraphy hardly being tested. Structural mapping using a good quality Bureau of Mineral Resources regional seismic survey and infill industry seismic data, in conjunction with seismic stratigraphy and well data, has generated an understanding of the structure and stratigraphy of the pre- Eocene basin, which suggests that exploration potential exists in structural and stratigraphic leads of both Paleocene and Cretaceous age.The Paleocene structure is influenced by the reactivation of normal faults developed at the time of the mid Cretaceous rift unconformity and reflects drape over deeper features. Consequently fault dependent structural closures often persist from Paleocene to (?)Jurassic levels. Possible stratigraphic traps are also observed against horst blocks and around the basin margins. The longitudinal fault directions are northwest and west northwest with an oblique northerly direction and a prevailing north northeasterly transverse direction.The Paieocene and Upper Cretaceous part of the Eastern View Coal Measures consists of sands, shales and coals deposited in alluvial fans, on flood plains, and in lakes. These are underlain by Early Cretaceous Otway Groups, sands, shales and volcanics. Both intervals have potential reservoir and source rocks and often occur at mature depths. No pre-Otway Group sediments have been encountered in wells in the Bass Basin. However, the Permo- Carboniferous and possibly Triassic strata that occur in Northern Tasmania exhibit reservoir and source rock potential and may extend offshore beneath the Bass Basin.Pre-Eocene structural and stratigraphic studies of the Bass Basin thus point to reservoir and hydrocarbon source potential for possible multiple hydrocarbon exploration targets.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Priatin Hadi Wijaya ◽  
Deny Setiady ◽  
Jusfarida Jusfarida ◽  
R. Wibowo

ABSTRAKPerairan Wokam Aru Utara, Papua Barat merupakan bagian tepi utara passive margin Mesozoik Arafura – Australia. Hasil survei dengan KR. Geomarin III di perairan Wokam 2014 diperoleh lintasan seismik Multi Kanal 1.182 km, dan pemeruman batimetri/sub bottom profiles (SBP) 1.510 km. Metode dilakukan interpretasi penampang seismik hasil survei, pengikatan sumur pemboran dan seismik, analisis petrofisika dan pemetaaan geologi bawah permukaan. Pada penampang seismik telah dilakukan interpretasi aspek struktur geologi dan perlapisan sedimen yang sebelumnya telah diikat dengan data sumur ASA-1X, ASM-1X dan ASB-1X untuk tiga horizon yaitu Top Neogen, Top Paleogen dan Base PaleogenPeta bawah permukaan Paleogen – Neogen menunjukan beberapa klosur yang berpotensi di bagian batas paparan dengan palung Aru serta bagian barat. Pada bagian Tenggara terdapat kenampakan onlapping sedimentasi Tipe struktural yang berkembang sebagai perangkap secara dominan berupa graben – half graben dan tilted faul. Onlaping sedimentasi yang mebaji juga dapat berpotensi.Struktur geologi pada area penelitian secara umum dikontrol oleh sesar utama Zona Sesar Palung Aru Utara di tepian paparan sampai lereng, mengarah utara - timur laut ke selatan - barat daya. Struktur ikutan yaitu sesar-sesar normal mengarah utara - timur laut ke selatan - barat daya di paparan sebelah timur zonar sesar utama.Studi awal potensi migas ini teridentifikasi empat lokasi potensi perangkap hidrokarbon dari umur Paleogen - Neogen, yaitu satu lokasi dari Peta Base Paleogen, dua lokasi Top Paleogen dan satu lokasi Top Neogen. kata kunci: Wokam, Aru, migas, seismik, struktur, interpretasi, jebakan, Geomarin III ABSTRACTThe waters of Wokam North Aru, West Papua are part of the northern edge of the Mesozoic passive margin of Arafura - Australia. Survey results with KR. Geomarin III in the waters of Wokam 2014 obtained a multi-channel seismic trajectory of 1,182 km, and bathymarism/sub bottom profiles (SBP) 1,510 km. The method is to interpret the seismic cross-section of the survey results, tie drilling and seismic wells, petrophysical analysis and mapping the subsurface geology. In the seismic section, an interpretation of the structural aspects of the geology and sediment layers has been carried out previously tied to data from the ASA-1X, ASM-1X and ASB-1X wells for three horizons, namely Top Neogen, Top Paleogene and Base Paleogene.The subsurface map of the Paleogene - Neogeneous surface shows several potential closures in the exposure boundary with the Aru Trench as well as the western part. In the Southeast, there is the appearance of sedimentation onlapping. Structural types that develop as traps are predominantly graben - half graben and tilted fault. The onlaping sedimentation also has potential. The geological structure in the study area is generally controlled by the main fault of the North Aru Trench Zone on the edge of the exposure to the slope, heading north - northeast to south - southwest. Follow-up structures are normal faults pointing north - northeast to south - southwest on the eastern exposure of the main fault zone.This preliminary study of oil and gas potential identified four potential locations for hydrocarbon traps from the Paleogene - Neogene age, namely one location from the Paleogene Base Map, two Top Paleogene locations and one Top Neogen location.Keyword: Wokam, Aru, oil and gas, seismic, structure, interpretation, traps, Geomarin III


2010 ◽  
Vol 50 (1) ◽  
pp. 47 ◽  
Author(s):  
Irina Borissova ◽  
Barry Bradshaw ◽  
Chris Nicholson ◽  
Heike Struckmeyer ◽  
Danielle Payne

Acreage release by the Australian Government in 2010 offers exploration opportunities in the frontier Mentelle Basin for the first time. The Mentelle Basin is a large deep-water basin on the southwest Australian margin. It consists of a large, very deep water (2,000—4,000 m) depocentre in the west and several depocentres in the east, in water depths of 500–2,000 m. The major depocentres are estimated to contain 7–11 km of sediments. Initial rifting in the Mentelle Basin occurred in the Early Permian, followed by thermal subsidence during the Triassic to Early Jurassic. In the Middle Jurassic renewed extension led to the accumulation of very thick sedimentary successions in half-graben depocentres. Early Cretaceous continental breakup was accompanied by extensive volcanism resulting in a thick syn-breakup volcanic succession in the western Mentelle Basin. Assessment of the petroleum prospectivity of the Mentelle Basin is based on correlations with the adjacent Vlaming Sub-basin. These correlations suggest that the Mentelle Basin depocentres are likely to contain multiple source rock intervals associated with coals and carbonaceous shales, as well as regionally extensive reservoirs and seals within fluvial, lacustrine and marine strata. Petroleum systems modelling suggests that potential source rocks are thermally mature and commenced generation in the Early Cretaceous. The Mentelle Basin offers a wide range of play types, including faulted anticlines and fault blocks, sub-basalt anticlines and fault blocks, drape and forced fold plays, and a large range of stratigraphic and unconformity plays.


Author(s):  
S., R. Muthasyabiha

Geochemical analysis is necessary to enable the optimization of hydrocarbon exploration. In this research, it is used to determine the oil characteristics and the type of source rock candidates that produces hydrocarbon in the “KITKAT” Field and also to understand the quality, quantity and maturity of proven source rocks. The evaluation of source rock was obtained from Rock-Eval Pyrolysis (REP) to determine the hydrocarbon type and analysis of the value of Total Organic Carbon (TOC) was performed to know the quantity of its organic content. Analysis of Tmax value and Vitrinite Reflectance (Ro) was also performed to know the maturity level of the source rock samples. Then the oil characteristics such as the depositional environment of source rock candidate and where the oil sample develops were obtained from pattern matching and fingerprinting analysis of Biomarker data GC/GCMS. Moreover, these data are used to know the correlation of oil to source rock. The result of source rock evaluation shows that the Talangakar Formation (TAF) has all these parameters as a source rock. Organic material from Upper Talangakar Formation (UTAF) comes from kerogen type II/III that is capable of producing oil and gas (Espitalie, 1985) and Lower Talangakar Formation (LTAF) comes from kerogen type III that is capable of producing gas. All intervals of TAF have a quantity value from very good–excellent considerable from the amount of TOC > 1% (Peters and Cassa, 1994). Source rock maturity level (Ro > 0.6) in UTAF is mature–late mature and LTAF is late mature–over mature (Peters and Cassa, 1994). Source rock from UTAF has deposited in the transition environment, and source rock from LTAF has deposited in the terrestrial environment. The correlation of oil to source rock shows that oil sample is positively correlated with the UTAF.


2000 ◽  
Vol 171 (4) ◽  
pp. 431-440 ◽  
Author(s):  
Lahcen Boutib ◽  
Fetheddine Melki ◽  
Fouad Zargouni

Abstract Structural analysis of late Cretaceous sequences from the northeastern Tunisian Atlas, led to conclude on an active basin floor instability. Regional tectonics resulted in tilted blocks with a subsidence reorganization, since the Campanian time. These structural movements are controlled both by N140 and N100-120 trending faults. The Turonian-Coniacian and Santonian sequences display lateral thickness and facies variation, due to tectonic activity at that time. During Campanian-Maastrichtian, a reorganization of the main subsidence areas occurred, the early Senonian basins, have been sealed and closed and new half graben basins developed on area which constituted previously palaeohigh structures. These syndepositional deformations are characterized by frequent slumps, synsedimentary tilting materials, sealed normal faults and progressive low angle unconformities. These tilted blocks combined to a subsidence axis migration were induced by a NE-SW trending extensional regime. This extension which affects the Tunisian margin during the Upper Cretaceous, is related to the Tethyan and Mesogean rifting phase which resulted from the combined movements of the African and European plates.


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