玛湖凹陷斜坡区KE89—MAh9古鼻凸的发现及油气勘探意义

KE89-MAh9paleo-salient discovery in the slope of Mahu Sag and its hydrocarbon exploration significance

为探索玛湖凹陷斜坡区主扇之间低勘探程度区的油气勘探潜力及成藏模式,利用钻井、测井和地震资料在黄羊泉扇和克拉玛依扇之间新发现了KE89—MAh9二叠系古鼻凸;参考露头剖面,利用断层生长指数、地震时间切片、AE法声发射最大古应力值测定、FMI测井最大古应力方向测定等多种地球物理手段,综合分析古鼻凸的成因及演化过程;明确古鼻凸对三叠系百口泉组一段(T_1b_1)沉积及成藏的控制作用。结果表明:古鼻凸顶面为T/P区域不整合面,由F1、F2两条同沉积逆冲断层夹持控制,由晚海西期近东西向逆冲推覆作用形成,最终受早印支期近南北向右行走滑作用改造而定型;古鼻凸南翼下倾部位T_1b_1段新发现"超覆线—迎烃面—通油源断层"配置条件良好的潜在油气富集区63.4km^2/12块,揭示了玛湖凹陷斜坡区存在地层超覆圈闭勘探新领域。

In order to explore the oil & gas potential among main-fans in the slope area of Mahu Sag,KE89-MAh9 paleo-salient of Permian is discovered between Huangyangquan Fan and Karamay Fan with the joint use of drilling,logging and seismic data.With refering to outcrops,the genesis and evolution process of the paleo-salient is comprehensively analyzed by different geophysical means such as fault growth index,seismic time slices,maximum ancient stress estimations with acoustic emission(AE),and the maximum ancient stress direction determined by formation microscanner image(FMI)logging.The control of paleo-salient on the deposition and accumulation of T1 b1 formation is clarified.The following understanding are obtained based on our study:A.The paleo-salient top is an unconformity surface in T/P,controlled by the clamping of F1 and F2 co-sedimentary overthrust faults,formed by the near east-west overthrust of late Hercynian,and reconstructed and finalized by the right lateral sliding and twisting of early Indosinian;B.63.4 km2/12 blocks with good configuration conditions is found in the T1 b1 formation in the lower part of the south flank of the paleo-salient,revealing new formation overburden traps in the slope area of Mahu Sag.