辛置煤矿水力压裂卸压增透影响半径数值模拟研究

Numerical simulation of pressure relief and antireflection radius influenced by hydraulic fracturing in Xinzhi coal mine

随着开采深度的增加,辛置煤矿瓦斯涌出量显著增大。为了提高瓦斯抽采效率,拟采用水力压裂卸压增透技术。理论分析了水力压裂对煤层的卸压增透作用,基于此利用RFPA模拟软件对辛置煤矿2-559回采工作面水力压裂卸压增透进行了数值模拟。研究表明,水力压裂主要在以下3个方面对煤体起到增透作用:使煤体卸压、提高煤层透气性;湿润煤体,增加塑性;改善瓦斯抽放环境。辛置煤矿2-559回采工作面水力压裂所需压力约为15 MPa,压裂半径为5-6 m,以此可以初步确定现场施工过程中水力压裂钻孔间距以不大于10m为宜。

With the increase of mining depth, the gas emission of Xinzhi coal mine increases significantly. In order to improve the efficiency of gas drainage, the mine intends to use the hydraulic fracturing technology for pressure relief and antireflection. In this paper the pressure relief and antireflection by hydraulic fracturing was theoretically analyzed. On this basis, the pressure relief and antireflection by hydraulic fracturing of working face 2-559 of Xinzhi coalmine was simulated using RFPA. The results showed that hydraulic fracturing plays the role of antireflec- tion in the following three areas： pressure relief, improve permeability of coal seam; wet coal, increase its plastici- ty ; improve gas drainage environment. For this face, the pressure about 15 MPa can influence 5-6 m from the hole. This can initially identify that the space between gas drilling holes not greater than 10m is appropriate.