China Coal Energy Company Limited
CCTEG Coal Mining Research Institute Co. , Ltd.

针对坚硬顶板工程尺度条件下压裂防冲裂隙演化规律研究不足造成压裂效果难以评价的难题,选取门克庆煤矿3106工作面为工程背景,以高位厚硬砂岩顶板长孔水力压裂研究为切入点,选取钻孔漏失率及瞬变电磁技术,研究坚硬顶板压裂前、后不同层位岩层裂隙钻孔漏失率与瞬变电磁电阻率的时空演化规律,验证了坚硬顶板弱化前、后覆岩裂隙发育规律及扩展范围,为水压致裂裂隙演化规律及影响范围的压裂效果评价提供理论指导。研究结果表明:当钻孔处于裂隙不发育区域时,压裂层位所在区域压裂前、后钻孔漏失量呈现出明显的倍数增长趋势,从钻孔漏失量角度验证了压裂岩层区域的裂缝扩展范围,结合瞬变电磁在岩层裂隙含水量增加后呈现的降阻现象验证了裂隙发育范围的可靠性,为水力致裂裂隙演化规律及影响范围研究提供理论指导,为坚硬顶板工程尺度条件下水力压裂效果评价提供了新方法。

To clarify the uncertainty of fracturing effect due to the insufficient research on the law of fracture evolution and burst-prevention cracks under hard roof engineering conditions, No. 3106 working face of Menkeqing Coal Mine was selected as the research background. Starting with long hole hydraulic fracturing research of the high, thick hard sandstone roof, drilling leakage rate and transient electromagnetic technology were used to study the evolution of drilling leakage rate and transient electromagnetic resistivity in different layers of rock strata fissures before and after fracturing. The development law and expansion range of overlying rock fractures before and after the weakening of hard roofs were verified, which provided theoretical guidance for evaluating the law of hydraulic fracturing evolution and the influence range of hydraulic fracturing. The results indicate that when the borehole is in undeveloped fissure area, the drilling leakage rate in the fracturing layer shows a significant increase before and after fracturing. This confirms the fracture extension range in the fractured layer area from the perspective of drilling leakage. The reliability of the fracture development range was verified by the phenomenon that the resistance of transient electromagnetism reduced with the increase of water content in rock fractures. It provides theoretical guidance for studying the evolution and impact range of hydraulic fracturing and offers a new method for evaluating the effectiveness of hydraulic fracturing under hard roofs.

苏士杰,孙如达,赵乾,等.窄煤柱厚硬砂岩顶板防冲弱化裂隙发育规律[J].煤炭工程,2024,56(6):135-143.