Optimized Electric Submersible Pumping to Extend Economic Oil Production in a High Water Cut Environment

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Abstract The economic life of the Equity Oil Company operated lease in the Ashley Valley Field of Uintah County, UT has been extended significantly from efficient use of electric power, Early efforts to reduce power consumption inefficiencies included replacement of flowlines to lower surface backpressure, installation of a central capacitor bank to eliminate power factor penalty payments and a well respacing project. This paper shall focus on recent efforts concerning submersible pumping optimization including the use of increased efficiency stage and motor designs and proper equipment selection to operate at maximum efficiency. Operating Environment The primary reservoir in the Ashley Valley Field is Weber sandstone of Pennsylvanian age at an average depth of 4,200 ft. The Ashley Valley Field is on a northwest - southeast trending anticline located in the Uintah Basin of northeastern Utah. The field was discovered in October, 1948 and is recognized as the first commercial oil discovery in Utah. A structure map is presented as Figure 1. Initially, all wells flowed and were essentially free of water. No initial gas cap was present in the reservoir. The active fresh water drive resulted in the installation of submersible pumps on the Equity lease in 1960. Production performance is presented as a water-oil ratio (WOR) versus cumulative production plot in Figure 2. Average daily production is currently 85 BOPD and 35,100 BWPD from four wells. Produced fluids from all wells flow into a 3,000 bbl gunbarrel separation tank and through a series of retention pits for final separation. Chemical injection at the wellhead also aids in separation of oil from water. The discharge from the final retention pit is a source of agriculture irrigation water. Additional operating environment data is provided as Table 1. Life Expectancy and Failure Mode of ESP's Field History/Failure Modes. A field failure history quantifies run times, operating conditions and failure modes in Tables 2 and 3.