煤矿安全2025，Vol.56Issue(2)：58-66,9.DOI:10.13347/j.cnki.mkaq.20231783
煤层气井排采中断后恢复模式对支撑裂缝内煤粉运移的影响
Influence of recovery model of coalbed methane wells after drainage interruption on coal fines migration in propped fractures
摘要
Abstract
In the drainage process of coalbed methane well,the interruption of drainage will induce a large amount of coal fines to stay in propped fractures,causing damage to the permeability of propped fractures.Based on the solid-liquid two-phase flow and gas-liquid-solid three-phase flow two patterns,experiments were carried out to investigate the effect of recovery mode after drainage in-terruption on coal fines migration in propped fractures.The permeability evolution law of propped fractures under the one-stage re-covery mode and step-by-step recovery mode was compared,and the mechanism of coal fines migration under different recovery modes was revealed.The results show that the one-stage recovery mode can increase the permeability of propped fractures above the pre-interruption level under the condition of solid-liquid two-phase flow,but the step-by-step recovery mode is difficult to restore the permeability of propped fractures to the pre-interruption level.Under the condition of gas-solid-liquid three-phase flow,both the one-sta-ge recovery mode and the step-by-step recovery mode can increase the permeability of gas phase and liquid phase beyond the pre-inter-ruption levels,and the one-stage recovery mode presents a better improvement effect than the step-by-step recovery mode.Under the conditions of solid-liquid two-phase flow and gas-liquid-solid three-phase flow,the retention forms of coal fines in propped fractures are mainly solid-liquid interface and gas-liquid interface adhesion,which is the main reason for the different improvement effects of the permeability of propped fracture under a same recovery mode.The flow rate amplification of the first-stage recovery mode is much greater than that of the step-by-step recovery mode,resulting in greater wall shear stress and stronger gas-liquid interface disturbance effects.As a result,the promotion and discharge effect on retained coal fines is stronger,and the improvement effect on permeability is better.During the stages of single-phase water drainage and gas-water joint drainage,in order to suppress the impact of drainage in-terruption on the permeability of propped fractures,the first-stage recovery mode should be adopted after the interruption of drainage.关键词
煤层气/煤粉运移/支撑裂缝/排采中断/排采恢复Key words
coalbed methane/coal fines migration/propped fracture/drainage interruption/drainage recovery分类
矿山工程引用本文复制引用
毛崇昊,皇凡生,胡秋嘉,刘世奇,张聪,雷兴龙..煤层气井排采中断后恢复模式对支撑裂缝内煤粉运移的影响[J].煤矿安全,2025,56(2):58-66,9.基金项目
国家自然科学基金资助项目(42002182,42372184) （42002182,42372184）
