Pulsed Shockwave: Effect of Different Discharge Energy and Repeat Number on Rock Mechanical Properties

Abstract

Pulsed shockwave can be used as a technique for oil and gas production stimulation by changing the mechanical properties of rock. Based on the hydro-electric effect, the discharge equipment creates a pressure shockwave. The mechanical energy carried by the shockwave can cause damage to the rock. In this paper, the effect of discharge energy and repeat number on the rock’s mechanical properties was studied. A set of discharge pulse devices which consists of a charging and discharging system, a discharge chamber, and a test system were built. Experiments were performed with discharge energy between 2.5 kJ–8.0 kJ and repeat number between 20–100. The mechanical properties of rock affected by shockwave were tested by triaxial test. The results show that the rock fracture resistance decreases with the increase of discharge energy to a certain extent. In addition, under the same discharge energy conditions, more damage can be caused in the rock through repeated discharge.