US3735813A

US3735813A - Storm choke

Info

Publication number: US3735813A
Application number: US00123742A
Authority: US
Inventors: W T Mack; T Tyler Quinn
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-03-12
Filing date: 1971-03-12
Publication date: 1973-05-29
Anticipated expiration: 1990-05-29

Abstract

There is disclosed a storm choke adapted to close a well tubing and the annulus between the tubing and the well casing into which the tubing is run in response to predetermined changes in the velocity of well fluid flowing upwardly through the tubing and casing, respectively.

Description

United States Patent [191 Mack et al.

[451 May 29, 1973 3,090,443 5/ 1963 Bostock ..166/224 2,644,527 7/1953 3,288,221 11/1966 Howard et al ..166/129 Primary Examiner-James A. Leppink Attorney-Hyer, Eickenroht, Thompson & Turner [5 7 ABSTRACT 13 Claims, 7 Drawing Figures 1 STORM CHOKE [76] Inventors: William T. Mack, P.O. BOX 3112; Thomas Quinn, 122 West Amherst both of Tyler, Tex.

[22] Filed: Mar. 12, 1971 [21] Appl.No.; 123,742

[52] US. Cl. ..166/183, 137/519.5, 166/188,

. 166/224 [51] Int. Cl. ..E21b 33/00 [58] Field of Search ..166/133, 183, 224, 166/188; 137/5123, 519, 532, 594

[56] References Cited UNITED STATES PATENTS 2,447,546 8/1948 Spencer ..166/133 5 19 i :A v i r /9 PATENTEM-T-KYZFBIQR 3,735,813

' SHEET 1 UF 3 Tho/27oz: Quinn INVENTORS lax $056M warn "M STORM CHOKE This invention relates to so-called storm chokes for use in closing selected portions of an oil or gas well at a subsurface level. More particularly, it relates to improvements in storm chokes of the type which are adapted to close automatically in response to predetermined changes in velocity of fluid flowing upwardly within such portions of the well.

In the caseof offshore wells, where these chokes are now required by law, these changes in velocity usually result from a loss of control over the pressure of fluid within the well portion, which may occur due to damage to or destruction of an underwater wellhead or a well casing extending from a wellhead above water to In some of these prior storm chokes, the closure element comprises a ball carried within a cage beneath a conical seat about the lower end:of a bore through the tubing, and it has been foundthat either the ball or the seat, or both, will wear rapidly, particularly due. to contact by abrasive well fluids. Usually, this weartakesthe form of vertical grooves, which cause the. choke to leak due to lack of full seating contact between the ball and seat. Also, since weight of the ball determines the velocity change to which it responds, the choke cannot be adjusted to respond to different conditions without pulling it from the well.

Its also possible for the well to lose pressure control over well fluid in the annulus between the tubing and casing, such as in the case of 'dual production wells, or,

ing a reduced bore therethrough adapted to form a continuation of a tubing string, a downwardly and outwardly conically shaped seat on the body about the lower end of the bore, and a similarly shaped closure element movable vertically toward and away from the seat for opening and closing the bore. In use, this closure element functions similarly to those of prior storm chokes in that it is adapted to close in response to a predetermined change in velocity of well fluid flowing upwardly through the tubing. However, due to the conical shapes of the seat and closure element, there is a large area of contact between them in the closed position of the closure element. Consequently, considerably more wear on one or both of the seat and closure element is required to cause leakage between them in the closed position.

A rod extends. upwardly from the closure element and loosely through the bore, and an enlarged part on the rod in seatable on the body above the upper end of the boreto normally suspend the closure element in its of the closure element, and thus the change in velocity in the case of single production wells, upon failure of the production packer. As far as we know, however, existing storm chokes of the type above-described responsive to velocity changes provide control over only the well tubing, and the combination tubing and annulus storms that are offerred do not provide independent control over the tubing and annulus. Further more, they are of very complicated construction.

An object .of this invention is to provide a'tubing storm choke in which leakage due to wear is less likely than in the prior chokes above described.

Another object is to provide a tubing storm choke which may be adjusted to respond to different velocity changes without pulling the choke from the well.

A further object is to provide a storm choke for closing the annulus which is responsive to velocity changes in the annulus, and is of simplified construction and easily disposable in the annulus.

Still another object. is to provide a choke for closing both the tubing and annulus which, provides independent control over each, and, more particularly, is responsive to velocity changes therein.

' Still a further object is to provide such a tubing and annulus choke which may be run into the well in a single trip.

These and other objects are accomplished, in accordance with the illustrated embodiment of the present invention, by a. storm choke whichincludes a body havto which it responds.

. More particularly, the upper end of the rod has a neck to which a weight-imparting member may be releasably connected merely in response to its being lowered through the tubing string. Thus, such weight imparting members may be added or subtracted, as desired, so as to adjust the choke without pulling it from the well.

Preferably, the enlarged part on the rod comprises a guide part which fits closely within the body above the bore therethrough, another guide part is suspended from the closure element for fitting closely within the body below the reduced bore. Because of these guide parts, there is little or no chance for the closure element to assume a cocked position, so that it is maintained in position for. engaging with a large area of the seat.

In the preferred embodiment of the invention, the. body has threads on its upper and lower ends to permit it to be connectedto threads on the ends of the tubing string above and below the body, whereby the body may be connected as part of and run into the casing on the string. This not only avoids the necessity for complex locking parts and seals between the body and interior of the tubingstring, but also provides a convenient,

support for a choke for closing the annulus between the tubing string and the well casing into which it is run, whereby such annulus choke may be installed merely upon running the tubing.

Thus, the annulus choke comprises a tubular member which surrounds the body in spaced relation to it and has an annular upwardly facing closure element disposed beneath an annular, downwardly facing seat about the body. More particularly, the tubular member is mounted on the body for movement between a lower position in which the closure member on it is below the seat to open the spacebetween the body and member, and an upper position in which the closure element engages the seat to close such space.

The tubular member fits relatively closely within the well casing and carries means for sealing between its outer side and the well casing. Thus, upon upward movement of the tubular member and closure element thereon to close the space between the body and tubular member, the seal means is adapted to provide a complete closure of the annulus. According to its preferred construction, the annulus storm choke includes a sleeve which is supported by and sealably slidable vertically over the tubular member, and at least one seal ring surrounding the tubular member and radially expandable upon upward movement of the sleeve to seal between the member and well casing. In use, the sleeve will move upwardly, and thereby expand the seal rings between the tubular member and well casing, after the space between the tubular member and body has been closed. Thus, closure of this space reduces the flow area between the body and the well casing to such an extent that the well fluid is effective to cause the tubular member to more upwardly to expand the seal ring.

Although an annulus storm choke of the abovedescribed construction has many advantages in and of itself, it is particularly useful in connection with tubing storm choke of the construction previously described, since both such chokes may be installed into the well merely upon running of the tubing into the well casing.

In the drawings, wherein like reference characters are used throughout to designate like parts:

FIG. 1 is a longitudinal cross section of a combination tubing and annulus storm choke constructed in accordance with the preferred embodiment of the invention, as the tubing is run into the casing;

FIG. 2 is a view similar to FIG. 1, but upon landing of the choke at a desired subsurface level in the well casing;

FIG. 3 is a view similar to FIG. 2, but upon closing of the tubing choke and partially closing the annulus choke;

FIG. 4 is a view similar to FIG. 3, but upon complete closing of the annulus choke;

FIG. 5 is a cross-sectional view of the choke, as seen along broken line 55 of FIG. 1;

FIG. 6 is a cross-sectional view of the choke, as seen along broken line 6-6 of FIG. 1; and

FIG. 7 is a cross-sectional view of the choke, a seen along broken line 7-7 of FIG. 1.

With reference now to the details of the abovedescribed drawings, the combination tubing and annulus choke, which is indicated in its entirety by reference character 10, is connected as a part of the tubing string 11 which extends within the well casing 12. As well known in the art, in addition to being run into and landed within the well casing during original completion of the well, the tubing may be run into the casing during a rework of the well.

When the tubing string is landed at a desired subsurface level, a production packer (not shown but beneath the level of FIGS 2-4) between it and the casing is caused to pack off the annulus 13 so as to isolate well fluid within the tubing from well fluid within the annulus above the packer. In the case of dual production, well fluids are thus produced separately through the tubing and through the annulus above the packer. Also, and as previously mentioned, even in the case of single production through the tubing, well fluid may flow into the annulus above the packer in the event the packer fails.

The choke 10 comprises a body 14 which has

threads

15 and 16 on its upper and lower ends for connection to threads on the upper and lower portions of the tubing string 11, respectively. The body 14 is generally tubular except for a midportion 17 which is both inwardly and outwardly enlarged. The inward enlargement forms a reduced bore 18 through the body 14 which, together with

bores

19 and 20 through the upper and lower ends of the body 14, provides a continuation of the tubing 11 in which the body is connected.

There is a downwardly and outwardly, conically shaped seat 21 about the lower end of the reduced bore 18, and a similarly shaped closure element 22 is carried by the body beneath the seat 21 for selectively opening and closing the bore through'the body. As shown, the closure element is supported by a rod 23 which extends upwardly from and loosely through the bore 18 into the upper bore 19 of the body. A perforated disc 24 is welded about the rod 23 for seating on the upper end of the inward enlargment of body portion 17 so as to support the closure element 22 in a lower position below the seat 21 for opening the bore 18 (FIG. 2) to the flow of well fluid upwardly through the tubing string. However, the disc 24 is free to move upwardly within the bore 19 so that, upon a predetermined change in velocity of the well fluid, the ventura effect within bore 18 will cause the closure element to move upwardly to engage the seat 21 and thus close the bore 18 (FIGS. 3 and 4).

As shown, the disc 24 fits closely within the bore 19 so that, during vertical movement between its upper and lower positions, it guides the upper end of the rod in a substantially vertical path. Another perforated disc 25 is welded about the rod beneath the closure element 22 to guide its lower end in a substantially vertical path. Thus, the closure element 22 is prevented from assuming a cocked position with respect to the seat 21.

As previously described, the conical shapes of the seat and closure element provide a large seating area between them in the closed position of the closure element, so that there must be considerable wear between them to cause leakage. Also, the closure element is free of frictional engagement with parts immediately surrounding it, so that it is more precisely responsive to a predetermined change in velocity of the well fluid within the tubing 11.

As also previously described, the rod 23 from which the closure element 22 is supported also provides a means above the bore 18 to which weight-imparting members may be selectively added or subtracted for adjusting the effective weight of the closure element, and thereby the velocity change to which it is responsive. Thus, as shown in the drawings, there is a head 27 on the upper end of the rod 23 to which a weightimparting member 28 has releasably connected by latch fingers 29 about its lower end. The member 28 has a head 30 about its upper end to which additional weight-imparting members may be connected.

As well known in the art, the fingers 29 may be connected to the head 27 merely upon lowering or raising of the member 28 by means of a wireline. Thus, in the event the effective weight of the closure element 22 is to be reduced, its merely necessary for the operator to lower a wireline through the tubing 11 for releasing fingers 29 and lifting the member 28 from the head 27. Al-

ternatively, in the event the-effective weight of the closure element 22 is to be increased, one or more additional members 28 may be lowered on a wireline through the tubing 11 for connection above the member 28. It will also be understood that these members may take various shapesand sizes, and further that the connection between their upper and lower ends may be nothing-more than a slip fit.

As the tubing and choke are run into the casing 12, the closure element 22 may be either in its opened or its closed position (FIG. 1), or intermediate the two, depending on the speed at which the tubing is run. However, when the tubing lands, the closure element 22 will be urged downwardly relative to the seat, due to the upward jaron the tubing. Thus, the element moves to the open position of FIG. 2 to permit well fluid to be produced through the choke 10, as indicated by the arrows in FIG. 2.

In the event difficulty were to be encountered in lowering the tubing with the bore 18 closed, the closure element 22 could be maintained in the open position by a suitable shear pin or the like positioned between the guide part 24 and the bore 19. Then, as the tubing landed, the pin would be sheared to permit the element to move to open position. However, as will be described to follow, the portion of the choke for controlling annulus 13 is maintained in an open position as the choke is lowered, so that ordinarily the bore 18 may be closed.

The portion of the choke 10 for controlling the annulus includes a tubular member 31 which surrounds the body 14 in spaced relation thereto to provide an annu lar passageway 32 therebetween and which is mounted on the body for movement between a lower position (FIGS. 1 and 2), and an upper position (FIGS. 3 and 4). In its upper position, the tubular member closes off the annular passageway 32 to the upward flow of well fluid within the annulus 13 of the well, and in its lower position, opens such passageway 32 to the flow of well fluid within the annulus 13, as indicated by the arrows of FIG. 1. As previously described, this may be well fluid from a production zone of the well separate from well fluid produced from another production zone, or, alternatively, it may be well fluid from the same zone that is produced through the tubing 11 and has access through the annulus past the production packer.

As shown, the tubular member 31 has a reduced bore 33 through its upper end, and a flange at the upper end of bore 33 which fits closely aboutthe upper end of the body 14 so as to guide the tubular member vertically as it shifts between its upper and lower positions. More particularly, and as shown in the drawings, the flange has a series of ports 34 through it for connecting the annular passageway 32 with the annulus 13 of the well above the member 31.

The midportion of tubular member 31 has an enlarged bore 35 to surround the outward enlargement on portion 17 of the body 14. The cylindrical portions of the passageway 32 between the

bores

33 and 35 of the tubular member are connected by a conical portion between conically shaped inner and outer shoulders 36a and 36b on the tubular member and body, respectively. These shoulders face oppositely to one another, and pins 37 extend from the shoulder 36b for engaging the shoulder 36a to maintain the conical portion of passageway 32 open in the lower position of the tubular member. As shown in FIGS. 3 and 4, when the tubular member 31 is raised to its upper position relative to body 14, the shoulder 36a will move upwardly away from the pins 37.

A collar 33 is threaded onto the lower end of the bore 35 of the tubular member to provide an upwardly and outwardly conically shaped closure element 40 beneath a similarly shaped seat 41 on the lower end of the outward enlargement of portion 17 of the body 14. In the lower position of member 31, closure element 40 is spaced from seat 41 to open passageway 32.

As previously described, the tubular member 31 carries means for sealing between it and the well casing 12.'More particularly, and as will be described to follow, this sealing means is of such construction that, when the choke is landed within the well casing upon landing of the tubing 11, the great majority of the flow of well fluid upwardly between the tubular body 31 and the well casing 12 is diverted to the passageway 32. Thus, upon a predetermined change in velocity of fluid flowing upwardly within the annulus 13, the ventura effect within passageway 32 will cause the closure element 41) to be lifted from its open position to its closed position of FIGS. 3 and 4.

Due to the restriction of flow between the sealing means about member 31 and the casing, it may be necessary to maintain passageway 32 open as the choke 111 is run into the well casing on the well tubing. Thus, as shown in FIG. 1, shear pins 42 extend from the upper end of the body 14 above the flange on the upper end of the tubular member so as to maintain the latter in its lower position, and thereby maintain the passageway 32 open as the choke is run in. However, as the tubing lands, the member 31 is jarred upwardly to shear the pins 42, as indicated in FIG. 2, and thereby free the tubular member for movement upwardly to close the passageway 32 in response to a predetermined velocity change of well fluid in the annulus. Of course, in its landed positions, and before such velocity change occurs, the tubular member 31 will normally move downwardly to open position due to its own weight.

The means for sealing between the tubular member 31 and the well casing 12 comprises a series of O-rings 43 carried about the tubular member for disposal closely within, but in non-selling engagement with, the casing as the choke is run into the well. As previously described, these O-rings are adapted to be expanded outwardly to seal against the well casing when the passageway 32 has been closed, thereby tightly closing the entire annulus to the upward flow of well fluid.

As shown in the drawings, there are a series of 0- rings 43 separated by expander rings 44, and the 0- rings and expander rings are in turn supported between an outwardly extending flange on the upper end of member 31 and the upper end of a sleeve 45 vertically slidable about a reduced outer diameter portion 46 of the tubular member 31. More particularly, an inwardly enlarged portion on the lower end of the sleeve 45 carries an O-ring 47 for sealably sliding over the reduced diameter portion 46 so that, upon closure of the passageway 32, well fluid will urge the sleeve upwardly to the position of FIG. 4 to fully sealoff the annulus.

Although both the tubing and annulus portions of the choke are shown closed in FIGS. 3 and 4, it will be understood that each may be either open or closed independently of the other. 1

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcornbinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

l. A tubing storm choke, comprising a body having a reduced bore therethrough adapted to form a continuation of a tubing string, a downwardly and outwardly conically shaped metal seat on the body about the lower end of the bore, shiftable means including a similarly shaped metal closure element disposed in the body beneath the seat for movement vertically upwardly from a lower position spaced from the seat to open the bore to an upper position engaged with the seat to close the bore, said shiftable means also including a rod extending upwardly from the closure element and loosely through the bore to provide an annular flow path therebetween, and means on the rod seatable on the body to normally suspend the closure element in its open position, said closure element being urged to said lower position solely in response to the weight of said shiftable means, and to said upper position solely in response to a predetermined change in velocity of well fluid through the annular flow path.

2. A choke of the character defined in claim 1, wherein means seatable on the body comprises a guide part closely fittable within the body above the reduced bore.

3. A choke of the character defined in claim 2, including a guide part suspended from the closure element and closely fittable within the body below the reduced bore.

4. A choke of the character defined in claim 1, wherein the upper end of the rod has a reduced neck to which a weight-imparting member may be releasably connected upon lowering through the tubing string above the body.

5. A choke of the character defined in claim 1, said shiftable means includes a weight-imparting member adapted to be lowered through the string and onto the upper end of the rod.

6. A choke of the character defined in claim 1, wherein said body has threads on its upper and lower ends for connection with threads on the ends of the string above and below the body.

7. An annulus storm choke, comprising a body having a bore therethrough and means on its upper and lower ends to connect it in a tubing string for lowering therewith into a well casing, a generally tubular member surrounding the body in spaced relation thereto to form an annular passageway therebetween, an annular, downwardly facing seat about the body, an annular, upwardly facing closure element on the tubular member, means mounting the member from the body for movement upwardly, in response to a predetermined change in the velocity of well fluid within the annulus from a lower position in which the said closure element is below the seat to open the passageway between the body and member and an upper position in which the closure element engages the seat to close said passageway, and means for sealing between the outer side of the tubular member and well casing when said passageway is closed.

8. A choke of the character defined in claim 7, wherein the sealing means includes a sleeve supported by and sealably slidable vertically over the tubular member, and at least one seal ring surrounding the tubular member and radially expandable upon upward movement of the sleeve to seal between said member and the well casing.

9. A choke of the character defined in claim 8, wherein said tubular member has a downwardly facing shoulder thereabout, and said seal means includes at least one seal ring between the upper end of the sleeve and said shoulder.

10. A combination tubing and annulus storm choke, comprising a body having a bore therethrough and means on its upper and lower ends for connecting it in a tubing string, valve means carried by the body for movement from a position opening said bore to a position closing said bore in response to a predetermined increase in velocity of well fluid flowing upwardly through the bore, and valve means carried by the body for movement from a position opening said annulus to a position closing the annulus between said tubing string and casing in response to a predetermined increase in velocity of well fluid flowing upward through the annulus.

11. A combination tubing and annulus storm choke, comprising a body having a bore therethrough and means on its upper and lower ends for connecting it in a tubing string, a seat about the bore through the body, a closure element carried by the body for engaging said seat to close said bore in response to a predetermined increase in velocity of well fluid flowing upwardly through the bore, a tubular member carried about the body tqprovide an annular passageway therebetween, a seat about the outer side of the body, a closure element on the tubular member for engaging the outer seat to close the passageway between the tubing string and casing in response to a predetermined increase in velocity of fluid flowing upwardly through the annulus, and means about the tubular member for sealing between said member and the well casing into which the tubing string is run.

12. A choke of the character defined in claim 11, wherein the body has inwardly and outwardly enlarged portions intermediate its upper and lower ends, said seat about the bore is formed on the lower end of the inwardly enlarged portion, and the outer seat is formed on the lower end of the outwardly enlarged portion of the body.

13. A choke of the character defined in claim 12, wherein the upper end of the tubular body haa an inwardly extending portion for guidably sliding over the body above the outwardly enlarged portion thereof.

Claims

1. A tubing storm choke, comprising a body having a reduced bore therethrough adapted to form a continuation of a tubing string, a downwardly and outwardly conically shaped metal seat on the body about the lower end of the bore, shiftable means including a similarly shaped metal closure element disposed in the body beneath the seat for movement vertically upwardly from a lower position spaced from the seat to open the bore to an upper position engaged with the seat to close the bore, said shiftable means also including a rod extending upwardly from the closure element and loosely through the bore to provide an annular flow path therebetween, and means on the rod seatable on the body to normally suspend the closure element in its open position, said closure element being urged to said lower position solely in response to the weight of said shiftable means, and to said upper position solely in response to a predetermined change in velocity of well fluid through the annular flow path.

11. A combination tubing and annulus storm choke, comprising a body having a bore therethrough and means on its upper and lower ends for connecting it in a tubing string, a seat about the bore through the body, a closure element carried by the body for engaging said seat to close said bore in response to a predetermined increase in velocity of well fluid flowing upwardly through the bore, a tubular member carried about the body to provide an annular passageway therebetween, a seat about the outer side of the body, a closure element on the tubular member for engaging the outer seat to close the passageway between the tubing string and casing in response to a predetermined increase in velocity of fluid flowing upwardly through the annulus, and means about the tubular member for sealing between said member and the well casing into which the tubing string is run.