南黄海盆地中、古生界盖层条件

Conditions of the Mesozoic-Paleozoic Cap Rocks in the South Yellow Sea Basin

分析南黄海盆地中、古生界的盖层条件,可为该区油气地质条件研究以及后期油气资源评价提供基础。充分利用现有钻井、测井、地震等多种实际资料,在对盆地及邻区构造、地层、沉积等地质背景分析的基础上,进行了盖层条件的分析。结果表明,南黄海盆地中、古生界主要发育5套盖层,包括钻井已经钻遇的上二叠统龙潭—大隆组泥质岩、下三叠统泥灰岩和膏岩、下白垩统湖相泥质岩,以及两套经地震解释和海陆对比划分的下寒武统、下志留统泥质岩;盆地现存盖层条件的好坏是中、古生界油气藏能否得以保存的关键条件,其中下古生界整体要优于上古生界,上古生界的青岛坳陷要好于烟台坳陷,海相中生界总体较差。

Analyzing the conditions of the Mesozoic-Paleozoic cap rocks in South Yellow Sea Basin provides the basis for oil and gas resource evaluation in the study area.By full use of existing drilling,well log and seismic data,this paper analyzed the cap-rock conditions based on the analysis of structure,stratigraphy and sedimen-tology in the basin and its adjacent area.The results suggest that five sets of cap rocks have developed in the Mesozoic-Paleozoic in South Yellow Sea Basin,including the argillaceous rocks of the Longtan-Dalong Forma-tion,the muddy limestone and gypsum rocks of the Lower Triassic,the lacustrine argillaceous rocks of the Low-er Cretaceous,and two sets of argillaceous rocks of the Lower Cambrian and the Lower Silurian described by seismic interpretation and regional correlation.Whether the existing cap-rock condition in the basin is good or not plays a key role in the Mesozoic-Paleozoic oil and gas preservation.The cap-rock condition in the Lower Pa-leozoic as a whole is superior to the Upper Paleozoic.For the Upper Paleozoic,the cap rocks of the Qingdao de-pression are better than the Yantai depression.In contrast,cap rocks of the marine Mesozoic are generally poor.