Polymer Composition for Reducing Permeability in a Fractured High-Viscosity Oil Reservoir
Abstract
In fractured reservoirs, water from injection wells quickly moves through the reservoir and enters to the production well. As part of this research, a polymer composition for fractured reservoirs was developed. The polymer composition consists of polyacrylamide, lignosulfonates, hydrochloric acid and salt. Dependences for assessing the properties of the composition on the content of the components are obtained. Laboratory experiments were carried out to evaluate the results of the interaction of the gel-forming composition with formation water. It has been established that a layer of the composition with a thickness of less than 1 mm, upon contact with water, dissolves after 48 hours, while the rest of the gel volume remains intact, that is, the gel-forming mass is preserved. Core experiments prove that the polymer composition reduces fracture permeability by up to 99%. The composition has a high viscosity and therefore penetrates shallowly into rocks with low permeability. In such rocks, the composition blocks the filtration channels at a short distance from the inlet surface. During the day, the composition is converted into a gel and blocks the movement of formation water through the filtration channels. By changing the content of components in the composition, you can increase or decrease the rate of gel formation and its viscosity.