Design of low-consumption epoxy resin porous plugging material via emulsification-curing method

Abstract

Since the higher cost of epoxy resin, its application in reservoir plugging at high temperature and high salinity was seriously restricted. Herein, the expensive epoxy resin was used as the supporting skeleton to provide the mechanical strength required for plugging, while water was introduced via emulsification - curing method in the closed non-connected pores to reduce the material consumption. The curing kinetics of epoxy resin was studied using differential scanning calorimetry (DSC). On this basis, the high temperature stability and dynamic gel time of the epoxy resin emulsion were examined, and the microstructure and mechanical properties of the cured material were tested. Firstly, in the shear rate range of 10–100 s−1, the viscosity of epoxy resin emulsion was less than 1200 mPa·s under the condition of 20 ℃, meanwhile, the viscosity value was less than 100 mPa·s in high temperature environment of the reservoir (120 ℃), which meets the demand of mixing and injection. Secondly, in the W/O emulsion state, the curing reaction rate was accelerated. However, when the curing agent 4,4′-methylenebis[2,6-diethyl]aniline (DTD) is used instead of 3,3′-diethyl-4,4′-diaminodiphenyl methane (DEDDM), utilizing steric effect of double ethyl group, the thickening time is extended from 55 to 60 min to 110–120 min. Finally, after curing the epoxy resin emulsion, although mostly occupied by pore water (fw=50%), the increase in the curing degree made the elastic modulus increase from 0.017 MPa to 3.220 MPa compared with the pure epoxy resin, and the uniaxial compressive strength can reach 25.14 MPa.This design method can reduce the material consumption of epoxy resin by 30–35% while controlling leakage, providing an effective way for the construction of plugging materials in high temperature (120 ℃) and high salinity (21.81 ×104 mg/L) environment.