Exploration in the southwest Malita Graben: initial results and remaining potential

2013 ◽  
Vol 53 (2) ◽  
pp. 428
Author(s):  
Kelsey Jewett ◽  
Anne-Claire Lorage ◽  
Said Amiribesheli ◽  
Han Kee Tan
Keyword(s):  
Middle Jurassic ◽  
Late Jurassic ◽  
Upper Jurassic ◽  
Reservoir Quality ◽  
High Co2 ◽  
Fault Block ◽  
Fault Leakage ◽  
Net To Gross ◽  
Hydrocarbon Charge ◽  
Initial Results

In 2011, Total E&P Australia and Petronas Carigali drilled two exploration wells in permit WA-403-P in the northern Bonaparte Basin. Both wells targeted the Middle-Jurassic play of the Elang/Plover formations that have yielded all commercial discoveries in the area. Notably, the wells were drilled in a less-explored area near the axis of the basin, targeting reservoirs at or more than 4,000 m. Pre-drill, the critical risks were recognised as burial-related reservoir degradation and cross-fault leakage into Upper Jurassic to Lower Cretaceous sands. The first well, Durville-1, was drilled on a poorly imaged three-way dip closure to the south of the Flamingo High. A gas column with high CO2 content was encountered in thick, high net-to-gross sands of lowermost Berriasian age. Drilling was terminated before the Elang Formation was reached. The second well, Laperouse-1, was drilled on a well-imaged fault block near the southern margin of the Malita Graben. The structure was formed in the Late Jurassic and lacks recent fault activation; thus, it was anticipated that early hydrocarbon charge might protect the reservoir from severe diagenesis. Laperouse-1 encountered a thick succession of Tithonian to Berriasian water-bearing sand packages; it reached total depth in the Elang Formation. The WA-403-P drilling campaign has confirmed the presence of thick Cretaceous sandstone in the area, although significant discrepancies in reservoir quality are observed between Durville-1 and Laperouse-1.

First record ofOphthalmosaurus(Reptilia: Ichthyosauria) from the Tithonian (Upper Jurassic) of Mexico

2010 ◽  
Vol 84 (1) ◽  
pp. 149-155 ◽  
Author(s):  
Marie-Céline Buchy
Keyword(s):  
Middle Jurassic ◽  
Late Jurassic ◽  
Field Work ◽  
First Record ◽  
Upper Jurassic ◽  
Marine Transgression ◽  
North East ◽  
The Pacific ◽  
Invertebrate Assemblages ◽  
Marine Reptile

From the Middle Jurassic on, the Tethys basin opened westward; the existence of a Carribean corridor linking the European and Pacific realms now appears well supported by comparison of marine reptile assemblages (e.g., Gasparini and Fernández, 1997, 2005; Gasparini et al., 2000; Fernández and Iturralde-Vinent, 2000; Gasparini and Iturralde-Vinent, 2001, 2006; Gasparini et al., 2002). Marine transgression in Mexico began during the Callovian, as evidenced by the evaporites of the Minas Viejas Fm. However, microfossils and invertebrate assemblages indicate that the Mexican Gulf remained isolated from both the European Archipelago and the Pacific, at least temporarily, until the middle Berriasian; the Florida uplift and southward movement of Yucatan were proposed as possibly forming a barrier (Salvador et al., 1993; Adatte et al., 1994, 1996; Goldhammer, 1999; Goldhammer and Johnston, 2001; Gasparini and Iturralde-Vinent, 2006). After almost a decade of field work and examination of collections, the Late Jurassic marine reptile assemblage of north-east Mexico confirms the conclusions drawn from microfossils and invertebrates. Poorly diagnostic ichthyosaur remains, with various thalattosuchians, numerically dominate the assemblage. Sauropterygians are rare, mainly represented by large pliosaurids of unclear affinities, a few vertebrae attributed to elasmosaurids, and a unique cryptoclidid. Turtles are yet to be reported (Frey et al., 2002; Buchy et al., 2003, 2005b, 2006a–d; Buchy, 2007, 2008a, b; material currently under study).

The Dunlin Field, Blocks 211/23a and 211/24a, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 95-102 ◽  
Author(s):  
A. Baumann ◽  
B. O'Cathain
Keyword(s):  
North Sea ◽  
Middle Jurassic ◽  
Upper Jurassic ◽  
Reservoir Properties ◽  
Oil Accumulation ◽  
Western Margin ◽  
Shetland Islands ◽  
Fault Block ◽  
Delta System ◽  
Cumulative Production

AbstractThe Dunlin Oilfield is located in the East Shetland Basin, 160 km northeast of the Shetland Islands. It lies in UK Blocks 211/23a and 211/24a in about 500 ft of water. The field was discovered in June 1973 by well 211/23-1. The oil accumulation is trapped, in a north-south oriented, tilted fault block at the western margin of the Viking Graben, at a depth of about 8500 ft TVSS. The reservoir is contained in the formations of the Middle Jurassic Brent Group. In the Dunlin area they form a 450 ft thick sequence of sands and intercalated minor shales, which has been deposited by a shore face and delta system prograding northwards across the Viking Graben. The seal is formed by the shales of the Middle/Upper Jurassic Heather Formation. Reservoir properties of the Brent sands are fair to good with porosities of up to 30% and average permeabilities in the range from 10 to 4000 md. Development of the field is carried out from a single platform, from which production started in 1978. To date 40 development wells have been drilled and the total cumulative production amounts to 282 MMBBL of an ultimate recovery of 363 MMBBL.

The Murchison Field, Block 211/19a, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 165-173
Author(s):  
John Warrender
Keyword(s):  
North Sea ◽  
Middle Jurassic ◽  
Upper Jurassic ◽  
Lower Jurassic ◽  
Oil Field ◽  
Medium Size ◽  
Fault Block ◽  
International Boundary ◽  
Northern North Sea ◽  
The Uk

AbstractThe Murchison oil field forms part of the Brent oil province in the East Shetland Basin, northern North Sea. The field, which straddles the UK-Norway international boundary, was discovered in 1975 and began production with Conoco (UK) Ltd as Operator, in 1980. Like many oil accumulations in the East Shetland Basin the trap consists of a northwesterly dipping rotated fault block of Jurassic-Triassic age sourced and sealed by unconformable Upper Jurassic shales. The productive reservoir consists of Middle Jurassic Brent Group sandstones which represent the south to north progradation of a wave/tide influenced delta system. The Brent Group on Murchison has an average thickness of 425 ft with average porosities of 22% and permeabilities in the 500-1000 md range in producing zones. The maximum hydrocarbon column thickness is approximately 600 ft. The oil is undersaturated and no gas cap is present. Recoverable reserves are 340 MMBBL from a total oil in place figure of 790 MMBBL. Oil production which is via a single steel jacket platform peaked at 127 000 BOPD in 1983 and currently averages 45 000 BOPD. Economic field life is expected to be at least 20 years.The Murchison Field is located in the East Shetland Basin, northern North Sea at approximate latitude 61° 23' N, longitude 1° 43.5' E, 120 miles northeast of the Shetland Islands (Fig. 1). The field straddles the UK-Norway international boundary with the greater portion in the UK Block 21 l/19a and the lesser portion in Norway Block 33/9. Water depth is -512 ft BMSL. In the context of the North Sea the field is of medium size with an areal closure of approximately 7 square miles and contains 790 million barrels of oil in place. The productive reservoir consists of coastal deltaic sandstones of the Middle Jurassic Brent Group which lie between the marine shales of the Lower Jurassic Dunlin Group and the marine, organic-rich shales of the Upper Jurassic Humber Group. The trap is structural comprising a single, northwesterly dipping rotated fault block which has been sourced and sealed by the overlying Upper Jurassic shales. The field is named after the Scottish geologist Sir Roderick Impey Murchison (1792-1871), who is best known for his contribution to Palaeozoic stratigraphy.

The Hutton, NW Hutton, Q-West and Darwin fields, Blocks 211/27 and 211/28, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 850-862 ◽  
Author(s):  
J. G. Gluyas ◽  
H. Turnell ◽  
R. Ball ◽  
J. Henderson ◽  
M. Mulcahy ◽  
...  
Keyword(s):  
North Sea ◽  
Middle Jurassic ◽  
Upper Jurassic ◽  
Petroleum System ◽  
Reservoir Quality ◽  
Significant Component ◽  
Associated Gas ◽  
Complex Series ◽  
Oil Generation ◽  
Clay Formation

AbstractHutton (discovered in 1973) and NW Hutton (discovered in 1975), together with Q-West (discovered in 1994) and Darwin (discovered in 1983, undeveloped), are part of a single petroleum system. The main fields were defined as two separate legal entities. Although Q–West covered multiple blocks, it was wholly developed via the Hutton platform.Together, Hutton and NW Hutton produced 328 MMbbl of oil and a small quantity of associated gas from Middle Jurassic Brent Group sandstones. The trap is a complex series of tilted fault blocks sealed by Mid–Upper Jurassic Heather and Kimmeridge Clay Formation mudstones. Oil was sourced from the Kimmeridge Clay Formation, which is mature for oil generation in the hanging walls to the field-bounding faults and deep on the footwall flanks.NW Hutton underperformed relative to Hutton. In part this was due to the poorer reservoir quality encountered at depth compared with the shallower Hutton Field but a significant component of the underperformance was due to the way in which the field was developed and then operated. Both fields contain areas of unproduced and unswept oil, with the NW Hutton portion having the largest remaining oil in place.

Limoniidae (Diptera) in the Upper Jurassic of Shar Teg, Mongolia

Zoosymposia ◽  
2009 ◽  
Vol 3 (1) ◽  
pp. 131-154 ◽  
Author(s):  
ELENA D. LUKASHEVICH
Keyword(s):  
Middle Jurassic ◽  
Late Jurassic ◽  
Upper Jurassic

A diverse Late Jurassic crane fly assemblage is described from Shar Teg locality (SW Mongolia), viz. Architipula krzeminskii n.sp., A. ampla n.sp., Mesotipula sigmoidea n.sp., ?M. brevicella n.sp., M. (Metatipula n.subgen.) continens n.sp., Tipunia undata n.sp., T. jorgi n.sp., Cretolimonia jurassica n.sp., C. pygmaea n. sp., Eotipulina sharategica n.sp., E. paula n.sp., E. evidens n.sp. and Eotipuloptera sp. The genus Praearchitipula Kalugina, 1985 is transferred to Pediciidae; it is the first Mesozoic record of this family (Middle Jurassic of Siberia). One species originally included in Praearchitipula is transferred to Mesotipula: M. parvula (Kalugina, 1985) n.comb. from the Middle Jurassic of Siberia.

Middle Jurassic turtles from the Sichuan Basin, China: a review

2011 ◽  
Vol 149 (4) ◽  
pp. 675-695 ◽  
Author(s):  
HAIYAN TONG ◽  
IGOR DANILOV ◽  
YONG YE ◽  
HUI OUYANG ◽  
GUANGZHAO PENG
Keyword(s):  
Middle Jurassic ◽  
Sichuan Basin ◽  
Late Jurassic ◽  
Upper Jurassic ◽  
The Other ◽  
Dominant Group ◽  
Genus Level ◽  
The Family ◽  
The Sichuan Basin ◽  
The One

AbstractThe turtle fauna of the Middle Jurassic Xiashaximiao Formation in the Sichuan Basin and the type series ofChengyuchelys baenoidesYoung & Chow, 1953 are revised. By the absence of a mesoplastron and other shell characters, both the holotype and paratype ofChengyuchelys baenoidesbelong to the family Xinjiangchelyidae and come probably from the Upper Jurassic Shangshaximiao Formation. The Middle Jurassic turtle assemblage of the Sichuan Basin is composed of two entities: the Bashuchelyidae fam. nov. (Bashuchelysgen. nov.,Chuannanchelysgen. nov.) andProtoxinjiangchelysgen. nov. on the one hand, andSichuanchelyson the other hand, with the former as the dominant group. Bashuchelyids and xinjiangchelyids are closely related to one another, whileSichuanchelysis more primitive and has no shared apomorphic features with bashuchelyids. The whole assemblage appears to be endemic to the Sichuan Basin at genus level and distinct from the Late Jurassic turtle fauna of the same basin in its relict nature and absence of the Polycryptodira.

scholarly journals New data on the microvertebrate fauna from the Upper Jurassic or lowest Cretaceous of Ksar Metlili (Anoual Syncline, eastern Morocco)

2019 ◽  
Vol 157 (3) ◽  
pp. 367-392
Author(s):  
Maxime Lasseron ◽  
Ronan Allain ◽  
Emmanuel Gheerbrant ◽  
Hamid Haddoumi ◽  
Nour-Eddine Jalil ◽  
...  
Keyword(s):  
North Africa ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Upper Jurassic ◽  
Poor Knowledge ◽  
Early Cretaceous Period ◽  
Eastern Morocco ◽  
Dispersal Events ◽  
Cretaceous Period ◽  
Northwestern Africa

AbstractThe Middle Jurassic – Early Cretaceous period witnessed the emergence of some major representatives of modern continental vertebrate groups (stem lissamphibians, squamates, therian mammals and birds) and angiosperms, at a time when fragmentation of Pangaea was underway. The successive Moroccan microvertebrate faunas of Ksar Metlili (?Berriasian) and Guelb el Ahmar (Bathonian) from the Anoual Syncline significantly improve our poor knowledge of Gondwanan and especially African palaeobiodiversity at this time. They are among the richest known from the Mesozoic of Gondwana, and are well placed in northwestern Africa to record faunal interchanges with Laurasia. Here we focus on the Ksar Metlili fauna, first documented in the 1980s and most recently resampled in 2010, which produced 24 541 microremains representing 47 species of 8 main groups (Chondrichthyes, Actinopterygii, Sarcopterygii, Lissamphibia, Lepidosauromorpha, Testudinata, Archosauromorpha and Synapsida). It includes remarkable taxa: the oldest stem boreosphenidan mammals from Gondwana, probably some of the last non-mammaliaform cynodonts, a basal ornithischian, possibly freshwater teleosaurid crocodylomorphs, and some of the rare occurrences of choristoderes and albanerpetontids in Gondwana. Comparison of the Ksar Metlili fauna with that of Guimarota (Kimmeridgian, Portugal) further provides evidence of numerous shared taxa of Laurasian affinities, in contrast to the occurrence of few taxa with Gondwanan affinities. This suggests complex palaeobiogeographical relationships – implying both vicariance and dispersal events – of North Africa within Gondwana at the Jurassic–Cretaceous transition. Finally, the faunal similarities with the Guelb el Ahmar fauna question the Cretaceous age of the Ksar Metlili fauna, suggesting an alternative possible Late Jurassic age.

Jura-Cretaceous (Oxfordian to Cenomanian) stratigraphy of the north-central Bowser Basin, northern British Columbia

1989 ◽  
Vol 26 (5) ◽  
pp. 1001-1012 ◽  
Author(s):  
H. O. Cookenboo ◽  
R. M. Bustin
Keyword(s):  
British Columbia ◽  
Lower Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Upper Jurassic ◽  
Thick Section ◽  
North Central ◽  
The North

Three new formations of Late Jurassic and Early to mid-Cretaceous age are defined for a 2000 m thick section of Jura-Cretaceous rocks exposed in the north-central Bowser Basin. The Currier Formation (Oxfordian to Kimmeridgian or Tithonian) consists of 350–600 m of interbedded shales, siltstones, sandstones, coals, and carbonates. The McEvoy Formation (Barremian to as young as Albian) consists of 400–800 m of siltstones and shales with minor sandstones, thin coals, limestones, and conglomerates. The Devils Claw Formation (in part mid-Albian to Cenomanian) consists of 300–600 m of strata characterized by thick pebble and cobble conglomerates, with associated coarse sandstones and minor siltstones and shales.Two successive coarsening-upward sequences are identified in the study area. The first begins with Middle Jurassic marine shales of the Jackson unit grading upwards to coarser Upper Jurassic facies of the Currier Formation. The Currier Formation is conformably or unconformably overlain by siltstones and shales of the Lower Cretaceous McEvoy Formation, which forms the base of a second coarsening-upward sequence. Conglomerates appear with increasing frequency in the upper McEvoy and are the dominant lithology of the overlying Devils Claw Formation. The contact between the McEvoy and Devils Claw formations is gradational. The Devils Claw Formation forms the top of the second coarsening-upward sequence.The Currier Formation (Late Jurassic) is equivalent to the upper units of the Bowser Lake Group. The McEvoy and the Devils Claw formations (Barremian to Cenomanian) are coeval with the Skeena Group (Hauterivian? to Cenomanian). A probable unconformity separating the Upper Jurassic Currier Formation from the Lower Cretaceous McEvoy Formation correlates with a hiatus in the southern Bowser Basin and probably represents a regional unconformity.

The Clyde Field, Block 30/17b, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 279-285
Author(s):  
D. A. Stevens ◽  
R. J. Wallis
Keyword(s):  
Production Rate ◽  
North Sea ◽  
Late Jurassic ◽  
Water Injection ◽  
Reservoir Quality ◽  
Reservoir Pressure ◽  
Shallow Marine ◽  
The North ◽  
Fault Block ◽  
The North Sea

AbstractThe Clyde Field, which was discovered in 1978, is located on the SW edge of the North Sea Central Graben. The reservoir is developed with Late Jurassic shallow marine sands of the Fulmar Sand Formation. An estimated 408 MMBBL of oil is present (Annex B), of which 154 MMBBL is considered recoverable.The structure of the Clyde Field takes the form of a rotated Jurassic fault block, truncated at its crest by a major unconformity. Oil is retained within a combination trap, sourced from Late Jurassic Kimmeridge Clay thermally matured in the highly productive basinal lows, adjacent to the field.Reservoir sand quality is highly variable, ranging from excellent with permeabilities in excess of Id, to poor with permeabilities of less than 1 md. The principal control on reservoir quality appears to be original depositional texture, although strong diagenetic effects are also present.Production is from a single, centrally located, platform provided with thirty slots. Aquifer support is insufficient to maintain reservoir pressure at the current plateau production rate of 50 000 BOPD and so a programme of water injection has been implemented.

scholarly journals A new Middle–Upper Jurassic succession on Hold with Hope, North-East Greenland

2004 ◽  
Vol 5 ◽  
pp. 51-71
Author(s):  
Henrik Vosgerau ◽  
Michael Larsen ◽  
Stefan Piasecki ◽  
Jens Therkelsen
Keyword(s):  
Sea Level ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Lower Triassic ◽  
Upper Jurassic ◽  
Delta Front ◽  
North East ◽  
Fault Block ◽  
Uplifted Block ◽  
Major Fault

A succession of marine, Jurassic sediments was recently discovered on Hold with Hope, NorthEast Greenland. The discovery shows that the area was covered by the sea during Middle–Late Jurassic transgressive events and thus adds to the understanding of the palaeogeography of the area. The Jurassic succession on northern Hold with Hope is exposed in the hangingwalls of small fault blocks formed by rifting in Late Jurassic – Early Cretaceous times. It unconformably overlies Lower Triassic siltstones and sandstones and is overlain by Lower Cretaceous coarsegrained sandstones with an angular unconformity. The succession is up to 360 m thick and includes sandstones of the Lower–Upper Callovian Pelion and Middle–Upper Oxfordian Payer Dal Formations (Vardekløft Group) and heteroliths and mudstones of the Upper Oxfordian – Lower Kimmeridgian Bernbjerg Formation (Hall Bredning Group). The Pelion Formation includes the new Spath Plateau Member (defined herein). The palaeogeographic setting was a narrow rift-controlled embayment along the western margin of the rifted Jurassic seaway between Greenland and Norway. It was open to marine circulation to the south as indicated by the distribution and lateral facies variations and a dominant south-westwards marine palaeocurrent direction. The Pelion and Payer Dal Formations represent upper shoreface and tidally influenced delta deposits formed by the migration of dunes in distributary channels and mouthbars over the delta front. The boundary between the two formations is unconformable and represents a Late Callovian – Middle Oxfordian hiatus. It is interpreted to have formed by subaerial erosion related to a sea-level fall combined with minor tilting of fault blocks and erosion of uplifted block crests. In Late Jurassic time, the sand-rich depositional systems of the Pelion and Payer Dal Formations drowned and offshore transition – lower shoreface heteroliths and offshore mudstones of the Bernbjerg Formation accumulated. The fault block crest forming the eastern basin margin was inundated by a rise in relative sea level. Major fault activity probably occurred in latest Jurassic – Early Cretaceous times when the major fault block originally defining the Hold with Hope basin was split into smaller blocks.

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