川东地区长兴组白云岩储层成因与成岩系统  

Origins and diagenetic system of dolomite reservoirs in the Upper Permian Changxing Fm,eastern Sichuan Basin

作　　者：党录瑞[1] 郑荣才[2] 郑超[1] 文其兵[1] 陈守春[1] 廖军[1] 

机构地区：[1]中国石油西南油气田公司重庆气矿 [2]"油气藏地质及开发工程"国家重点实验室.成都理工大学

出　　处：《天然气工业》2011年第11期47-52,123,共6页Natural Gas Industry

基　　金：国家自然科学基金(项目编号:41172120和40672073)

摘　　要：对于川东地区上二叠统长兴组礁滩相白云岩储层的成因一直存在争议,为此,对该区白云岩成因类型、地球化学特征(铁、锰、锶微量元素,碳、氧、锶稳定同位素)及流体包裹体特征进行了综合研究。从成岩流体性质和产物的组合特征出发,按"水文体制"将长兴组白云岩划分为准同生阶段海源同生卤水、早成岩阶段源于飞仙关组地层封存热卤水、中—晚成岩阶段复合源混合热卤水、构造隆升阶段有深部热液参与的混合热液4个成岩系统。各系统成岩流体性质虽有不同,但对多期次的埋藏白云岩化作用和白云岩储层的形成、演化与分布都有重要的继承性控制作用:准同生阶段一般不具备储集意义;早成岩阶段是储层发育的基础阶段;中—晚成岩阶段扩大了储层分布范围和发育规模;构造隆升阶段是提高储层质量的关键时期,也是控制优质白云岩储层在区域上沿构造活动带分布的主要因素,可作为预测优质白云岩储层的重要依据。There is much debate over the origins of dolomite reservoirs of reef-bank facies in the Upper Permian Changxing Fm in the eastern Sichuan Basin.In view of this,a comprehensive study is performed on the genetic types,geochemical behaviors(trace elements such as Fe,Mn and Sr,stable isotopes of C,O and Sr)and fluid inclusions of the dolomite in the study area.Based on the properties of diagenetic fluids and the assemblage features of their products,and according to'hydrological system',four diagenetic systems are identified in the dolomite of the Changxing Fm,namely the marine-derived associated brine during the penecontemporaneous stage,the sealed hot brine derived from the Feixianguan Fm in the early diagenetic stage,the mixed hot brine during the middle-late diagenetic stage,and the mixed hydrothermal fluid involving deep thermal water during the tectonic uplift stage.Although their diagenetic fluid properties are different,they all have crucial inherited controls on the multi-stage burial dolomitization and the formation,evolution and distribution of the dolomite reservoirs.In the penecontemporaneous stage,reservoirs were generally poorly developed.In the early diagenetic stage,the development of reservoirs initiated.In the middle-late diagenetic stage,the scale of reservoirs enlarged.In the structural uplifting stage,the reservoir quality was improved.Structural uplifting is the major factor controlling the regional distribution of quality dolomite reservoirs along the active structural zone,thus it can be regarded as the important basis for the prediction of quality dolomite reservoirs.

关 键 词：川东地区 晚二叠世 白云岩 储集层成因 地球化学特征 成岩流体 成岩系统 长兴组 流体包裹体 

分 类 号：P618.13[天文地球—矿床学]