改性纳米SiO_(2)驱油剂结构表征及流变性能研究

Structural characterization and rheological properties of modified nano-SiO_(2) oil repellents

为了显著提高低渗油藏的原油采收率,相对于传统聚合物驱油剂,纳米流体因其优异的流度控制、润湿性改变性能以及良好的耐温、耐盐、抗剪切的特点而受到研究者青睐。通过一系列的实验对改性二氧化硅(SiO_(2))的结构和性能进行了表征以及测定了其纳米流体在不同条件下的表观黏度,研究了温度、纳米颗粒浓度和矿化度对改性SiO_(2)纳米流体流变性能的影响。实验表明:改性纳米SiO_(2)具有良好的稳定性且平均粒径小,为22.92 nm,以及具有一定的交联结构;温度升高,溶液的表观黏度降低;并且随着纳米颗粒浓度的增加,溶液表观黏度呈现先增大后减小的趋势,浓度为0.5%的溶液在高剪切速率下黏度最大,最大为1.833 mPa·s;而矿化度提高后,溶液表观黏度降低。通过对改性SiO_(2)纳米颗粒的研究,其具有良好的耐温、耐盐、抗剪和控制注入流体流度的特性,对提高采收率具有一定的积极意义。

To improve oil recovery significantly in low permeability reservoirs,nanofluids are favored by researchers for mobility control,wettability modification properties,as well as good temperature,salt,and shear resistance compared to conventional polymer drives.The structure and properties of modified silica(SiO_(2))were characterized and the apparent viscosity of its nanofluid was measured under different conditions through a series of experiments,and the effects of temperature,nanoparticle concentration and mineralization on the rheological properties of modified SiO_(2) nanofluid were investigated.Experiments showed that the modified nano-SiO_(2) had excellent stability and small average particle size of 22.92 nm,as well as a certain cross-linked structure.The apparent viscosity decreased with increasing temperature;moreover,with the increase of nanoparticle concentration,the apparent viscosity of first increasing and then decreasing,and the solution with the concentration of 0.5% showed the greatest viscosity at high shear rate,with a maximum of 1.833 mPa·s;as salinity increased,the apparent viscosity of the solution decreased.Through the study of modified SiO_(2) nanoparticles,they had favorable properties of temperature resistance,salt resistance,shear resistance and control the fluidity of the injected fluid,which has a certain positive significance for enhancing oil recovery.