煤层水力压裂合理参数分析与工程实践

煤层水力压裂技术是近年来应用于高瓦斯低透气性突出煤层的一种卸压增透消突技术,人们对水力压裂的卸压增透消突机理有了较充分的认识,现场工程应用的效果也较好,但有关煤层水力压裂参数是如何确定的系统分析却是很少。笔者在阐述水力压裂机理及压裂过程的基础上,系统地阐述高瓦斯低透气性突出煤层水力压裂所需的注水压力、流量、注水时间、注水速度、孔间距、封孔长度等技术参数以及煤体内在因素的影响作用;最后在义安矿FD003工作面进行了水力压裂试验研究和效果考察,得出适合义安矿的水力压裂合理注水参数。通过水力压裂,煤层瓦斯抽放量和抽放浓度得到大幅度提高,达到了卸压增透防突效果,同时起到了润湿煤体和降尘效果。

Theoretical Analysis and Practical Study on Reasonable Water Pressure of Hydro-fracturing Technology

Hydro-fracturing technology is a depressurization antireflection elimination outburst technology for low permeability outburst coal seam with high methane.At present,the depressurization antireflection elimination outburst mechanism is sufficiently mastered,and its application effectiveness in field engineering is also good,but how to determine hydro-fracturing parameters is not systematically described.Based on the hydro-fracturing mechanism and technics,the hydro-fracturing parameters and affecting factors are systematically analyzed,such as the water pressure,flux,water injection time,water injection velocity,borehole space,and borehole-sealed length.By field engineering test applied in the low permeability outburst coal seam with high methane,the reasonable hydro-fracturing parameters of FD003 working face in Yi'An coal mine were obtained.Effectiveness tests show that the drainage quantity and drainage concentration increase greatly,and the effectiveness of depressurization antireflection elimination outburst is also achieved as well as the one of wetting coal and dust suppression.