Optimization of Salt-Resistant Polymer and Analysis of Site Application Effect in Daqing Oilfield

The proportion of sewage dilution polymer flooding block in Daqing Oilfield is more than 80%, the polymer viscosity loss is large, and the consumption increases by nearly 60%, so it is urgent to carry out research on salt-resistant polymer flooding technology. Two kinds of salt-resistant polymers were selected preliminarily through domestic and foreign investigation, and the salt-resistant polymers suitable for Daqing Oilfield were optimized by studying the viscosity characteristics and oil displacement efficiency of the salt-resistant polymers. The results show that the viscosity of salt- resistant polymer is better than that of ordinary polymer. The viscosity retention ratio of LH salt-resistant polymer is more than 80%, and that of GL salt-resistant polymer and ordinary polymer is less than 50%. After 60 days of polymer aging, the salt-resistant polymer flooding effect was significantly better than that of the ordinary polymer flooding under the condition of artificial core and natural core, which reduced the dosage and achieved better oil displacement efficiency. The effect of LH salt-resistant polymer is better than GL salt-resistant polymer. The injection-production capability, reservoir mobilization status and oil displacement efficiency of the salt-resistant polymer test areas are all significantly better than those of the conventional polymer flooding blocks. By March 2019, the salt-resistant polymer test area enhanced oil recovery by 16.9%, and the final enhanced oil recovery is predicted to be more than 19.6%. Salt-resistant polymer flooding, as an important mean to reduce the amount of polymer and improve the quality and efficiency, will provide important support for the continuous and stable production of Daqing Oilfield.