元坝地区千佛崖组二段页岩层序与储层特征分析  

Analysis of Shale Sequence and Reservoir Characteristics of Second Member of Qianfoya Formation in Yuanba Area

作　　者：黄曼宁[1] Huang Manning(Geophysical Research Institute,SINOPEC Exploration Company,Chengdu Sichuan 610041)

机构地区：[1]中国石化勘探分公司物探研究院,四川成都610041

出　　处：《中外能源》2024年第6期57-65,共9页Sino-Global Energy

基　　金：中国石化“十条龙”科技攻关项目“涪陵地区侏罗系陆相页岩油气勘探评价技术”(编号:P21078-1)。

摘　　要：川东北元坝地区千佛崖组二段半深湖相页岩具有良好的页岩油气勘探前景。通过层序划分,对页岩岩相发育特征进行研究,对不同页岩岩相控制下的储层特征进行分析,明确准层序格架下不同页岩岩相的成因及对储层发育的影响。研究结果表明:千佛崖组二段可划分为7个准层序,根据准层序内的沉积特征,可将准层序划分为湖侵旋回为主型、湖退旋回为主型和均衡型3种不同的沉积模式。千佛崖组二段页岩发育有纹层状页岩相、层状页岩相和块状页岩相三种主要岩相类型,纹层状页岩相整体孔隙更发育,连通性更好,储集物性更好;层状页岩相整体孔隙发育程度和储集物性较纹层状页岩相次之;块状页岩相孔隙发育情况不佳,连通性一般,物性较差。页岩储层受岩相影响呈现出不同的特征,页岩岩相的纵向演化明显受准层序的控制,不同准层序类型的页岩岩相发育特征存在明显差异。整体来看,优质储层在最大洪泛面附近更为发育,优质页岩储层主要发育在湖侵旋回为主型准层序的中上部,有机质富集、孔隙发育且连通性好,是下一步勘探的有利目标;湖退旋回为主型准层序的中下部发育次优储层。The semi-deep lacustrine shale in the second member of the Qianfoya Formation in the Yuanba area in northeastern Sichuan has good shale oil and gas exploration prospects.Through sequence division,this paper studies the development characteristics of shale lithofacies,analyzes the reservoir characteristics under the control of different shale lithofacies,and clarifies the genesis of different shale lithofacies in the parasequence framework and their influence on reservoir development.The research results show that the second member of the Qianfoya Formation can be divided into seven parasequences.According to the sedimentary characteristics within the parasequences,the parasequences can be divided into three different sedimentary modes:lake transgression cycle-dominated type,lake regression cycle-dominated type,and equilibrium type.The shales in the second member of the Qianfoya Formation have three main lithofacies types:laminar shale facies,layered shale facies,and massive shale facies.The laminar shale facies have more developed overall pores,better connectivity,and better reservoir properties.The overall pore development degree and reservoir properties of the layered shale facies are inferior to those of the laminated shale facies.The massive shale facies have poorly developed pores,general connectivity,and poor physical properties.Shale reservoirs show different characteristics due to the influence of lithofacies.The vertical evolution of shale lithofacies is controlled by parasequences,and there are obvious differences in the development characteristics of shale lithofacies for different parasequence types.High-quality reservoirs are more developed near the maximum flooding surface.High-quality shale reservoirs,mainly developed at the upper and middle parts of the parasequences dominated by the lake transgression cycle,are favorable targets of the next step of exploration for being rich in organic matter,well-developed pores,and good connectivity.Suboptimal reservoirs are developed at the middle and lower pa

关 键 词：层序划分 准层序格架 页岩岩相 纹层状页岩 孔隙结构 储集物性 

分 类 号：P61[天文地球—矿床学]