急倾斜含瓦斯煤层THM多场耦合机理及应用

1.神华新疆能源有限责任公司,新疆 乌鲁木齐 830027; 2.中煤科工集团 重庆研究院有限公司,重庆 400037; 3.瓦斯灾害监控与应急技术国家重点实验室,重庆 400037; 4.西安科技大学 能源学院,陕西 西安 710054

耦合模型; 煤层气; 温度; 孔隙率; 渗透率

Coupling mechanism of the thermo-hydro-mechanical(THM) in the extremely steep gas-bearing coal seams and its application
CHANG Bo1,CHEN Jian-qiang1,LIU Jun2,3,SUN Huan4,YAN Rui-bing4

(1.Shenhua Xinjiang Energy Co.,Ltd.,Urumqi 830027,China; 2.China Coal Technology Engineering Group Chongqing Research Institute,Chongqing 400037,China; 3.State Key Laboratory of Gas Disaster Detecting,Preventing and Emergency Controlling,Chongqing 400037,China; 4.College of Energy Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)

coupling model; coal seam gas; temperature; porosity; permeability

DOI: 10.13800/j.cnki.xakjdxxb.2016.0606

备注

以揭示急倾斜含瓦斯煤层温度场(Thermal)、渗流场(Hydrological)及应力场(Mechanical)的耦合影响作用为目的 ,通过借助多物理场数值分析软件(COMSOL),建立急倾斜含瓦斯煤层THM多场耦合数值计算模型,计算得出单孔抽采瓦斯过程中急倾斜煤岩体渗透率、温度及瓦斯压力随时间变化关系,并依托现场瓦斯抽采实践,提出合理的急倾斜煤层瓦斯治理措施与建议。结果 表明:单孔抽采过程中随着时间延长,抽采影响范围越大,瓦斯压力逐渐减小; 随着瓦斯抽采钻孔深度增加,单孔内部瓦斯压力增大,但压力变化梯度逐渐减小,孔壁温度小于其附近煤体温度; 依据单孔瓦斯抽采过程中煤岩体温度、压力及时间的非线性关系,制定了采空区埋管抽采、顶板走向高位钻孔抽采及卸压拦截抽采3种技术方案,工程应用效果显著。

Aimed at revealing the coupling mechanism of the thermal,hydrological and mechanical(THM)fields,numerical model of multi physics of the THM fields has been established on the extremely steep thick coal seams with CH4 gas.Relations of permeability,temperature and CH4 gas pressure have been revealed during the gas extraction in the extremely steep thick coal seams.The solutions and suggestions have also been proposed reasonably depending on the in-situ CH4 gas extraction.The results show that the gas extraction zone is extending as the stress dropping and the time duration.However,the stress gradient is decreasing as the deeper drilling boreholes.The temperature in the coal mass is higher than the borehole wall.Based on the non-linear relations of the temperature,the pressure and the time duration,the technical schemes of the gob extraction,the high level extraction along the trending and the intercept extraction and pressure liberation have been designed correspondingly.These methods have a significant effect on the practice.