Low Salinity Oil Recovery: An Exciting New EOR Opportunity for Alaska’s North Slope

摘要

Laboratory studies conducted over a period of many yearsrnhave indicated that oil recovery could be improved byrninjecting lower salinity water (less than about 5,000 ppm).rnAlthough the recovery mechanisms are still uncertain, theyrnappear to be similar to those found in alkaline flooding.rnRecent successful field trials have led to serious evaluation ofrnfield-scale implementation of low salinity EOR.rnFour sets of single well chemical tracer tests (SWCTT)rnperformed in Alaska confirmed that the favorable laboratoryrnresults could be replicated in the field. The SWCTT resultsrn(two in the Ivishak sandstone, one each in the Kuparuk andrnKekiktuk sandstones) showed that waterflood residual oilrnsaturation (Sorw) was substantially reduced by low salinityrnwater injection. The low salinity EOR (LoSal) benefits rangedrnfrom 6 to 12% OOIP, resulting in an increase in waterfloodrnrecovery of 8 to 19%. Based on these encouraging results, lowrnsalinity oil recovery is being actively evaluated for NorthrnSlope reservoirs.