ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00325.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00326.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The offshore West Korea Bay (WKB) Basin is one of several NE‐SW rift basins which formed over thin continental crust in Korea and eastern China during the Late Mesozoic and Early Cenozoic, and is characterised by a two‐layered structure, with a Cenozoic basin superposed on a pre‐Tertiary basin. Paraffinic oils recovered from Mesozoic and Tertiary sandstone intervals are thought to have been generated from different source beak. The Sim Uuju Formation consists mainly of fluvially‐derived shales and sandstones deposited in a large, open, fresh‐water, deep, tectonic lake. which occupied wide sub‐basins formed by normal faults under a semi‐humid climate, as a result of initial rifting during the Upper Jurassic. A probable source bed (400– to 500–m thick) has been geochemically located in the basinal offshore area of the Sim Uuju sequence penetrated by Well 606. The Jurassic bed could be considered as a potential source for the Mesozoic oil, provided that it contains the right type and amount of organic matter which has reached the stage

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00327.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A revised lithostratigraphical framework of the Early to “Middle” Cretaceous strata of the Central North Sea (UK sector) derived from the rigorous examination of more than 100 commercial boreholes is presented. previously published frameworks have tended toward oversimplification of the Early to “Middle” Cretaceous, as the interval was considered initially to be of minor importance with regard to prospectivity. However:there is a general feeling in the industry that the Early to “Middle” Cretaceous is prospective. particularly with regard to subtle stratigraphical traps like theKilda/BosunandScapafields. It is inevitable that as more attention, due to hydrocarbon exploration, is paid to an interval that the stratigraphical models used progress from the simplistic to the complex. The framework presented here is the result of a pragmatic approach in that it is based upon the integration of previously published schemes. with the erection of new units derived from new analyses and interpretation. The complete lithostratigraphical framework is defined. explained and discussed with reference to borehole examples in the Centra

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00328.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Megascale monoclinal flexures (‘geowarpings“) with maximum angles of dip ranging from 5° to 13° occur in the Zagros‐Taurus range of Iraq and Iran. They face south and SW. with amplitudes of 1.4 to 14.44 kms and axial lengths of 43 to 230 kms. meir axes are parallel to the host mountain range and lie in an en Pchelon configuration, and many are located in the high mountain zone, at or close to the mountain front (i.e. the border with the foothills zone).Neotectonic and stratigraphic evidence suggests the contemporaneous development of these flexures with their host fold‐belt during the collision of the Eurasian and Afro‐Arabian Plates, which culminated during Upper Miocene‐Pliocene time. Differential vertical movements caused greater shortening and thickening in the upwarded regions (10–33%). which lie closer to the plate suture zones, compared to the downwarped regions (3–17%).Development of the geowarpings resulted in circumstances favourable for hydrocarbon generation in downwarped regions. where source rocks were buried sufficiently deeply to produce oil and gas: this then migrated upwards to be trapped in the growing folds, and was sealed by Miocene evaporites. On the other hand, upwarped regions were elevated, and suffered extensive erosion, leading to a reduction in the depth of burial of potential source rocks, and consequently limited possibilities of hydrocarbon generation. Furthermore. the non‐deposition and/or erosion of Miocene evaporites in upwarped regions led to the dissipation of considerable volumes of the hydrocarbons which might have been generated. The effect of geowarpings on oil and gas reserves is evident from the distribution of oil‐ and gasfields. which are almost exclusively located in the downwarped. foothills zone.Geowarpings may be located in the Taurus Range of E Turkey and NE Syria. but a lack of accurate data makes this difficult to investigate. Further studies are needed to develop an efficient exploration plan for oil

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00329.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Most oil‐ and gasfields result from the migration of hydrocarbons from the generating source bed to the resenvoir and trap. Exceptions are producing source‐bed formations (coal‐bed gas, e.g. the Permian Spraberry Trend. West Texas). Where vertical hydrocarbon migration is active. oil/gas accumulations can be found in reservoirs of geological ages which are considerably different from those of the generating source beds. In such cases (eg. the North Sea gas province: Louisiana offshore: Niger Delta: Vienna Basin), early recognition of vertical migration may well bring about the most effective exploration results. In many basins. vertical migration is less evident than lateral migration, leading to distinct, vertically‐stacked hydrocarbon systems isolated from each other (e.g. the Po Valley, Powder River and Sine Basins). Vertical migrotion from one source‐bed level, or the mixing of hydrocarbons from different hydrocarbon systems, occurs where major faults or vertically‐rising materials (salt, igneous rocks) create critical vertical pathways. In such cases, vertical migration can be an important factor in the location and existence of hydrocarbon ac

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00330.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Isolated carbonate banks in starved basins are very attractive targets for hydrocarbon prospecting. In the Zechstein (Late Permian) Main Dolomite (Ca2) Basin of Western Poland, six such banks or isolated platforms have been penetrated by wells, and gas and/or oil has been found in all of them. The largest is the Chartów Platform. which lies a few tens of kilometres from the edge of the carbonate shelf and shows well‐defined facies zonation, Three shallowing‐upward cycles may be distinguished in the bank‐edge sands, while the central (lagoonal) region and lower slope show a single deepening‐upward sequence. Local rapid subsidence, usually balanced by the rate of deposition, is inferred for the edge of the Chartów Platform: this subsidence was not balanced in other zones.The driving force for increased local subsidence may have been related to subtle block movements, and the break‐up of the P21 (Werra) evaporite platform. The rate of increased subsidence fluctuated: pulses of relatively rapid subsidence disturb the sequence, which was controlled by sea‐level fluctuations.Differential subsidence and sea‐level changes are common during the evolution of evaporite basins, and isolated platforms similar to the Chartów structure may be common in other evaporite basins, where isolated banks are located between the central an

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00331.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The GCöynük and Seyitomer oil shales overlie coal seams. An investigation of their geochemistry by solid‐state and high‐resolution nuclear magnetic resonance, infra‐red spectroscopy and gas chromatography/mass spectrometry of the extracted bitumen suggests a classification as immature Type I kerogens. However. the n‐alkane distribution is consistent with a substantial input from terrestri

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00332.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00333.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1991.tb00334.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY