煤层气低速非达西渗流解析模型及分析  

Analytical model of low-velocity non-Darcy flow of coalbed methane and its analysis

作　　者：宋洪庆[1] 朱维耀[1] 王一兵[2] 岳明[1] 刘卫东[2] 

机构地区：[1]北京科技大学土木与环境工程学院,北京100083 [2]中国石油勘探开发研究院廊坊分院,河北廊坊065007

出　　处：《中国矿业大学学报》2013年第1期93-99,共7页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(10772023);中国石油科技创新基金项目(2010D50060201);中央高校基本科研业务费专项基金(FRF-TP-12-003A)资助

摘　　要：基于渗流理论中质量守恒和动量守恒方程,建立了考虑煤层气解吸效应和低速非达西渗流特征的渗流数学模型,推导出全新的煤层气低速非达西径向流压力分布解析解和产能方程,定量计算后对低渗透煤层气产能低和储层难以有效动用进行了理论分析。研究结果表明:1)拟启动压力梯度每增加1kPa/m,储层有效动用半径下降约30%,因此拟启动压力梯度的存在使得井筒外围储层难以有效动用,对煤层气开发影响较大;2)解吸能力每增加1倍,煤储层的有效动用半径增加15%左右,因此煤层气开采过程中储层解吸能力越强,压降效果越好,储层波及范围则越大.Based on the conservation equation of mass and momentum, this research established a mathematical model for considering desorption effect and low-velocity non-Darcy flow of coal- bed methane, and deduced the new analytical solution and productivity equation of coalbed methane well with low-velocity non-Darcy flow. After quantitative calculation, detailed theoreti- cal analysis of mining problems such as low production and effective deployment was presented in this study. The results show that with every increas of 1 kPa/m of the threshold pressure gradient（TPG）, control radius in reservoirs decreases about 30%. Therefore, the existence of TPG makes the peripheral fluid flow of the wellbore more difficult to start effectively,and leads to low production rate. Besides, with every increas of 1 times of TPG,control radius reduces about 15%. Thus,the faster the desorption rate,the better the pressure drop and the larger the swept area.

关 键 词：煤层气 非达西 解吸 渗流 解析模型 

分 类 号：P618.11[天文地球—矿床学]