Pumps – Motor driven – Including means for facilitating assembly or disassembly of...
Reexamination Certificate
1999-08-02
2001-02-27
Thorpe, Timothy S. (Department: 3746)
Pumps
Motor driven
Including means for facilitating assembly or disassembly of...
C166S242600, C166S242700, C166S105000
Reexamination Certificate
active
06193474
ABSTRACT:
TECHNICAL FIELD
This invention relates in general to well pumps, and in particular to a well pump which is operated by a submersible electric motor and is retrievable through tubing.
BACKGROUND ART
Electrical submersible well pumps for deep wells are normally installed within casing on a string of tubing. Usually the tubing is made up of sections of pipe screwed together. Coil tubing deployed from a reel is also used to a lesser extent. The motor is supplied with power through a power cable that is strapped alongside the tubing. The pump is typically located above the motor, is connected to the lower end of the tubing, and pumps fluid through the tubing to the surface. One type of a pump is a centrifugal pump using a large number of stages, each stage having an impeller and a diffuser. Another type of pump, for lesser volumes, is a progressive cavity pump. This pump utilizes a helical rotor that is rotated inside an elastomeric stator which has double helical cavities. The stator is located inside a metal housing.
Periodically, the pump assembly must be pulled to the surface for repair or replacement. This involves pulling the tubing, which is time consuming. A workover rig is necessary for production tubing, and a coiled tubing unit is needed to pull coiled tubing. Often, the electrical motor needs no service, rather the service needs to be performed only on the pump. Sometimes the only change needed is to change the size of the pump without changing the size of the motor. However, the motor, being attached to the lower end of the pump, is also pulled along with the tubing. Damage to the power cable is not uncommon when pulling the tubing.
SUMMARY OF INVENTION
In this invention, the motor is secured to the lower end of the tubing. The power cable to the motor is strapped alongside the tubing. The pump, however, is sized to be lowered through the tubing. The pump has a driven shaft extending downward from it that mates with a drive shaft extending upward from the motor. When the pump reaches the motor, the driven shaft will stab into the drive shaft.
A head assembly is located at the upper end of the pump for engagement by a running tool to lower the pump through the tubing and retrieve it. The head may be secured to wireline, wire rope or coiled tubing which inserts through the production tubing. The head lands within a sub in the production tubing to latch the pump in place. The pump pumps well fluid up through the tubing.
When it is desirable to change out or repair the pump, the operator lowers a running tool through the production tubing and latches it to the head. The operator pulls the pump, leaving the motor in place. Subsequently, the running tool lowers the repaired or replacement pump back through the tubing into engagement with the motor.
The electric motor assembly is mounted to a coupling housing which is secured to the lower end of the tubing. The coupling housing has an anti-rotation key within its bore. The drive shaft of the electric motor assembly extends into the coupling housing.
The lower end of the pump assembly driven shaft is located within a tubular guide. The guide extends slidingly into the coupling housing as the pump assembly is being lowered. The guide rotatably receives the lower portion of the drive shaft. The guide has an engagement member on its exterior which engages the internal anti-rotation member in the bore of the coupling housing.
REFERENCES:
patent: 3677665 (1972-07-01), Corkill
patent: 4416593 (1983-11-01), Cummings
patent: 4592427 (1986-06-01), Morgan
patent: 4678031 (1987-07-01), Blandford et al.
patent: 5145007 (1992-09-01), Dinkins
patent: 5501580 (1996-03-01), Barrus et al.
patent: 5736582 (1998-04-01), Devillez
patent: 5746582 (1998-05-01), Patterson
patent: 5871051 (1999-02-01), Mann
patent: 5954483 (1999-09-01), Tetzlaff
Baker Hughes Incorporated
Bradley James E.
Felsman, Bradley, Vaden, Gunter & Dillon L.L.P.
Thorpe Timothy S.
Tyler Cheryl J.
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