不同含水条件下黏土孔隙分布特征及甲烷吸附能力

发布时间：2018-02-25 20:31

本文关键词： 黏土矿物孔隙分布比表面积含水饱和度甲烷吸附　出处：《煤炭学报》2017年09期 　论文类型：期刊论文

【摘要】：选用常见的页岩黏土矿物伊利石和高岭石,开展了不同湿度平衡样品的N2吸附/脱附实验和高压CH4吸附实验,研究黏土矿物孔隙分布特征的变化,并从微观上量化评价含水饱和度,分析其对甲烷吸附的影响。研究结果表明:水分的存在主要影响黏土矿物微小孔隙的分布,高湿度条件下(RH=98%)的毛细凝聚作用导致微小孔隙(5.15 nm)在孔径分布曲线上消失及比表面积的大幅下降。同时研究表明:黏土吸水能力与微小孔隙发育程度密切相关,当RH=98%时,微孔更为发育的高岭石含水饱和度(S_w=71.43%)高于伊利石(S_w=46.15%),且在此条件下,由于小孔凝聚以及吸附特征的改变(气-固吸附转变为气-液界面吸附),样品甲烷吸附能力下降近85%。因此,干燥条件下的实验结果不能代表实际页岩储集特征。
[Abstract]:Using common shale clay minerals Illite and kaolinite, N2 adsorption / desorption experiments and high pressure CH4 adsorption experiments were carried out to study the change of pore distribution characteristics of clay minerals. The effect of water saturation on methane adsorption is analyzed. The results show that the presence of water mainly affects the distribution of tiny pores in clay minerals. Under high humidity, the capillary agglomeration of RHX98) results in the disappearance of micropores on the pore size distribution curve and the significant decrease of specific surface area. The study also shows that the water absorption capacity of clay is closely related to the degree of micropore development, and when RH = 98, the water absorption capacity of the clay is closely related to the degree of micropore development. The water saturation of the more developed kaolinite is 71.43), which is higher than that of the Illite Swtl (46.15g). Under this condition, the methane adsorption capacity of the sample decreases by nearly 85 because of the change of pore aggregation and adsorption characteristics (gas-solid adsorption changes to gas-liquid interface adsorption). The experimental results under dry conditions can not represent the actual shale reservoir characteristics.
【作者单位】：中国石油大学(北京)石油工程教育部重点实验室;延长石油集团有限责任公司;
【基金】：国家科技重大专项资助项目(2017ZX05039005,2016ZX05042) 国家自然科学基金资助项目(51490654)
【分类号】：P618.13

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