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). In Phase I, which has been completed, the following results were obtained. Two new wells were drilled in the field and live cores were recovered. Analyses of the cores proved that viable microorganisms were present and since no sulfate-reducing bacteria (SRB) were found, the area in which the wells were drilled, probably had not been impacted by injection water, since SRB were prevalent in fluids from most wells in the field. Laboratory waterflooding tests using live cores demonstrated that the rate of flow of simulated production water through the core increased with time when used alone while the rate of flow decreased when nitrate and phosphate salts were added to the simulated production water. Since there is only a small amount of pressure on the influent, the simulated production water was not forced to sweep other areas of the core (as would be expected in the reservoir since the water is injected under pressure). The field demonstration (Phase II) involves adding nutrients to four injector wells and monitoring the surrounding producers. The exact kind and amounts of nutrients to be employed and the schedule for their injection were formulated on the basis of the information obtained in the laboratory waterflooding tests conducted using the live cores from the field. Results obtained in these tests will not only be compared to historical data for the wells but also to four injectors and their corresponding producers (control) which were chosen for their similarity to the four test patterns. A preliminary geological and petrophysical characterization of the reservoir has been made and baseline chemical and microbiological data obtained on all of the test and control wells in the first test pattern (two injector wells and nine producing wells). Injection of nutrients began in the first test well on November 21, 1994.