Reservoir Evaluation and Development ›› 2018, Vol. 8 ›› Issue (5): 64-69.

• Non-conventional Reservoir • Previous Articles     Next Articles

Study on effect and law of electric pulse hydraulic fracturing of low permeability coal

Bao Xiankai1,2,Duan Dongming1,Cao Jiaxing1,Wu Jinwen3,Zhao Jinchang2   

  1. 1. School of Civil Engineering, Inner Mongolia University of Science and Technology, Baotou, Inner Mongolia 014010, China
    2. School of Mining Technology, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China
    3. School of Science, North University of China, Taiyuan, Shanxi 030051, China
  • Received:2018-03-16 Online:2018-10-26 Published:2018-12-05


In order to reveal the effect and rule of hydraulic fracturing by high voltage electric pulse on coal crack, the analysis and the experiment about high voltage electrical hydraulic fracturing was carried out based on the principle of electro-hydraulic effect. Then three specimens were made. In the case of constant hydrostatic pressure at 3 MPa, different voltages(9 kV, 11 kV and 13 kV) were applied. The coal samples before and after the experiment were respectively scanned by ultrasonic nondestructive testing techniques to analyze the distribution and expansion of the coal internal cracks, and establish the numerical model to analyze the crack propagation rule and the surrounding stress distribution under experimental conditions. The results showed that the changes of the head ultrasonic wave's time could reflect the change of the crack in the coal sample before and after the experiment. The effect of the pure hydrostatic pressure at 3 MPa on the crack was very slight. While with the increase of the discharge voltage in the water, the new cracks inside the specimen and the density of cracks increased, and the fissure area extended from the central drilling to the edge of the test piece, coal crack effect was obvious. During the loading process, the maximum stress increased gradually and changed with the crack propagation.

Key words: high voltage electric pulse, ultrasonic nondestructive testing, electro-hydraulic effect, crack

CLC Number: 

  • TE122