无围压下高电压脉冲放电在岩石压裂中的应用

Application of High Voltage Pulse Discharge in Rock Fracturing Without Confining Pressure

岩石压裂技术可以有效改善油气渗透性和导流能力,提高油气产量。为此,研究了高压大电流脉冲放电对岩石的压裂效应,研制了一套高能电弧压裂装置,并在无围压情况下进行了岩样压裂造缝实验。此装置主要由高频高压充电电源、储能单元、放电开关、放电电极和安全泄放装置组成,其最高工作电压为20 k V,最大储能为40 k J。在无围压条件下,对10块人造水泥砂岩进行了低能量和高能量压裂实验。实验结果表明,单次脉冲放电电压越高、单次储能越大、放电次数越多、岩样质地密度越小,高能电弧压裂效果越好。

The rock fracturing technology can effectively enhance the permeability, the flow conductivity, and the pro- duction of oil and gas. Hence, we researched the fracturing effect of high-voltage large-current on rock, and developed a high-energy arc fracturing device to carry out a series of fracture experiments in the absence of confining pressure. The device is mainly composed of high-voltage high-frequency charging supply, energy storage capacitor, discharging switch, discharging electrode, and safety discharging device. The maximum energy of the pulse power supply is 40 kJ and the working voltage is up to 20 kV. Then we conducted fracturing experiments on ten pieces of cement sandstone at low energy and high energy in the absence of confining pressure. The results show that the fracturing effect of high-energy arc can be enhanced with the larger discharge voltage of single-pulse, single energy storage, discharge times, and the lower rock density.