塔里木盆地轮古西地区奥陶系断裂特征及其对油气富集的控制作用

Ordovician Fault Properties and Its Effect on Hydrocarbon Enrichment in Western Lungu of Tarim Basin

针对塔里木盆地轮南古潜山轮古西地区奥陶系断裂解释存在的难点,利用最新的三维地震资料,结合区域构造背景,采用平面上参考相邻塔河地区的断裂发育规律,纵向上参考多层地震属性,对断裂进行了精细刻画和认识。结果表明:轮古西地区奥陶系断裂按形成时间分为中晚加里东期、海西期,按规模分为Ⅰ级、Ⅱ级、Ⅲ级;同时,断裂对潜山地貌、沟谷水系、岩溶储层具有重要的控制作用,进而影响油气的富集成藏;断裂对油气富集的控制作用主要表现在Ⅰ级及部分Ⅱ级断裂控制油气的垂向运移通道,并通过控制古地貌影响油气的平面优势运移方向,而Ⅲ级及另外部分Ⅱ级断裂通过影响岩溶作用进而控制着碳酸盐岩缝洞型储层的发育和分布。该认识对轮古西地区碳酸盐岩油气藏的勘探开发具有一定的指导意义。

The latest 3D seismic data is used to improve the Ordovician fault interpretation in the Lunnan ancient buried-hill western Lungu of Tarim Basin by combining with the regional tectonic setting. A fine fault characteriza- tion of provided by referring the fault distribution pattern of the adjacent Tahe on the plane and referring multi-layer seismic attributes in the vertical direction. Research indicates that the Ordovician faults in western Lungu can be classified as Middle-Late Caledonian and Hercynian according to their development time and also can classified as Grade-Ⅰ, Grade-Ⅱ and Grade-Ⅲ according to the fault scale. The fault greatly controls the buried-hill geomor- phology, ravine drainage system and karst reservoirs, and then affect the hydrocarbon enrichment. The effect of fault on hydrocarbon enrichment mainly includes the longitudinal hydrocarbon migration channel controlled by the Glade -Ⅰ and part of Grade-Ⅱ faults. Tbe paleogeomorphology is controlled by the Grade-Ⅰ and part of Grade-Ⅱ faults to dominate the planar predominant migration direction of hydrocarbon. The Grade-Ⅲ and other part of Grade-Ⅱ faults control the development and distribution of carbonate fracture-cave reservoir by affecting karstification. This finding could prnvide certain guidance for the exploration and development of carbonate reservoirs in the western Lungu.