适用于特稠油的耐高温高盐纳米二氧化硅降黏驱油剂

High-temperature and High-salinity Resistant Nano-SiO₂ Viscosity-reducing Oil Displacement Agent for Extra-heavy Oil

陆炫烽 陈立峰 吴春洲 李 岗 张兆年 盛威威 宋 嫒 黄飞扬

LU Xuanfeng CHEN Lifeng WU Chunzhou LI Gang ZHANG Zhaonian SHENG Weiwei SONG Yuan HUANG Feiyang

乳化降黏是稠油提高采收率的关键技术之一。普通降黏剂无法同时满足特稠油热采时的高温与高矿化度要求，导致降黏剂失活、降黏效果差、采收率低。以纳米硅溶胶、两亲型分散剂、修饰剂硅烷偶联剂、增效剂两亲型表面活性剂等为原料，制得纳米降黏驱油剂，表征了驱油剂的微观结构，评价了驱油剂对特稠油的降黏效果、耐温耐盐性能、吸附性能和驱油效果。结果表明，驱油剂配方组成为：50% SiO2+40%分散剂+4.2%表面修饰剂+ 5.8%增效剂。驱油剂粒径约 50 nm，粒径分布均匀，分散性良好。1%驱油剂未老化前，对特稠油的降黏率达84.99%，在矿化度为 15 g/L、350 ℃下老化2 h后的降黏率为 83.62%，降黏性能保持率为 98.39%。驱油剂可使砂岩表面由疏水性转变为亲水性。在 50 ℃、液固比为 10∶1、平衡吸附时间为 15 h的条件下，驱油剂在油砂表面的静态吸附量为1.377 mg/g 砂；1%驱油剂在填砂管的动态吸附量为0.745 mg/g 砂，在油藏中的吸附损失较低，符合化学驱对表面活性剂的吸附损失要求。在一维驱替实验中，驱油剂的驱油效率比普通蒸汽驱提高了 26.7 百分点，在 350 ℃、老化2 h后的驱油性能保持率为 97.0%。纳米降黏驱油剂具有良好的降黏效果、耐温耐盐性能、吸附性能和驱油效果，可降低驱油成本，有效提高特稠油的热采开发效果。

Emulsification and viscosity reduction is one of the key techniques for enhancing the recovery efficiency of heavy oil. Due to the inability of conventional viscosity reducers to meet the high temperature and high salinity requirements during thermal recovery of extra-heavy oil，issues such as viscosity reducer deactivation，poor viscosity reduction performance，and low recovery rates often arise. Using nano-SiO2 sol，amphiphilic dispersant，modifier silane coupling agent，and synergist amphiphilic surfactant as raw materials，a nano-SiO2 viscosity-reducing oil displacement agent was prepared. The microstructure of the oil displacement agent was characterized. Its viscosity-reducing effect on extra-heavy oil，temperature and salt resistance，adsorption performance， and oil displacement efficiency were evaluated. The results showed that the formula of the oil displacement agent was obtained as follows：50% SiO2，40% dispersant，4.2% surface modifier and 5.8% synergist. The particle size was about 50 nm with uniform distribution and good dispersibility. The viscosity reduction rate of 1% original oil displacement agent for extra-heavy oil reached 84.99%. After aging for 2 hours at 350 ℃ and a salinity of 15 g/L，the viscosity reduction rate was 83.62%，maintaining 98.39% of its performance. The oil displacement agent changed the sandstone surface from hydrophobic to hydrophilic. Under the condition of 50 ℃，a liquid-solid ratio of 10∶1，and an equilibrium adsorption time of 15 hours，the static adsorption capacity of the oil displacement agent on oil sand was 1.377 mg/g sand. The dynamic adsorption capacity of 1% agent in a packed sand tube was 0.745 mg/g sand，indicating low adsorption loss in the reservoir，which met the requirements for chemical flooding. In a one-dimensional displacement experiment，the oil displacement efficiency of the agent was 26.7 percentage points higher than that of conventional steam flooding. After aging at 350 ℃ for 2 hours，the oil displacement performance retention rate was 97.0% . The nano-SiO2 viscosity-reducing oil displacement agent had excellent viscosity reduction， temperature and salt resistance， adsorption performance and oil displacement efficiency，which effectively lowered oil recovery costs and then enhanced thermal recovery of extra-heavy oil.

10.19346/j.cnki.1000-4092.2024.03.011