煤矿井下水平保压取心保压触发装置研制与试验研究

R&D and experimental research of pressure-preserved triggering device for horizontal pressure-preserved coring in coal mines

瓦斯含量是煤矿安全开采和煤层气资源开发利用的重要评价指标,而保压取心技术是提高煤层瓦斯含量精确测定的有效途径。针对煤矿水平保压取心特殊工况,基于煤矿原位保压保瓦斯取心原理与技术,为提高保压煤样的采取率,研制了保压触发装置,系统设计了装置的密封保压单元、液压驱动模块和捞矛头与水平打捞器连接-脱卡机构等关键部件。搭建了保压触发装置工作性能地面试验系统,对装置性能进行试验研究。结果表明:在保压控制器阀盖5个典型的翻转方向工况下,保压触发装置的各功能模块均稳定运行,保压控制器均完成了翻转闭合;同时,钢丝绳顺利从取心钻杆内取出,有效防止取心器从孔底提至孔口过程中钢丝绳缠绕,避免引起设备故障。采用电动试压泵对已完成工作性能试验的取心器保压舱进行打压测试,结果表明:在最高压力为4.1 MPa条件下,压力表读数稳定,取心器保压舱内带压流体不发生泄漏,表明保压触发装置可触发取心器的密封保压功能。最后,在煤矿井下实际条件下对装置性能进行试验,结果表明:保压触发装置可在煤层实际工况下稳定实现取心器的密封保压功能,煤样采取率高达90%。保压触发装置的研发可促进煤矿水平保压取心技术的发展,对煤层瓦斯含量的精准测定具有重要意义。

Gas content is an important evaluation index of safe coal mining,as well as the exploitation and utilization of coalbed methane resources.Pressure-preserved coring is an effective way to improve the measurement accuracy of gas content in coal seams.Aiming at the special operating conditions of horizontal pressure-preserved coring in coal mines and based on the principle and technology of pressure-and gas-preserved coring in coal mines,this study developed a pressure-preserved triggering device and systematically designed the key components of the device,such as the sealing and pressure-preserved unit,the hydraulic drive module,and the salvager-unstuck mechanism between the spearhead and horizontal fisher.The purpose is to improve the recovery rate of pressure-preserved core samples.Furthermore,this study developed the ground test system for the performance of the pressure-preserved triggering device and conducted experimental research on the technological performance of the device using this system.As shown by the results,various function modules of the device operated stably,and the pressure-preserved controller successively turned over in five typical directions of the controller’s valve cover.Meanwhile,the wire rope was successively taken from the coring drill rod,effectively avoiding equipment failures caused by the winding of the wire rope when the corer was lifted from the borehole bottom to the borehole head.After the performance test,the pressure chamber of the corer was tested using an electric pressure test pump.The test results show that under the maximum pressure of 4.1 MPa,the pressure gauge readings remained stable,and the pressure fluids inside the pressure chamber did not leak,further indicating that the device can trigger the sealing and pressure-preserved functions of the corer.Finally,this study carried out an industrial test of the device under practical operating conditions of a coal mine.The results also show that the pressure-preserved triggering device can achieve the sealing and pressure-preserved functions of the corer stably under the actual working conditions of coal seams,with a coal sample recovery rate of up to 90%.The results of this study can promote the development of horizontal pressure coring technology for coal mines and are of great significance for the accurate determination of gas content in the coal seam.