井下水力压裂钻孔囊袋式两堵多注封孔技术及应用

Borehole Cementing Sealing Technology with Packer of Hydraulic Fracturing in Underground Coal Mine and Its Application

煤矿井下水力压裂钻孔主要应用于高瓦斯低透气性煤层的增透,封孔质量是影响压裂效果的关键因素之一。为了提高水力压裂钻孔的封孔质量,提出囊袋式"两堵多注"封孔的思路。在现有封孔技术的基础上,开发出了一套适用于煤矿井下水力压裂钻孔的囊袋式封孔技术,保证了水力压裂钻孔封孔质量。在淮南矿业集团公司9个煤矿共计施工97个水力压裂孔,在30MPa的压裂压力下,未出现孔口跑浆现象。压裂后煤层透气性系数达到原始状态下的5倍以上,单孔抽采纯量和抽采单元内抽采纯量均达到原始状态下的2倍以上。

The hydraulic fracturing drilling in the coal mine is mainly applied to increase the permeability of the coal seam, and the sealing quality is one of the key factors that affect the fracturing. In order to improve the quality of borehole sealing, a new sealing method of borehole cementing is proposed. A suit of sealing technology with packer is developed based on the existing sealing technology, which meets the technical requirements of hydraulic fracturing in underground coal mine. The results show that there are no leakage of mud at the 30 MPa fracturing pressure of the 97 hydraulic fracturing boreholes in Huainan Mining Industry Company. After fracturing, the permeability coefficient of coal seam is 5 times more than that of the original state, the drainage quantity of single hole and the unit is all 2 times more than that of the original state.