陕南地区牛蹄塘组页岩孔隙结构特征及吸附能力  

Pore structure characteristics and adsorption capacity of Niutitang Formation shale in southern Shaanxi

作　　者：陈相霖 郭天旭 石砥石[1,2] 侯啓东 王超[1,2] CHEN Xianglin;GUO Tianxu;SHI Dishi;HOU Qidong;WANG Chao(Oil and Gas Resources Survey Center,China Geological Survey,Beijing 100083,China;Key Laboratory ofUnconventional Oil & Gas Geology,China Geological Survey,Beijing 100029,China;School of EarthSciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]中国地质调查局油气资源调查中心,北京100083 [2]中国地质调查局非常规油气地质重点实验室,北京100029 [3]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《岩性油气藏》2019年第5期52-60,共9页Lithologic Reservoirs

基　　金：国家重大科技专项“大型油气田及煤层气开发”（编号：2016zx05034-002）;中国地质调查局项目“南方页岩气资源潜力评价”（编号：DD20160181）和“桂中—南盘江页岩气地质调查”（编号：DD20190088）联合资助

摘　　要：为揭示陕南地区下寒武统牛蹄塘组页岩孔隙结构特征及其吸附能力,采用场发射扫描电镜观察、有机地球化学分析、全岩X射线衍射、氮气吸附和等温吸附实验等方法,通过定性观察和定量表征相结合的方式,来研究该组页岩的孔隙结构类型,并探讨页岩孔隙结构和吸附能力的主控因素。结果表明:陕南地区牛蹄塘组页岩主要发育有机质孔、粒内孔、粒间孔和微裂缝等4种孔隙类型,页岩孔径为1.8~316.7 nm,BET比表面积为1.34~13.20 m^2/g,平均值为6.83 m^2/g,BJH吸附总孔体积为0.003~0.011 cm^3/g,平均值为0.006 cm^3/g;影响页岩孔隙发育的直接因素包括总有机碳含量和热演化成熟度,二者与孔隙体积和比表面积均呈正相关性;影响页岩孔隙发育的间接因素包括汉南古隆起周缘的构造运动和沉积环境,二者对牛蹄塘组页岩热演化成熟度、埋藏深度、厚度和岩性变化均具有较大影响,从而间接控制着页岩孔隙结构的发育特征;页岩吸附能力主要受有机碳含量、孔隙体积和比表面积等因素的影响,三者与甲烷吸附气量均呈正相关性。该研究结果对陕南地区寒武系页岩气资源潜力评价及选区评价均具有重要意义。In order to reveal the pore structure characteristics and adsorption capacity of rich organic shale of Cambrian Niutitang Formation in southern Shaanxi,a series of experimental testing techniques and methods such as field emission scanning electron microscopy,organic geochemistry,X-ray diffraction(XRD),nitrogen adsorption and isothermal adsorption experiment,were used to study the pore structure types by combining qualitative observation and quantitative characterization,and the main controlling factors of pore structure and adsorption capacity of shale were discussed.The results show that the main shale pore types of Niutitang Formation are organic pores,intragranular pores,intergranular pore and microfractures.The pore diameter is 1.8-316.7 nm,the BET specific surface area is 1.34-13.20 m^2/g with an average value of 6.83 m^2/g,the BJH adsorbed total pore volume is 0.003-0.011 m L/g with an average value of 0.006 mL/g.The direct factors affecting shale pore development are total organic carbon content and thermal maturity,which are positively correlated with pore volume and specific surface area.The indirect factors affecting shale pore development are tectonic movement and sedimentary environment around Hannan paleo-uplift and,which have great influences on thermal maturity,burial depth,thickness and lithologic changes of Niutitang Formation shale,thus indirectly control the development of shale pore structure.The adsorption capacity of shale is mainly affected by total organic carbon content,pore volume and specific surface area,which are positively correlated with methane adsorption volume.The research results are of great significance to the potential evaluation of Cambrian shale gas resources and the evaluation of selected areas in southern Shaanxi.

关 键 词：孔隙结构 吸附能力 页岩气 牛蹄塘组 陕南地区 

分 类 号：P618.13[天文地球—矿床学]