Field Polymer Stability Studies

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Abstract This paper presents the highlights of the results obtained from a field test designed to study shear degradation of polyacrylamide polymers. Recently, most major research polymers. Recently, most major research laboratories have been studying shear degradation in the laboratory; however, no extensive field testing has been reposed. The field test consisted of injecting Pusher 700 into a well at four different rates Pusher 700 into a well at four different rates and back producing the polymer fluid. Laboratory measurements were made on location to determine polymer quality. These measurements were made in an oxygen-free environment in order to minimize chemical degradation of the polymer. Both surface and bottom hole sampling techniques were employed. Fluid samples were bottled under controlled conditions and brought back to our research laboratory for core flood experiments. Fluid entry profiling of the well was done before, during, and after polymer injection; and pressure transient tests were; conducted to pressure transient tests were; conducted to determine in situ polymer effectiveness. These tests indicated that the combined effect of shear degradation and calcium ion contamination due to anhydrite dissolution could reduce polymer effectiveness to an economically unattractive level. Introduction The influence of mechanical or shear degradation on the effectiveness of partially hydrolyzed polyacrylamides as mobility control agents has been receiving considerable attenbon. One of the earliest papers indicative of the importance of this involved the use of these polymers to control water production in oil polymers to control water production in oil wells. More recent studies have involved laboratory experiments designed to predict the degree of mobility control loss to be expected during the injection of polymers into a porous medium.