昌吉凹陷西斜坡不整合对地层圈闭的控制作用

Control effect of unconformity structure of west slope of Changji Sag on stratigraphic traps

为了明确昌吉凹陷西斜坡地层油气藏分布特征及下一步勘探方向,文中在三维地震精细解释的基础上,综合应用测井、录井等资料,系统分析了研究区不整合结构的宏观样式及分布规律,进一步结合不整合的宏观样式以及不整合面上下地层岩性组合的配置方式,研究了地层圈闭的控制因素。研究表明:由凹陷区向凸起区依次发育平行式、平超式、截超式以及截平式等4种不整合宏观样式;针对不同宏观样式,系统开展盖层条件(泥岩顶板、风化黏土层)、遮挡条件(断裂、地层超覆线及地层削蚀线)等圈闭要素分析是在斜坡区寻找地层圈闭的关键。

In order to clarify the distribution characteristics and future exploration direction of the stratigraphic reservoirs in the west slope of Changji Sag, the macro-styles and distributive rules of unconformity structure are analyzed systematically in this paper by using the data of well logs and drilling records with fine 3 D seismic data interpretation. The controlling factors of stratigraphic traps are further studied considering the configuration modes between the macro-styles and the lithological association around the surfaces of unconformity. The research suggests that four types of macro-styles, such as parallelism-parallelism, parallelism-overlap,truncation-overlap and truncation-parallelism were developed from the depression area to the bulge area in turn in the study area.Systematic analysis of cap rock condition(mudstone roofs and weathered clay layers) and occlusion condition(fault and stratigraphic overlying lines and erosion lines) are the key to searching for stratigraphic traps in the slope area.