准噶尔盆地中部1区块侏罗系三工河组毯砂成岩演化及其物性演化分析

Analysis of the diagenesis evolution and porosity evolution of J_1s carpet sand in block 1 of central Junggar basin

通过储层镜下观察分析,研究准中1区块三工河组二段毯砂储层的微观特征;根据自生矿物之间的交代关系及矿物的溶解—充填等现象,分析各成岩作用发生的先后顺序;结合油气充注史研究,建立储层成岩演化序列与油气充注的耦合关系,分析主成藏期毯砂的物性及其输导能力.结果表明:该毯砂受成岩作用改造强烈,现今储层物性整体以低孔低渗为主,孔隙类型主要为次生溶蚀孔,储层经历多期溶解、多期胶结的过程,并伴随多期油气充注;在主成藏期,毯砂埋藏较浅,处于成岩早期,物性较好,可成为较好的横向输导层,在油源断层较少的情况下,与各级断层一起构成断—毯式输导体系,使油气得以大范围输导.

Through the analysis of thin sections,the J1s2reservoir microscopic characteristics of block 1in central Junggar basin were studied.Then according to the metasomatism relationship among each authigenic mineral and the relationship of dissolution and filling,the sequence of each diagenesis was analyzed,also combined with the research of hydrocarbon charge history,the coupling relationship between reservoir diagenetic evolution sequence and the hydrocarbon charge were established.The reservoir physical property and its transport ability in the main period of accumulation were researched.The results show that later digenesis have a strong effect on its physical property,it belongs to low porosity and low permeability reservoir,and the main type of pore is secondary dissolution pore.The diagenetic evolution has experienced multi-period dissolution and cementation,and also with multiple phase of hydrocarbon filling.In the main period of hydrocarbon charging,the reservoir was shallow,mainly in early diagenesis stage,so had a good physical property,and could become good horizontal transporting and conducting layer.In the case of less source-related faults,the carpet sand could form fault——carpet transportation system with relative faults,and the hydrocarbon had a good migration condition.