定向水力压裂裂隙扩展动态特征分析及其应用

Analysis on Dynamic Characteristics of Cracks Extension in Directional Hydraulic Fracturing and Its Application

为减少煤矿井下水力压裂卸压盲区,扩大压裂影响范围,提高卸压增透效果,在分析水力压裂起裂机理和裂隙发展特征的基础上,提出定向水力压裂技术,分析定向水力压裂过程中煤体的裂隙发展分布规律,并利用RFPA2D-Flow软件模拟了压裂的起裂、扩展和延伸过程,对定向压裂与非定向压裂的效果进行了比较。最后将定向水力压裂技术在平煤集团十二矿己15-31010工作面进行了现场应用,得出在27 MPa的水压下,单孔压裂有效影响半径达6 m;单孔瓦斯抽放平均浓度较未压裂时提高80%,平均流量上升了382%,取得了显著的效果,具有良好的推广应用价值。

In order to reduce roof-floor blind area of hydrofracture in underground mines,expand influenced range of fracturing,and improve the effect of hydrofracture,a directional hydraulic fracturing technique was proposed on the basis of analyzing the mechanism of crack initiation and the characteristics of fracture development.And the process of crack starting,extending and elongating was simulated with RFPA2D-Flow.The effect of directional hydraulic fracturing and the effect of non-directional hydraulic fracturing were compared.Finally the directional hydraulic fracturing technique was applied in the F15-31010 mining workface of the Twelfth Coal of Pingdingshan Coal Mining Group.The results show that single drillhole fracturing effective radius rises to 6m under the pressure of 27 MPa,and the average concentration of single-drillhole gas drainage promotes 80%,average flow up 382% than that it is not fractured.All these suggest that the technology obtains remarkable effect,and has a high application value.