煤矿回采工作面钻孔注水联合探测试验研究

Experimental Study on Combined Detection of Drilling Water Injection in Coal Mining Face

为了解决工作面水害隐患和初步探测水力压裂影响范围,工作面形成后在正常煤层区域利用钻孔进行高压注水,促进煤层孔隙和裂隙发育,同时模拟工作面富水区,基于高压水的流动扩散性与富水区显著的物性差异,采用矿井高密度电法、矿井瞬变电磁法、高频电磁波CT对该区域注水前后进行联合探测试验,对综合物探成果进行对比分析,研究其电性参数的变化规律和初步圈定水力压裂后煤层的影响范围。探测试验研究表明:注水点附近煤层的视电阻率和衰减系数在注水前后发生明显变化,扩散半径约30 m范围内视电阻率降低2～4倍,扩散半径约10 m范围内衰减系数增幅20%左右。

To solve the hidden danger of water hazard in working face and preliminarily detect the influence range of hydraulic fracturing,after the formation of working face,high-pressure water injection is carried out by using boreholes in normal coal seam area to promote the continuous development of pores and cracks in coal seam.At the same time,the water-rich area of working face is simulated.Based on the significant physical difference between the flow and diffusion of high-pressure water and the water-rich area,mining is carried out.The high density resistivity method,transient electromagnetic method and high frequency electromagnetic wave CT were used to carry out joint detection test before and after water injection in this area.The comprehensive geophysical prospecting results were compared and analyzed.Detection test results show that apparent resistivity and attenuation coefficient of coal seam near water injection point change obviously before and after water injection.The apparent resistivity decreases 2~4 times in the range of diffusion radius of about 30 m,and the attenuation coefficient increases about 20%in the range of diffusion radius of about 10 m.