Esp Performance In Sand-Laden Fluids In The Bellshill Lake Field

Abstract

Abstract Electric Submersible Pumps (ESPs) used by Petro-Canada Inc. In the Bellshill Lake Basal Quartz pool, were first used as a means of high volume lift in 1976. ESPs were traditionally used in areas of the reservoir that had very well consolidated sands where sand production was very limited. In March 1987, ESPs were run in the more permeable and porous areas of the reservoir consisting largely of unconsolidated sandstones. Reservoir inflow was very prolific, as was the sand production. ESPs in these wells initially ran anywhere from two to three days before catastrophic failure occurred. Ultimately, rubber bearing radially stabilized ESPs were installed and proved to be very successful. A production test was conducted to determine the volume of sand produced with the reservoir fluids and the duration of the peL1k sand production, To monitor the pump wear, ESPs were pulled at various intervals over time and pit tested to determine the loss of pump efficiency. Over the past 41/2 years, efforts have been directed at improving ESP performance while pumping sand laden fluids and have been very successful in minimizing ESP failures related to sand production. This paper documents the early production testing of the rubber bearing ESPs, and the resulting standards and procedures that were developed for ESPs in the Bellshill Lake field. Introduction The Bellshill Lake field is located in east-central Alberta approximately 350 km northeast of Calgary (Fig. I). The Bellshill Lake field comprises the Ellerslie Unit which currently produces 1300 m3/d of oil, 26 500 m3/d of water and 90 103m3/d of associated solution gas. The field also has 3% H2S and 7% CO2 content in the fluids produced. The Bellshill Lake Ellerslie Unit consists of 372 producing oil wells of which 24 are ESP installations. In March 1987, Petro-Canada starred experiencing catastrophic failures of new ESP installations after only two to three days run time. It was determined shortly thereafter that the cause of the failures was a high concentration of abrasives in the produced fluid. As a result of these failures, a study was initiated to identify the problems associated with ESPs and abrasives and determine what the economic solution was to this situation. Consideration was given to whether or not abrasives could indeed be produced by ESPs, and if so, what volume of abrasives or sand were being produced. Additional consideration was given ro determine if there was any relation of sand produced to the fluid production rates and reservoir drawdown. Effects of Abrasives on ESPs It is known and accepted(l) that abrasives/sand are produced with oil to some degree in most oil wells. The control of sand production is a complex and often very expensive problem. Conventional methods include the use of sand screens, gravel packs, high density perforating and limited drawdowns. The production of abrasives or sand in reservoir fluids, exhibit some obvious (rends. Previous research and field experience(1) indicate that sand production increases when the rate is changed and increased, and that the sand production may not decrease when the flow rate is decreased.