A Study Of The Dodsland Viking Sand Oil Reservoir Dodsland Field9 Saskatchewan

Publication Rights Reserved 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 considered for publication in one of the two SPE magazines with the paper. This paper presents as of the results of the study of the Dodsland Viking sand reservoir located in the province of Saskatchewan, Canada. It is the first engineering paper written about the field where production is found in a 15-mile trend, at a depth of approximately 2,300 ft. Theological data incorporated in this paper are based on the work of M. B. B. Crockford which was presented to the AAPG Regional Meeting in Billings, Mont., during Feb., 1960. The data and material are of interest in the presentation and the paper timely because of the large areal extent of the potentially oil-productive sand and because the field has many producing and completion problems. The reservoir is characterized by a thin, gently-dipping, shallow sandstone reservoir rock. The up-dip portion of the sand is gas-bearing and covers approximately 70,000 acres, while the oilbearing portion may cover as much as 20,000 acres. Down-dip limits appear to be governed by a deterioration in reservoir quality. The predominating recovery mechanism is expected to be a solution gas drive, possibly assisted in localized parts of the field along the gas-oil contact zone by an expanding gas-cap. Primary oil reserves may reach 10 million bbl. The sand is fine grained, friable, argillaceous, and approximately 10 ft in net thickness. The oil has a gravity of 38 degrees API. The performance of the individual wells is characterized by a rapid initial decline in productivity, followed by a leveling off in the decline as production continues. The reservoir rock properties are such that completion damage to the sand as a result of using fresh water base drilling fluid is probably quite severe. The rock characteristics and the performance of the individual wells indicate the need for large volume, high injection rate, fracture treatments utilizing a coarse propping agent. Introduction The Dodsland Viking sand field is located in southwestern Saskatchewan, about 200 miles northwest of Regina, about 50 miles east of the Alberta-Saskatchewan border, and about 200 miles north of the International Boundary [Fig. 1]. The field limits as defined by the Saskatchewan government cover all of Townships 30 to 32, Ranges 20 to 22, W.3.M., with the exception of the wells in Sections 6 and 7, Township 31, Range 22, which are included within the field limits of the Coleville-Eureka Viking pool. Situated immediately west of the Dodsland field are the Eureka and Coleville oil fields while the Smiley and Buffalo Coulee fields are nearby.