Use of Polymers to Control Clay Swelling

Abstract

Abstract The injection of water to displace oil is one of the main methods used to increase oil recovery. High injection rates are generally desired, and in some cases the flood will not be economic unless high rates are maintained. The presence of clays which swell in the presence of water offers a complication to the problem of maintaining adequate infectivity. In the course of this study we observed that certain polymers, when present in dilute concentrations in the water, had the ability to reduce the response of these clays to fresh water. Two polymers, one anionic and the other nonionic, were found to be very effective in controlling the clays present in Berea cores. Successful control of clay swelling was obtained by the use of solutions containing as little as 1.0 ppm of polymer, but at this low concentration appreciable volumes of treating solution were required. These results suggest that some minimum amount of polymer must be adsorbed to prevent clay swelling. In Berea sandstone, this minimum amount appeared to be of the order of 0.03 mg per cc of pore space. A series of tests made using 10.0 ppm polymer showed that the polymer could be made to move through the porous system in which 0.066/mg of polymer was adsorbed per cc of pore space. This amount, equivalent to 0.023 lb of polymer per barrel of pore space, appears to be of economic interest.