北三台凸起多边断层对油气成藏的影响

The Effect of Polygonal Fault in Beisantai Bulge on Oil and Gas Accumulation

为研究准噶尔盆地北三台凸起断层对油气成藏的影响,在地震资料解释的基础上,结合区域构造、岩性组合、黏土矿物组成、压力分布、已知油藏特征等因素,对断层发育特征、形成机制及其与油气藏关系进行了描述与探讨。结果表明:该套断层具有"垂向层控性"、"平面多边性"特征,属于典型的多边断层,主要是细粒沉积物在密度反转作用机制下形成的;多边断层发育的地层下部紧邻二叠系平地泉组烃源岩,在油气聚集成藏过程中起到了运移通道的作用,密集的空间断层网络为油气藏局部连片提供了条件,在精细勘探中应当高度重视多边断层的解释与分析。该研究对北三台凸起的油气滚动勘探和油藏精细评价有一定的指导意义。

In order to investigate the effect of fault in Beisantai bulge in Junggar basin on oil and gas accumulation, the development characteristics, forming mechanism and their relationship with reservoirs are described and dis- cussed, based on seismic interpretation, regional structure, lithological association, clay mineral composition, pressure distribution and known reservoir characteristics. The results show that the fault is a typical polygonal fault, with ＂vertical strata-bound attribute＂ and ＂planar polygonality＂, which are formed by fine-grained sediment un- der density inversion effect. The lower part of the formation where polygonal faults are developed is close to source rock in Pingdiquan formation, Permian System and acts as migration pathway during oil and gas accumulation. The dense spatial fault network provides conditions for local connectivity of reservoirs and the interpretation and analysis of polygonal fault should be strengthened during fine exploration. The research provides guidance for oil and gas pro- gressive exploration and reservoir fine evaluation in Beisantai bulge.