关键词: 三元复合驱, 硅垢, 形成机理, 预测模型, 大庆油田

Abstract: The scale deposit in oil strata and bottom of oil wells is a great trouble in situ tests of alkaline-surfactant-polymer (ASP) flooding area of Daqing Oilfield.In order to confirm the factors affecting the scaling,the dynamic and static water-rock reaction simulation tests for alkali,surfactant,polymer and their compound system were carried out under the relative conditions based on the properties of stratum rocks and fluid in the test area.A predictive model for silica scaling was established according to the solubility product theory.The model was used to predict the quantity of silica scaling in the test site of Xingbei Oilfield in Daqing area.The results show that the alkali in the ASP solution system makes evident denude effect to oil stratum rocks,which enforces some ions forming silica scale,such as Si⁴⁺、Al³⁺、Ca²⁺、Mg²⁺ ions.Those ions enter into solution and form amorphous SiO₂ in some specific conditions.The analytical results on some scaling samples collected in situ show that the values of prediction and practice are consistent.This prediction method can be used to select quality of water injected into oilfield for reducing damage of storing oil strata.

Key words: alkaline-surfactant-polymer compound flooding, silica scaling, scale forming mechanism, prediction method, Daqing Oilfield