Electrical Submersible Pumps for the Montrose Field - Their Application and Post Operational Experience

ABSTRACT The North Sea Montrose Field has been on production since July 1976. Since mid 1979 artificial lift has been necessary on certain wells, due to their high water cuts. This paper reviews the application of electrical submersible pumps for artificial lift on Montrose Field, the choice and sizing of equipment, completion design and the installation procedure. Problems encountered and post-appraisal of the electrical submersible pump installations, together with any changes made to remedy the problems and improve pump performance, are discussed. Specific items covered include the experience with rotary gas separators, the run life and performance of submersible pumps, and the economics of submersible pumps for artificial lift. Submersible pumps have been used to maintain production which has decreased on certain wells in the Montrose Field due to increasing water cuts. The submersible pumps have been run in high angle holes (65°), at measured depths of approximately 10,000 ft., with production of high GOR (900 SCF/BBL) and in the presence of sand. The reservoir pressure is a maximum of 3000 psig and the reservoir temperature is 255°F. Experience gained by Amoco with submersible pumps in the offshore environment of the North Sea is applicable to other operators and their artificial lift requirements, especially where high production rates and hostile environments are encountered. It has been shown to date that electrical submersible pumps can be run in the North Sea, but with only limited success. Advantages exhibited over gas lift (presently the only viable alternative to electrical submersible pumps in the North Sea), are the comparatively low initial installation costs and an application on a well by well basis, rather than a field wide basis; however, these advantages can only be achieved provided a satisfactory pump run life is obtained. A total of ten electrical submersible pumps have been installed on the Montrose Field, with an average run life of approximately four weeks, and a maximum run life of approximately three months.