ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00157.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Analysis of a number of petroleum provinces has emphasised the importance of sedimentary factors as well as subsidence processes. Subsidence appears to depend on a small number of mechanisms ‐ tectonics, heat flow and gravity. Taking into account thegeodynamic context in which these processes develop, it is possible to compile a classification of subsidence types which is distinct from the usual classifications in terms of basins. The type of subsidence influences the deposition rate, which determines both the potential and the habitat of petroleum. Moreover, existing statistics sho w that the number of “giant”fielako, r thep otential of a petroleum province largely depend on the types of subsidence and subsequent tectonic processes.However, it is also important to consider the history of a basin in terms of flows: geothermal flows from the mantle and crust; and water and hydrocarbon flows through the sedimentary volume. For these flow transfers, climatic and sedimentary factors, as well as variations in sea level, play a role which is as important as subsidence and uplift in controlling the distribution of non‐deposition areas, unconformities, seals and reservoirs. For example, periods of generalized transgression are favorable to both the development of carbonate platforms, and the formation of impervious horizons, seals and source rocks capable of sealing pre‐existing rifts.Therefore, a petroleum province can be considered as the final result of an organized set of geological events (in space and in time) that can be called apetroleum system. In such a system, thesequence ofsubsidencemovements and associatedflows isjust asdecisiveas lithological and geometric factors in the formation of a group of pools. This concept of the succession of geodynamics and sedimentary processes which affect petroleum potential is developed, and specific examples of petroleum systems from the North Sea, the Arabian Platform and the Congo Basin are

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00158.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

A brief account of the geology of the Bombay High oilfield on the Western Shelf of India is presented. The L‐III reservoir, its development and exploration utilising a 3‐D, 3‐phase black oil mathematical model is discussed in detail.The Bombay High, a giant offshore located 160km WNW from Bombay city on the Western continental shelf of India, was discovered in 1974. It was put in production in two tears and production has been raised gradually to 240,000 b/d. There commercially exploitable hydrocarbon‐bearing zones–L‐II(limestone), S‐I (sand) and L‐III (limestone) of Miocene age have been identified. At present, the emphasis is on xploration of the L‐III reservoir which contains over 80% of the total reserves of the field. It is composed mainly of wackestone, mudstone and monor packstone. Cyclic sedimentation is identified. Each cycle is represented by four facies: in ascending order they are–lagoonal, algal mound, foraminiferal mound and coastal marsh. The porosity is mainly intergranular, intragranular, moldic, vuggy and microfissures. The solution cavities interconnected by micro‐fissures provide excellent permeability.It is a saturated reservoir with a large gas cap and extensive aquifer, which has left a narrow strip for locating production wells to give water‐or gas‐free oil production. For optimum location of production wells, a 3‐D, 3‐phase black‐oil mathematical and radial coning model was adopted. This assumes intervening shales to be non‐barrier between sub‐layers, and intervening shales within the resrvoir to be partly in communication, giving due consideration to spatial variaton in porosity and thickness of layers. This has paid dividends and reservoir performan

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00159.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Two Karroo basins in the coastal area of Tanzania were selected for source‐rockn analysis i.e. for analysis of potential or probable oil and gas generation. A several hundred ft thick middle section, of a mostly terrestrial, fluviatile‐lacustrine nature up to a deltaic sequence with a minor marine intercalation, showed many laminated fine, pelitic‐lutitic strata in a generally fine sedimentary cycle with large quantities of organic residues. Source‐rock evaluation and geochemical analysis were carried out and yielded moderate values of organic carbon content (up to 2.4%), with maceral composition of mainly structureless organic matter and some vitrinite. They probably represent marginal source rocks for oil and gas which have been “overcooked” during organic metamorphism, and are now

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00160.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

In North Belgium, unusually thick Namurian strata are shown to be rrelate to the existence of deep basin. The presence of a listric growth fault is demonstrated in the Upper Carboniferous, somewhat limiting the Namurian Basin.The associated roll‐over structure may contain sandstones with sufficient porosity to become an attractive exploration target for ga

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00161.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

A simple model is outlined which links continental sedimentary environments and facies with their relative position within a basin, and with the prevailing climate. The model may be used for predicting vertical and lateral facies changes within a succession of continental sediments. It is a useful tool both in the search for hydrocarbon reservoirs, and in the understanding of reservoir properties.

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00162.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Local geothermal gradients in South Iraq were used in calculating the time‐temperature indices of source rock maturation, as modified by Waples (1980). Accordingly, Cretaceous, Jurassic, Triassic and probably Paleozoic rocks are calculated to be with in the thermal petroleum generative zone in several parts of southern Ira

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00163.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Detaile dgeological field investigations in the SE Zagros Mountains reveal that this portion of the Zagros was formed by epeirogenic vertical uplifyt. This vertical movement probably started in the Early Paleozoic and continued through geologic time, as shown by disconformities and dominantly shallow‐water sedimentary rocks. Movements of Infra‐Cambrian salt may have contributed to this vertical uplift to produced box‐type folds which are geometrically and genetically different from folds in the NW segment of the Zagros geosyncline. Three late stage of vertical uplift with different magnitudes were measured and studied. Terraces along the mehran River, elevated alluvial cones, and elevated ancient shorelines are among the most spectacular features supporting the vertical uplift of this r

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00164.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Water‐sensitivity tests have been performed on samples of the Triassic Hopeman Sandstone from Clashach Quarry near Elgin in Scotland. Despite the apparent lack of clay minerals in the samples, the permeability of core plugs to NaCl and KCl brines decreases with progressive volume of efflunent, and drops dramatically when distilled water is flushed through. The permeability to CalCl brines remains constant, however, emphasising the stabilsing effect of polyvalent cations. These results are explained by cation exchange, expansion of electric double layers and the consequent migration of fine

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00165.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Conan's time‐temperature relation in oil genesis as derived from first‐order reaction kinetics is algebraically correct, but its application to natural petrolieum generation is invalidated by the assumption that the ratio of initial kerogen concentration to degraded kerogen concentration is constant from deposition to the initiation of intense oil generation. The ratio can only remain constant if no reaction is occurring and, therefore, Connan's data on “reaction time” in petroleum generation (assumed to be the age of the sediment)only measured th time elapsed since the system formed. Thus, the widely cited pseudo‐activation energy of 11–14 kcal/mole computed from Cannan's equation for the start of oil generation from kerogen is

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00166.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY