Effects of Sand on the Components and Performance of Electric Submersible Pumps

The increasing world demand for oil has pushed oil companies to extract it from the ocean at extreme depths. With the increase in depth comes an increase in operation costs, especially the deep-sea equipment changeover cost. To be able to push the oil to the ocean surface, Electrical Submersible Pumps (ESPs) are commonly used as artificial lift. The changeover cost of these pumps in deep-water has been estimated to sometimes be as much as forty times the cost of a new pump.

One common reason for the failure of ESPs is the erosion and abrasion created by the fine sands that seep through the gravel pack mesh in the well hole. These fine sand particles are most destructive to the bearings and bushings due to their capability to enter the clearances lubricated by the pumped fluid. Over time, the sustained abrasion and erosion in the different components of the ESP will affect the performance of the pump and could lead to its damage.

This work describes the design, construction and evaluation of an erosion test rig built at the facilities of the Turbomachinery Laboratory in Texas A&M University. The test rig is capable of introducing 100 mesh (6 mil) sand into the flow loop, measure its concentration and separate it at the exit with minimal water loss.

The pump under study is a Baker Hughes 10.25" WJE1000. The performance of the pump is described by measuring the head, flow rate, power and efficiency. The pump is equipped with accelerometers to detect the casing vibration as well as proximity probes in five locations along the pump to detect the internal vibrations of the shaft near the bearings as well as impeller radial movement. The baseline data, to be used for comparison with the worn out pump, has been shown and recommendations for the study method and operation of the rig are given.