Paper: Response of Anton-Irish Clearfork Crude To Miscible Displacement Tests

Approximately fifty billion barrels of stock tank oil were originally in place in the larye carbonate reservoirs of the Permian Basin. Two-thirds of this oil occurred in the San Andres and Grayburg strata. Much of the recent work utiliziny carbon dioxide as the miscible displacing fluid has been conducted in San Andres reservoirs, yet other strata may also offer substantial opportunities. Ten to fifteen percent of the original oil-in-place was reported to be in Clearfork or Yeso reservoirs. One of the Clear Clearfork producers in West Texas is the Anton- Irish oil field. The estimated original oil in place was near 500 million barrels. The cumulative production to l/1/84 was 150 million barrels. This leaves more than 300 million barrels of stock tank oil as a possible target for a successful EOK project. If the EOR project should recover as much as fifteen percent of the original oil-in-place this would increase the oil recovery by 75 million barrels of stock tank oil. Hence the purpose of this work was to conduct a laboratory study to determine the response of a Clearfork crude oil to different miscible displacement oil recovery processes. Carbon dioxide yas was used as the displacing fluid on one series of tests, and LPG slugs pushed by nitrogen were used in a second series of tests. This paper reports the results of the study.