Abstract: The hydrocarbon accumulation in Pre-Caspian Basin is closely related to the territorial salt in Kungurian of Early Permian. Block Sagizski in the southeast Pre-Caspian Basin is rich in hydrocarbon. The main exploration target is the Post-Salt Strata (including the strata over and between salt domes ). Based on previous researches, eight typical hydrocarbon reservoirs or oil and gas bearing structures in block S, including Ashikol S., Kaganai, Sarly S., Taskuduk, Sarykumak E., Kardasyn, Kopa and Oryskazgan, were analyzed. As a result, the characteristics of source rocks, reservoirs, cap rocks, traps, fluids, passage systems and preservation conditions were compared. The analysis of a wide range of data shows that three periods of hydrocarbon accumulation exist within the Post-Salt Strata. They are the period from later Triassic to the end of early Jurassic, the end of the late Jurassic as well as the period from late Cretaceous to Eogene, respectively. The control factors on hydrocarbon reservoirs were found. It is shown that salt windows are the key to hydrocarbon accumulation, reservoirs control the distribution of hydrocarbon reservoirs, and faults also have a great influence on the distribution of hydrocarbon reservoirs. Eight kinds of hydrocarbon accumulation models were established. All above results provide a scientific guidance for the next oil and gas exploration in block S.
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Received: 07 January 2010
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