纳米SiO_(2)表面活性剂对高盐低渗储层的驱油效果

Oil displacement effect of nano-SiO_(2) surfactant on high salinity and low permeability reservoir

针对花土沟油田低渗高盐的储层特征,制备了一种改性纳米SiO_(2)表面活性剂,对其耐盐性、界面张力、润湿性与静态吸附作用进行评价,并对研究区不同物性的低渗岩心进行了驱油实验。结果表明,当纳米SiO_(2)质量分数达到0.1%时,纳米SiO_(2)表面活性剂在17×10^(4) mg/L的矿化度下具有良好的耐盐稳定性及分散能力、低界面张力、较好的润湿性反转能力和低静态吸附性。岩心驱替实验表明,纳米SiO_(2)表面活性剂具有增油降压的效果,且岩心物性越低,增油降压效果更佳。

In view of the low permeability and high salinity characteristics of the reservoir in Huatugou oilfield,a modified nano-SiO_(2) surfactant is prepared,and its salt resistance,interfacial tension(IFT),wettability and static adsorption property are evaluated.Oil displacement experiments are carried out on low permeability cores with different physical properties in the study area.It is found when the weight concentration of nano-SiO_(2) reaches 0.1 wt.%,it has a good salt stability,a good dispersion ability,a low IFT value,a good wettability alteration ability,and low static adsorption at a brine of 17×10^(4) mg·L^(-1).Core flooding experiments show that nano-SiO_(2) surfactant has the effect of increasing oil production and reducing the injected pressure,especially the performance being better for the cores with worse physical properties.