Performance of Domes Unit Carbonated Waterflood - First Stage

Abstract

Abstract Carbonated water has been injected as a slug, followed by non-carbonated water, in the Bartlesville sand formation of the Domes unit in northeastern Oklahoma. Initial results are shown for the first stage of the flood, consisting of nine enclosed five-spots comprising 132 acres. Production history indicates the carbon dioxide have been transferred to the residual oil and has mostly been retained in the reservoir. A large portion of the formation is apparently being bypassed due to stratification and reservoir fracturing. Results of pressure shut-in tests are shown to indicate vertical fractures being opened by injection pressures. The tests have been used to help balance the flood and increase oil recovery from poorly swept areas. Introduction The Domes unit is composed of 13 quarter-sections located in Sections 34 and 35 of T-27N, R-10E; and Sections 2 and 3 of T-26N, R-10E in Osage County, Okla., 15 miles west of Bartlesville (Fig. 1).The unit is jointly owned by Cities Service Oil Co. and Oil Recovery Corp. The unit was organized March 1, 1961, with Cities Service as the operator owning a 63.52 per cent working interest, and Oil Recovery Corp. owning 36.48 per cent. Initial operations of the unit have been to conduct a carbonated waterflood of the Bartlesville formation. Primary Development and Recovery Development of this area began in 1910 with gas production from the Mississippi Chat at a depth of 1,950 ft. In 1914, development of the Bartlesville sand began and continued through the early 1920's. About 60 wells were drilled during this period but were all plugged when waterflooding was started. Only minor drilling was done for the next 30 years until the advent of hydraulic fracturing. when extensive redrilling of the area occurred. Wells drilled during 1952 and 1953 were completed for potentials of 50 to 100 BOPD after fracturing. This redrilling resulted in an additional 30 wells. Primary oil recovery from the Bartlesville sand in the developed unit area averaged 80 bbl/acre-ft. The NE/4, Section 34 and SW/4, Section 34, due to extensive fracture treatments, have recovered 115 bbl/acre-ft. Primary oil production is estimated to have been 1,255,000 bbl from the total unit area at the start of secondary development. Reservoir properties are shown in Table 1. Secondary Development-First Stage Secondary development started in Section 34 in the summer of 1961. Most of the wells used had been drilled in 1952 and 1953. Thirteen producing wells were converted to injection and three additional injection wells were drilled to complete nine five-spot patterns (Fig. 1). The patterns range from 12 to 20 acres, comprising a total of 132 acres. Besides the enclosed producing wells, four outside producing wells existed at the beginning of the flood. Additional producing wells surrounding the enclosed area were added early in 1962. JPT