多场多相耦合下多孔介质压裂–渗流试验系统的研制与应用

Development and application of fracturing and seepage experimental system for multi-physical field and multiphase coupling of porous media

自行研制了多场多相耦合下多孔介质压裂–渗流试验系统。该系统由主机、电液伺服液压泵站、气压与水压供给系统、测量与控制系统等组成,最大轴向压力1 000 k N、最大围压60 MPa,试件尺寸为?50 mm×100 mm和?100×200 mm两种。该系统具有如下特点:(1)可以模拟多孔介质不同地应力、不同采动应力、不同温度、不同流体压力等多场耦合条件下的试验研究;(2)可以进行不同地应力、不同水压、不同温度条件下岩样的水力压裂试验,并可以精确测量压裂过程中岩样的应力、变形等的变化情况;(3)可以进行不同地应力及采动应力条件下多孔介质水、气等多相流体的渗流试验研究;(4)设计真空系统,可对系统内部的真空度进行控制,使试验条件控制更加精确;(5)系统主体部件围压室设计吊装在提升机构上并可进行上下限位,实现试验操作人员、试验系统及试验环境的系统安全。利用该系统对储层原煤及砂岩试件进行常规三轴加载试验及水力压裂试验,验证了该试验系统的可靠性。该试验系统为多场耦合条件下储层渗流及增渗的机制研究提供理论依据,对深部煤岩动力灾害控制及非常规天然气开采提高采收率具有重要的指导意义。

Fracturing and seepage experimental system for multi-physical field and multiphase coupling of porous media was self-developed. The system consisted of host, electrohydraulic servo pumping station, gas pressure and water pressure supply system, measurement and control system. The maximum axial stress is 1 000 kN and the maximum confining pressure is 60 MPa, and two kinds of specimen size are 050 mm× 100 mm and 0100 mm×200 mm. Characteristics of the system are illustrated as follows. （1） The experimental research of multi-physical coupling of porous media can be performed under different in-situ stress and mining stress and temperature and fluid pressure conditions. （2） The hydraulic fracturing test could be conducted and the change of permeability before and after fracturing can be measured accurately. （3） The seepage test of porous media of hydrosphere multiphase fluid can be performed under different in-situ stress and mining stress conditions. （4） Vacuum system is designed to precisely control the test conditions, it can control vacuum of system internal. （5） The system main component confining pressure chamber is designed of lifting on the hoisting mechanism to limit the displacement, it realizes system security of test operator and test system and test environment. Based on this experimental system, conventional triaxial loading and hydraulic fracturing test was performed on the raw coal and sandstone specimen and its reliability was verified. The experimental system can be used to provide theoretical basis for the seepage and enhanced permeability mechanism of reservoir under multi-physical field coupling conditions. The research has an important guiding significance on controlling of deep coal and rock dynamic disasters and enhancing recovery of unconventional gas.