A New Empirical Model for Viscosity of Sulfonated Polyacrylamide Polymers

Abstract

Copolymers of acrylamide with the sodium salt of 2-acrylamido-2-methylpropane sulfonic acid—known as sulfonated polyacrylamide polymers—had been shown to produce very promising results in the enhancement of oil recovery, particularly in polymer flooding. The aim of this work is to develop an empirical model through the use of a design of experiments (DOE) approach for bulk viscosity of these copolymers as a function of polymer characteristics (i.e., sulfonation degree and molecular weight), oil reservoir conditions (i.e., temperature, formation brine salinity and hardness) and field operational variables (i.e., polymer concentration, shear rate and aging time). The data required for the non-linear regression analysis were generated from 120 planned experimental runs, which had used the Box-Behnken construct from the typical Response Surface Methodology (RSM) design. The data were collected during rheological experiments and the model that was constructed had been proven to be acceptable with the Adjusted R-Squared value of 0.9624. Apart from showing the polymer concentration as being the most important factor in the determination of polymer solution viscosity, the evaluation of the model terms as well as the Sobol sensitivity analysis had also shown a considerable interaction between the process parameters. As such, the proposed viscosity model can be suitably applied to the optimization of the polymer solution properties for the polymer flooding process and the prediction of the rheological data required for polymer flood simulators.

An Experimental Study on Hydrodynamic Retention of Low and High Molecular Weight Sulfonated Polyacrylamide Polymer

“…This behavior was expected since most polymer solutions exhibit shear thinning because of the decrease in the hydrodynamic size of the polymer [33,34]. Increasing shear rate causes greater breakage and destruction of the entanglements between the polymer molecules, thereby reducing polymer viscosity [35,36]. An increase in shear rate may also result in higher retention as more porous media will be exposed to the polymer solution due to the reduced hydrodynamic size of the polymer.…”

A review of current and future food applications of natural hydrocolloids

“…The main reason is that charged polymers have a more expanded arrangement in solution due to intramolecular charge repulsions. A significant drop in viscosity can be induced by adjusting either the pH or the ionic strength of the solution, which would promote aggregation of the polymer chains by reducing the degree of dissociation of the charged groups (Tengku Mohd et al ., ; Akbari et al ., ).…”

Global Sensitivity Analysis of Quantiles: New Importance Measure Based on Superquantiles and Subquantiles

“…Variance-based SA (generally called Sobol SA) introduces uncertainty as variance and decomposes the variance of the output of the model or system into portions that can be attributed to inputs or sets of inputs [2,3]. Sobol SA is very popular; the principles of the method are often mentioned [4][5][6][7][8] and many articles have applied Sobol SA in their research [9][10][11][12][13].…”

“…To better understand the essence of the computation of sensitivity indices, screening of statistics l and R is performed when Xi is fixed. The aim is to identify similarities and differences between l and R, rather than to accurately quantify sensitivity using Equations (8), (13) and (18). Samples R|Xi and l|Xi are plotted for 400 LHS runs of Xi, otherwise the solution is the same as in the previous chapter.…”

“…The output R is not monotonically dependent on e 0 . The practical consequence is that in the case of an even number of LHS runs, it is sufficient to compute the nested loop in Equations (8), (13) and (18) only once for the positive value of random realization e 0 , because the solution is the same for a negative value. This reduces the computational cost of estimating indices Q 3 , K 3 and S 3 by half.…”