四川盆地合川-潼南地区茅二段滩相白云岩储层特征、主控因素及勘探意义.pdfVIP

四川盆地合川-潼南地区茅二段滩相白云岩 储层特征、主控因素及勘探意义 摘要： 由于四川盆地合川-潼南地区二叠系茅口组二段白云岩储层特征、主控因素认识不清，严重制约了勘探目标选择。厘 清茅口组白云岩发育特征及主控因素是预测白云岩储层分布的关键，基于岩心、测井资料、岩石学、地球化学和年代学技 术，开展白云岩储层的岩石类型、储集空间、储层类型、物性特征以及储层主控因素分析，并通过井震结合预测了储层分 布。结果表明：茅二段白云岩储层岩性以细- 中晶云岩、残余颗粒云岩为主，储集空间主要为粒内溶孔、晶间 （溶）孔、溶 洞及构造缝和溶缝，为低孔、低渗储层；白云岩储层主要发育在茅二段中部，横向分布稳定，在古地貌高部位的储层单层 厚度大，叠置连片；古地貌背景下的滩相沉积、准同生岩溶作用、准同生白云岩化作用及构造断裂作用共同控制了茅二段 2 白云岩储层的发育和分布；储层厚度与地震振幅呈正相关性，茅二段白云岩储层发育面积约为1 250 km ，主要分布在矿权 区中部和东北部地区，与茅二段古地貌高隆起带基本吻合。研究成果促进了川中地区茅口组勘探思路的转变，可有效支撑 下一步勘探部署。 关 键 词：四川盆地；合川-潼南地区；茅口组；白云岩储层；主控因素；勘探意义 Characteristics, controlling factors and exploration significance of shoal facies dolomite reservoirs in 2nd member of Maokou Formation in Hechuan⁃Tongnan area of Sichuan Basin Abstract ：Unclear understanding of characteristics and controlling factors of dolomite reservoirs in 2nd member of Permian Maokou Formation in Hechuan⁃Tongnan area of Sichuan Basin seriously restricts exploration target selec ⁃ tion. Determination of dolomite development characteristics of Maokou Formation is the key for predicting dolomite reservoirs distribution. Rock types, reservoir space, reservoir types and reservoir properties are analyzed based on core and logging data, petrology, geochemistry and chronological techniques, and reservoir distribution is predicted by well⁃seismic tie. The results show that dolomite reservoirs in 2nd member of Maokou Formation have lithology dominated by fine⁃medium crystalline dolomite and residual granular dolomite, and accumulation space dominated by intergranular dissolution pores, intercrystalline(dissolution) pores, vugs, structural fractures and dissolution frac⁃ tures, being low porosity and low permeability reservoirs . Dolomite reservoirs are mainly developed in middle part of 2nd member of Maokou Formation with stable lateral distribution. Reservoirs in high p