韦兰胶溶液的流变性及其影响因素研究

Study on Rheological Property of Welan Gum Solution and Its Influential Factors

应用哈克旋转流变仪研究了韦兰胶水溶液在地层温度40℃下静态、动态流变性及其影响因素。结果表明:韦兰胶水溶液黏度高,是一种非牛顿流体,其流变曲线符合幂律模式,具有剪切稀释性、良好的抗温性和较高的黏弹性,无触变性。浓度升高,韦兰胶水溶液的黏度增加,黏弹性增大。当韦兰胶水溶液质量浓度为1 g/L时,G'与G″在低频区相交,当质量浓度大于1 g/L时,G'与G″无交点,且G'>G″,表现为类似固体的弹性行为。韦兰胶水溶液在不同酸碱环境下均表现出良好的稳定性,盐(Na Cl、Ca Cl2)对其黏度影响不大。韦兰胶良好的增黏性、抗温性使其有望成为新型的钻井液添加剂,较强的黏弹性可以在三次采油中应用。

The static and dynamic theological properties of the aqueous solution of Welan gum and their influence factors are studied using Haake rotational rheometer at the simulation formation temperature（40 ℃ ）. The results show that the Welan gum solution is a nonNewtonian fluid with high viscosity, whose rheological curve is in agreement with the power-law model, and it has shear thinning behavior, good temperature resistance,high viscoelasticity and no thixotropy. The viscosity and viscoelasticity of Welan gum solution increases when its concentration is increased. G＇ curve of the Welan gum solution intersects with its G curve in the low frequency section when the solution mass fraction is 0.1%. However,there is no intersection of G＇ and G curves and G＇ is always greater than G when the solution mass fraction is higher than 0.1%, which is the elastic behavior similar to solid. The Welan gum solution shows favorable stability under different acid and alkali circumstance, and the salt（ NaCl and CaCl2 ）has little effect on the apparent viscosity of the Welan gum solution. Welan gum is expected to be a new type of drilling fluid additives due to the good thickening property and temperature resistance behavior of its aqueous solution, and it would also be widely applied to tertiary recovery due to the good viscoelasticity of its aqueous solution.