Carbon Dioxide Displacement of a West Texas Reservoir Oil

Publisher Website
Google Scholar
Abstract
This paper presents results of an extensive study to understand CO2 displacement of Levelland (TX) reservoir oil. The work was conducted to support Levelland CO2 pilots currently in progress. Experimental displacement tests were conducted at various pressures, core lengths, and CO2 frontal advance rates. The experimental system included a novel analytical technique to obtain effluent compositional profiles within the oil-moving zone at test conditions. The results of this study show that at pressures greater than the CO2 minimum miscibility pressure (MMP), a multicontact miscible displacement mechanism predominates. Miscibility is developed in situ by vaporization-or extraction-type mass transfer. The laboratory lengths required for CO2 to develop miscibility and exhibit miscible displacement efficiency were found dependent on the phase equilibria of the CO2/Levelland oil system. Displacements requiring the greatest length to develop miscibility were at pressures where single-contact mixtures of CO2 and Levelland oil form two liquid phases. A companion paper10 demonstrates the use of the analytical technique developed in this study to obtain process data from a CO2 field pilot test. In addition, the mechanistic information obtained from this study is used to interpret the process data from the pilot test. The results have application to other reservoir oils whose phase equilibria with CO2 are similar to the CO2/ Levelland oil system.