The utilization of the microflora indigenous to and present in oil-bearing formations to selectively plug the more porous zones thereby increasing oil recovery during waterflooding. Annual report, January 1--December 31, 1995

This project is a field demonstration of the ability of in situ indigenous microorganisms in the North Blowhorn Creek Oil Field to reduce the flow of injection water in the more permeable zones thereby diverting flow to other areas of the reservoir and thus increase the efficiency of the waterflooding operation. This effect is to be accomplished by adding inorganic nutrients in the form of potassium nitrate and orthophosphate to the injection water. Work on the project is divided into three phases, Planning and Analysis (9 months), Implementation (45 months), and Technology Transfer (12 months). This report covers the second year of work on the project. During the first year of the project, Phase 1 was completed and Phase 2 begun. Two wells were drilled in an area of the field where approximately 20 feet of Carter sand were found and appeared to contain oil bypassed by the existing waterflood. Cores from one well were obtained and used in laboratory core flood experiments. On the basis of the results, the schedule and amounts of nutrients to be employed in the field were formulated. The injection of nutrients into the first of four injector wells began November 21, 1994. The addition of nutrients into three additional injector wells began in January and February, 1995. Of the four injectors in the test patterns, two are receiving potassium nitrate and sodium dihydrogen phosphate while the other two are receiving 0.1% molasses in addition. Early, but as yet inconclusive, results from producing wells fin the first test pattern indicate increasing oil production and/or decreasing water-oil ratio. Preliminary geological and petrophysical characterization of the reservoir has been made and baseline chemical and microbiological data have been obtained on all wells in all test and control patterns