鄂尔多斯盆地东缘煤储层孔隙结构特征差异及影响因素

发布时间：2018-08-20 16:40

【摘要】：以鄂尔多斯盆地东缘煤储层为研究对象,通过镜质体最大反射率(Rmax)测试、压汞和低温液氮吸附实验等手段,探讨分析了煤储层孔隙结构发育特征及影响因素。结果表明:研究区煤储层视孔隙度偏低,且自北向南呈明显降低趋势,煤储层的孔隙发育情况以小孔、微孔为主,煤储层的BET比表面积平均为1.26 m~2/g,其中北部煤储层比表面积较大,煤储层BJH总孔容平均为0.00341 mL/g;受惰质组相对含量、压缩程度及次生孔隙影响,随着煤变质程度的增加,煤岩的孔隙度、BJH总孔体积和BET比表面积呈现"大—小—大"的变化规律,当R_(max)值为1.5%左右时,为最小值;煤储层随着所受应力的增强,微孔趋于闭合,其他各类孔数量均减小,整体上为小孔含量相对增加,煤中吸附孔隙类型由封闭型孔变为开放型孔,应力作用对煤岩的渗流孔隙的发育具有较强的控制作用,主要体现在煤岩中大孔对煤层气的贡献要优于其他孔隙。
[Abstract]:Taking the coal reservoir in the eastern margin of Ordos Basin as the research object, the pore structure development characteristics and influencing factors of coal reservoir were analyzed by means of (Rmax) test of vitrinite maximum reflectance, mercury injection and low temperature liquid nitrogen adsorption test. The results show that the apparent porosity of coal reservoirs in the study area is on the low side and decreases obviously from north to south. The pore development of coal reservoirs is dominated by small pores and micropores. The average BET specific surface area of coal reservoir is 1.26 mm2 / g. The specific surface area of northern coal reservoir is larger, and the BJH total pore volume of coal reservoir is 0.00341 mL / g on average, which is affected by the relative content of inertinite, compression degree and secondary porosity, with the increase of coal metamorphic degree. The total pore volume and BET specific surface area of coal and rock show the law of "big-small-large", and the minimum value is when the R _ (max) value is about 1.5%, and the micropore tends to close with the increase of stress, and the number of other kinds of pores decreases with the increase of stress. As a whole, the content of pore is increasing relatively, and the type of adsorption pore in coal is changed from closed pore to open pore. The stress effect has a strong control effect on the development of percolation pore of coal and rock. It is mainly reflected in the contribution of macropores to coalbed methane in coal rocks than in other pores.
【作者单位】：中联煤层气有限责任公司;中海石油(中国)有限公司非常规油气分公司;中国地质大学(北京)能源学院;
【基金】：国家科技重大专项课题(2011ZX05042-001)~~
【分类号】：P618.13

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