四川盆地中部合川—潼南地区茅二下亚段白云岩储层特征及成储机制  

Characteristics and formation mechanism of dolomite reservoirs in the lower submember of Maokou Member 2 in Hechuan⁃Tongnan area,central Sichuan Basin

作　　者：印长海[1,2] 师江波 谭秀成[3] 王显东 田小彬 鞠林波[1,2] 韦裕琳 汪海燕[1,2] 谭万仓 肖笛[3] 李明隆 杨文杰 YIN Changhai;SHI Jiangbo;TAN Xiucheng;WANG Xiandong;TIAN Xiaobin;JU Linbo;WEI Yulin;WANG Haiyan;TAN Wancang;XIAO Di;LI Minglong;YANG Wenjie(Exploration and Development Research Institute of Daqing Oilfield Company,Ltd,Daqing,Heilongjiang 163712,China;Daqing Oilfield Research Branch of Key Laboratory of Carbonate Reservoirs,CNPC;Southwest Petroleum University Research Branch of Key Laboratory of Carbonate Reservoirs,CNPC)

机构地区：[1]中国石油大庆油田有限责任公司勘探开发研究院,黑龙江省大庆市163712 [2]中国石油集团碳酸盐岩储层重点实验室大庆油田研究分室 [3]中国石油集团碳酸盐岩储层重点实验室西南石油大学研究分室

出　　处：《海相油气地质》2024年第2期136-146,共11页Marine Origin Petroleum Geology

基　　金：中国石油集团有限公司上游领域基础性前瞻性项目“残留型海相盆地构造-岩相古地理重建技术研究”(编号:2021DJ0501);国家自然科学基金面上项目“四川盆地早中二叠世白云岩及储层差异成因与峨眉山大火成岩省幕式响应”(编号:42172166)联合资助。

摘　　要：近年来四川盆地中部合川—潼南地区中二叠统茅二下亚段白云岩储层勘探取得了重要突破,但储层强非均质性制约了有利区带的预测。基于岩心和薄片观察、物性实验及地球化学分析,系统剖析茅二下亚段白云岩储层的基本特征,讨论白云岩的成因和储层形成机制。结果表明:(1)茅二下亚段储集岩以针孔状白云岩与孔洞状白云岩为主,储集空间类型为晶间(溶)孔、溶洞和裂缝;储层类型为以裂缝-孔洞型为主,裂缝-孔隙型为辅;以片状喉道为主,孔喉配置关系中等,裂缝为主要的渗流通道;针孔状白云岩平均孔隙度为2.50%,平均渗透率为0.806×10^(-3)μm^(2),孔洞状白云岩平均孔隙度为4.32%,平均渗透率为1.047×10^(-3)μm^(2)。(2)高能滩相是白云岩储层形成的物质基础,多期岩溶作用是形成优质储层的关键。准同生期白云石化作用增强了岩石抗压实能力,有助于储层孔隙的保持;茅口组沉积末期热液白云石化以胶结充填先期孔隙为主,降低了白云岩的储集性能。The Middle Permian Maokou Formation is an important stratigraphic series for increasing reserves and production in Sichuan Basin.The preliminary exploration mainly focused on the limestone fissure type reservoirs related to the weathered crust at the top of the Maokou Formation.In recent years,with the breakthrough of a series of high-yield wells in the central Sichuan region,the significant exploration potential in dolomite of the Maokou Member 2 has been demonstrated,including the intraplatform shoal dolomite reservoir of the lower member of Permian Maokou Member 2 in Hechuan-Tongnan area,while the strong reservoir heterogeneity restricts the further exploration.Based on core and thin section observation,physical property experiments and geochemical analysis,the basic characteristics of dolomite reservoir of the lower submember of Maokou Member 2 in Hechuan-Tongnan area are systematically analyzed,and the genesis and formation mechanism of dolomite reservoir are discussed.The results show that the dolomite reservoir of lower submember of Maokou Member 2 consists of pinhole dolomite and vuggy dolomite,and the reservoir space is characterized by intercrystal(dissolved)pore,karst cave and fracture as the main seepage channel.The reservoir type is mainly fracturevuggy reservoir,and secondly fracture-pore reservoir.The average porosity and permeability of pinhole dolomite of the full diameter sample are 2.50%and 0.806×10^(-3)μm^(2),and these of vuggy dolomite are 4.32%and 1.047×10^(-3)μm^(2).Combined with previous sedimentation and diagenesis research,it is considered that the high energy shoal facies is material base for reservoir development and multi-stage karstification is the key for the formation of high quality reservoir.Penecontemporaneous dolomitization is the key to reservoir space preservation by enhancing the compaction resistance of rocks.The late hydrothermal dolomitization of Maokou Formation related with the Dongwu Movement(Emei taphrogenesis in the upper-Yangtze region)in the late Middle Permian

关 键 词：白云岩 储层特征 成储机制 茅口组 四川盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]