Submersible pump with stage erosion control
A technique facilitates long-term operation of a submersible pump which may be used in an electric submersible pumping system. According to an embodiment, the submersible pump comprises at least one stage, e.g. a plurality of stages. Each stage uses an impeller which may be rotated within a diffuser to establish a fluid flow through the pump. Additionally, each stage comprises an erosion control system positioned between the impeller and the diffuser to reduce erosion and/or the effects of erosion so as to extend the life of the submersible pump.
1 . A system for use in a well, comprising:
an electric submersible pumping system having:
a submersible motor;
a motor protector; and
a submersible pump powered by the submersible motor, the submersible pump comprising a housing containing a plurality of stages arranged to pump well fluid, each stage having an impeller that is configured to discharge the well fluid into a corresponding diffuser, the impeller being mounted on a shaft and being rotatable relative to the diffuser, each stage further comprising an erosion control system positioned between the impeller and the diffuser to extend the life of the submersible pump,
wherein the erosion control system includes:
an impact wall, the impact wall having a constant distance from a centerline of the submersible pump, the impact wall including a first thickness extending along an inner surface of the housing and coupled by an inclined transition section to a wall of the diffuser downstream of the impact wall, the wall having a second thickness smaller than the first thickness, such that an undeviated fluid flow discharged from the impeller directly impacts the impact wall; and
a tubular protective sleeve disposed radially between the shaft and the diffuser, wherein the tubular protective sleeve axially abuts a first impeller of a first stage and a second impeller of a second stage, and wherein the tubular protective sleeve extends into a diffuser exit flow region.
2 . The system as recited in claim 1 , wherein the erosion control system is located at least in part in a break water zone of the diffuser where the well fluid exits the impeller and impacts the impact wall.
3 . The system as recited in claim 1 , further comprising a truncated impeller tip which reduces the outside diameter of the impeller.
4 . The system of claim 1 , wherein an end of the impact wall at least partially defines an upstream end of the diffuser.
5 . A method, comprising:
assembling an electric submersible pumping system having a submersible motor, a motor protector, and a submersible pump powered by the submersible motor;
providing the submersible pump with a housing containing a plurality of stages arranged to pump well fluid, each stage having an impeller that discharges the well fluid into a corresponding diffuser, the impeller being mounted on a shaft and rotatable relative to the diffuser; and
protecting each stage of the plurality of stages with an erosion control system positioned between the impeller and the diffuser to extend the life of the submersible pump,
wherein the erosion control system includes:
an impact wall, the impact wall having a constant distance from a centerline of the submersible pump, the impact wall including a first thickness extending along an inner surface of the housing and coupled by an inclined transition section to a wall of the diffuser downstream of the impact wall, the wall having a second thickness smaller than the first thickness, such that an undeviated fluid flow exiting the impeller directly impacts the impact wall; and
a tubular protective sleeve disposed radially between the shaft and the diffuser, wherein the tubular protective sleeve axially abuts a first impeller of a first stage and a second impeller of a second stage, and wherein the tubular protective sleeve extends into a diffuser exit flow region.
6 . The method as recited in claim 5 , further comprising positioning the erosion control system at least in part in a break water zone of the diffuser where the well fluid exits the impeller and impacts the impact wall.
7 . The method as recited in claim 5 , further comprising forming the erosion control system by truncating at least a portion of an impeller tip of the impeller.
8 . The method of claim 5 , wherein an end of the impact wall at least partially defines an upstream end of the diffuser.
9 . An electric submersible pump comprising:
a housing containing a plurality of stages, each stage comprising:
an impeller; and
a diffuser, wherein the impeller is disposed about a shaft and is configured to rotate relative to the diffuser, and wherein at least one of the plurality of stages comprises a tubular spacer disposed along an inner surface of the housing axially between consecutive diffusers, the tubular spacer including an inner surface a constant distance from a centerline of the electric submersible pump at a location where an undeviated fluid flow discharged from the impeller directly impacts the tubular spacer, a hardness of the tubular spacer is greater than a hardness of the diffuser; and
a tubular protective sleeve disposed radially between the shaft and the diffuser, wherein the tubular protective sleeve axially abuts a first impeller of a first stage and a second impeller of a second stage, and wherein the tubular protective sleeve extends into a diffuser exit flow region.
10 . The pump of claim 9 , wherein the spacer comprises white iron.
11 . The pump of claim 9 , wherein the spacer comprises ceramic or cermet.
12 . The pump of claim 9 , wherein the spacer replaces a lower tubular portion of an upper diffuser of the consecutive diffusers.
13 . The pump of claim 9 , wherein an end of the tubular spacer at least partially defines an upstream end of a stage of the plurality of stages.