Study on Optimization and Performance Evaluation of Plugging Adjustment in Heavy Oil Compound Flooding Technology

Abstract

Aiming at the problems of high water cuts in the later stages of multi-throughput and the inability to effectively develop the remaining oil between wells in ordinary heavy oil reservoirs. The development of block flood control and viscosity reduction complex flooding was proposed, in which the flood control agent can achieve the blocking and deep regulation of high permeability channels. Dissection, effectively expanding the volume of subsequent viscosity reducing agents. Through a large number of preferred evaluations, a polymer with viscosity-increasing properties for certain mineral formation water salinity, low viscosity at injection temperature, and high viscosity at the bottom hole temperature (65 ° C) was selected, and other properties of the polymer were tested. The results show that the polymer is hydrophobically associative and has temperature-sensitive properties. As the temperature increases, the polymer viscosity first increases and then decreases. At the reservoir temperature, the maximum viscosity of 3000 mg/L polymer reaches 919 mPa.s; The polymer also has excellent anti-aging properties and shear resistance. After storage at the reservoir temperature (65 °C) under anaerobic conditions for 90 days, the viscosity retention rate reaches 97%; In the shear force of the reservoir (7.5 s⁻¹) conditions, the viscosity of the polymer will not decrease due to multiple shears. The displacement effect of 1# polymer was verified by the dual-tube high-low-permeability mold displacement experiment. The results show that the polymer can effectively block the high-permeability layer and effectively use the low-permeability layer.