Pressure Maintenance in SACROC Unit Operations January 1, 1959

Abstract

Abstract The SACROC Unit pressure maintenance plan does not depend on water injection alone for improving reservoir conditions, but in conjunction with 66 water injection wells located along the longitudinal axis of the Kelly-Snyder field, some 400 producing wells along the edge of the field have been shut in and their allowables transferred to more efficiently producing wells in the central portion of the field on either side of the line of injection wells. This supplemental history will generally follow the pattern of the previous paper, bringing reported operations tip to date and also presenting additional data pertinent to the stages of development occurring thus far in the life of SACROC Unit. Introduction It is one thing to discover an oil reservoir of 2,800 million STB, but quite another thing to produce it. The comparison between estimated recovery by pressure maintenance and ultimate recovery indicated by primary production resulted in the creation of SACROC Unit. The organizational setup of SACROC is most complex and little understood except by those intimately involved with overall operation, but no space will be taken to discuss that subject in this paper. Original Reservoir Conditions The Canyon Reef reservoir of the Kelly-Snyder field encompasses some 50,000 productive acres. The field was developed by approximately 82 operators with the wells drilled on 40-acre spacing. The Canyon Reef reservoir is encountered at an approximate depth of 6,700 ft, and varies from 0- to 795-ft thick. It is a low mound shape with gently dipping flanks. Average porosity of net reef is 10.03 per cent, and average porosity of gross is 7.11 per cent. Net pay is defined as reef having 3 per cent or greater porosity. The average permeability is 30.6 md to air. Initial oil saturation was 100 per cent of hydrocarbon pore space. Average interstitial water saturation was 28.2 per cent and the average reservoir temperature 130°F. The characteristics of the reservoir fluids are shown in Table 1.