Study of the reinforced mechanism of fly ash on amphiphilic polymer gel

Abstract

Amphiphilic polymer gels are widely used in heterogeneous reservoirs for conformance control technology. However, in high temperature and high salinity of calcium and magnesium reservoirs, amphiphilic polymer gels cannot maintain effective performance. In this work, a novel reinforced amphiphilic polymer gel (F-PADC gel) was prepared by physically mixing polymer solution and fly ash (FA), which is an extremely low cost material. The viscoelasticity and stability of the F-PADC gel were studied by rheometry and micro-rheometry. The reinforced mechanism of FA on amphiphilic polymer gels was revealed. The results show that the addition of FA can make the gel more robust with a denser network structure. On the fifth day, the elastic modulus ( G ′) increases from 5.2 to 7.0 Pa and the viscosity modulus ( G ″) increases from 0.4 to 0.6 Pa at the frequency of 1 Hz, which improves the viscoelasticity of the gel system. More importantly, the F-PADC gel does not degrade after aging at 85 °C for 180 d. And its viscoelasticity increases obviously, G ′ and G ″ increase to 110.0 Pa and 3.5 Pa, respectively, showing excellent anti-aging stability. Moreover, FA amphiphilic polymer gels have a good injectivity and a perfect plugging rate of 98.86%, which is better than that of sole amphiphilic polymer gels. This novel mixed FA amphiphilic polymer gels can prove to be a better alternative to conventional polymer gels to enhance oil recovery in high temperature and high salinity reservoirs.