哈拉哈塘地区走滑断裂与断溶体油藏特征

塔里木盆地北部哈拉哈塘地区奥陶系碳酸盐岩地层发育大量的走滑断裂,被多期岩溶作用改造后形成缝洞型储集体,在上覆盖层及侧向致密灰岩封堵下,形成了碳酸盐岩独特的断溶体圈闭。利用高精度三维地震的相干属性和振幅属性,结合钻井资料和生产动态数据,综合研究了哈拉哈塘地区走滑断裂与断溶体油藏的关系。研究结果表明,哈拉哈塘地区走滑断裂具北强南弱的特征,北部主干断裂带以辫状和马尾状为主,南部主干断裂带多呈线状和雁列式。不同的构造样式控制了哈拉哈塘地区发育板状、雁列式、辫状和叶片状4类断溶体圈闭,油气沿着主干断裂向分支断层运移,最终在断溶体高部位富集成藏。断溶体的连通性及油气在断溶体中的位置,共同决定了油井的产量。

Characteristics of Strike-Slip Faults and Fault-Karst Carbonate Reservoirs in Halahatang Area,Tarim Basin

A large number of strike-slip faults are developed in the Ordovician carbonate strata of Halahatang area in the northern Tarim basin.Fractured-vuggy reservoirs formed along these faults after multiple periods of karstification.Covered by the overlying cap rock and blocked by the lateral tight limestone,the unique“fault-karst trap”formed.Using the high-precision 3D seismic attributes of coherence and amplitude,and combining with drilling data and production performance,the paper comprehensively studies the relationship between strike-slip faults and fault-karst traps in the Halahatang area.The study results show that the strike-slip faults in Halahatang area have a characteristic of“strong activity in the north and weak activity in the south”,the main fault zone in the north of the Halahatang area are mainly composed of braided and horsetail fractures,and the main fault zone in the south of the area are dominated by linear and echelon fractures.The development of 4 types of fault-karst traps such as platy,echelon,braided and foliated traps were controlled by different structure styles,oil and gas migrated along the main faults to branch faults and finally accumulated in the higher positions of the fault-karst bodies.Both the connectivity of the fault-karst bodies and the positions of hydrocarbon enrichment in the fault-karst bodies determine the well production.