Design and Operation of a 160,000-BFPD Centralized Production and Injection Scheme at Weyburn

Unitization of the Weyburn Oilfield was necessary to facilitatewaterflooding the limestone producing formation. At its inception, on July 1,1963, the Unit comprised 550 wells producing through 115 tank batteries. Underunitized operation, advantage was taken of the unrestricted market for oil andthe removal of regulatory production restrictions, permitting productionpractice on a maximum- efficient-rate basis. Production facilities wereconsolidated and injection facilities installed, so that emulsion treating andinjection water pumping are concentrated at one centrally located plant. This paper describes the design criteria and the operating experience of thecentralized production and injection scheme from March, 1964, to date. Adescription is given of the pre-unit operation and equipment, and of the designconsiderations to convert to an optimum gathering system through test and groupsatellites to a central treating plant. The reasons for the choice of one plantrather than several are outlined. The design of the emulsion flow streamthrough heat exchangers, free water knockout vessels, a flow splitter, fourhorizontal heater treaters and finally to three storage tanks is presented. Theselection of the source water supply and equipment, and the sizing ofhigh-pressure water pumps and gas engine drives are discussed, as well as thecorrosion-protected, radial water injection system. The alternatives consideredfor the large-size artificial lift equipment installed on producing wells aregiven. Comments on equipment performance and costs are made. Introduction The Weyburn Oilfield is located 85 miles south and east of Regina, Saskatchewan (Figure1). The producing zone is comprised of the Mississippian Midale beds, which lie at an average depth of 4,600 ft fromsurface. On July 1, 1963, 53 owners of 550 wells consolidated their operationsby unitizing 70 sq. miles of productive oil land, and appointed Central-Del Rio Oils Limited as Operator. Utilization was necessary to partially restorereservoir pressure by waterflooding. Studies indicated that waterflooding wouldincrease the recovery from 13.8 per cent to 31.7 per cent of the initialoil-in-place.