低界面张力黏弹表面活性剂驱油体系性能

In view of the poor adaptability of conventional chemical oil displacement methods in unconventional reservoirs and unable to effectively improve crude oil recovery, a new low interfacial tension viscoelastic surfactant oil displacement system (SZK) was proposed in this paper, and the performance and oil displacement effect of SZK were evaluated from the aspects of interfacial activity, rheology, static adsorption, temperature and salt resistance and oil displacement experiment. The results show that SZK has a single component and can reduce the interfacial tension to the order of 10-2 mN/m at a lower concentration (2 000 mg/L) compared with the compound system. SZK has good environmental adaptability and the static adsorption capacity on oil-bearing core powder is small (the maximum is 15.87mg/g). When the temperature is 70 ℃ or the mineralization is 16 570 mg/L, the oil-water interfacial tension is always maintained in the range of low interfacial tension, with good viscosity and elasticity, and good temperature and salt resistance. Injection of 0.5 PV SZK with a mass concentration of 2 000 mg/L can increase the water drive recovery of 50 mD low permeability homogeneous core by 13.53%, and the comprehensive water drive recovery of heterogeneous core (grade difference of 5-15) by 9.36%-22.52%. The system describes in this paper shows high adaptability to low permeability reservoirs and oil displacement performance, which can provide a theoretical reference for the study of chemical oil displacement methods in unconventional reservoirs.