断陷湖盆碳酸盐岩储层预测研究

Study on Carbonate Reservoir Prediction in Faulted Lacustrine Basin

为更准确地对断陷湖盆碳酸盐岩这类特殊储层进行预测,在沾化凹陷西部探索性地采用高分辨率层序地层学方法,以湖泛面为界面把沙四上亚段划分为3个四级层序。四级层序在垂向上的高度不对称性和平面上的分带性控制着储层的分布:在垂向上,随基准面下降储层物性变好;在平面上,储层整体呈近平行于边界断层带状分布,陡坡带台地亚相发育好储层,凹陷中央浅滩亚相发育较好储层,陡坡带局限台地亚相和缓坡带混合坪亚相发育差储层。

To predict more accurately the special reservoirs like carbonate rock in faulted lacustrine basin,high resolution sequence stratigraphic method was applied as an exploratory method in western Zhanhua sag,dividing Es4 upper sub-member into three 4th order sequences by taking the lake flooding surface as the interface. The severely vertical asymmetry and the areal zonation of these4 th sequences control the reservoir distribution: vertically,reservoir physical property gets better as datum surface becomes deeper;areally,reservoirs distribute in stripes generally nearly parallel to the boundary fault. Good reservoirs developed in the platform sub-facies of steep slope zone,fairly good reservoirs developed in the shoal sub-facies of the central sag,and poor reservoirs developed in the restricted platform sub-facies of steep slope zone and in the migmatitic terrace sub-facies of gentle slope zone.