不同坚固性系数f值煤渗透率分布特征及其井下水力压裂适用性分析

(1.西安科技大学 安全科学与工程学院,陕西 西安 710054; 2.西安科技大学 西部矿井开采及灾害防治教育部重点实验室,陕西 西安 710054)

煤层渗透率; 坚固性系数; 水力压裂; 瓦斯抽采

Distribution characteristics of coal seam permeability with different solidity coefficient f and applicability analysis of hydraulic fracturing of underground coal mine
XU Gang1,2,JIN Hong-wei1,2,LI Shu-gang1,2,HAO Meng1

(1.College of Safety Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Key Laboratory of Western Mine Exploitation and Hazard Prevention,Ministry of Education,Xi'an University of Science and Technology,Xi'an 710054,China)

coal seam permeability; solidity coefficient; hydraulic fracturing; gas extraction

DOI: 10.13800/j.cnki.xakjdxxb.2019.0309

备注

针对煤层水力压裂存在的盲目性和效果不确定性等焦点问题,首先以潞安矿区夏店煤矿为例,通过渗透性实验研究了煤坚固性系数f值,煤体结构和渗透率之间的关系,构建了基于坚固性系数的煤层水力压裂渗透率预测模型; 然后在分析煤层水力压裂增透机理的基础上,研究了不同煤坚固性系数煤层水力压裂的适用性。结果 表明:煤体渗透率与坚固性系数f值的关系近似呈正态分布,存在某一确定的fc值使煤渗透率最大; 煤层水力压裂的适用性与其坚固性系数大小有关,当压裂前煤f值小于fc值时,水力压裂增透作用效果有限; 当压裂前煤f值大于fc值时,压裂后煤渗透率增加较多,增透效果较好,适用于井下水力压裂技术的实施。工程应用结果与理论分析结果一致。

Aiming at the focal problems such as the blindness and the uncertainty of the hydraulic fracturing in coal seam,taking Lu'an Coalfield as an example,the relationship between coal solid coefficient f and coal body structure and coal seam permeability was studied through the permeability experiment,and the permeability prediction model of coal seam hydraulic fracturing based on the solid coefficient is constructed.Then on the basis of analyzing the mechanism of coal seam hydraulic fracturing increasing permeability,the effect of hydraulic fracturing with different coal solidity coefficient has been studied.The results show that the relationship between coal permeability and solid coefficient f is approximately normal distribution,and there is a certain fc value that makes the coal permeability maximum.The applicability of hydraulic fracturing is related to the size of solidity coefficient,when the f value of coal before fracturing is less than the fc value,the effect of hydraulic fracturing is limited.When the f value of coal before fracturing is greater than the fc value,the permeability of coal increases greatly and the effect of antireflection is better after fracturing,which is suitable for the implementation of hydraulic fracturing technology.The application results agree with the theoretical analysis results.