Imperial's Steelman Unit Ia and II Waterflood System

Abstract

Abstract In January, 1962, full-scale water flooding began in the Steelman field ofsoutheastern Saskatchewan. The field has been developed on 80-acre spacing andthe injection pattern is an inverted nine-spot. The main requirements of theflood are a high quality water and flexibility in injection rates andpressures. To accomplish these ends water from the high capacity Blairmore sandis distributed to the injection plants, where it is filtered andinhibitor-treated, before injection into high pressure lines radiating to theinjection wells. The pressure and rate of injection to each well is controlledat the injection plant. Plant operation is semi-automatic and source wellpumps, filters, engines and injection pumps are protected by safety controls.Corrosion throughout the injection system is controlled through coatings andinhibitor and bacteriacide injection. The design of the injection system was influenced by the results of a pilotoperation which commenced in 1958. The use of dry gas engines and diatomaceousearth filters are some of the design improvements derived from pilotexperience. This presentation discusses the design of surface facilities forthe water floods in Steelman Units IA and II, which were installed by ImperialOil Limited in 1961. Introduction The Steelman field is on the northern rim of the Williston Basin insoutheast Saskatchewan, approximately 15 miles north of the InternationalBoundary (Figure 1).The reservoir, at an average depth of 4,700 ft., isa stratigraphic trap of Mississippian limestone known locally as the MidaleBeds. The zone is thin and heterogeneous with low permeability. To date, 760wells have been drilled on 80-acre spacing. Recovery has been estimated at 16per cent under natural depletion and 35 per cent under water flooding.