RESPONSE OF AN ELLENBURGER CRUDE TO CO2 SLUGS PUSHED BY NITROGEN.

Laboratory studies to determine the response of an Ellenburger crude of West Texas when displaced by carbon dioxide at various pressures indicate promising oil recovery rates. Tests on 40. 4 degree API separator crude oil at a reservoir temperature of 130 F resulted in oil recoveries ranging from 63% to more than 95% as the reservoir pressure increased from 700 to 2,500 psi. Since CO//2 may be in short supply, the possibility of using a slug of CO//2 pushed by nitrogen was also studied. For the slug tests, the carbon dioxide slugs ranged from 3. 9% hydrocarbon pore volume to 10% of the hydrocarbon pore volume. All slugs were pushed by nitrogen. The oil recovery ranged from approximately 74 to 93% over this slug size. The results from carbon dioxide displacement studies at 70 F and 250 F are also discussed.