Laboratory Testing of Nanosilica-Reinforced Silicate and Polyacrylamide Gels

Summary One of the most common methods used to reduce excessive water production is water shutoff operations. These types of operations include injection of gel for flow profile modification. The most widely used gels are polyacrylamide- and silicate-based gels. As a way to improve and optimize gel characteristics, nanosilica can be added to the gelant solution. In this paper, laboratory testing of nanosilica-reinforced silicate and polyacrylamide gels is presented. Bulk gelation and capillary tubing tests were used for determination of gelation time, and core flooding tests on low permeability carbonate core samples were conducted as a way to assess gel-plugging ability. Tests showed that gelation time for both types of gels was faster when nanosilica was added. The strength of the polyacrylamide-based gel was enhanced. Silicate gel samples with nanosilica led to a 17% higher reduction in permeability compared to pure silicate gel, and polyacrylamide gel with the addition of nanosilica has almost 43% higher permeability reduction compared to pure polyacrylamide gel.