孟尚志, 李勇, 吴翔, 郭晖, 徐延勇. 煤层气和致密气合采产能方程及影响因素[J]. 煤炭学报, 2018, (6). DOI: 10.13225/j.cnki.jccs.2018.4019
引用本文: 孟尚志, 李勇, 吴翔, 郭晖, 徐延勇. 煤层气和致密气合采产能方程及影响因素[J]. 煤炭学报, 2018, (6). DOI: 10.13225/j.cnki.jccs.2018.4019
MENG Shangzhi, LI Yong, WU Xiang, GUO Hui, XU Yanyong. Productivity equation and influencing factors of co-producing coalbed methane and tight gas[J]. Journal of China Coal Society, 2018, (6). DOI: 10.13225/j.cnki.jccs.2018.4019
Citation: MENG Shangzhi, LI Yong, WU Xiang, GUO Hui, XU Yanyong. Productivity equation and influencing factors of co-producing coalbed methane and tight gas[J]. Journal of China Coal Society, 2018, (6). DOI: 10.13225/j.cnki.jccs.2018.4019

煤层气和致密气合采产能方程及影响因素

Productivity equation and influencing factors of co-producing coalbed methane and tight gas

  • 摘要: 煤系煤层气、致密气、页岩气("三气")资源量丰富,实现同井筒合采将极大提高资源动用率和开发经济效益,但是当前多层合采条件下气、水的流动状态并不清楚。运用等值渗流理论,建立两层气藏压裂直井模型,推导了煤层气和致密气合采产能方程,分析了排水期和气水同产期的影响因素。结果表明:借鉴电路并联原理,可以建立多层合采渗流方程,求取排水期和气水同产期的合理生产压差;在排水期,岩石压缩系数越小,排水量越大,合理的排采压差也越高,泄流半径和初始渗透率等对排水量有影响,但对排采合理压差没有影响;在气水同产期,初始渗透率和岩石压缩系数对排采合理压差有一定影响,但兰氏应变常数、裂缝导流能力和弹性模量等对排采合理压差基本没有影响。相关成果对认识多层合采条件下气、水流动过程,开展产能分析,建立合理的排采制度具有重要的指示意义。

     

    Abstract: Coalbed methane,tight gas and shale gas(three gases) occurred in coal bearing strata are rich in resources and achieving a co-production from one well bore will significantly improve the resource recovery rate and economic benefits. However,the flow state of gas and water under the co-production process are still unclear. In this paper,a two layered gas reservoirs model in fractured vertical well was firstly established using the equivalent seepage theory. The production equation was proposed and the factors influencing the production rate during the gas drainage and gas-water co-producing rate was also analyzed. The results show that:the multi-layer linear seepage equation is established by re- ferring to the parallel principle,and the reasonable production pressure difference can also be acquired;during the wa- ter drainage period,the smaller the physical compressibility is,the higher the water production rate,and the higher the pressure difference is;the flow discharge radius and the initial permeability affect the water production rate,but show little influence on reasonable pressure difference;during the gas and water co-production period,the initial permeabili- ty and Langmuir stress constant have some influence on reasonable pressure difference,however,the coal compressibil- ity,fracture diversion ability and elastic modulus have little effect on pressure difference determination. The results are of significance in clearing the flow process of gas and water,conducting production analysis,and establishing reasona- ble drainage system.

     

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