Barry J Blair discusses advances in the electric submersible, subsea and traditional pump markets
Pump requirements for longer life and increased production are creating a chain reaction of demands, innovations, and improvements in bearing technologies.
Technological advances in steam assisted gravity drainage (SAGD) demand that electric submersible pumps (ESPs) operate in higher temperatures, and sometimes, at higher speeds. These high temperatures place increased demands on the thrust bearings in the motor seal/protector section of the string. Given the high cost of a well’s downtime, equipment is expected to continue to perform even in abnormal conditions, such as contamination. Hence, there is an increased demand for bearings that can operate with abrasives, especially if a seal fails.
New ceramic/cermet bearings, like the Hidrax HT thrust bearing, can address SAGD demands for high temperature capabilities – in excess of 300°C (572°F) – and have the potential to handle abrasives too.
In the subsea pump industry, multiphase pumps introduce a wide range of fluids and fluid viscosities, as well as abrasives, to the equipment operating conditions. These conditions drive bearing advances that increase durability and load capacity. Furthermore, subsea pump manufacturers place a premium on increased operating life, due to the cost of repairing a subsea pump.
Therefore, the subsea market is applying ceramic/cermet bearings to handle high loads and high temperatures, as well as low-viscosity fluids and abrasives. Advanced bearing designs for the subsea market also offer superior load levelling and pivot mechanisms that eliminate the possibility of pivot wear and levelling link binding while providing improved load-equalising capabilities over an extended pump life.
To increase output and efficiency of traditional oil-lubricated pumps, recent bearing developments are directed at having a higher load capacity without affecting bearing life. New designs, such as novel pad geometries, and new materials, such as polymers and metallics, that provide higher load capacity may allow for a reduction in losses associated with thrust balancing. Also, the ability to handle higher loads allows the manufacturer to use a smaller bearing, resulting in lower power loss and increased pump efficiency. If power loss reduction is not required, the higher load capacity provides a more durable bearing with higher safety margins for a given size and load.
When seeking a bearing solution, pump manufacturers and operators need to look to advanced materials and designs that can keep pace with other technological advances in the industry to extend pump operating life and improve production. Significant investment in research and testing is being made to evaluate the durability and capabilities of existing and new bearing designs, including a plethora of material options.
[photo caption] The Hidrax HT thrust bearing can address the increased ESP temperatures in SAGD wells, which are reported as high as 270°C (518°F).
Barry J Blair is Chief Engineer at Waukesha Bearings.