沾化凹陷古近系沙二上亚段储集层特征及评价

Characteristics and Evaluation of Reservoir of Upper Es_2 of Paleogene in Zhanhua Sag

通过对沾化凹陷84口探井的钻井、测井、岩石薄片、铸体薄片等资料的系统分析,详细研究了沾化凹陷沙二上亚段砂岩储集层的展布及特征。储集层主要为三角洲、扇三角洲前缘亚相的水下分流河道微相砂体和滨浅湖亚相的滩坝微相砂体,储集层的岩性主要为岩屑石英砂岩和岩屑砂岩,储集空间以原生孔隙为主,储集层孔隙度为8%～24%,渗透率为(1～100)×10-3μm2.以孔隙度、渗透率、孔隙结构参数、孔隙组合类型特征、岩石学结构特征等为主要依据,将储集层划分为Ⅰ类、Ⅱ类、Ⅲ类。Ⅰ类储集层储集性能最好,主要分布于凹陷东南部;Ⅱ类储集性能次之,主要分布于凹陷东部和北部;Ⅲ类储集层储集性能较差,主要分布于凹陷西北部、垦东凸起西侧和孤岛凸起的南侧。

Through systematical analysis of data of drilling, well-logging, thin-section and cast-section in 84 wells, the distribution and characteristics of the sandstone reservoir of upper Es2 of Paleogene in Zhanhua sag are studied in detail. The reservoir is characterized by the micro-facies sands of both fan delta frontal sub-aqueous distributary channel and beach bar of littoral and shallow lake, with lithology of lithoclasitic quartz sandstone and lithic sandstone, and dominated by primary pores of 8%-24% and permeability of （1-100）×10^-3μm^2. According to the characteristics of porosity, permeability, pore configuration, pore combination and petrological structure, the reservoir is classified into three types of Ⅰ, Ⅱand Ⅲ. Type Ⅰ is high-quality reservoir distributing in the southeastern Zhanhua sag; type Ⅱ is medianquality one which lies in the eastern and northern Zhanhua sag, while type Ⅲ is poor one in the northwestern Zhanhua sag, the west of Kendong swell and the south of Gudao swell.