高强电爆震致裂煤岩增渗数值模拟研究
作者:
作者单位:

1.中国中煤能源集团有限公司西南分公司;2.重庆大学 煤矿灾害动力学与控制全国重点实验室;3.中国矿业大学北京 应急管理与安全工程学院

中图分类号:

TD 712

基金项目:

重庆市级人才计划“包干制”项目(cstc2024ycjh-bgzxm0201)


Numerical simulation study on permeability enhancement of high strength electric detonation cracked coal rock
Author:
Affiliation:

1.China Coal Energy Group Co,Ltd Southwest Branch;2.State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University

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    摘要:

    为了提高低渗透性煤层气的抽采效率,深入探究高强电爆震技术对煤体裂缝生成及其扩展演化规律的影响,利用有限元软件LS-DYNA对高强电爆震冲击波致裂煤体过程进行模拟,主要从放电参数、地层条件和煤体物理力学参数等因素分析对煤体致裂效果。研究结果表明:随着放电电压的增大,煤体粉碎区、裂隙区及其破裂面积和半径均增加;放电次数增加时,煤体粉碎区逐渐增大,裂纹数量增加,但裂纹延伸长度呈现出先增大后减小的趋势,但裂纹的延伸长度却呈现出先增大后减小的变化态势,这表明在实际应用中存在一个最佳的放电作业次数范围;在相同放电电压下,随着煤体硬度的增强,对煤体的破碎程度减弱,煤体强度较弱的软煤,致裂效果最好;对于同种煤样,放电电压增大不仅加剧了煤体的破碎程度,而且增加了裂纹的数量,延长了裂纹的长度;在地应力条件方面,当水平主应力差小时,煤体易形成径向网状裂隙;应力差大时,则倾向于形成垂直于最小主应力方向的平直主裂隙。水平地应力的增加会抑制裂隙的扩展,导致煤体破裂半径和破裂度降低。

    Abstract:

    To improve the extraction efficiency of low-permeability coalbed methane and thoroughly investigate the effects of high strength electric detonation on the generation and propagation of fractures in coal, the finite element software LS-DYNA was used to simulate the process of high-strength electric detonation shock wave cracking coal. The effect of coal cracking is mainly analyzed from the factors such as discharge parameters, formation conditions and physical and mechanical parameters of coal. The results show that with the increase of discharge voltage, the crushing area, fracture area, fracture area and radius of coal increase. When the number of discharges increases, the coal crushing zone gradually increases, and the number of fractures increases, but the crack extension length shows a trend of increasing first and then decreasing, but the crack extension length shows a trend of increasing first and then decreasing, which indicates that there is an optimal range of discharge times in practical applications. Under the same discharge voltage, the degree of fragmentation in the coal decreases as its hardness increases, with softer coals exhibiting the best cracking effect. For the same coal sample, an increase in the discharge voltage not only intensifies the fragmentation but also enhances the number and length of fractures. In terms of in-situ stress conditions, a small horizontal principal stress difference favors the formation of radial network fractures in the coal, while a large stress difference tends to produce straight primary fractures perpendicular to the direction of the minimum principal stress. An increase in horizontal in-situ stress inhibits crack propagation, leading to a reduction in the rupture radius and degree of fragmentation in the coal body.

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杨涛,郭臣业,聂百胜,等. 高强电爆震致裂煤岩增渗数值模拟研究[J]. 科学技术与工程, , ():

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  • 收稿日期:2024-11-20
  • 最后修改日期:2025-01-06
  • 录用日期:2025-01-24