软煤夹层水射流层状卸压增透抽采瓦斯数值模拟及试验

刘晓; 李勇; 宣德全; 胡世雄; 荆天祥; 徐森

doi:10.3969/j.issn.1001-1986.2021.02.007

软煤夹层水射流层状卸压增透抽采瓦斯数值模拟及试验

doi: 10.3969/j.issn.1001-1986.2021.02.007

刘晓^1,4,
李勇^1, ,,
宣德全^2,3,
胡世雄¹,
荆天祥¹,
徐森¹

基金项目:

国家自然科学基金青年项目(51804100)； 2015 年河南省科技攻关项目(152102310095)

详细信息

第一作者:
刘晓,1981年生,男,河北怀安人,博士,副教授,研究方向为煤矿瓦斯灾害预测及治理、煤层气勘探开发.E-mail:lx1224lx@163.com

通信作者:
李勇,1996年生,男,河南信阳人,硕士研究生,研究方向为煤矿瓦斯抽采理论与技术.E-mail:1655501539@qq.com

中图分类号: TD713
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出版历程
- 收稿日期: 2020-11-13
- 发布日期: 2021-04-25

Numerical simulation and test of gas drainage with water jet layered pressure relief and permeability enhancement in soft coal seam

摘要

摘要: 水力冲孔是煤层瓦斯增透抽采的主要技术措施，其主要以出煤量考察卸压效果，但是也存在出煤量大、卸压不均一、应力易集中等问题。因此，提出软煤夹层水射流层状卸压增透抽采瓦斯技术，考虑瓦斯压力压缩和煤基质吸附瓦斯膨胀对本体变形的影响，建立应力场、裂隙场、渗流场耦合条件下的多物理场理论模型，并结合COMSOL数值模拟软件对软煤夹层水射流分支数、卸压影响范围内煤体的瓦斯压力和瓦斯含量变化规律进行了研究。研究表明：当水射流分支长半轴为2 m，短半轴为0.22 m时，水射流分支数为6个时较为合理；在相同出煤率情况下，相同时间内瓦斯压力和含量均随着与钻孔距离的增加而减小，抽采180 d，水射流层状卸压有效抽采半径约为常规水力冲孔有效抽采半径的2.14倍，且在有效影响范围2 m时，水射流层状卸压瓦斯含量降低量为7 m³/t，而常规水力冲孔瓦斯含量降低量为4.1 m³/t，水射流层状卸压瓦斯降低量为常规水力冲孔的1.71倍；在新义煤矿现场试验中发现，当水射流层状卸压出煤率为常规冲孔出煤率的0.29~0.71倍，抽采较高浓度瓦斯时长仍是常规水力冲孔的2倍。软煤夹层水射流层状卸压增透抽采瓦斯技术的提出，对未来煤矿井下软煤夹层水力冲孔技术的发展有着重要的意义，为井下瓦斯的治理提供了新的方法和方向。
- 软煤夹层 /
- 层状卸压 /
- 瓦斯抽采 /
- 数值模拟 /
- 多物理场耦合 /
- 新义煤矿
Abstract: Hydraulic punching is the main technical measure to enhance permeability and drainage of coal seam gas. The pressure relief effect is mainly evaluated by the coal output. However, there are some problems such as large coal output, uneven pressure relief and easy stress concentration. Therefore, this paper puts forward the soft coal interlayer water jet layered pressure relief and permeability increasing gas drainage technology. Considering the influence of gas pressure compression and coal matrix adsorption gas expansion on the coal mass deformation, a multiphysics theoretical model under the coupling condition of stress field, fracture field and seepage field was established. With COMSOL numerical simulation software, the branch number of water jet、the variation law of gas pressure and gas content of coal within the influence range of pressure relief in soft coal interlayer were analyzed. The results show that when the long half axis of water jet branch is 2 m and the short half axis is 0.22 m, the number of jet branch number is 6 in numerical model which is more reasonable. Under the same coal output rate, the gas pressure and content decrease as the distance from the borehole increases. After 180 days of drainage, the effective drainage radius of layered pressure relief by water jet is about 2.14 times that of the conventional hydraulic punching. When the effective influence range is 2 m, the gas content of layered pressure relief by water jet is reduced by 7 m³/t, while that of conventional hydraulic punching is reduced by 4.1 m³/t. In the field application of Xinyi Coal Mine, it is found that when the layered coal discharge rate of water jet is 0.29-0.71 times of the conventional punching, and the time of extracting high concentration gas is still 2 times of the conventional hydraulic punching. The soft coal interlayer water jet layered pressure relief and permeability increasing gas drainage technology is of great significance to the development of soft coal interlayer hydraulic punching technology in the future, providing a new method and direction for coal mine gas control.
- soft coal interlayer /
- layered pressure relief /
- gas drainage /
- numerical simulation /
- multiphysics coupling /
- Xinyi Mine

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参考文献(20)

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