Experimental investigation of the flow conductivity characteristics in shale's single fracture under the PHF stimulation

Abstract

The pulsating hydraulic fracturing (PHF) technology can be employed to improve the shale's permeability more effectively comparing to the conventional fracturing method. To understand the mechanism of flow conductivity under the PHF, we investigated the shale's conductivity capacity using pulsating fracturing test device. The experiments are conducted on the different closure pressures to monitor the shale's flow conductivity in the artificial fracture under the pulsating fracturing stimulation. The results reveal that the fracture surface coincidence degree (FSCD) and the flow rate are affected by the closure pressure, as well as there is a good linear correlation between variations of FSCD and flow rate. As the closure pressure increases from 4 MPa to 6 MPa, the flow rate declines by 58.82%. Moreover, a prediction model for the conductivity capacity in shale's single fracture under pulsating hydraulic fracturing is proposed. It can well predict the fracture conductivity capacity when the closure pressure range in 4–10 MPa, which is helpful to evaluate the economic benefits of fracturing.