柴达木盆地英西地区深部混积岩储层特征及控制因素

Reservoir characteristics and controlling factors of deep diamictite in Yingxi area, Qaidam Basin

采用张雄华对混积岩的分类方法,对柴达木盆地英西地区深部储层混积岩的岩石类型进行了划分,并将其简化为灰（云）岩、泥岩及砂岩三大类。利用铸体薄片、全岩分析、核磁共振及孔隙度等资料,对英西地区深部混积岩储层进行了综合分析与研究。该区储层岩性复杂,岩石类型主要为灰（云）岩类,岩石矿物成分包括陆源碎屑、碳酸盐及黏土矿物。储层孔隙度为0.58%~8.58%,平均为2.69%;渗透率为0.010~0.501 m D,平均为0.053 m D,具有低孔、低渗特征,孔渗相关性差。储集空间以晶间孔、微孔隙和裂缝为主,溶蚀孔不发育。碳酸盐含量和储层裂缝发育程度是该区储层物性的主控因素,压实作用对储层孔隙度具有一定影响。

Based on the classification method of diamictite proposed by Zhang Xionghua, the lithology of deep diamictite in Yingxi area of Qaidam Basin was classified simply into three types： carbonatite, mudstone and sandstone.The data of thin section, whole rock mineral analysis, nuclear magnetic resonance and core porosity were used to study the reservoir characteristics of deep diamictite in Yingxi area. The main rock type of the reservoir is micrite limestone（dolomite）, and the minerals include terrigenous minerals, carbonate minerals and clay minerals. The porosity ranges from 0.58% to 8.58%, with the average value of 2.69%, and the permeability ranges from 0.010 m D to 0.501 m D, with the average value of 0.053 m D. The reservoir has the characteristics of low porosity and low permeability,and the correlation between the two parameters is poor. The reservoir spaces mainly include intergranular pores and fractures, with fewer dissolved pores. The content of carbonate minerals and compaction are the main controlling factors for reservoir properties.