塔里木盆地塘古巴斯坳陷北东向断裂带特征、成因及石油地质意义

塔里木盆地塘古巴斯坳陷主要发育东南部基底卷入逆冲断裂和西北部盖层滑脱逆冲断裂两种类型的NE向断裂带，平面上组成巨型的向NW凸出的弧形断裂系。NE向断层多数为逆冲性质，少数兼有走滑性质。多数断裂带沿走向具有构造样式的分段特征，主要表现在主断层逆冲方向及其控制的褶皱形态方面，主要分布在弧形构造的尾端。在垂向上具有多套构造变形的分层叠加特征，主变形层集中在上寒武统-奥陶系，并且西北缘的断层多在中寒武统膏盐岩层内发生滑脱，其他层系变形微弱。NE向断裂体系的主要形成时期是晚奥陶世晚期—志留纪初期，是对加里东中期塔里木地块与北昆仑-阿尔金地块碰撞的响应，是盆地东南缘阿尔金-车尔臣早古生代前陆褶皱冲断体系的组成部分。NE向断裂体系的形成受阿尔金-车尔臣边界大断裂走滑-逆冲应力场、寒武系膏盐岩软弱层分布、基底起伏及边界断裂走向4个因素控制。NE向断裂带局部控制了奥陶系碳酸盐岩溶蚀-缝洞型储层和台缘礁滩型储层的发育。在烃源落实的条件下，可选择性探索断裂带翼部等有利圈闭目标。

NE-trending fault belts in Tanggubasi Depression of the Tarim Basin: Features,genetic mechanism,and petroleum geological significance

NE-trending faults are well developed in Tanggubasi Depression,Tarim Basin.Most of them can be divided into either southeastern basement-involved thrusting fault style or and a northwestern cover-decollement thrusting fault style,and present a huge arcuate faulting system bulging northwestward on map view.These NE-trending faults are mostly thrusting faults,but a few are characteristic of both thrust and strike-slip.Many faults show features of structural segmentation along strike,which are mainly displayed by the difference of main faults' thrusting directions and their related folds,and mainly located at the tail end of the arcuate structure.Meanwhile,most faults are characteristic of the layered superposition of multiple structural deformations vertically,and the major deformative layers concentrate in the Upper Cambrian-Ordovician sequences,and faults on the northwestern margin usually detach in the Middle Cambrian gypsolytes,while weak deformations are shown in other strata.The NE-trending fault system,a product of the collision between Tarim massif and North Kunlun-Altyn massif,is mainly developed during the late of Late Ordovician-earliest Silurian,and is an integral part of the Early Paleozoic foreland fold-thrust system of the Altyn-Cherchen faults on the southeastern margin of Tarim Basin.The formation of the NE-trending fault system is controlled by four factors,including the strike-slip and thrusting stress field of the major faults on the margin of Altyn-Cherchen,the distribution of the Cambrian gypsolyte weak layers,basement relief,and boundary fault strikes.The NE-trending fault belt locally controls the development of the Ordovician carbonate reservoirs of dissolution-fracture-cavity type and reef-shoal reservoirs at the platform margins.Favorable trap targets such as the fault zone wings can be selectively explored if the hydrocarbon source conditions are confirmed to be favorable.