A novel CO2-resistant dispersed particle gel for gas channeling control in low-permeability reservoirs

Abstract

A novel CO2-resistant dispersed particle gel (CR-DPG) for gas channeling control was successfully prepared by shearing an organic–inorganic composite bulk gel. The basic properties, CO2-resistance characteristics, gas channeling control capacity and enhanced oil recovery potential were systemically investigated. The prepared CR-DPG particles were regular spheres, which could maintain a uniform dispersion during the injection process. The CO2 resistance test was carried out at 90 ℃ and CO2 pressure of 20 MPa. After the CO2 resistance test, the dispersion stability of CR-DPG decreased, and the particles coalesced to form large aggregates instead of degrading, exhibiting excellent CO2 resistance. Furthermore, the mechanical strength of the CR-DPG particles aged for different time was measured using atomic force microscope (AFM). Due to the silica gel particles, the CR-DPG particles retained high mechanical strength in the long-term experiment, which could maintain a high plugging effect for a long time during CO2 flooding. A fractured core flowing model was employed to investigate gas channeling control capacity and EOR potential of CR-DPG. The CR-DPG particles could migrate to fractures in-depth, in which particles coalesced to form large aggregates and adsorbed to mitigate gas channeling. In addition, CR-DPG had great potential for enhanced oil recovery by 10.4 %. This work provides an alternative material with a simple preparation process and low cost for gas channeling control in oilfields with CO2 flooding.