辽河盆地西部凹陷沙四上亚段页岩岩石类型、储集性能及影响因素  

The Types,Reservoir Performances and It's Influence Factor for the Shales of the Upper Part of Es4 in Western Sag,Liaohe Basin

作　　者：黄双泉[1] Huang Shuangquan(Institute of Exploration and Development of Liaohe Oilfield, Panjin, Liaoning 124010, China)

机构地区：[1]辽河油田勘探开发研究院,辽宁盘锦124010

出　　处：《非常规油气》2020年第3期16-23,共8页Unconventional Oil & Gas

基　　金：国家专项“渤海湾盆地辽河探区深层油气形成条件与有利区综合评价”子课题部分成果(No.2017ZX05008-006-002-003)资助。

摘　　要：以辽河坳陷西部凹陷沙四上亚段深湖页岩为研究对象,在岩石薄片鉴定的基础上,通过EM观察、矿物含量分析等,研究沙四段页岩岩石类型和储集空间类型、孔隙结构,探索页岩储烃能力的控制因素。研究区页岩分为云质页岩、灰质页岩和黏土质页岩等3类;页岩以发育裂缝—孔隙双介质储集空间和指数级范围孔喉系统为典型特征,储集空间主要为宏观裂缝、页理缝、溶孔,平均孔径在5.6~17.0 nm之间,孔隙度平均为2.89%,渗透率平均值为0.178 mD。不同类型页岩具有不同的孔隙结构,灰质页岩为主体平行板状狭长型裂缝,黏土质页岩和云质页岩属于孔缝混合型。脆性指数差异较大,云质页岩最高,其次为灰质页岩,黏土质页岩脆性指数最差。页岩储集性的差异性受控于沉积环境、物源和气候等引起页岩性质差异,以及构造运动和成岩作用导致储集空间的后期改造。Based on observation of the cores of the late Shahejie epoch shale,developed in the deep-water environment,the types of shale and reservoir space types,pore structure were studied and the factors affecting reservoir capacity were analyzed by observation through electron microscope and analysis of mineral content.Three lithofacies,i.e.calcareous shale,dolomitic shale,clay-shale were identified by method of“three extremities”.The shales developed double-medium reservoir space types as“fracture and pore”and multiscale pore-throat system as middle-micro-nano pores.Reservoir space types can be classified into two types as macro and micro ones.The macros contain macro-fracture,lamellation fracture which controlled respectively by tectonic plays and sedimentary.Four types of reservoir mirco-space,including dissolved-pore,inter-crystal pore,micro-fracture and inter-skeleton pore in algae remains,were found in the shale.The pore structure in calcareous shale is paralle flattened and narrow fracture dominated,which in clay-shale and dolomitic shale are pore-fracture mixture.The average aperture is between 5.6 and 17.0 nm and the average measurable porosity(2.89%)and the average permeability(0.178 mD)shows the physical property of shale is unexcelled.The brittleness index for dolomitic shale is highest as 72,calcareous shale is second as 66 and followed by caly-shale as 41.The reservoir performances of shale are dominated by internal and external causes.Depositional environment,source and climate were key factors that lead to differences among shales.Tectonic movements and diagenesis cause the current styles of reservoir spaces.Internal factors are basis of generating of different reservoir performances,and external factors are keys to changing for reservoir performances.

关 键 词：辽河盆地 西部凹陷 沙四段 页岩 储集空间 影响因素 

分 类 号：TE132[石油与天然气工程—油气勘探]