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震旦系灯影组白云岩储层经历了多种类型的流体溶蚀作用,与构造演化相结合,从构造—流体耦合角度能够更好地研究白云岩储层流体改造过程和机理。对四川盆地野外和钻井岩心灯影组白云岩开展了详细的岩石学、矿物学观测、流体包裹体和微区碳氧同位素分析。结果表明,灯影组白云岩依次遭受了地表岩溶、环边放射状白云石胶结、晶粒状白云石胶结、方解石胶结、石英充填、油气充注、埋藏溶蚀和黄铁矿充填等成岩改造作用。晶粒状白云石主峰温度区间为190.0~200.0℃及220.0~230.0℃;石英中流体包裹体主峰温度区间为150.0~160.0℃。晶粒状白云石δ~(18)O_(VPDB)值均低于-10‰,具有热液白云石的特征。构造—流体耦合改造作用制约着灯影组白云岩储层的发育过程和机制,依次为,桐湾期构造抬升环境的大气降水岩溶作用,灯影末期构造沉降环境海水充填作用,早寒武世兴凯期以及二叠纪峨嵋期构造拉张环境下富Ca—Mg和富Si质热液流体溶蚀及相关晶粒状白云石和石英的充填作用,志留纪末期开始油气流体充注、埋藏溶蚀作用及黄铁矿充填作用,直至燕山—喜马拉雅阶段天然气的充注。
The Sinian Dengying Formation dolomite reservoir underwent various types of fluid erosion. Combined with tectonic evolution, the dolomite reservoirs could better study the fluid transformation process and mechanism of the dolomite reservoir from the structural-fluid coupling perspective. Detailed petrology, mineralogical observations, fluid inclusions, and carbon and oxygen isotope analyzes of microfacies are carried out in the dolomites in the field and drilling cores in the Sichuan Basin. The results show that the Dengying Formation dolomite has successively undergone diagenetic alterations such as surface karstification, radial dolomite cementation, grain-shaped dolomite cementation, calcite cementation, quartz filling, hydrocarbon filling, burial dissolution and pyrite filling. The main peak temperature range of crystalline dolomite is 190.0 ~ 200.0 ℃ and 220.0 ~ 230.0 ℃. The main peak temperature range of fluid inclusions in quartz is 150.0 ~ 160.0 ℃. The δ 18 O_ (VPDB) values of grain-shaped dolomite are both lower than -10 ‰, which is characteristic of hydrothermal dolomite. The structural-fluid coupling remodeling restricts the development process and mechanism of the dolomite reservoirs of the Dengying Formation, followed by the karstification of atmospheric precipitation in the Tongwan period tectonic uplift environment, the seawater filling of the sedimentary environment in the end of the light shadow, Xingkai period of the Early Cambrian and The dissolution of Ca-Mg-rich and Si-rich hydrothermal fluids and the associated filling of dolomite and quartz in the Permian Emeian tectonic pullout environment, the filling of oil-gas fluids, burial dissolution and yellow iron Filling of ore until the Yanshan - Himalayan natural gas filling.