走滑作用对渤海凸起区油气聚集的控制作用:以沙垒田凸起为例

The control of hydrocarbon accumulation by strike-slip motion within the Bohai Sea Rise:A case study from Shaleitian Uplift

渤海海域已发现油气中绝大部分受NE向走滑性质断层的控制,但对其具体控制过程缺乏深入分析。本研究选取NE向断层发育、且有相当油气发现的沙垒田凸起为解剖实例,从构造演化的角度对NE向断层控藏过程与机理进行了分析。结果表明,研究区NE向断层对油气运聚的控制作用是一个长期演化的累积效果,主要通过两个重要过程实现:中生代左旋活动分割基底,改造基底高点,控制油气运移路径;新近纪晚期右旋活动分割披覆构造,改造盖层高点,控制油气聚集场所。这一认识可为渤海其他地区油气勘探提供借鉴。

Although most oilfields discovered in the Bohai Sea were controlled by the NE-trending strike-slip fault, their controlling process was still poorly investigated. In this study, we choose the Shaleitian Uplift as one case to investigate the controlling process and mechanism of the NE-trending fault on the hydrocarbon accumulation. The result shows that the NE-trending fault had a long-term impact and cumulative effect on the hydrocarbon migration and accumulation. Two aspects about this impact are suggested： the Mesozoic sinistral motion of the NE-trending fault cut the basement, reworked the structural high of the basement, and consequently, controlled the migration pathways of hydrocarbon; whereas, the Cenozoic dextral motion of the NE-trending fault cut the draping structures and reworked the structural high of the Cenozoic strata, as a result, controlled the favorable site of hydrocarbon accumulation. Such understanding of the controlling process and mechanism of the NE-trending fault on the hydrocarbon accumulation can be widely referred in the hydrocarbon exploration of other areas offshore the Bohai Sea.