黏土岩孔隙内表面积对甲烷吸附能力的影响  

Impact of internal surface area of pores in clay rocks on their adsorption capacity of methane

作　　者：吉利明[1,2] 邱军利[1,2] 宋之光[3] 夏燕青[1,2] 

机构地区：[1]甘肃省油气资源研究重点实验室(中国科学院地质与地球物理研究所兰州油气资源研究中心),甘肃兰州730000 [2]中国科学院油气资源研究重点实验室,甘肃兰州730000 [3]中国科学院广州地球化学研究所有机地球化学国家重点实验室,广东广州510640

出　　处：《地球化学》2014年第3期238-244,共7页Geochimica

基　　金：国家重点基础研究发展计划项目(2012CB214704-02);国家科技重大专项(2011ZX05008-002-22)

摘　　要：黏土矿物是气页岩储层中天然气吸附的重要孔隙介质。孔隙测量显示,蒙脱石以3～6 nm的小孔占优势,高岭石以20～80 nm 中-大孔为主,伊蒙混层矿物中两类孔隙都很发育。绿泥石和伊利石孔隙率较低,均以中-大孔为主。虽然6 nm 以下的微-小孔不一定是黏土矿物孔隙的主要构成,但它们是孔隙内表面积的主要贡献者,20 nm以下的孔隙是吸附气的主要储存场所。各种黏土岩、粉砂岩及石英岩的内表面积与其甲烷吸附性能具有相同的大小次序：蒙脱石＞伊蒙混层＞高岭石＞绿泥石＞伊利石＞粉砂岩＞石英岩,而它们的内表面积与最大甲烷吸附量显示良好的正相关关系,指示黏土矿物的气体吸附能力受其孔隙内表面积的控制。研究表明,页岩储层天然气吸附能力主要决定于小于20 nm,特别是小于6 nm微孔隙的发育程度,岩石类型及成因间接地影响其孔隙特征和吸附能力。Clay minerals are important porous media of natural gas adsorption in gas shale reservoirs. Pore measurements show that montmorillonite has dominant micropores of 3-6 nm, kaolinite mainly meso-macropores of 20-80 nm, illite-smectite mixed layer are of the two types of pores at the same time. Porosities of chlorite and illite are low, mainly the meso-macropores. Although micro-mesopores less than 6 nm are not necessarily the main components of pores in clay minerals, they are a major contributor to the internal surface area. Less than 20 nm micro-mesopores are the important storage sites of adsorbed gas. The internal surface area of a variety of claystone, siltstone and quartzite and their adsorption capacity of methane have the order of： Montmorillonite 〉 illite-smectite mixed layer 〉 kaolinite 〉 chlorite 〉 illite 〉 siltstone 〉 quartzite, and their internal surface area display good positive correlation with the maximum adsorption amount of methane, indicating that the internal surface area of clay minerals control its gas adsorption capacity. Studies show that the natural gas adsorption capacity of shale reservoir is primarily determined by the abundance of less than 20 nm, in particular less than 6 nm pores, the rock type and causes indirectly affect the pore characteristics and the adsorption capacity.

关 键 词：黏土矿物 内孔隙 比表面积 甲烷吸附 页岩气 

分 类 号：P597[天文地球—地球化学]