复杂坚硬岩层井上下联合水力压裂控制技术研究

Research on control technology of coordinated hydraulic fracture under complicated hard rock strata condition

本文开展复杂坚硬岩层井上下联合水力压裂控制技术研究,基于板壳力学理论,揭示了坚硬岩层失稳临界弯曲应变能特征,提出了基于弯曲应变能指标的压裂目标层确定方法,建立了井上下联合水力压裂控制技术体系。以大同矿区石炭系特厚煤层综放开采矿井为工程背景,确定了井上下联合水力压裂技术方案,并进行了现场工业性试验。通过分析微震、液压支架工作阻力、巷道变形量监测数据和回采巷道超前支护形式等方面,验证了井上下联合控制技术的适用性和有效性。结果表明:井上下联合水力压裂控制技术可在坚硬岩层中形成明显裂缝,破坏了复杂坚硬岩层的整体性及其强度,平均来压步距减小了34.6%,平均液压支架工作阻力降低了约15.1%,平均超前巷道变形量减小了约35.0%。研究成果为复杂坚硬岩层控制开辟了新路径,可为复杂坚硬岩层的精准控制提供技术支撑。

The research on the coordinated hydraulic fracturing control technology of complicated hard rock layers is carried out in the paper.A method is proposed for the spatial position of intricate hard rock strata based on the theory of plate-shell mechanics,and for determining the fracturing target layer with the elastic energy index.The technical scheme of ground and underground coordinated fracturing is established,and industrial experiments are conducted,based on the background of a fully mechanized caving coal mine in the Carboniferous extra-thick coal seam in the Datong mining area.The adaptability and effectiveness of the ground and underground coordinated fracturing technology are confirmed by analyzing the microseismic,hydraulic support working resistance monitoring data and the advanced support form of tailgate.The results show that hard rock strata can be fractured with coordinated ground and underground fracturing technology obviously.Integrity and strength of hard rock strata are destroyed.The average weighting step is reduced by 34.6%,the average working resistance of hydraulic support is reduced by 15.1%,and the deformation of tailgate is reduced by 35.0%.The research results pave the way for the control of hard rock strata technically and of complicated hard rock.formations.