水力割缝辅助定向压裂煤体的割缝间距模型研究  

Slot spacing model of directional fracturing coal assisted by hydraulic slotting

作　　者：王刚[1,2] 范酒源 汪文瑞 徐浩 WANG Gang;FAN Jiuyuan;WANG Wenrui;XU Hao(State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;College of Mining and Safety Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China)

机构地区：[1]山东科技大学矿山灾害预防控制-省部共建国家重点实验室培育基地,山东青岛266590 [2]山东科技大学矿业与安全工程学院,山东青岛266590

出　　处：《采矿与安全工程学报》2020年第3期622-631,共10页Journal of Mining & Safety Engineering

基　　金：国家重点研发计划项目(2017YFC0805201):国家自然科学基金项目(51674158)。

摘　　要：为研究定向水力压裂的割缝间距,引入弹塑性力学理论与分形维数理论,分别建立缝槽力学模型与煤层注水渗透范围模型,分析缝槽的塑性区宽度及煤层注水的渗透范围。结合2个模型推导出定向水力压裂的割缝间距。以高家堡煤矿为例,检验割缝间距的合理性。同时,分析侧压系数、分形维数、迂曲度对割缝间距的影响效果。采用修正的Morris筛选法对影响定向水力压裂割缝间距的各因素进行灵敏度分析。研究结果表明:1)定向水力压裂割缝间距的理论值与现场实测值最大相对误差为8.643%,最大绝对误差为0.817 m,偏差较小,可为现场设计定向水力压裂的割缝间距提供理论参考。2)煤层注水渗透范围对定向水力压裂割缝间距的影响明显强于缝槽塑性区宽度。3)侧压系数对割缝间距影响较小,迂曲度与割缝间距呈现负相关性,分形维数与割缝间距呈现正相关性。4)煤层孔隙最大直径的灵敏度最大,迂曲度的灵敏度最小。In order to study the slot spacing of directional hydraulic fracturing,the elastoplastic mechanics theory and fractal dimension theory have been introduced to establish the mechanical model of the slot and the mechanical model of the coal seam water injection penetration range.The width of the plastic zone of the slot and the water injection penetration range of the coal seam have been analyzed.Two models have been combined to derive the slot spacing of directional hydraulic fracturing and the rationality of the slot spacing has been tested int Gaojiabao Coal Mine as an example.Simultaneously,the effects of lateral pressure coefficient,fractal dimension,and tortuosity on the slot spacing have been analyzed.The modified Morris screening method has been used for sensitivity analysis of various factors to the slot spacing of directional hydraulic fracturing.The results have shown that:1)For the theoretical value of the directional hydraulic fracturing slot spacing and the field measured value,the maximum relative error is 8.643%;the maximum absolute error is 0.817 m.The deviation is small,which can provide a theoretical reference for the slot spacing of directional hydraulic fracturing in the field.2)The influence of coalbed water injection penetration range on the slot spacing of directional hydraulic fracturing is significantly stronger than the groove plastic zone.3)The lateral pressure coefficient has little effect on the slot spacing,with the tortuosity in a negative correlation with the slot spacing,the fractal dimension in a positive correlation with the slot spacing.4)The sensitivity of the maximum diameter of the coal seam pores is the most,and that of the tortuosity is the smallest.

关 键 词：缝槽 塑性区宽度 煤层注水渗透范围 割缝间距 灵敏度分析 

分 类 号：TD714[矿业工程—矿井通风与安全]