塔里木盆地巴麦地区东段北东向走滑断裂体系特征及油气地质意义

塔里木盆地巴楚—麦盖提地区(简称“巴麦地区”)东段已发现的多个奥陶系油气藏与多期活动断裂密切相关，明确断穿寒武系膏盐层的通源断层是寻找该区油气藏的关键。基于大量新地震资料的断裂构造解析，结合前人研究，对巴麦地区东段的断裂体系，特别是走滑断裂的展布和活动特征进行了再认识。结果表明，巴麦地区在古隆起迁移演化和大型逆冲断裂带活动的同时，还发育一系列起变形调节作用的北东向展布的高角度小断距走滑断层，它们共同构成了该区变形构造体系。该区发育两类走滑断层，一类与北东向和近东西向展布的寒武系盐上滑脱断褶带同时或后期叠加发育，走向与逆冲断裂带走向一致，主要分布在和田古隆起边界和内部；另一类发育于大型逆冲断裂带围限的挤压缩短区，与近东西向逆冲断裂带呈大角度相交，主要分布于和田古隆起和巴楚断隆内。前者主要形成于海西晚期，喜马拉雅晚期局部弱活动，后者主要形成于喜马拉雅晚期。走滑断层叠加上经历过加里东中晚期和海西早期岩溶改造的奥陶系碳酸盐岩，更有利于形成有效的裂缝—溶蚀孔洞型储集体；它们贯通膏盐层上、下地层，活动期与盐下深层烃源岩主要生烃期一致，更有利于输导烃源向上运移到奥陶系聚集成藏。位于源上且与两类高角度走滑断裂连通的规模储集体是奥陶系有利勘探方向。

Characteristics of NE strike-slip fault system in the eastern section of Bachu-Maigaiti area,Tarim Basin and its oil-gas geological significance

Many Ordovician reservoirs discovered in the eastern section of Bachu-Maigaiti area ("Bamai area" for short) in the Tarim Basin are closely related to multi-stage active faults, making it the key to find oil and gas reservoirs in this area by identifying the source faults that cut through Cambrian gypsum-salt layers. Combined with the analysis of fault structure based on a large number of new seismic data and previous studies, the fault system in the eastern section of the Bamai area, especially the distribution and activity characteristics of strike slip faults are reunderstood. The results show that along with the migration and evolution of palaeo-uplift and the activities of large thrust fault zones in Bamai area, a series of high-angle and small-distance NE strike-slip faults that play a role of deformation and regulation are also developed, which together constitute the deformation tectonic system in the area. Two types of strike slip faults are developed in this area. One is superimposed and developed simultaneously or later with the NE and nearly EW Cambrian post-salt decollement zone of bruchfalten, with its strike consistent with that of the thrust fault belt, which is mainly distributed in the boundary and interior of the Hetian paleo-uplift. The other is developed in the compression-shortening zone confined by the large thrust fault belt, intersected with the nearly EW thrust fault belt at a large angle, and mainly distributed in the Hetian palaeo-uplift and Bachu faulted uplift. The former mainly formed in the late Hercynian period with weak local activities in the late Himalayan period, and the latter mainly formed in the late Himalayan period. The strike-slip faults superimposed with the Ordovician carbonate rocks that has experienced karst transformation in the middle and late Caledonian and early Hercynian are more conducive to the formation of effective fracture-karst vug reservoirs. They connect the upper and lower strata of the gypsum-salt layers, and their active period is consistent with the main hydrocarbon generation period of the deep subsalt source rocks, which is more conducive to transporting hydrocarbon source upward to the Ordovician system for accumulation. The large-scale reservoir located above the source and connected with two types of high-angle strike-slip faults is the favorable exploration direction of Ordovician.