Completion of Water Source Wells - Dollard and Instow Fields

Abstract

Abstract Waterflooding of oil fields in southwestern Saskatchewan has created ademand for huge quantities of makeup water. Marathon Oil Company, in itsoperation in the Dollard, Instow, and Rapdan fields in this part of the Province, has experimented with several aquifers and several types of wellcompletions. The development of a gravel packing technique in the extremelyfine grained, thick Belly River sands has established a reliable and economicalsource of water. The paper discusses Marathon's experience with various aquifers and types ofwell completions. It deals with the theoretical aspects of gravel packingand discusses in detail the particular type of gravel packing technique whichproved successful in withholding the extremely fine sands of the thick Belly River formation. Introduction Pressure maintenance operations in Marathon Oil Company's southeastern Saskatchewan operations (Figure 1) commenced with the construction ofwaterflood facilities in the Dollard Field in 1955. Early studies indicatedthat approximately 50 million barrels of water would be required to completethis project. Subsequent development of the Instow, Rapdan and Leon Lakewaterfloods established the need for another 70 million barrels of water. Throughout the past ten years, Marathon, as operator of the Dollard, Instowand Rapdan units in the Dollard-Instow area, has experimented with severalaquifers and with several types of water source well completions. The cost of supplying water for the various waterfloods has continually decreased astechniques improved, until at the present time an adequate, reliable and cheapsource of water has been ensured for the remaining life of the projects. Wells have been completed in the shallow Ravenscrag sands and in the Upper Belly River, Lower Belly River, Viking and Blairmore formations, covering adepth range of from 250 to 4,400 ft. The completion technique which proved themost successful involved gravel packing between a slotted liner and openhole.