New electric submersible pump (ESP) stage designs were developed to combat the rising cost of lifting fluid. Because power consumption is one of the greatest costs, it is desirable to have a highly efficient ESP and to operate the unit at the best efficiency point.
In the Devon Canada Corporation field in northern Alberta, Canada, where 146 ESPs are in operation, high water cuts necessitate the reduction of power costs to economically produce the wells. If the unit is designed and operated properly, optimal system efficiency can be obtained. The new hydraulic ESP stage designed by SLB operates at a much higher efficiency (68%) than other pumps at the same flow rate. This pump was installed and tested for a year in the Canadian field in two different wells with similar flow rate conditions. The result was an average reduction in motor nameplate horsepower in both wells of 18.5% and an average decrease in operating kW/h of 26%.
The new hydraulic stage design used in the two Canadian wells has a greater than 60% efficiency across a wide flow range, 220 to 410 m3/d at 50 Hz [1,600 to 3,000 bbl/d at 60 Hz]. The stage is designed with wide vane openings to handle a high percentage of free gas and also allow solids to pass without plugging. The pump fits into 5-in and 5.5-in casing, enabling the operator to produce wells more efficiently at these flow rates. The result for the two wells is a power cost savings of USD 31,210 per year.