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.

A method for stopping a submersible pump when the pump is snoring, wherein the pump is operatively connected to a control unit. The method includes regulating, by way of the control unit, the operational speed of the pump in order to direct an average power of the pump towards a predetermined set level. The method includes determining whether the instantaneous power of the pump is outside a predetermined range, by monitoring at least one of the parameters: power [P], current [I] and power factor [cos ϕ].The method further includes determining whether the operational speed of the pump is increasing, and stopping the pump due to snoring, by way of the control unit, when the instantaneous power of the pump is determined as being outside the predetermined range at the same time the operational speed of the pump is determined as increasing.

A method for stopping a submersible pump when the pump is snoring, wherein the pump is operatively connected to a control unit. The method includes regulating, by way of the control unit, the operational speed of the pump in order to direct an average power of the pump towards a predetermined set level. The method includes determining whether the instantaneous power of the pump is outside a predetermined range, by monitoring at least one of the parameters: power [P], current [I] and power factor [cos ϕ].The method further includes determining whether the operational speed of the pump is increasing, and stopping the pump due to snoring, by way of the control unit, when the instantaneous power of the pump is determined as being outside the predetermined range at the same time the operational speed of the pump is determined as increasing.

A power cable can include a conductor; an insulation layer disposed about the conductor where the insulation layer includes a first polymeric material; and a shield layer disposed about the insulation layer where the shield layer includes a second polymeric material where a solubility parameter of the first polymeric material is less than a solubility parameter of the second polymeric material.

A technique employs a system and methodology for improving sand control in pumps. The technique may be used in centrifugal pumps by providing uniquely constructed rib feature to facilitate sand control and thus reduction of erosion due to sand in the pumped fluid. The improved sand control is useful in centrifugal pumps employed in a variety of oilfield applications, such as in electric submersible pumping systems positioned downhole in a wellbore to pump oil or other fluids. The rib feature may be used in combination with a shield and arranged along diffuser bowl walls or other diffuser walls within sequential pump stages.

A multistage centrifugal pump includes an upstream housing and a downstream housing. The upstream housing and the downstream housing each have a first end, a second end and a plurality of turbomachinery stages. Each of the plurality of turbomachinery stages includes a diffuser and an impeller. A compression bulkhead is connected between the second end of the upstream housing and the first end of the downstream housing. The compression bulkhead applies a compressive force to the diffusers within the upstream housing.

Disclosed herein is an apparatus for an immersible pump. The apparatus can include a shaft for communicating with a motor. The shaft includes a first region having a first diameter, a second region having a second diameter that is less than the first diameter, and a tapering region between the two regions. A sleeve can be provided to receive the shaft. A sealing device includes a receiving area in which the tapering region is at least partially positionable to form a seal, and an abutment that is configured to form a seal with the sleeve and that is responsive to a force directed from the sleeve to enhance the seal with the tapering region. In some embodiments, the sealing device is provided with a circumferential outer wall for centering the sleeve about the shaft and/or for aligning the force with the abutment.

Disclosed herein is an apparatus for an immersible pump. The apparatus can include a shaft for communicating with a motor. The shaft includes a first region having a first diameter, a second region having a second diameter that is less than the first diameter, and a tapering region between the two regions. A sleeve can be provided to receive the shaft. A sealing device includes a receiving area in which the tapering region is at least partially positionable to form a seal, and an abutment that is configured to form a seal with the sleeve and that is responsive to a force directed from the sleeve to enhance the seal with the tapering region. In some embodiments, the sealing device is provided with a circumferential outer wall for centering the sleeve about the shaft and/or for aligning the force with the abutment.

A submersible pump assembly includes a centrifugal pump driven by a motor. The pump has a number of stages, each of the stages having a diffuser and an impeller. An upthrust washer is located between a diffuser upthrust surface and an impeller upthrust surface. Balance holes extend from an inlet on an upper side of the impeller to an outlet within one of the impeller passages. The upthrust washer overlies the inlets while the impeller is in the upthrust position. Slots are located at an interface between the upthrust washer and the impeller upthrust surface. Each of the slots registers with the inlet of one of the balance holes to allow fluid flow into the inlets of the balance holes while the impeller is in the upthrust position.

An electric submersible pump motor can include a housing; a cavity defined at least in part by the housing; a rotor disposed in the cavity; a stator disposed in the cavity where the stator includes stator laminations and stator windings disposed at least in part in slots of the stator laminations; and stator slot liners disposed at least in part in the slots of the stator laminations where the stator slot liners include polytetrafluoroethylene and/or expanded polytetrafluoroethylene.