塔里木盆地麦盖提斜坡及周缘断裂及其对油气成藏的控制作用

The faults and their controlling effects on the hydrocarbon accumulation in the Markit slope, SW Tarim Basin

麦盖提斜坡是塔里木盆地西南坳陷的一个次级构造单元,经历多期构造运动和翘倾活动,形成多期断裂活动和复杂的构造变形.这些断裂对研究区的油气成藏有直接的控制作用.本文在大量地震解释基础上,对断裂的期次、性质进行系统厘定;然后,分析其构造样式,落实其平面展布;进而,结合前人对主力烃源岩和成藏期次的研究结果和钻探资料,将断裂划分为沟通油气源断裂、岩溶期断裂、主成藏期断裂、成藏调整期断裂等4大断裂体系;最后,刻画4大断裂体系分布与作用范围.这些断裂构造分析成果,为麦盖提斜坡油气成藏规律研究奠定基础.

The Markit slope is a second order tectonic unit of the southwest depression in the Tarim Basin, NW China. After long and complicated tectonic history, various structural deformation features were formed in it and the adjacent areas. Particularly, there exist several faulting phases and numerous faults in the Markit slope. The faults and their related formations have direct and significant effects on the hydrocarbon accumulation in the study areas. On the basis of careful seismic interpretation, we have timed the faulting and identified the structural features in the Markit slope and peripheral systematically. The structural formation styles and fault distributions were depicted. Combined with the previous petroleum geochemistry study results, the faults in the study areas were classified into jointing source fault system, karst phase fault system, main reservoir forming phase fault system and reservoir adjustment phase fault system according to the effect of the faults during the hydrocarbon accumulation. The distributions and influence ranges of the 4 fault systems were also described. These fault analyzing results lay an important foundation for the study on the hydrocarbon accumulation regularities in the Markit slope and its periphery.