The purpose of this project was to improve water injectivity into the Grayburg formation at MORANCO's Rice-Hardin Waterflood in Lea County, NM. The project was a cooperative effort between the Petroleum Recovery Research Center, the New Mexico Petroleum Recovery Research Center, the New Mexico Energy and Minerals Department, the New Mexico Energy Research and Development Institute, and MORANCO of Hobbs, NM.
Laboratory tests with reservoir cores were conducted at the Petroleum Center. These tests indicated that certain chemical treatments had the ability to increase water permeability about 30%. The treatments were designed to reduce the oil saturation in a region about 8 to 10 feet out from the injection wellbore, and to improve injectivity by increasing the relative permeability to water.
Two of the most promising treatments were selected for the field trial. Rice No. I injection well was treated with a surfactant solution, and Hardin No. 3 was treated with an aromatic solvent followed by a surfactant solution. Costs of chemicals were approximately $3,000 per well. As a result of these treatments, slightly more water could be injected at pressures 400 psi less than the before-treatment levels. Since improvement in flow efficiency, observed from the injection rate and pressure data, is on the order of 50 to 60%, the field treatments apparently worked somewhat better than indicated by the laboratory tests.
Based on the encouraging results obtained from the trial, these concepts should have applicability in other waterflood projects and may also have potential in certain enhanced recovery projects where low injectivity is a problem. projects where low injectivity is a problem.