Coal Geology & Exploration


In order to study the effect of pressure drop funnel shapes on CBM well productivity, the change law of pressure and the shape of pressure drop funnel in different drainage stages of CBM wells were discussed, the mathematical models of pressure drop funnel were established, the concept of "desorption coefficient" and "effective desorption coefficient" for coal reservoir were proposed to quantitative study desorption effect of the coal reservoir. Taking a CBM well in the west of Guizhou as an example, the research results show that the logarithmic function model of pressure distribution of radial flow is difficult to accurately reflect the shape of pressure drop funnel at all stages. Four different types of pressure drop funnel models of logarithmic function, linear function, parabola function and elliptic function were compared and analyzed under the same desorption radius, the gas desorption volume and recovery ratio of the elliptic function model was the highest, recovery ratio reached 38%. The gas desorption volume and recovery ratio of the logarithmic function model were the lowest, and the recovery rate was less than 5%. Under the same drop funnels radius, the desorption radius and effective desorption radius of logarithmic, linear, paraboloid and elliptic function models were expanded successively, the desorption coefficient and effective desorption coefficient of the elliptic function model were the largest, when the pressure drop radius reached 140 m, the desorption radius of coal reservoir reached 135 m, the effective desorption radius reached 0.725, and the coal reservoir within the desorption radius was fully desorbed. By studying the change rule of productivity, recovery ratio and effective desorption radius under different pressure drop funnel shapes and different desorption radius, it is beneficial to master the law of reservoir pressure reduction in the process of CBM well drainage and to provide guidance for the desorption control of CBM well.


CBM, productivity, recovery ratio, drop funnel, effective desorption radius




[1] 胡海洋,倪小明,朱阳稳,等. 煤层气井渗透率时空变化规律研究及应用[J]. 特种油气藏,2016,23(5):106-109. HU Haiyang,NI Xiaoming,ZHU Yangwen,et al. Spa-tial-temporal permeability and its application in CBM well[J]. Special Oil & Gas Reservoirs,2016,23(5):106-109.

[2] 张崇崇,王延斌,倪小明,等. 煤层气直井排采过程中渗透率变化规律研究[J]. 中国矿业大学学报,2015,44(3):520-525. ZHANG Chongchong,WANG Yanbin,NI Xiaoming,et al. Research on permeability variation law of coal reservoir in drainage process of CBM vertical wells[J]. Journal of China University of Mining & Technology,2015,44(3):520-525.

[3] 冯其红,舒成龙,张先敏,等. 煤层气井两相流阶段排采制度实时优化[J]. 煤炭学报,2015,40(1):142-148. FENG Qihong,SHU Chenglong,ZHANG Xianmin,et al. Real-time optimization of drainage schedule for coalbed methane wells at gas-water two-phase flow stage[J]. Journal of China Coal Society,2015,40(1):142-148.

[4] 许小凯. 煤层气直井排采中煤储层应力敏感性及其压降传播规律[D]. 北京:中国矿业大学(北京),2016.

[5] 李金海,苏现波,林晓英,等. 煤层气井排采速率与产能的关系[J]. 煤炭学报,2009,34(3):376-380. LI Jinhai,SU Xianbo,LIN Xiaoying,et al. Relationship between discharge rate and productivity of coalbed methane wells[J]. Journal of China Coal Society,2009,34(3):376-380.

[6] 杜严飞,吴财芳,邹明俊,等. 煤层气排采过程中煤储层压力传播规律研究[J]. 煤炭工程,2011(7):87-89. DU Yanfei,WU Caifang,ZOU Mingjun,et al. Study on reservoir pressure transmission law during gas mining and drainage process of coalbed methane well[J]. Coal Engineering,2011(7):87-89.

[7] 王彩凤,邵先杰,孙玉波,等. 中高煤阶煤层气井产量递减类型及控制因素:以晋城和韩城矿区为例[J]. 煤田地质与勘探,2013,41(3):23-28. WANG Caifeng,SHAO Xianjie,SUN Yubo,et al. Production decline types and their control factors in coalbed methane wells:A case from Jincheng and Hancheng mining areas[J]. Coal Geology & Exploration,2013,41(3):23-28.

[8] 黄华州,桑树勋,苗耀,等. 煤层气井合层排采控制方法[J]. 煤炭学报,2014,39(增刊2):422-431. HUANG Huazhou,SANG Shuxun,MIAO Yao,et al. Drainage control of single vertical well with multi-hydraulic fracturing layers for coalbed methane development[J]. Journal of China Coal Society,2014,39(S2):422-431.

[9] 胡正田,万志杰,张东亮,等. 贵州官寨井田煤层气直井压裂工艺分析[J]. 煤田地质与勘探,2015,43(4):46-50. HU Zhengtian,WAN Zhijie,ZHANG Dongliang,et al. Analysis of CBM well fracturing in Guanzhai mine[J]. Coal Geology & Exploration,2015,43(4):46-50.

[10] 葛家理. 现代油藏渗流力学原理[M]. 北京:石油工业出版社,2003:81-89.

[11] 梁冰,贾立锋,孙维吉,等. 解吸-渗流作用下煤体变形及渗透规律试验研究[J]. 中国矿业大学学报,2018,47(5):935-941. LIANG Bing,JIA Lifeng,SUN Weiji,et al. Experimental on the law of coal deformation and permeability under desorption and seepage[J]. Journal of China University of Mining & Technology,2018,47(5):935-941.

[12] 李松,汤达祯,许浩,等. 深部煤层气储层地质研究进展[J]. 地学前缘,2016,23(3):10-16. LI Song,TANG Dazhen,XU Hao,et al. Geological evaluation theory and technology progress of coal reservoir dynamics during coalbed methane drainage[J]. Earth Science Frontiers,2016,23(3):10-16.

[13] 金军. 黔西松河井田松参1井煤储层物性垂向分布特征[J]. 煤炭科学技术,2016,44(2):27-32. JIN Jun. Vertical distribution features of coal reservoir physical property in Songcan No.1 well of Songhe mine field,west Guizhou[J]. Coal Science and Technology,2016,44(2):27-32.

[14] 赵欣. 煤层气产能主控因素及开发动态特征研究[D]. 徐州:中国矿业大学,2017.

[15] 刘升贵,袁文峰,张新亮,等. 潘庄区块煤层气井产气曲线特征及采收率的研究[J]. 煤炭学报,2013,38(增刊1):164-167. LIU Shenggui,YUAN Wenfeng,ZHANG Xinliang,et al.The production curve and recovery rate of coalbed methane well in Panzhuang block[J]. Journal of China Coal Society,2013,38(S1):164-167.

[16] 赵金,张遂安. 煤层气井底流压生产动态研究[J]. 煤田地质与勘探,2013,41(2):21-24. ZHAO Jin,ZHANG Sui'an. Production dynamics of CBM bottom hole pressure[J]. Coal Geology & Exploration,2013,41(2):21-24.



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