An experimental study on the viscosity of SPAM solutions with a new correlation predicting the apparent viscosity of sulfonated polyacrylamides

Abstract

Abstract Being one of the most commonly performed EOR methods, polymer injection is used to increase the mobility ratio and decrease water relative permeability to allow the injected fluid to sweep more oil towards the production well. Before the polymer solution is injected into the reservoir through the injection wells, the process of polymer injection must be simulated using commercial numerical reservoir simulators. In order to be able to simulate the process, the viscosity behavior of the solution must be known. Therefore, a model is required to estimate the viscosity of the injected fluids versus shear rate and polymer concentration. In this study, a new mathematical function based on the power-law fluid equation is presented, which can be applied to predict the viscosity of SPAM solutions. The two required parameters of the power-law equation are obtained by fitting a power-law function to the viscosity-shear rate data. Samples in different polymer concentrations (using two SPAM polymers with different molecular weights) were prepared and their viscosity was measured against different shear rates. The results were fitted to the power-law equation and their corresponding power-law parameters were recorded. A mathematical function was introduced and tested for each parameter. The new functions combined with the power-law equation were used to estimate the viscosity of different polymer solutions with different SPAM concentrations. The results showed that the model is capable of estimating the viscosity with acceptable precision. Furthermore, it is applicable in various temperatures and water salinities.