US3468258A - Wire-line suspended electric pump installation in well casing - Google Patents

Description

Sept. 23, 1969 A. ARUTUNOFF 3,468,258

WIRE-LINE SUSPENDED ELECTRIC PUMP INSTALLATION IN WELL CASING 1 F t 5 8 3 29 R 9 3 4 2 w 3 33 0 e N m M 2 4 /A VT 5 M. f I 4W m 1 6 AW S l 2 n F E o/. 0 2 a M 3 B 4 M M m ,5 A 2 I M /WT H C 3 5 9 c 5 M M m 2 4 2 4 M 8 2 1 m 0 3 Y 1 H J d e 1 i F ATTORNEY Sheets-Shem 1:

INVENTOR ARMA/S ARUTQ OFF ATTORNEY Se t. 23, 1969 A. ARUTUNOFF WIRE-LINE SUSPENDED ELECTRIC PUMP INSTALLATION IN WELL CASING Filed July so, 1968 a 5 M fia M m 6 L F M y m m w 5 w United States Patent O M 3,468,258 WIRE-LINE SUSPENDED ELECTRIC PUMP INSTALLATION IN WELL CASING Armasis Arutunoff, Bartlesville, kla., assignor to Reda Pump Company, Bartlesville, Okla, a corporation of Delaware Continuation-impart of application Ser. No. 621,924, Mar. 9, 1967. This application July 30, 1968, Ser. No. 748,677

Int. Cl. F04d 13/10; F04b 47/06; E21b 23/06 US. Cl. 10387 2 Claims ABSTRACT OF THE DISCLOSURE A wire-line suspended electric pump installation for use in a well casing, including a motor supported at its upper end by said wire-line, which is also provided with electrical conductors. A pump unit is suspended concentrically from the lower end of the motor by a vertical discharge tube which opens into the casing. A packer embraces the discharge tube below its discharge opening and seals against the casing. A slip unit having expandible slip members is fixed to the tube between the packer and pump, and includes means responsive to fluid pressure for expanding the slip members to support the weight of the pump and a column of fluid above the packer relieving longitudinal stress on the cable.

BACKGROUND OF THE INVENTION conventionally, motor and pump assemblies for oil wells and the like comprise a series of coaxial units arranged in superposed relation, including a pump unit, a motor unit, and a protecting unit, such for example as the general assembly disclosed in my prior Patent No. 2,783,400, issued on Feb. 26, 1957. Ordinarily, the pump unit is affixed at its upper end to the lower end of a string of tubing which extends within the casing to the earths surface. Liquid is thereby pumped from the lower portion of the casing, through the fluid inlet of the centrifugal pump, and upwardly within the tubing string to the earths surface.

While this system has worked satisfactorily for many years in pumping fluid, a string of tubing is relatively expansive, and, in addition, the lowering of the installation into position and removal thereof for repair of the pump requires strings of tubing to be assembled as the pump is lowered into position and disassembled upon removal from the casing, all of which is time-consuming and expensive.

SUMMARY OF INVENTION This application is a continuation-in-part of my copending application Ser. No. 621,924, filed Mar. 9, 1967, now Patent No. 3,411,454, granted Nov. 19, 1968.

The invention is designed to provide means for utilizing a centrifugal pump installation in a casing to force the fluid t0 the earths surface without the use of a string of tubing. The installation is simply lowered into the casing while suspended on a wire-line, and, at the proper elevation, locked in position for operation. One problem which has hampered the use of electric pumps suspended on wire-lines is that under conventional concepts, the wire-line is required to support the entire weight of the pump installation, plus the additional weight of the column of fluid in the casing above the pump installation.

-It is therefore the primary object of the invention to overcome this difficulty by providing a slip unit having expandible slip members which is fixed to either the motor unit or the pump unit, and including means responsive to the fluid pressure developed by the pump for expanding the slip members into engagement with the casing for 3,468,258 Patented Sept. 23, 1969 ICC supporting the weight of the pump and the column of fluid above the packer, which thereby relieves longitudinal stress on the cable.

In my said copending application Ser. No. 621,924, the pump unit is at the top of the installation and supported by the wire-line, while in the present embodiment, the motor unit is located at the top of the installation and supported by the wire-line. This arrangement simplifies the electrical connections, as it eliminates the necessity of having the electric wires from the wire-line passing through a seal and past the pump for connection to the motor.

THE DRAWINGS Referring to the drawings in which numerals of like character designate similar parts throughout the several views:

FIG. 1 is a sectional view through a casing, showing a typical motor and pump assembly and slip unit in side elevation with the pump unit above the motor;

FIG. 2 is an enlarged sectional view illustrating the packing unit and slip setting unit;

FIG. 3 is a further enlarged sectional view illustrating the slip setting mechanism;

FIG. 4 is a transverse sectional view taken on line 3-3 of FIG. 2;

FIG. 5 is a sectional view through a casing, illustrating the modified arrangement with the motor above the pump;

FIG. 6 is an enlarged sectional view illustrating the packing unit and slip setting unit of the modified installation; and

FIG. 7 is a transverse sectional view taken on line 77 of FIG. 6.

DETAILED DESCRIPTION Referring first to FIG. 1 of the drawings, 10 represents a conventional well casing which extends from the earths surface into a fluid producing formation. A pump installation comprising an electrically driven centrifugal pump 11, a motor protector 12, and a pump 13, coaxially arranged in superposed relation, is lowered into the casing 10 while suspended from a wire-line or cable 14, running from a suitable Winch at the earths surface (not shown). The pump 13 is driven by the motor 11 through a coaxial motor shaft extending through the motor protector 12 in the conventional manner.

The means for connecting the wire-line 14 to the pump installation will best be seen from FIG. 2. A pump discharge tube 15, connected to the pump outlet, is threaded as at 16 at its upper end for engagement with complementary threads in the lower extremity of a slip unit, generally indicated at 17, and comprising a generally cylindrical body 18. A vertically extending tube 19, integral with the body 18, communicates with and forms an extension of the pump discharge tube 15 and projects vertically above the body 18 where it is threadedly connected to a perforated discharge nipple 20 by a coupling 21. The upper extremity of the coupling 21 is threadedly connected to a wire-line connecting socket, generally indicated at 22, which firmly secures the entire installation to the lower end of the wire-line or cable 14. The particular construction of this connecting assembly forms the subject matter of another application and will not be described in detail here.

However, it should be stated that the wire-line 14 is of the type comprising an outer layer of preferably spirally-wound supporting wires 14a, and a central core 14b, in which are positioned in spaced relationship, a plurality of conductors 140, the lower ends of which are electrically connected to the motor 11.

In the embodiment shown in the drawings, the discharge nipple 20 is provided with a series of radial openings 20a which open into the interior of the casing 10, and the core 14b of the wire-line enters the upper end of the discharge nipple, centrally thereof, and is then directed outwardly through an opening 20b in the upper portion of the nipple, from whence it extends downwardly for connection to the pump.

A packing unit, generally indicated at 23, comprises an annular packer cup thimble 24 which slidably embraces the discharge tube extension 19 above the slip unit 17 and receives a frustoconical packer cup 25 formed of suit able packing material. The packer cup 25 is annularly recessed at its upper end as at 25a to receive an annular retainer 26 surrounding the tube extension 19 which positions the packer cup with the outer annular surface of its upper edge in sealing contact with the inner surface of the casing 10. The downwardly converging contour of the packer cup permits its sliding movement into the well casing, while the flaring cup causes a sealing action against the casing under the influence of a column of fluid in the casing.

A check valve 45 is preferably located at the upper end of discharge tube extension 19, which is designed to permit freedom of flow for the fluid being pumped upwardly through the system, but to restrict any downward flow upon stopping the pump. Without such a precaution, the weight of a column of fluid in the casing above the packer would result in such a speedy return of the fluid down through the casing as to cause the pump to rotate rapidly in reverse, with possible resultant damage to the unit.

Reverting now to the slip unit 17, the upper portion of the body 18 forms an integral cylindrical cup portion 27 which, together with the adjacent periphery of the tubular extension 19, defines an annular chamber 28, the lower portion of which communicates with the interior of the discharge tube extension 19 by means of ports 29. The upper extremity of the chamber 28 communicates with the casing by means of an outlet port 30, thus placing the chamber in communication with the pump discharge at its lower end and with the interior of the casing at its upper end.

An annular plunger 31 is slidably received within the chamber 28, encircling the tube extension 19 between the inlet ports 29 and the outlet ports 30 of the chamber. By means of a series of plunger rods 32, slidably mounted in vertical openings 33 in the body 18, the plunger 31 is connected to a guide ring 34. The guide ring 34 is slidably mounted on the pump discharge tube 15, and by means of a series of radially projecting peripheral lugs 35, it is pivotally connected to a corresponding series of wedge-shaped slips 36 by intermediate links 37. The lower ends of each of the slips 36 are provided with depending lugs 38 so that the pivotal connection of the links 37 to the lugs 35 of the ring 34 and the lugs 38 of the slips, provides a double pivot arrangement which facilitates both vertical and lateral movement of the slips, as will later appear.

The slips 36 are segmental units provided on their outer surfaces with outwardly and downwardly directed teeth 39, and their opposite or inner surfaces are inclined to wedgedly engage complementary surfaces 40 in a corresponding series of inclined, longitudinal grooves or recesses 41, spaced around the periphery of the body 18. As best seen in FIG. 4, the grooves 41 include male dovetail portions 42, and the inclined surfaces of the slips are provided with female dovetail portions 43 so that the slips are slidably retained relative to the body 18 in a manner such that when the guide ring 34 moves downwardly, the slips 36 are radially retracted inwardly to achieved positive clearance with the interior of the casing 10 in which the pump is positioned, and when the ring 34 moves upwardly, the slips are radially projected or expanded into gripping engagement with the inner wall of the casing by the wedge action of the complementry 4 inclined surfaces of the slips and grooves. The retracted and projected positions of the slips are shown in FIG. 3.

Normally, the slips 36 are biased toward their lower or retracted positions by means of coil springs 44 surrounding the respective plunger rods 32 between the bottom of the slip body 18 and the top of the ring 34. Both the inner and outer peripheries of the annular plunger 31 are provided with sealing rings 45 to insure fluid tight engagement between the plunger and the adjacent walls of the tube extension 19 and the chamber 28, respectively. Thus, when the fluid pressure of the pump 11 enters the lower portion of the chamber 28 through ports 29, the plunger 31 is forced upwardly in the chamber which vents into the casing through port 30 and the ring 34 is drawn upwardly, which, in turn, slides the slips 36 upwardly in their grooves, causing a wedging action between the body 18 and the casing 10 to lock the entire installation in place.

As shown in FIG. 1, as a precaution against an excessive rate of descent of the installation in the casing, I may provide an auxiliary slip unit 47 haw'ng slip members 47a which per se, forms the subject matter of another application. Briefly, this auxiliary unit is attached to the bottom of the installation and includes two arms 48 carrying rollers 49, the arms being pivotally mounted on a vertically slidable support 47b, connected to the slip members. The arms are normally urged outwardly to bring the rollers into rolling frictional engagement with the inner wall of the casing under the influence of spring means 50. These rollers are provided with radially projectible, weighted members, operable by centrifugal force, so that when the assembly descends at an excessive rate of speed, the centrifugal force of the rollers causes the projectible members to protrude beyond the peripheries of the rollers and engage stop means which prevent further rotation of the rollers. Thus, the rotary frictional engagement of the rollers with the casing is transformed into sliding frictional engagement to act as a brake, causing the slidable support 47b to move upwardly, to thereby set the auxiliary slip members 47a against the casing, preventing further descent of the installation.

In the modified form of the invention illustrated in FIGS. 57, the motor unit and pump unit are reversed. In other words, as shown in FIG. 5, the wire-line or cable 14 is connected directly to the top of the motor unit 111 by any suitable means, such as shown at 122, with the pump unit 113 coaxially suspended at the bottom of the installation. As best seen in FIG. 6, extending between the motor unit 111 and the pump unit 113, a pump discharge tube 119 is connected to the bottom of the motor unit as at 111a, and to the pump unit as at 113a, with the motor shaft extension 11112 running concentrically through the tubing and being connected to the pump by a spline as at 1131). The discharge tubing 119 is provided with discharge openings 120 which are located above the packing members so that the tube discharges directly into the well casing 10 above the packing.

This modified form of the invention embodies a variation in the construction of the slip unit which greatly simplifies its construction and operation. As in the other form of the invention, the slips 136 are slidably arranged around the body 118 by means of grooves 141 and dovetail portions 142, as best seen in FIG. 7. The inclined surfaces of the slips and grooves cause the slips to move radially outwardly simultaneously with their elevation. The bottom of each slip is provided with a depending abutment which normally rests upon the top of an annular plunger 151 surrounding the discharge tube 119 and vertically movable in a cylinder 152 which also surrounds the discharge tube. The lower portion of the cylinder 152 communicates with the interior of the discharge tube 119 by means of radial openings 129, and, preferably, the bottom of the plunger 151 is beveled as at 153 to facilitate the upward movement of the plunger in response to pressure from the discharge tube directed into the cylinder.

It will be apparent that as distinguished from the form of the invention shown in FIGS. 1 to 4, where the conductors 140 are required to pass through the seal 25 and past the slip unit body 18 for connection to the motor unit 11, the conductor of wire-line 14 is connected directly to the motor unit 111 at the top of the installation. Obviously, this greatly Simplifies the construction and installation of the installation.

OPERATION In the original embodiment, the assembled pump installation is lowered into the casing by means of wireline or cable 14 to the desired depth, and during this operation, the packer 25 slides easily downwardly in the casing, and the slips 36 are retained in retracted positions by the respective springs 44 to that they do not engage the interior wall of the casing.

When the pump installation reaches the desired depth in the well, still suspended by the wire-line 14, the motor 11 is energized through the wire-line and its conductors, which actuates the propellors of the centrifugal pump 13, drawing fluid from the lower portion of the casing through the pump inlet 13a and forcing it upwardly under pressure through the tubing extension 19 and outwardly into the casing through the perforated discharge nipple 20. Fluid under pressure enters the interior of the chamber 28 through inlet ports 29 and forces the plunger 31 upwardly. This upward force is transmitted by plunger rods 32 to the guide ring 34 and is thence transmitted to the Wedge slips 36 by the link connections 35, 37 and 38. The slips are thus forced upwardly and outwardly into gripping engagement with the interior of the casing to support not only the weight of the pump installation, but the column of fluid which has been forced into the casing above the packer 25. The weight of the fluid column forces the flaring portion of the packer 25 outwardly into sealing engagement with the interior surface of the casing, and the continued operation of the motor and pump installation advances the column up the interior of the casing to the earths surface.

As the weight of the fluid column increases during its upward advance through the casing, the wire-line 14 will be extended slightly by the additional tension applied thereto in supporting the weight of the fluid. This permits the slip body 18 to move slightly downwardly, forcing the teeth 39 of the slips 36 into increased gripping contact with the casing, which augments the effect of the plunger 31. Thus, the greater the weight of the fluid column above the pump, the more pressure is applied by the slips to hold the weight of the fluid column. In this way, the weight of the fluid column is supported by the slips so that the wire-line 14 is not required to Withstand the weight of the fluid column as well as the pump installation.

When pumping is terminated, energy is cut off from the conductors 14c, stopping the motor 11 and pump 13. Normally, fluid from the column above the packer will flow in reverse direction, back down through the perforated nipple at a rapid rate of descent. However, by means of the check valve 46, the descent of the column of fluid is restricted to avoid damage to the pump until the total fluid height is equalized and no fluid head load exists above the pump. When pressure equalization occurs in the chamber 28, the springs 44 force the slips 36 downwardly, unlocking them from contacting engagement with the interior of the casing. When the fluid level in the easing is equalized, the radial pressure on the packer cup a against the interior of the casing is likewise diminished, and in this state, the pump installation may be withdrawn from the well as desired by rewinding the wire-line 14 at the earths surface.

It will thus be seen that the invention provides a wireline electric bottom-hole pump which can be inserted into and removed from a well casing with a minimum of effort and time. When pumping action is initiated, the pump automatically causes engagement of the slips with the interior of the casing to support the fluid load in such a manner that the load is not supported by the wire-line. The pump automatically releases engagement with the casing when fluid is not being pumped, and the pump provides an arrangement for utilization of centrifugal pumps in a casing Without requiring the use of tubing.

The operation of the modified embodiment of the in vention is substantially the same as that previously described. The installation is lowered as before, and when the motor 111 is energized through the wire-line and its conductors, it actuates the propellors of the centrifugal pump 113, drawing fluid from the lower portion of the casing and forcing it upwardly under pressure through the tubing 119. The fl-uid enters the interior of the cylinder 152 through opening 129 and forces the plunger 151 upwardly. The plunger in turn, elevates the slips 136 by means of the abutments 150, and the slips are forced upwardly and outwardly in gripping engagement with the interior of the casing to support not only the Weight of the pump installation but the column of fluid which has been forced into the casing above the packer assembly 125.

From the foregoing, it is believed that the invention may be readily understood by those skilled in the art without further description.

I claim:

1. A tubingless electric pump installation including a well casing, an electric motor unit suspended solely by a wire-line within said casing and spaced concentrically inwardly from the walls of the casing to form a fluid passageway, an electric pump unit below and coaxial with said motor unit, suspended from the latter by a vertical pump discharge tube, spaced concentrically inwardly from said casing, a motor shaft extension passing through said tube, operatively connecting the motor and pump, said tube having discharge openings leading into said casing above said pump, packing means between said tube and casing below said discharge openings, a slip setting device for said motor and pump units, comprising a slip supporting body fixed to the periphery of said tubing, at least two radially expandible slip members mounted on the periphery of said body, releasibly engageable with the inner wall of said casing, and means responsive to fluid pressure developed by said pump for expanding said slip members into engagement with said casing.

2. An installation as claimed in claim 1, wherein said slip unit includes an annular pressure cylinder surrounding said tube, its lower end communicating with the interior of said tube, a vertically shiftable plunger slidably mounted in said cylinder, respective slip members having depending abutments engageable by the upper end of said plunger, whereby, upon the introduction of fluid pressure into the lower end of said cylinder, the plunger is elevated, and, by means of said abutments, actuates said slip members into engagement with said casing.

References Cited UNITED STATES PATENTS 1,374,116 4/1921 Schorr. 1,872,111 8/1932 Bricker. 2,698,058 12/1954 Page 166-212 ROBERT M. WALKER, Primary Examiner US. Cl. X.R.

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