柴西南翼山构造形成演化及其对油气成藏的控制

Formation and evolution of Nanyishan Structure and its control on hydrocarbon accumulation in western Qaidam Basin

于冬冬¹ 张永生¹ 侯献华¹ 邢恩袁¹ 王琳霖¹ 李凯 2

中国地质科学院矿产资源研究所国土资源部盐湖资源与环境重点实验室，北京 100037 中国地质大学（北京）地球科学与资源学院，北京 100083

MLR Key Laboratory of Saline Lake Resources and Environments, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China School of Geosciences and Resources, China University of Geosciences, Beijing 100083, China

在柴西区域演化史分析的基础上，利用平衡剖面恢复了南翼山构造的形成过程，最后结合油气藏解剖，分析了南翼山构造演化对油气成藏的控制作用。结果表明，南翼山构造的形成与柴西区域演化相匹配，其经历了3个演化阶段：路乐河期至下油砂山期处于弱伸展阶段，发育小型断陷；上油砂山期至狮子沟期为弱挤压阶段，构造应力反转，受NNE—SSW向挤压，狮子沟期挤压加强，形成背斜雏形；第四纪强烈挤压阶段，形成现今的背斜构造。构造形成演化对成藏的影响体现在油气储集、运移和成藏期次3方面：构造演化控制了裂缝的发育期次及分布，从而改善了南翼山低孔低渗储层质量；翼北和翼南2条深断裂及伴生裂缝，构成了油气运移的通道；喜山中期和晚期2次关键构造运动，控制了油气成藏期次。

Based on analysis of the evolution history in the western Qaidam Basin, the formation and evolution of the Nanyishan Structure were restored by using balanced section. Combined with the anatomy of oil and gas reservoirs, the structural evolution of Nanyishan and its control on the hydrocarbon accumulation were analyzed. The results show that the formation of the Nanyishan Structure is consistent with the regional evolution of the western Qaidam, which has undergone three stages of evolution: small rift was developed in weakly extensional stage from the Lulehe age to the lower Youshashan age; weakly compression stage from the upper Youshashan age to the Shizigou age, the tectonic stress reversed, an anticline began to form from extrusion of the NNE-SSW direction in the Shizigou age; current anticline structure in Quaternary intense compression stage. The influence of structural evolution on hydrocarbon accumulation is reflected in reservoir, migration and accumulation periods. The structural evolution controlled the development and distribution of fractures, which helped improve the quality of low porosity and low permeability reservoirs. Yibei Fault, Yinan Fault and relational fractures are the channels of oil and gas migration. The two key tectonic movements in the middle and late Himalayan periods controlled the hydrocarbon accumulation period.

10.6056/dkyqt201706002