Study on profile control system containing oily sludge produced from polymer flooding

Abstract

ABSTRACT In order to reasonably reutilize oily sludge produced from polymer flooding (OSPPF) in the Shengli oilfield, firstly, the basic characteristics of OSPPF are analyzed through SEM, pH meter, and a Particle Size and Zeta potential analyzer. Then, the effects of different factors on the gel profile control system were systematically analyzed. The optimized prescription of the gel profile control system was 0.4% polymer + 0.1% emulsifier + 16% OSPPF + 0.05% stabilizer + 1.2% crosslinker + 0.1% pH regulator, with a gelling time of 32 h and gelling viscosity of 49910 mPa·s at 60°C. Finally, the application performances of the profile control system were evaluated. The results showed that the profile control system had a good anti-shear performance which could continue to form a gel with a viscosity of 45138 mPa·s after 30 min shear. Meanwhile, the gel profile control system exhibited good viscoelasticity and thermal stability so that the viscosity retention was about 90% at 60°C after 180 days. Furthermore, the permeability ranged from 21.24 to 29.63 μm2, plugging rates were larger than 94% and it was suitable for profile control in high-permeability zones. Therefore, this technology not only solves the pollution problem of OSPPF but also enables resource reutilization.