川中地区上三叠统须四段砂体成因组合及对油气富集的影响  

Genetic Combination of the Sandbody in the Fourth Members of Xujiahe Formation (Upper Triassic) and Its Influence on Oil and Gas Reservoirs

作　　者：谢武仁[1] 李熙喆[1] 杨威[1] 张满郎[1] 谢增业[1] 金蕙[1] 

机构地区：[1]中国石油勘探开发研究院廊坊分院,河北廊坊065007

出　　处：《沉积学报》2009年第6期1084-1092,共9页Acta Sedimentologica Sinica

基　　金：中国石油天然气股份公司科技攻关项目(060101-2)部分成果

摘　　要：川中地区上三叠统须四段砂体厚度大,沉积稳定,为近物源区的三角洲沉积特征。沉积过程中,物源供应速率与可容纳空间增长关系的变化,导致须四段砂体自下而上由水退式、河道式和水进式三种不同成因类型的砂组纵向叠合而成;层序界面之上的河道式砂组为物性最好的成因砂体。水退式砂组主要由高能削截式河道、削截式河口坝和远砂坝组成,河道式砂组主要包括冲蚀下切式河道和高能削截式河道,水进式砂组主要包括低能河道、低能削截式河道、完整式河口坝和下缺式河口坝。由于不同的砂体组合,不同成因砂体间形成了不同的成岩相和储集相,河道式砂组以绿泥石衬边和溶蚀成岩相为主,物性好,为好的储集体;水进式砂组由压实和胶结相为主,物性较差;水退式砂组中溶蚀相和胶结相发育,物性较好,为中等的储集体。由于河道式砂组与水退式砂组呈沉积不整合相接触,呈现镶嵌关系,对天然气的运移起到通道作用,同时河道式砂组在平面上分布范围大,其中的高能削截式河道沉积稳定,为油气的富集提供了足够的空间,向上的水进式砂组发生储层致密化,形成有利的盖层,使河道式砂组发育区成为川中天然气富集的有利部位。The sandbody of Upper Triassic Xu 4 member in central Sichuan basin is thick, continuous sedimentation, and characterized by shore-shallow lacustrine-delta front-delta plain which is proximal. During sedimentation, there were different accommodation space/sedimentary supply values, the Xu 4 member sandbody consists of three vertical superposed types which is regressive,channel and transgressive from bottom to top; and the channel sandbody compo- sition on sequence boundary is the best genetic sandbody. Regressive sandbody mainly includes high energy truncation style channel,truncation style mouth bar and far bar sands;channel model sandbody mainly includes eroded style channel,high energy truncation style channel;transgressive sandbody mainly includes low-energy channel, low-energy truncation channel, complete mouth bar and lower part deletion mouth bar. Because the distribution of the different sand bodies combination, the different contributing sandbody formed different diagenetic facies and reservoir facies, the diagenesis of the channel sandbody is corrosion facies and lining chlorite facies, high-porosity, so it is good reservoir; the diagenesis of the transgressive sandbody is compaction and binder facies, poor physical property; the diagenesis of the transgressive sandbody is corosion and binder facies, better physical property, so it is medium reservoir. Because the interface between channel model and regressive model is unconformity which constitutes the pathways for gas mi- gration. In addition, the channel model sandbody is wide-ranging distribution, high energy truncation style channel sandbody stable depoition, and providing sufficient space for enrichment of oil-gas. The transgressive model sandbody reservoir on the top becoming tight as favorable caprock, and promotes the channel model sandbody to become the favorable position of central Sichuan basin.

关 键 词：川中地区 上三叠统 须四段 砂体成因 河道砂体 砂体组合 

分 类 号：TE122.221[石油与天然气工程—油气勘探]