摘要:
准噶尔盆地中拐地区二叠系佳木河组为扇三角洲环境下形成的富火山岩岩屑的致密砂岩储层。综合运用岩心观察、薄片鉴定、物性测试等对佳木河组储层成岩作用特征及其控制因素进行了研究,结果表明:佳木河组储层机械压实作用和胶结作用强,导致储层致密化;浊沸石、片沸石和方沸石是主要胶结作用产物;受佳木河组顶部不整合及烃源岩演化影响,发育弱酸性大气水溶蚀和晚期有机酸溶蚀2期溶蚀作用,浊沸石和方沸石溶孔是其主要表现形式,溶蚀面孔率平均为0.74%。而储层岩性、沸石胶结和逆掩断层活动控制佳木河组储层压实作用;火山岩岩屑是沸石胶结的物质基础,沉积相带和岩性控制不同区域沸石胶结物类型的差异性;弱酸性大气水淋滤是导致佳木河组储层溶蚀的主要原因。
Abstract:
The Jiamuhe Formation of the Permian in the Zhongguai area of the Junggar basin is a sort of tight sandstone reservoirs with a large amount of volcanic detritus, which were believed to be formed in a fan delta environment. Comprehensive studies of core observation, thin section identification and core geophysical property test, the deep research of diagenetic characteristics and controlling factors of tight sandstone reservoirs has been conducted. It shows that the intense compaction and cementation of the reservoirs in Jiamuhe Formation may lead to the densification of reservoirs, and that laumontite, heulandite and analcite occur as the main cements of the sandstones. Because of the unconformity above the Jiamuhe Formation and the thermal maturation of the source rock, there occur weak acidic meteoric water dissolution and organic acid dissolution in the reservoirs of the Jiamuhe Formation, which lead to the dissolution of zeolite cement. As the result, the plane porosity averages 0.74%. Petrology, zeolites cementation and thrust fault activity controlled the mechanical compaction of Jiamuhe reservoirs. Volcanic detritus were the material basis of zeolite cement precipitation, and sedimentary facies and lithology resulted in the differentiation of zeolite cement in different regions. Weak acidic meteoric water was the main factor that leads to the dissolution of Jiamuhe reservoirs.
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