三元复合驱硅垢沉积影响因素研究

Study on Influencing Factors of Silicon Scale Deposition in ASP Flooding

目前随着开采程度的提高,油田的结垢现象日益严重,导致采收率降低,诸多现状都表明结垢会给油田带来不利影响。在三元复合驱(ASP)过程中,碱会与地层中的硅酸盐岩产生碱溶反应,形成硅垢,堵塞地层孔隙、严重损害储层。针对所形成硅垢设计实验,研究了影响结垢的因素,着重研究温度、pH和Ca^(2+)、Mg^(2+)对硅垢形成的影响。研究表明:在三元复合驱体系下,pH在10到11之间硅沉积百分数急剧下降,说明pH对硅离子稳定性的影响非常大,温度对硅垢形成的影响比pH较小,钙镁离子的存在对硅沉积具有促进作用。

At present, with the improvement of exploitation degree, the scaling phenomenon in oilfield is becoming more and more serious, which leads to the decrease of oil recovery. Many current situations show that scaling will bring adverse effects on oilfield development. During ASP flooding, alkali will react with silicate rock in formation to form silica scale to plug formation pore and seriously damage reservoir. In this paper, an experiment was designed to study the factors affecting the formation of silicon scale, focusing on the effect of temperature, pH and Ca2+, Mg2+ on the formation of silicon scale. The results showed that, under ASP flooding system, the percentage of silicon deposition sharply decreased when pH was in the range of 10~11, which indicated that pH had a great influence on the stability of silicon ion. The temperature had smaller effect on the formation of silicon scale than pH, and the presence of calcium and magnesium ions had promoting effect on silicon deposition.