大水泥岩样的电脉冲压裂实验研究

在20 kV/40 kJ的重复频率压裂系统实验平台上，对大水泥岩样进行了电脉冲水中放电压裂实验。为了模拟井下实际工况，实验时将放电电极装入带有射孔的绝缘套管。水中脉冲放电时岩样中产生定向冲击压力波，冲击波作用于岩层使其产生裂缝。实验结果表明，冲击波通过绝缘套管作用于岩样时有一定的能量损失，部分冲击波压力会施加于绝缘套管，绝缘套管在整个实验期间没有发生形变，电脉冲放电对套管损伤作用极小，重复压裂冲击波会通过射孔在岩样上形成一定规模的微裂缝。去掉绝缘套管后，裸电极作用于岩样造缝效果会更好，裂缝明显的呈现对称规则。

Experimental study of fracturing under electric pulse for large cement sample

The electric pulse discharge experimental platform of 20 kV/40 kJ was set up and the impact fracture test of large cement sample was carried out. In order to simulate the actual working conditions, the discharge electrode was put into an insulated sleeve with perforation. While discharging in water, the directional impact pressure wave was produced in the rock sample, and the shock wave acted on the rock layer to produce cracks. The experimental results show that when the shock wave produced by the repeated electric pulse discharge acted on the big cement sample, it caused cracks on a certain scale, and the cracks on the rock sample surface are symmetrical. There was a certain energy loss when the shock wave moved through the insulating sleeve and part of the shock wave pressure was applied to the insulating sleeve, but the insulating sleeve did not deform during the discharging. The damage of electric pulse discharge on insulating sleeve is minimal.