耐温耐盐CO_(2)泡沫体系性能评价

Performance Evaluation of Heat-resistant and Salt-resistant CO_(2)Foam System

通过表面活性剂复配并添加纳米颗粒稳泡剂的协同作用来增强CO_(2)泡沫性能,优选得到泡沫体系0.2%SDS+0.3%C 12 E 4+0.05%N1,考察了其发泡性、稳定性、流变性以及吸附性。结果表明,泡沫体系在84℃和19.7 MPa条件下,其泡沫体积能达到570 mL,泡沫半衰期为88.6 min,泡沫综合指数为37876.5 mL·min;老化90 d后泡沫体积保持率达69.5%;泡沫体系黏性模量大于弹性模量,含油体积分数大于10%时,出现“遇油消泡”特性;吸附后的泡沫保留率高达73.8%;泡沫通过剪切稀释进入油层深部,形成有效封堵,封堵后的平衡压差是转注前的3倍左右,封堵性良好。为高温高盐油藏CO_(2)气窜控制技术的现场应用奠定基础。

The performance of CO_(2)foam can be improved by compounding of surfactants and addition of nanoparticle foam stabilizer.The foam system 0.2%SDS+0.3%C 12 E 4+0.05%N1 was obtained by optimization of many formulas,and its foaming,stability,rheology,and adsorption properties were thoroughly investigated.The results showed that under the conditions of 84°C and 19.7 MPa,the foam volume of the foam system could reach 570 mL,with a foam half-life of 88.6 min and a comprehensive index of 37876.5 mL·min.After aging for 90 days,the volume retention rate of the foam reached 69.5%.Interestingly,when the viscous modulus of the foam system exceeds its elastic modulus and the volume fraction of oil is greater than 10%,the"oil defoaming"phenomenon appeares.Moreover,the foam retention rate after adsorption is as high as 73.8%.The foam enters the deep part of the reservoir through shear dilution to form an effective plugging.The equilibrium pressure difference after plugging is approximately three times that before injection,indicating good plugging performance of the foam system.The search results lay a foundation for the field application of gas channeling control technology in high temperature and high salinity reservoirs.