Investigating the effect of preformed particle gel on conformance control of naturally fractured tight sandstone reservoirs: An experimental study using pressure transfer test method

Abstract

The recovery of oil and gas resources is limited by the high water production from wells in unconventional reservoirs. While water intrusion prevention measures have been extensively investigated in highly permeable reservoirs, there has been limited research in tight unconventional reservoirs. In this study, a Pressure Transfer Test (PTT) method was used to evaluate the effect of preformed particle gel (PPG) on the conformance control of naturally fractured tight sandstone reservoirs. The study analyzed and compared four types of naturally fractured cores, and performed experiments on the PPG plugging effect under different natural fracture types, injection pressures, and salinities using a PTT device. The results showed that among the four fracture types, vertical and oblique penetrations had the highest plugging effect, with a 12% higher rate than fractures without effective channels. The injection pressure also had a significant impact on the plugging efficiency, with a 99.13% blocking rate at 12.5 MPa, which was almost completely plugged. Meanwhile, the salinity of the injected fluid had a decreasing effect on the PPG plugging efficiency, with the lower salinity of 1 wt% improving the plugging efficiency by 15% compared to high salinity. The experimental results and analysis were used to propose the plugging mechanism of PPG in different types of naturally fractured tight reservoirs. This study provides valuable experimental and theoretical references for the field application and further studies of PPG in naturally fractured tight reservoirs.