Pumps – Motor driven – Including means for facilitating assembly or disassembly of...
Reexamination Certificate
1999-11-10
2001-11-27
Thorpe, Timothy S. (Department: 3746)
Pumps
Motor driven
Including means for facilitating assembly or disassembly of...
C417S359000, C417S424200, C166S066400, C166S105000, C166S381000, C166S378000
Reexamination Certificate
active
06322331
ABSTRACT:
TECHNICAL FIELD
This invention relates in general to a hydrocarbon production well, and in particular to a well utilizing a centrifugal pump operated by a submersible electric motor, wherein the pump is retrievable through a main tube of a tubular junction. Wire line tools may be inserted through a bypass tube of the tubular junction.
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 may also be used. 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 plurality of stages, each stage having an impeller and a diffuser. Another type of pump, for lesser volumes, is a progressing cavity pump. A progressing cavity pump utilizes a helical rotor that is rotated inside an elastomeric stator that 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.
Also periodically, well workovers must be performed. In some prior art wells, wire line tools are routed through a main tube of a Y-tool, while the pump assembly is positioned in the bypass tube of the Y-tool. However, in these wells, the motor and pump must be pulled together, thereby subjecting the power cable to damage.
Therefore, a pump assembly is needed that permits a pump to be retrieved without pulling the motor, yet allows workover tools to be used for well workovers.
SUMMARY OF INVENTION
In this invention, the motor is secured to the lower end of the tubing. A power cable to the motor is strapped alongside the tubing. The centrifugal 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 special Y-tool or tubular junction is provided having a main leg and an offset leg. The seal section and motor are secured to the main leg, thereby allowing the offset leg of the tubular junction to be used for wireline operations. The tubular junction supports or incorporates an eye and locking apparatus that mates with the bottom of the through tubing conveyed (TTC) pump or intake. The tubular junction incorporates intake passages in the main leg that allow well fluid to access the pump intake.
The bypass tube is used for well workovers or other operations which do not require pulling the tubing. It will be necessary to first remove the pump with a quick and inexpensive method such as wireline. After removal of the pump, a wireline-deployed tool may be necessary to divert the workover tools into the bypass tube, because the bypass tube is offset from the production tubing or liner. This wireline tool will have a means of retaining the tool as it lands in position so that the workover tool goes in the correct direction.
The upper end of the pump is designed for engagement by a running and retrieving tool. The running and retrieving tool is used to lower the pump through the tubing and retrieve it. The pump may be secured to wireline, wire rope or coiled tubing which inserts through the production tubing. 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 pump. 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: Re. 35454 (1997-02-01), Cobb
patent: 1896110 (1933-02-01), Simmons
patent: 4452305 (1984-06-01), Schwendemann
patent: 4898244 (1990-02-01), Schneider
patent: 5224545 (1993-07-01), George et al.
patent: 5284210 (1994-02-01), Helms et al.
patent: 5706896 (1998-01-01), Tubel et al.
patent: 5732773 (1998-03-01), Parks et al.
patent: 5746582 (1998-05-01), Patterson
patent: 5871051 (1999-02-01), Mann
patent: 5954483 (1999-09-01), Tetzlaff
patent: 2325483A (1998-11-01), None
Pump Bypass Tool; 1992; Centrilift; Baker Hughes Incorporated.
Cozzens Kent H.
Swatek Mike Allen
Baker Hughes Incorporated
Bracewell & Patterson L.L.P.
Solak Timothy P.
Thorpe Timothy S.
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