多种流体作用下的白云岩储层发育过程和机制  

Dynamic Development Process and Mechanism of Dolomite Reservoir under Multi-fluid Alterations

作　　者：朱东亚[1] 张殿伟[1] 刘全有[1] 何治亮[1] 李双建[1] 张荣强[1] 

机构地区：[1]中国石化石油勘探开发研究院,构造与沉积储层实验室,北京100083

出　　处：《天然气地球科学》2015年第11期2053-2062,共10页Natural Gas Geoscience

基　　金：国家“973”项目(编号:2012CB214802);国家自然科学基金项目(编号:41230312;41372149)联合资助

摘　　要：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。By taking consideration of tectonic evolution,the complicate diagenetic processes of the Sinian Dengying Formation dolomite reservoir can be well discussed.Detailed petrographic observation,measurements of homogenization temperature and carbon and oxygen isotopes were carried out.The complicate diagenesis includes subaerial meteoric karst,filling of fibrous prismatic dolomites,crystal grain dolomites,calcites and quartz,entrapment of hydrocarbons,mesogenetic dissolution,and filling of pyrites.The maximal frequency of the homogenization temperatures of the fluid inclusions in the crystal grain dolomites is 190.0-200.0℃ and 220.0-230.0℃.The maximal frequency in the quartz is 150.0-160.0℃.The δ^（18）O（VPDB）values of the crystal grain dolomites are commonly lower than-10‰,indicating that the dolomites are hydrothermal dolomites.The dissolution and filling processes of the Dengying Formation dolomite reservoirs were generally related to the activities of fluids,which were controlled by tectonic environments.The coupled tectonicfluid alterations of the dolomite reservoirs include meteoric dissolution during Tongwan tectonic uplifts,dolomite cementation from seawater during the Dengying stage,hydrothermal dissolution and dolomite and quartz cementation during the Early Cambrian and Permian tectonic tension environments,emplacement of hydrocarbon-bearing fluids and related mesogenetic dissolution and filling of pyrites in the Late Silurian,and finally entrapment of gases during Yanshan-Himalaya deep burial stage.

关 键 词：灯影组 白云岩 成岩作用 构造活动 流体改造 

分 类 号：TE122.31[石油与天然气工程—油气勘探]