煤矿井下智能压裂泵系统研究
Research on intelligent fracturing pump system in coal mine
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摘要: 为解决坚硬难垮落顶板治理、瓦斯抽采增透等安全高效开采技术面临的核心装备支撑不足难题,研究了一套煤矿井下智能压裂泵系统。该系统攻克了泄液回收大流量压力控制技术、压裂过程变频压力实时调节技术以及智能控制和监测技术等关键难题。研究阀芯硬密封副技术、可靠性开启技术、瞬态大流量流道和容腔设计及泄液回收技术和压力检测及泄压技术为一体的泄液回收大流量压力控制技术,研制了最大流量1 000 L/min、额定压力40 MPa的大流量泄液回收压力控制阀,实现大流量工况下压力精确控制和泄液回收功能。压裂过程变频压力实时调节技术是以坐封、起裂及压裂过程的压力需求函数,通过控制器、传感器、变频泵站及电控流量阀组成的控制闭环,实现了3~40 MPa大压力范围的压裂压力精确控制。智能控制和监测技术攻克了低压自动坐封、压力自动跟随起裂和压裂自动识别等核心技术难题。在榆林大梁湾煤矿、陕煤集团孟村煤矿和华晋集团沙曲一矿进行了井下超长孔复合压裂关键技术的实施验证,完成了坚硬岩层顶板水力压裂治理的工业性试验,现场试验得出:煤层起裂时间范围在4~15 min,起裂压力范围在15~21 MPa,压裂后维持压力在12~16 MPa,单次注水量范围在1.3~5.5 m3。应用表明,该系统能够满足超长距离坚硬难垮落顶板的弱化及治理对水力压力装备的要求。Abstract: In order to solve the problem of insufficient core equipment support for safe and efficient mining technologies such as hard and stable roof treatment,gas drainage and permeability enhancement,a set of underground intelligent underground fracturing pump system was studied. The key technical problems such as large-flow pressure control technology for flow recovery,real-time adjustment of frequency conversion pressure during fracturing,and intelligent control and monitoring technologies were solved. The valve core hard sealing technology,reliable opening technology,transient large flow channel and cavity design,leakage recovery technology,pressure detection and pressure relief technology were integrated into the drainage recovery large flow pressure control technology. A large flow discharge recovery pressure control valve with a maximum flow of 1 000 L/min and a rated pressure of 40 MPa was developed to realize accurate pressure control and discharge recovery under large flow conditions. The real-time frequency conversion pressure regulation technology was on the basis of the pressure demand function of the fracturing process,including sealing,initiation and fracturing process. Based on the control closed-loop in terms of the controllers,sensors,frequency conversion pump stations and electronically controlled flow valves,the precise control of fracturing pressure in a large pressure range from 3 MPa to 40 MPa was realized. The intelligent control and monitoring technology has overcomeLMcore technical problems such as the low pressure automatic sealing,automatic pressure follow-up initiation,and automatic identification of fracturing. The key technology of underground ultra long hole composite fracturing was verified,and the industrial test of hydraulic fracturing treatment of hard rock roof was completed in Yulin Daliangwan Coal Mine,Mengcun Coal Mine of Shaanxi coal group and Shaqu No.1 Coal Mine of Huajin Group. Field test shows that the time of coal fracturing initiation is in the range of 4-15 minutes,the initiation pressure is in the range of 15-21 MPa,the pressure during fracturing is maintained at 12-16 MPa,and the amount of single injection is in the range of 1.3-5.5 m3. The application shows that the system can meet the requirements for the equipment used for the weakening and treatment of the ultra-long-distance hard and stable roof.