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黄婷, 刘正. 榆社-武乡区块煤储层孔隙结构特征及其影响因素[J]. 煤炭科学技术, 2019, (7).
引用本文: 黄婷, 刘正. 榆社-武乡区块煤储层孔隙结构特征及其影响因素[J]. 煤炭科学技术, 2019, (7).
HUANG Ting, LIU Zheng. Analysis on pore structure characteristics and influencing factors of coal reservoir in Yushe-Wuxiang Block[J]. COAL SCIENCE AND TECHNOLOGY, 2019, (7).
Citation: HUANG Ting, LIU Zheng. Analysis on pore structure characteristics and influencing factors of coal reservoir in Yushe-Wuxiang Block[J]. COAL SCIENCE AND TECHNOLOGY, 2019, (7).

榆社-武乡区块煤储层孔隙结构特征及其影响因素

Analysis on pore structure characteristics and influencing factors of coal reservoir in Yushe-Wuxiang Block

  • 摘要: 为研究低孔低渗煤储层制约煤层气井高产的原因,以沁水盆地中东部榆社-武乡区块山西组和太原组煤储层为研究对象,采用扫描电镜电子成像技术和低温液氮吸附试验分析方法,研究探讨了煤储层孔隙结构特征及其影响因素。结果表明:研究区煤储层纳米级孔隙多发育在镜质组中,少数发育在惰质组中,以变质成因孔最为常见,亦发育原生孔和矿物质孔;孔隙形态以墨水瓶形孔和狭缝形孔为主;煤储层平均比表面积1.3429m2/g,平均孔容0.125px3/g,平均孔径15.7442nm,孔隙系统渗流能力较差。随着变质程度加深和镜质组百分含量增加,比表面积呈现出简单的递增趋势;而孔容、孔径最重要的影响因素为煤体结构,碎裂煤的孔容和孔径要明显高于原生结构煤。

     

    Abstract: To study the reasons for controlling high productivity of coalbed methane wells in low porosity and low permeability coal reservoirs,the coal reservoirs of Shanxi and Taiyuan Formations in Yushe - Wuxiang Block located in the central and eastern Qinshui Basin were studied. The pore structure characteristics and influencing factors of coal reservoirs were studied and analyzed by scanning electron microscopy (SEM) electronic imaging technology and the cryogenic liquid nitrogen adsorption experiment. The results show that the nano-scale pores of coal reservoirs mostly developed in the vitrinite group while a few of them developed in the inverting group. Among them, the metamorphic pore is the most widely encountered. The protogenetic pores and mineral pores also developed. The pore morphology is mainly ink-bottle holes and slit holes. The average specific surface area of coal reservoir is 1.342 9 m2/g, and the average pore volume is 0.005 0 cm3/g. Additionally, the average pore diameter is 15.744 2 nm. The influent capacity of pore system is poor. The contribution of specific surface area is dominated by micropores. The specific surface area shows a simple increasing trend as the metamorphism deepened and the percentage content of the vitrinite increased. However, the coal structure is the most important factor in influencing the pore volume and pore diameter. The pore volume and pore diameter of fractured coal are apparently higher than that of the protogenetic coal.

     

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