利川龚家垭口三叠系飞仙关组储层成岩作用及孔隙演化  

Diagenesis and Pore Evolution of the Triassic Feixianguan Formation Reservoir in Gongjiayakou,Lichuan

作　　者：杨鹏 袁海锋[1] 叶子旭 YANG Peng;YUAN Haifeng;YE Zixu(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu,610059)

机构地区：[1]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059

出　　处：《中国煤炭地质》2023年第5期34-45,共12页Coal Geology of China

基　　金：国家自然科学基金资助项目(41872130)。

摘　　要：近年来,四川盆地环开江-梁平海槽区域飞仙关组滩相储层油气勘探取得了重大突破,指示了良好的勘探前景,对鄂西海槽西侧地区滩相储层的勘探具有借鉴意义。重点分析鄂西海槽西侧地区下三叠统飞仙关组储层成岩作用及孔隙演化,从利川龚家垭口剖面野外地质观察及野外岩样薄片观察入手,结合阴极发光分析、激光微区LA-ICP-MS微量元素分析及87 Sr/86 Sr同位素分析等技术手段,明确了龚家垭口飞仙关组滩相储层成岩作用类型及孔隙演化特征。认识如下:①研究区储层主要分布在飞二段顶部及飞三段,储集岩以台地边缘颗粒滩沉积的残余砂屑(鲕粒)白云岩,云质鲕粒灰岩、砂屑灰岩及鲕粒灰岩为主,局部发育晶粒白云岩,储集空间类型主要为粒间孔、粒间溶孔、粒内溶孔、晶间孔、晶间溶孔和铸模孔等;②研究区飞仙关组储层成岩作用总体可分为两类,一类是以胶结充填作用、压实压溶作用为主的破坏性成岩作用,另一类是以溶蚀作用及白云石化作用为主的建设性成岩作用,储层段白云石化模式为较局限环境下的同生—准同生期渗透回流白云石化模式,白云石化流体为高盐度局限海水,同时存在大气淡水的参与;③研究区颗粒滩储层经历多种成岩作用改造,颗粒岩类孔隙度为1.12%~2.5%。晶粒云岩因白云石化作用较发育,孔隙度分布在2%~4%,总体上孔隙度较低。综合研究认为,鄂西海槽西侧台缘带白云岩储层具有更大的勘探潜力。In recent years,great breakthroughs have been made in the oil and gas exploration of beachfacies reservoirs of the Feixianguan Formation in the area around the Kaijiang-Liangping trough in the Sichuan Basin,indicating good exploration prospects,which is of reference significance to the exploration of beach facies reservoirs in the west side of western Hubei Trough.This paper focuses on the analysis of reservoir diagenesis and pore evolution of the Feixianguan Formation on the west side of the Western Hubei Trough,based on the field geological observation and thin section observation of the Gongjiayakou section in Lichuan,combined with cathode luminescence analysis,laser micro-area LA-ICP-MS trace element analysis,and 87 Sr/86 Sr isotope analysis,the diagenesis types and pore evolution characteristics of beach facies reservoirs of Feixianguan Formation in Gongjiayakou section are clarified.Understanding is as follows:①Reservoirs in the study area are mainly distributed in the third member of the Feixianguan Formation and the top of the second member of the Feixianguan Formation.The reservoir rocks are mainly residual arenaceous or residual oolitic dolomite,dolomitic oolitic limestone,calcarenite,and oolitic limestone deposited in the platform-margin grain shoal facies,and crystalline dolomite is locally developed.The reservoir space types are mainly intergranular pores,intergranular solution pores,intragranular solution pores,intergranular solution pores,intergranular solution pores and mold pores.②The reservoir diagenesis of the Feixianguan Formation in the study area can be divided into two types.One is the destructive diagenesis dominated by cemented filling and compaction and pressure solution,the other type is constructive diagenesis dominated by dissolution and dolomitization,the dolomitization model of the reservoir is contemporaneous to penecontemporaneous infiltration reflux dolomitization model in a relatively restricted environment,the dolomitization fluid is confined seawater with high salinity and

关 键 词：飞仙关组 台内滩 成岩作用 白云石化 孔隙演化 龚家垭口 

分 类 号：TE122.23[石油与天然气工程—油气勘探]