Abstract

Polyacrylamide solutions are widely used in modern technology as thickening agent, for turbulent reduction and many other uses. They have been extensively used in enhanced oil recovery. In many cases, polyacrylamide comes into contact with surfactants which lead to a change in its rheological properties. In this study, an experimental work was carried out to investigate the effect of the nonionic urfactant (X-100) on the rheological properties of polyacrylamide, using cone-and-plate Rheometer. Polyacrylamide and the surfactant in the tested solutions ranged by weight from 0.02%-0.1% and 0.001%-0.05% respectively. The scope of the study includes the measurements of surface tension, steady-state behavior, yield stress, creep and recovery, thixotropy, transient shear stress response, and dynamic response. Results have shown a dramatic decrease in the surface tension with increasing surfactant up to the critical concentration. Polyacrylamide solutions have shown three different behaviors, a first Newtonian region, then a region of dramatic shear thinning, and finally a shear thickening region. Dynamic viscosity have shown shear thinning up to a critical value above which the solutions gave a constant shear thickening behavior and also showed that Cox-Merz rule is not valid in this range of tested solutions. The viscoelastic and thixotropic responses of the tested solutions were small. The effect of surfactant was generally low.