摘要
为了解决低渗透煤层抽采效果差、钻孔工程量大及抽采周期长的难题,提出水力压裂卸压增透技术。借助RFPA~(2D)-Flow软件模拟了压裂过程中压裂孔附近煤层从发生破裂、裂隙裂纹的生成演化、扩展延伸到最终贯通的完整过程,得到钻孔附近煤体的裂隙裂纹演化规律:伴随注水压力的持续升高,裂隙裂纹范围及最大剪应力也在增加,且随着压裂孔附近裂隙裂纹的延伸扩展,最大剪应力升高的同时在不断靠近控制孔;通过在斜沟煤矿18205材料巷实施水力压裂现场试验,发现当水压升高至16 MPa时有效影响半径为7 m,试验结果与模拟结果基本一致;压裂影响区域钻孔抽采浓度提高3. 43倍,抽采纯量增大8. 65倍,煤层透气性系数升高13. 4倍,抽采效果得到明显改善。
In order to solve the problems of poor extraction effect,large drilling capacity and long extraction period in low permeability coal seams,the technique of hydraulic fracturing decompression is proposed. Using RFPA~(2D)-Flow software to simulate the complete process of coal seam near the fracturing hole from rupture,crack generation evolution,extension to final penetration during fracturing process,the law of crack evolution of coal body near drilling is obtained: accompanied by continuous increase of water injection pressure. The crack range and the maximum shear stress are also increasing,and the maximum shear stress increases as the crack extends near the fracturing hole. By carrying out the hydraulic fracturing field test in the 18205 material lane of Xiegou Coal Mine,it is found that when the water pressure rises to 16 MPa,the effective influence radius is 7 m,and the test results are basically consistent with the simulation results. The drilling and extraction concentration in the area affected by fracturing increased by 3. 43 times,the purity of extraction increased by 8. 65 times,and the permeability coefficient of coal seams increased by 13. 4 times,and the extraction effect was significantly improved.
引文
[1]周西华,王鹏辉,门金龙,等.高瓦斯特厚煤层下分层千米钻孔瓦斯抽采技术[J].煤田地质与勘探,2016,44(4):20-24.
[2]毕建乙.马堡煤矿大直径顶板走向长钻孔瓦斯抽采技术研究[D].阜新:辽宁工程技术大学,2015.
[3]杨道华,王保锋,雷云,等.野川煤矿综放开采覆岩三带高度发育研究[J].中州煤炭,2014,11(2):1-3.
[4]周西华,毕建乙,王海东,等.高瓦斯低透气性煤层水力压裂增透技术研究[J].世界科技研究与发展,2015,37(3):243-246.
[5]毕建乙,王宗贵,张辉.基于气动风机的某矿工作面上隅角瓦斯治理技术[J].现代矿业,2018,34(6):28-31.
[6]何福胜,毕建乙,王海东.液态CO2相变致裂增透强化抽采技术研究[J].中国矿业,2018,27(S2):146-150.
[7]边小峰,毕建乙,张辉,等.基于COMSOL的顺层钻孔瓦斯抽采半径技术研究[J].煤炭与化工,2018,41(5):92-97.
[8]李国辉,毕建乙.液CO2相变致裂增透技术在低透气性煤层的应用[J].现代矿业,2017,33(8):228-231.
[9]何福胜,毕建乙,王海东.低透气性煤层水力压裂增透数值模拟研究[J].中国煤炭,2018,44(10):136-142,173.
[10]许江,马天宇,彭守建,等.煤岩体水力压裂动态演化物理模拟试验研究[J].煤炭科学技术,2017,45(6):9-16.
[11]石欣雨,文国军,白江浩,等.煤岩水力压裂裂缝扩展物理模拟实验[J].煤炭学报,2016,41(5):1 145-1 151.
[12]吴拥政,康红普.煤柱留巷定向水力压裂卸压机理及试验[J].煤炭学报,2017,42(5):1 130-1 137.
[13]何福胜,毕建乙.低渗自燃煤层采空区瓦斯与火共治平衡点研究[J].能源技术与管理,2017,42(6):1-4.
[14]边俊奇,毕建乙.斜沟煤矿褐煤燃烧状态判定研究[J].能源技术与管理,2018,43(2):79-81,141.
[15]毕建乙,张辉,王宗贵.大采高工作面采空区瓦斯抽采对自燃“三带”影响[J].山东煤炭科技,2018,42(7):92-95.
[16]李国辉,毕建乙,张辉,等.斜沟煤矿13号煤层自然发火特性试验研究[J].煤炭与化工,2018,41(4):111-115.
[17]李国辉,毕建乙.斜沟煤矿综放开采覆岩“三带”发育高度研究[J].能源技术与管理,2017,42(6):59-61.