滨里海盆地Sagizski区块盐上层系油气藏特征

 滨里海盆地的油气藏与下二叠统空谷阶区域性的盐岩密切相关。该盆地东南部的 Sagizski区块（简称S区块）油气富集，目前的主要勘探目标为盐上层系（包括盐上地层和盐间地层）。在前人研究的基础上，通过对该区块Ashikol S.、Kaganai、Sarly S.、Taskuduk、Sarykumak E.、Kardasyn、Kopa和Oryskazgan 8个典型油气藏或含油气构造的精细解剖，总结并对比了其生油岩、储层、盖层、圈闭、流体、输导体系、保存条件等特征，并综合多方面的资料分析，认为S区块盐上层系的油气藏共有三次成藏期，时间分别在三叠纪末期至早侏罗世末期、晚侏罗世末期和晚白垩世至古近纪；指出了S区块油气藏的主控因素：盐窗是油气成藏的关键，储层控制油气藏的分布，断裂对油气藏的分布有很大影响；并建立了该区块8种油气成藏模式，为下一步油气勘探提供了科学资料。

Characteristics of Hydrocarbon Reservoirs in the Post-salt Strata in Block Sagizski, Pre-Caspian Basin

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.