An electrical submersible well pump assembly has first and second permanent magnet motors. The first motor drive shaft is connected to a coupling that has internal splines for receiving an externally splined end of the second motor drive shaft. Alignment devices rotationally align magnetic poles of the first drive shaft with the magnetic poles of the second drive shaft prior to securing the housings of the first and second motors together. The alignment devices may be a coupling irregularity in the internal splines that is at a controlled orientation relative to the magnetic poles of the first shaft and a shaft irregularity in the external splines that prevents the second drive shaft from fully engaging the coupling unless the shaft irregularity is in a specified rotational position relative to the coupling irregularity.

A submersible pump and related methods are disclosed herein. The pump assembly includes a pump housing and a motor with a motor housing/cap and an output shaft connected to an impeller that is disposed in a volute. In some forms, a separate power circuit compartment is formed integral to one of the pump housing and/or volute to store power circuitry that allows a DC pump to be used and powered by AC voltage. In other forms, the power circuit compartment is formed separate from the pump assembly and fastened or connect to the pump assembly. In preferred forms, the power circuit compartment is positioned relative to the pump assembly at a point where it will be maintained at least partially within the fluid surrounding the pump to dissipate heat from the power circuit. Numerous methods are also disclosed and contemplated herein.

The invention provides a flow system, a subsea valve (100), and a method of use in a subsea pipeline filling, flooding or pigging operation. The flow system comprises a subsea valve (100) comprising a valve inlet and a valve outlet configured to be coupled to a subsea pipeline (13). A pump (112) comprises a pump inlet connected to a fluid source and a pump outlet connected to the valve inlet. The pump is operable to pump fluid from the fluid source and into the subsea pipeline via the subsea valve. The subsea valve comprises a movable valve member and a biasing mechanism, by which the valve member is urged by a biasing force towards a closed position that prevents flow of fluid through the valve and into the subsea pipeline. The valve member is operable to be moved to an open position on activation of the pump to provide a pressure increase at the valve inlet sufficient to overcome the biasing force. In use, opposing sides of the valve member are exposed to ambient subsea pressure such that the subsea valve is pressure balanced.

The invention provides a flow system, a subsea valve (100), and a method of use in a subsea pipeline filling, flooding or pigging operation. The flow system comprises a subsea valve (100) comprising a valve inlet and a valve outlet configured to be coupled to a subsea pipeline (13). A pump (112) comprises a pump inlet connected to a fluid source and a pump outlet connected to the valve inlet. The pump is operable to pump fluid from the fluid source and into the subsea pipeline via the subsea valve. The subsea valve comprises a movable valve member and a biasing mechanism, by which the valve member is urged by a biasing force towards a closed position that prevents flow of fluid through the valve and into the subsea pipeline. The valve member is operable to be moved to an open position on activation of the pump to provide a pressure increase at the valve inlet sufficient to overcome the biasing force. In use, opposing sides of the valve member are exposed to ambient subsea pressure such that the subsea valve is pressure balanced.

A subsea water injection pump includes components that are cooled and lubricated by the process fluid. The pump includes opposing stages of impellers in a “back-to-back” arrangement such that the axial forces of the impeller stages partially or nearly fully offset each other. In some cases, a combination of barrier fluid and process fluid is used for lubrication and cooling.

A method for providing artificial lift with an electric submersible pump system includes providing an electric submersible pump system having a motor, a pump assembly, a seal assembly, and a shaft assembly extending along a central axis from the motor to the pump assembly. The pump assembly includes two or more pump sections and a coupling with a transmission mechanism is located between the two or more pump sections. The motor rotates a motor shaft segment of the shaft assembly that is in engagement with a first pump section and starts the first pump section. One of the transmission mechanisms is moved from a disengaged position to an engaged position where the coupling conveys the rotation of the motor shaft segment to the adjacent shaft segment and starts another of the two or more pump sections.

A method for providing artificial lift with an electric submersible pump system includes providing an electric submersible pump system having a motor, a pump assembly, a seal assembly, and a shaft assembly extending along a central axis from the motor to the pump assembly. The pump assembly includes two or more pump sections and a coupling with a transmission mechanism is located between the two or more pump sections. The motor rotates a motor shaft segment of the shaft assembly that is in engagement with a first pump section and starts the first pump section. One of the transmission mechanisms is moved from a disengaged position to an engaged position where the coupling conveys the rotation of the motor shaft segment to the adjacent shaft segment and starts another of the two or more pump sections.

A thrust balancing apparatus for a pump includes a housing, a balancing chamber, a connecting tube, a balancing disk, a bushing, a washer, and a pair of upthrust washers. The balancing chamber defines an upper cavity and a lower cavity. The connecting tube is configured to establish fluid communication between the balancing chamber and an exterior of the housing. A first portion of the balancing disk is disposed within the upper cavity. A second portion of the balancing disk passes through the lower cavity. A third portion of the balancing disk is external to the balancing chamber. The washer is disposed between the balancing disk and the bushing. The pair of upthrust washers are disposed between the balancing disk and the balancing chamber.

Cooling devices for use with electric submersible pump motors include a refrigerator attached to the end of the electric submersible pump motor with the evaporator heat exchanger accepting all or a portion of the heat load from the motor. The cooling device can be a self-contained bolt-on unit, so that minimal design changes to existing motors are required.

Provided is a chemical injection pump that is installed below an electric submersible pump. In general, the chemical injection pump is either driven by an electric motor that draws power from the electric submersible pump motor or from energized fluid leaving the electric submersible pump output port. The electric submersible pump provides electric or hydraulic power to run the chemical injection pump. Therefore, no surface chemical injection pump is required and hence less space is needed.