黔南地区下石炭统打屋坝组页岩气储层孔隙结构特征及含气性评价  

Pore structure characteristics and gas-bearing properties of shale gas reservoirs of Lower Carboniferous Dawuba Formation in southern Guizhou

作　　者：杨博伟 石万忠[1,2] 张晓明[1,2] 徐笑丰 刘俞佐 白卢恒 杨洋 陈相霖 YANG Bowei;SHI Wanzhong;ZHANG Xiaoming;XU Xiaofeng;LIU Yuzuo;BAI Luheng;YANG Yang;CHEN Xiangin(School of Earth Resources,China University of Geosciences,Wuhan 430074,China;Key Laboratory of Tectonics and Petroleum Resources,Ministry of Education,China University of Geosciences,Wuhan 430074,China;Chengdu Research Institute of Exploration and Development,PetroChina Daqing Oilfield Company,Chengdu 610041,China;Oil and Gas Survey Center,China Geological Survey,Beijing 100029,China)

机构地区：[1]中国地质大学资源学院,武汉430074 [2]中国地质大学教育部构造与油气资源重点实验室,武汉430074 [3]中国石油大庆油田公司成都勘探开发研究院,成都610041 [4]中国地质调查局油气资源调查中心,北京100029

出　　处：《岩性油气藏》2024年第1期45-58,共14页Lithologic Reservoirs

基　　金：国家“十三五”油气重大专项“页岩气区域选区评价方法研究”(编号:2016ZX05048-002)资助。

摘　　要：通过场发射扫描电镜观察、全岩X射线衍射分析、N2与CO_(2)等温吸附实验等,对黔南地区下石炭统打屋坝组页岩孔隙结构特征及含气性进行系统研究。研究结果表明:①黔南地区下石炭统打屋坝组页岩岩相类型主要为灰质页岩相和灰/泥混合质页岩相,含硅泥质页岩相少量发育;页岩有机质丰度偏低,成熟度较高。②研究区打屋坝组页岩孔隙类型可分为无机质孔隙、有机质孔隙和微裂缝,其中无机质孔隙占主导;页岩孔径分布呈多峰态,以小于1nm的微孔及2.0~2.4nm和6.0~8.0nm的低值介孔为主;页岩孔体积主要由介孔和宏孔提供,可控制游离气的赋存;页岩比表面积主要由微孔和介孔提供,可控制吸附气的赋存。③研究区打屋坝组页岩含气性主要受孔隙结构和保存条件的控制,其中孔隙结构的主要影响因素为有机质和矿物组分,有机质和黏土矿物含量对孔隙的发育具有积极作用,而脆性矿物含量在一定程度上抑制了孔隙的发育;强烈的构造变形是导致研究区页岩气保存条件较差的主要原因,可利用保存指数定性-定量评价打屋坝组页岩气的保存条件并进行有效分级。The pore structure characteristics and gas-bearing properties of shales of Lower Carboniferous Dawuba Formation in southern Guizhou were studied by using field emission scanning electron microscopy,whole-rock X-ray diffraction analysis,and isothermal adsorption of N2and CO_(2).The results show that:(1)Calcareous shale lithofacies and calcareous/clayey mixed shale lithofacies are developed in Lower Carboniferous Dawuba Forma‐tion in southern Guizhou,with a small amount of siliceous clay shale lithofacies developed.The shale has low organic matter abundance and high maturity.(2)The pore types of shales of Dawuba Formation in the study area include inorganic pores,organic pores and microfractures,among which inorganic pores are the dominant type.The pore size distribution of shale shows a multi-peak pattern,dominated by micropores less than 1 nm and low-value meso-pores of 2.0-2.4 nm and 6.0-8.0 nm.The pore volume of the shale is mainly provided by mesopores and macro‐pores,which control the occurrence of free gas.The specific surface area of the shale is mainly provided by micro-pores and mesopores,which control the occurrence of adsorbed gas.(3)The gas-bearing properties of Dawuba Formation shales in the study area are mainly controlled by pore structure and preservation conditions,and organic matters and mineral components are the main factors affecting pore structure.The organic matter content and clay mineral content have a positive effect on the development of shale pores,and the brittle mineral content inhibits the development of shale pores.The complex tectonic deformation in the study area has led to poor shale gas preser-vation conditions,and the preservation index can be used to qualitatively-quantitatively evaluate the preservation conditions of shale gas of Dawuba Formation and make effective classification.

关 键 词：页岩气储层 孔隙结构 无机质孔 有机质孔 含气性 构造变形 保存条件 打屋坝组 下石炭统 黔南地区 

分 类 号：TE122.1[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]