A Case History of Polymer Waterflooding Brelum Field Unit

Abstract

This paper was prepared for the 48th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Las Vegas, Nev., Sept. 30-Oct. 3, 1973. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract Three and one-half years of polymer waterflooding in the Brelum Field Unit have provided sufficient data to evaluate the project's performance. Addition of polymer will increase the ultimate recovery of the flood by 250,000 barrels over a conventional waterflood. Increased recovery is attributed to improved reservoir conformance. The predicted producing rate was not reached predicted producing rate was not reached because of lower than anticipated injection rates. Polymer flooding has resulted in a stabilized producing rate and low water-oil ratios for the past three and one-half years. General polymer breakthrough has not occurred polymer breakthrough has not occurred to date. Operational problems with the polymer flood have been minor and are polymer flood have been minor and are generally related to reduced injectivity. Introduction A case history of three and one-half years of polymer waterflooding the Lower Government Wells Reservoir in the Brelum Field is reviewed. The polymer flood utilizes eight producing wells and 12 injection wells in a staggered line drive pattern. The areal extent of the total pattern. The areal extent of the total reservoir is 427 acres containing 4275 productive acre-feet with an initial oil productive acre-feet with an initial oil in place estimated to be 5.1 million barrels. The Unit encompasses 264.5 acres containing 2400 productive acre-feet with an original hydrocarbon volume of 2.9 million barrels in place. RESERVOIR CHARACTERISTICS I. GEOLOGY The Brelum structure is a combination monoclinal fault and stratigraphic trap. The trap is bounded by an oil-water contact on the northeast and by pinchouts on the south and west. (Refer pinchouts on the south and west. (Refer to Figure 1.) The Lower Government Wells Sand, which is the producing horizon, occurs at an average depth of 1950 feet and is a member of the Jackson Group of Eocene Age.