水射流割缝-注氮驱替联合促抽瓦斯模拟
Simulation on water jet slotting-nitrogen injection displacement combined with gas drainage
双海清 1张星 2李宝军 3林海飞 1周斌 1高海东 3崔名威4
作者信息
- 1. 西安科技大学 安全科学与工程学院,陕西 西安 710054;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
- 2. 西安科技大学 安全科学与工程学院,陕西 西安 710054;陕西铜川工业技师学院,陕西 铜川 727000
- 3. 陕西黄陵二号煤矿有限公司,陕西 延安 716000
- 4. 西安科技大学 安全科学与工程学院,陕西 西安 710054
- 折叠
摘要
针对低透气性煤层瓦斯抽采困难的问题,提出了水射流割缝-注氮驱替联合促抽瓦斯工艺,分析了工艺流程及原理.通过数值模拟建立普通煤层和割缝煤层模型,分别考察布孔间距和注气压力对不同煤层注氮驱替效果的影响,并对比相同条件下不同煤层注气影响范围,研究煤层割缝对注氮驱替效果的影响.结果表明:布孔间距由3m提升为7m注抽20d时,普通煤层注气影响范围由6.5m缩小为2.2 m,而割缝煤层由7.9m缩小为3.6 m;注气压力由1.0 MPa提升为3.0 MPa注抽20d时,普通煤层注气影响范围由1.0m提升为5.3 m,割缝煤层在相同注气压力条件下注气影响范围均大于普通煤层;煤层割缝对注氮驱替主要影响在水平方向,割缝区域临近缝槽之间互相贯通,形成椭圆形的复合区域;在分别抽采10,20,30 d情况下,普通煤层注气影响范围分别为1.56,2.65,6.51 m,而割缝煤层分别为2.16,5.75,11.55 m.煤层割缝可以有效提高瓦斯压力下降速率,在注气阶段,割缝组瓦斯纯量超普通组105.17%.割缝煤层注氮可以有效提高注气影响范围,增强瓦斯抽采效果,为联合促抽瓦斯工艺的进一步研究提供参照依据.
Abstract
Aiming at the difficulty of gas extraction in low permeability coal seams,a combined gas ex-traction process of water jet slotting-nitrogen injection displacement is proposed,and the process flow and principle were analyzed.Through numerical simulation,control models and slotted coal seam mod-els were established,and the effects of hole spacing and gas injection pressure on nitrogen injection dis-placement effect in different coal seams were investigated,respectively.The influence range of nitrogen injection in different coal seams under the same conditions is compared,and the influence of coal seam slotting on nitrogen injection displacement effect is studied.The results show that:When the hole spac-ing is increased from 3 m to 7 m for 20 days,the influence range of gas injection in control coal seam is reduced from 6.5 m to 2.2 m,while that in slotted coal seam is reduced from 7.9 m to 3.6 m.When the gas injection pressure is increased from 1.0 MPa to 3.0 MPa for 20 days,the influence range of gas injection in control coal seam is increased from 1.0 m to 5.3 m,and the influence range of gas injec-tion in slotted coal seam is larger than that in control coal seam under the same gas injection pressure.The main influence of coal seam slotting on nitrogen injection displacement is in the horizontal direc-tion.The slotting area is adjacent to the slot and communicates with each other to form an elliptical composite area.Under the condition of 10 d,20 d and 30 d extraction,the influence range of gas injec-tion in control coal seam is 1.56 m,2.65 m and 6.51 m,respectively,while that in slotted coal seam is 2.16 m,5.75 m and 11.55 m,respectively.Coal seam slotting can effectively improve the decreasing rate of gas pressure,and the simulation results are basically consistent with the field industrial test re-sults.Nitrogen injection in slotted coal seam can effectively improve the influence range of gas injection and enhance the effect of gas extraction,which provides reference for further research on combined gas extraction technology.
关键词
联合工艺/瓦斯抽采/割缝注气/注气影响范围/煤层瓦斯压力Key words
combined process/gas extraction/slotting gas injection/influence range of gas injection/coal seam gas pressure引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据