潜江凹陷北部潜江组油气运移特征

Hydrocarbon Migration Characteristics of Qianjiang Formation in the Northern Qianjiang Depression

以潜江凹陷北部潜江组为研究对象,在详细分析油气运移影响因素的基础上,利用流体包裹体、含氮化合物测试资料及盆地数值模拟技术系统地研究了其油气运移特征。研究表明:①潜北地区的油气运移特征与烃源岩、压力场、膏盐岩、输导体系及构造运动等因素密切相关,其中烃源岩发育特征决定了油气运移的时间和空间范围;浮力和异常高压是油气从洼陷中心向边缘运移的动力,而构造运动促进了油气运移作用的发生;膏盐岩的发育决定了油气以分层侧向运移为主;骨架砂体为油气侧向运移的通道,断层为油气纵向运移的路径;②潜江组总体经历了3期油气运移,其中荆河镇组-广华寺组沉积中期为油气运移主要时期;③油气由各洼陷中心向边缘运移存在多个优势运移方向,位于优势运移路径上的构造圈闭和岩性圈闭均具有勘探潜力。

Based on detailed analysis of the factors that influence hydrocarbon migration,this paper analyzes hydrocarbon migration characteristics of Qianjiang Formation in the northern Qianjiang Depression by using the data of fluid inclusions and nitrogen compounds, and the technique of basin modeling. The results show that：（1）The characteristics of hydrocarbon migration are closely related to source rock properties, pressure conditions, gypsum salt rock, and the passage system and active tectonics in the northern Qianjiang Depression. The characteristics of source rock determine the time and space scope of hydrocarbon migration. The buoyancy and high pressure control the migration dynamics which made the hydrocarbon move from the center to the edge of sags. Tectonic movements promoted the hydrocarbon migration, and the development of gypsum-salt rock determines the hierarchically lateral hydrocarbon migration. The sand body provides the passageway of lateral hydrocarbon migration, and the fault provides the passageway of vertical hydrocarbon migration;（2）There are three stages of hydrocarbon migration in Qianjiang Formation, and the main migration happened in the Jinghezhen to middle Guanghuasi periods;（3）Multiple superior hydrocarbon migration directions exist from the center to the margin of the depression, and structural traps and lithologic traps in the superior migration pathways have high exploration potential.