Latching Device

Abstract

In combination with a flow control device to be lowered into and selectively withdrawn from a tubular receiver having an inwardly projecting shoulder, a latching device for latching the flow control device in the receiver. The latching device may comprise a stem member connected to the flow control device; a tubular body surrounding the stem member for limited axial movement between first and second positions thereon and having an annular recess on the exterior thereof; a sleeve member surrounding the body for limited axial movement between first and second positions relative to the stem member and having a plurality of radial apertures therethrough; and a plurality of latches carried by the sleeve member for movement between retracted positions within the apertures, in which the latching device may freely pass the receiver shoulder, and extended positions in which portions of the latches project out of the apertures for engagement with the receiver shoulder to latch the flow control device in the receiver.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to oil and/or gas well equipment. More specifically, the present invention pertains to retrievable downhole well equipment. Still more specifically, the present invention pertains to latching apparatus for retrievably latching a well flow control device or the like at a subsurface location within a well.

2. Description of the Prior Art

Many times it is desirable to install flow control devices, such as gas lift valves, chokes, etc., or other downhole equipment, at some subsurface location within a well. For example, it may be desired to install a gas lift valve at some subsurface location within the tubing string so that gas may be injected into the flow stream to lighten the fluid, allowing production flow without pumping. In such cases, it is desirable to install the valve in a retrievable manner so that the valve may be pulled for repair or replacement.

Various latching devices have been developed for attachment to such a valve for retrievably latching the valve at a designated location within the tubing string. Usually a mandrel or receiver is provided for receiving the valve and its associated latching device. The receiver may even be provided with an offset pocket in which the valve is to be installed. Usually a latch shoulder is provided to cooperate with the latching device in latching the valve in place. Sometimes the latch shoulder forms a complete ring and other times it may be only a short segment projecting inwardly from the receiver walls.

Several types of retrievable latches have been designed and built. One such latch is shown in U.S. Pat. No. 3,074,485 -- McGowen, Jr. In such a latching device, a locking ring is provided around a sleeve member which is reciprocal on a stem member. The locking ring is normally disposed, by means of a biasing spring, around an enlarged portion of the sleeve member so that lateral movement of the locking rings is prevented. However, upon contacting a latch shoulder within the receiver, the ring is displaced against the biasing force of the spring, to a smaller diameter portion of the sleeve member, permitting the ring member to be laterally displaced in an eccentric position. This allows the ring member to pass the latch shoulder. When past the latch shoulder, the ring member returns to its original position surrounding the enlarged portion of the sleeve member. An annular shoulder prevents the ring from being displaced in a downwardly direction so that the attached control device is then latched within the receiver until shear connections are disrupted allowing the latching member to be released.

Such a latching device is widely used and accepted. However, the device is not completely free of problems. It is possible with such a device for the latching ring to become stuck or cocked in an eccentric position rendering the device inoperable.

SUMMARY OF THE PRESENT INVENTION

The present invention pertains to an improved latching device which is suitable for use with flow control devices such as gas lift valves. Unlike the previously discussed prior art, the latching device of the present invention is provided with latches which are not subsceptible to being stuck in a cocked, inoperative position.

The latching device of the present invention may comprise a stem member for connection to the flow control device; a tubular body surrounding the stem member for limited axial movement between first and second positions thereon and having an annular recess on the exterior thereof; a sleeve member surrounding the body member for limited axial movement between first and second positions relative to the stem member and having a plurality of radial apertures therein; and a plurality of latches carried by the sleeve member for movement between retracted positions within the apertures, in which the latching device may freely pass a receiver shoulder, and extended positions in which portions of the latches project out of the apertures for engagement with the receiver shoulder to latch the flow control device in the receiver.

When the body and sleeve members are in their respective first positions, the latches are held in their extended positions by the body member. The latches are biased toward such a position with a biasing member such as a spring. Upon engagement of at least one of the latches with the receiver shoulder and application of a predetermined axial force, the sleeve member is movable to its second position in which the latches are in registration with the annular body recess, permitting retraction of the latches and movement of the latching device by the receiver shoulder into a locked position therein. Upon breaking a frangible connection between the stem and body members, the body member is movable to its second position, permitting retraction of the latches and unlocking the latching device for removal from the receiver.

The latching device of the present invention is designed preferably for use with wireline equipment. However, it could easily be adapted for use with "through-the-flowline" or "pump-down" equipment. It is extremely rugged and simple to operate and relatively more reliable than the latching devices of the prior art. Although the latching device is primarily for locking flow control devices, such as gas lift valves, within a tubing string, it may be used with other well equipment such as dummy valves, chokes, packers, etc. Many other objects and advantages of the present invention will become apparent from a reading of the following description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is an elevation view, partially in section, illustrating a latching device, according to a preferred embodiment of the invention, employed to retrievably lock a gas lift valve in a receiver installed in the tubing string of a well;

FIG. 2 is a quarter sectional elevation view of a preferred embodiment of the invention shown attached to the upper end of a gas lift valve;

FIG. 3, taken along line 3--3 of FIG. 2, is a cross-sectional view of the latching device of the present invention showing the latches thereof in more detail;

FIGS. 4 and 5 are quarter-sectional elevation views of the latching device of FIGS. 1-3 showing the device in operation during running and pulling, respectively;

FIG. 6 is a detailed sectional view of an alternate latch design for use with the latching device of the present invention; and

FIG. 7, taken along lines 7--7 of FIG. 6, is a horizontal cross-sectional view of the alternate latch design. Note: For purposes of illustration, FIGS. 2-7 are shown rotated 180.degree. relative to FIG. 1 so that latch shoulder 5 appears on the right rather than the left as in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring first to FIG. 1, there is shown a portion of a well having a tubing string T surrounded by casing string C, leaving an annulus A therebetween. Connected in the tubing string T by any suitable means is a receiver or mandrel M. The receiver M may be provided with an offset side pocket P for receiving a gas lift valve V. The side pocket P may be provided with apertures 1 communicating with the tubing string T and apertures 2 communicating with the annulus A. The gas lift valve V is provided with upper and lower seal assemblies 3 and 4, respectively, for isolating the respective apertures 1 and 2.

Normally gas is introduced into annulus A from the surface of the well for injection into the tubing string T. The gas lift valve V may open in response to casing or tubing pressure or differential pressure therebetween to admit gas from annulus A through ports 2 for injection into the tubing string T through port 1.

The gas lift valve V is shown attached to the latching device L of the present invention by which the valve is retrievably held within the side pocket P. A radially projecting shoulder 5 is provided within the receiver M, for engagement with the latching device L, and serves to hold the latch and valve assemblies in place. Latching device L and valve V may be lowered into the receiver M from the surface of the well by means of a wireline or other suitable methods.

Referring now to FIGS. 2 and 3, the latch device L comprises a stem member 10, a tubular body 11, sleeve member 12, a plurality of latches 13 and a biasing member 15. The stem 10 may be provided with a threaded pin portion 16 for attachment to a threaded box portion 17 of the valve V and by this means the latching device is connected to the valve V. The stem member 10 is also provided with an annular shoulder 18 and may be provided with a head portion 19.

The tubular body member 11 surrounds the stem member and is mounted thereon for limited axial movement between a first position, as shown in FIG. 2, and a second position, as shown in FIG. 5. However, the body member 11 is initially retained in its first position by shear pin 20 which is placed in corresponding holes within the stem head 19 and an upper portion of the body member 11. The body member is provided with a downwardly facing annular shoulder 21 and is also provided with an external annular recess 22, the purpose of which will be more fully understood hereafter.

The tubular sleeve member 12 is provided with a plurality of radial apertures 23 in which the latch members 13 are carried. Like the body member 11, the sleeve member 12 is also movable from a first position, as shown in FIG. 2, to an axially displaced second position, relative to stem member 10, as shown in FIG. 4. However, the sleeve member 12 is normally retained in the first position by biasing member 15, a helical spring in the present case. Movement of the sleeve member 12 in the downward position, as shown in FIG. 2, is limited by annular shoulder 24 which may be provided on the stem member 10.

As previously stated, the latches 13 are carried in the apertures 23 of the sleeve member 12. The latches are mounted for movement between extended positions, as shown in FIGS. 2 and 3, in which the latches project out of the apertures and retracted positions (see FIGS. 4 and 5) in which the latches do not extend beyond the outer surface of the sleeve member 12. As long as both the body member 11 and sleeve member 12 are in their first positions, as shown in FIGS. 2 and 3, the latches are held in extended positions by body member 11. However, if the sleeve member 12 is allowed to move to its second position, as shown in FIG. 4, the latches 13 may be retracted within apertures 23 since they are now in registration with the annular body recess 22. Likewise, if the body member 11 is moved to its second position, as shown in FIG. 5, the latches may be retracted within apertures 23 since the body member has moved out of registration with the latches 13 no longer preventing their retraction. Sleeve member 12 and latches 13 may be provided with cooperating shoulders 25 and 26 respectively by which the latches 13 are prevented from completely escaping the sleeve member 12.

FIGS. 6 and 7 illustrate an alternate embodiment of the invention in which ball type latches are provided. Parts of FIGS. 6 and 7 are referenced with prime numbers of the corresponding parts in FIG. 1-3. The main components stem 10', body 11', sleeve 12', etc. are essentially the same as in the first described embodiment. However, instead of lug type latches, ball latches 13' are provided. Radial holes 23' are formed in the sleeve member 12' for mounting of the ball latches 13'. The holes 23' may be counterbored to provide shoulders 25' preventing outward exit of the balls 13'. Like in the first described embodiment, the ball latches 13' are normally held in their extended positions, as shown in FIGS. 6 and 7, by a portion of the body member 11'. However, when either the body member 11' or sleeve member 12' are permitted to move to their second positions, the ball latches 13 are free for retraction within the apertures 23', since the body member 11' no longer prevents such movement.

One advantage of having ball type latches, as in FIGS. 6 and 7, is that the overall latch and valve assembly may be reduced in length. This is sometimes critical in side pocket installations.

STATEMENT OF OPERATION

Referring primarily to FIGS. 4 and 5, an explanation of the running and pulling of a valve with a latch assembly L will be given. In running in, the latch device L and valve V may be attached to a running tool 30. (See FIG. 4) The running tool 30 may be the type which is provided with a tangential shear pin 31 for disposition within an annular recess 27 surrounding the upper portion of body member 11. The running tool 30 may also be provided with a downwardly facing frusto-conical surface 32 for bearing against either one or both of the stem 10 and body 11. The running tool 30 may be attached, along with other tool devices, to a wireline running to the surface of the well. The tool 30 may comprise other components such as kickover and orientation apparatus for aligning the valve with the side pocket P. Kickover and orientation apparatus are well known in the prior art and will not be further described herein.

Once the latching device and valve V have been lowered through the tubing string into the receiver M, the valve V is properly oriented for entrance into the side pocket P. The latching device L, including its sleeve 12 and latches 13, is in the initial position of FIG. 2. As the valve V enters the pocket P the extended latches 13 come into contact with the receiver shoulder 5. Downward forces, by means of weights and the like, are applied to the running tool 30, and consequently the latching device L, causing the sleeve member 12 to shift upwardly to its second position (as shown in FIG. 4), compressing the biasing spring 15. Once the sleeve member 12 has reached the second position, in which the latches 13 are in registration with annular body recess 22, there is nothing to prevent retraction of latches 13 within the apertures 23. In fact, due to the cooperating cam surfaces 13a and 5a of latches 13 and latch shoulder 5, respectively, this is exactly what happens. (It should be noted at this point, that if the latching shoulder 5 does not completely surround the latching device L, one or less than all of the latches 13 may be retracted.)

Once the latches 13 are fully retracted, as in FIG. 4, there is nothing to prevent the latching device L and valve V to move further into the pocket P for full engagement therewith. During this movement, the latches 13 pass by the shoulder 5 until they are once again free to move to their extended positions. The latches are then forced into these extended positions by cooperating cam surfaces 13b and 11a as the sleeve member 12 is returned to its first position by biasing spring 15. At this point the latches 13 are extended, as in FIGS. 1 and 2, and held in this position by body 11. The valve V is then latched in place by engagement of the latches 13 with the lower portion of latch shoulder 5. No upwardly directed forces, resulting from fluid pressures and the like, can move the body 11 or sleeve 12 to positions permitting retraction of latches 13. Thus the valve V is firmly latched in place. The tool member 30 may be removed by simply applying an upwardly directed force to the wireline (not shown) shearing the tangential shear pin 31.

If it is subsequently desired to remove the valve V, a pulling tool 33 (see FIG. 5) is lowered through the tubing string on a wireline. The pulling tool 33 may be provided with collet like finger extensions having inwardly directed lips 35 for engagement with an annular flange 11b surrounding the upper portion of body member 11. A downwardly force may be applied to the pulling tool 33 causing the collet fingers 34 to expand outwardly until the lips 35 pass the flange extension 11b and spring inwardly to engage the lower portion thereof.

Then an upwardly directed force may be applied to the pulling 33 through the wireline. Since latches 13 are engaging shoulder 5, sleeve member 12 and stem 10 are prevented from moving upwardly in response to the force. Body member 11 is also prevented from moving upwardly until a predetermined amount of force is reached, shearing the pin 20. However, as soon as the pin 20 is sheared, there is nothing to prevent the body member 11 from moving upwardly to its second position, as shown in FIG. 5.

Once the body member 11 has moved to its second position, there is nothing to prevent the retraction of latches 13 within apertures 23 since the lower portion of the body member 11 no longer lies behind the latches 13. A continued upward force will cause the latches 13 to be retracted due to the cooperation between the mutually engageable cam surfaces 5b and 13b on shoulder 5 and latches 13, respectively. With the latches 13 retracted, the latch device L and consequently valve V is free for passage by the latch shoulder 5 and removal from the pocket P. The entire latch and valve assembly may then be removed from the well for repair or replacement.

The alternate ball latch embodiment of FIGS. 6 and 7 is run and pull in the same manner as the embodiment illustrated in FIGS. 1-5.

As can be clearly seen from the foregoing description, the latching device of the present invention is simple to manufacture and operate. It is highly reliable and versatile.

Although only two embodiments of the invention have been described herein, many variations may be made by those skilled in the art without departing from the spirit of the invention. It is, therefore, intended that the scope of the invention be limited only by the claims which follow.

Claims

I claim:

1. Latching apparatus for selectively locking and releasing a well tool in and from a tubular receiver comprising: a well tool and a tubular receiver, said tubular receiver having an internally projecting shoulder;

stem means connected to said well tool;

body means surrounding said stem means for limited axial movement relative thereto and having an external annular recess thereon;

sleeve means surrounding said body means for limited axial movement relative to said stem means and having radial apertures therethrough;

latch means carried in said sleeve means apertures for movement between retracted positions within said apertures and extended positions in which portions of said latch means project out of said aperture means for engagement with said receiver shoulder; and

biasing means engaging and biasing said sleeve means toward a first position in which said latch means is locked in said extended position, said biasing means being capable of being overcome by an axial force applied to said latching apparatus upon movement of said apparatus into said receiver thereby allowing said sleeve means to move to a second position in which said latch means is in registration with said body recess permitting retraction of said latch means and passage of said latch means by said receiver shoulder, said biasing means forcing said sleeve means to return to said first position upon said passage by said receiver shoulder, said body means forcing said latch means into said extended positions locking said well tool in said tubular receiver.

2. Latching apparatus as set forth in claim 1 in which said stem and body means are provided with cooperating release means initially preventing said limited axial movement of said body means.

3. Latching apparatus as set forth in claim 2 in which, after said locking of said well tool in said tubular receiver, an axially directed force of a predetermined value will activate said release means, releasing said body means for said limited axial movement and registration of said annular body recess with said latch means permitting movement to said retracted positions.

4. Latching apparatus as set forth in claim 1 in which said latch means comprises a plurality of lug like latches having shoulders cooperating with shoulders in said sleeve appertures to prevent escape of said latches therefrom.

5. Latching apparatus as set forth in claim 1 in which said latch means comprises a plurality of ball like latches, said appertures comprising counterbored holes providing annular shoulders preventing exit of said latches from said holes.

6. Latching apparatus as set forth in claim 1 in which said sleeve means surrounds said body means in a close sliding fit so that said sleeve means concentrically surrounds said body and stem means at all times during said limited axial movement.

7. In combination with a flow control device, a tubular receiver having an inwardly projecting shoulder, said flow control device to be lowered into and selectively withdrawn from said tubular receiver, a latching device for latching said flow control device in said receiver comprising:

stem means connected to said flow control device;

tubular body means surrounding said stem means for limited axial movement thereon between first and second positions and having an annular recess on the exterior thereof;

sleeve means surrounding said body means for limited axial movement between first and second position relative to said stem means and having a plurality of radial apertures therethrough;

latch means including a plurality of latches carried by said sleeve means for movement between retracted positions within said apertures, in which said latching device may freely pass said receiver shoulder, and extended positions in which portions of said latches project out of said apertures for engagement with said receiver shoulder to latch said flow control device in said receiver, said latches, when said body means and said sleeve means are in their respective first positions, being held in said extended positions by said body means; and

biasing means engaging and biasing said sleeve means toward said first position, siad sleeve means, upon engagement of at least one of said latches with said receiver shoulder and application of a predetermined axial force in one direction to said latching device, being movable to said second position in which said latches are in registration with said annular body recess, permitting retraction of said latches and movement of said latching device by said receiver shoulder into a locked position therein.

8. The combination of claim 7 in which said biasing means comprises a helically wound spring member, one end of which bears against an annular surface on said body means and the other end of which bears against an annular surface on said sleeve means.

9. The combination of claim 8 in which said sleeve means and said body means are in a close sliding fit so that said sleeve means concentrically surrounds said body and stem means at all times.

10. The combination of claim 7 in which said body means is temporarily held in said first position by release means preventing retraction of said latches as long as said sleeve means is in its first position.

11. The combination of claim 10 in which said release means is actuatable upon application of a predetermined axial force in an opposite direction permitting said body means to move to said second position and permitting retraction of said latches unlocking said latching device and allowing removal of said flow control device from said receiver.