Electric Submersible Pumps —Reducing Failures Through Improved Field Procedures In The South Swan Hills Unit
Authors: Passmore R.G. , Kupsch N.W. 
Published: March 2010

The Amoco Canada-operated South Swan Hills Unit is currently producing under a combined water, hydrocarbon miscible and dry gas flood. Nearly 85 per cent of the daily production of 6 500 m3 oil and 25 000 m3 water is lifted by 106 submersible pump installations.

The average run life of a submersible pump in the Unit has historically been about six months. The adverse conditions contributing to this relatively short operating time include high temperatures, high pressures, the depth of the reservoir, small casing diameter, corrosion, changing gas/oil ratios with the associated problems of gas breakthrough and asphaltene plugging. These combined factors have hampered attempts to lengthen the average run life of a submersible pump installation.

Concentrated efforts in the past two years, aimed at improving field operations, are now being seen as having a positive impact on submersible pump performance. This paper describes procedures which were initiated and the resulting advancements which have been made in this area.

Introduction

The South Swan Hills Unit is located 225 km northwest of Edmonton, Alberta (Fig. 1). The Unit (Fig. 2), formed in 1962 and operated by Amoco Canada Petroleum Company Ltd., consists of 191 production and 60 injection wells. Production is from the Swan Hills formation of the Beaverhill Lake Group, which is a limestone reef complex. Bottomhole temperature is 112 °C at a depth of 2500 mKB.

FIGURE 1. Location of the South Swan Hills Unit. (Available in full paper)

In 1963, the west side of the Unit was put on a secondary recovery water flood. In 1973, a secondary miscible flood project was initiated in the central portion of the Unit. The enriched gas solvent injection is nearing completion, with all injection wells to be converted to dry gas by August 1982. In 1978, the east portion of the field was placed on waterflood. The number of submersible pump installations peaked at 118 in 1980 and has since been reduced to 106. Previous and present local ions are also shown on Figure 2.

History

The South Swan Hills Unit currently produces about 6 500 M3/d of oil and 25 000 m3/d of water (Fig. 3). Since the first submersible pump was installed in the Unit in January 1971, production has become increasingly dependent on this form of artificial lift (Fig. 4). Currently, 58 per cent of all production wells utilize submersible pumps, representing 85 per cent of total Unit production.

With the exception of the first year of submersible pump operation, the annual failure rate has always been higher than the number of installations (Fig. 5) as a result of the harsh operating environment. During 1980, the 118 locations had experienced 239 failures.

Because of the increasing failure rate and the tremendous associated operating cost (approximately $45 000 per changeout), Amoco began an intensified study in early 1980 in an attempt to reduce this failure rate.

The study reinforced that the major causes of failure were the result of electrical problems, gas interference (often causing mechanical failures), foreign material and corrosion as well as operational procedures.