US3850239A

US3850239A - Storm choke

Info

Publication number: US3850239A
Application number: US00294744A
Authority: US
Inventors: G Rosewald
Original assignee: Cities Service Oil Co
Current assignee: Cities Service Oil Co
Priority date: 1972-10-03
Filing date: 1972-10-03
Publication date: 1974-11-26
Anticipated expiration: 1991-11-26

Abstract

Accidental blow out of a producing oil or gas well is prevented by means of a storm choke located within a production tubing which extends from the surface to a producing petroleum reservoir. The valve disc is equipped with operating means which continuously urges the disc toward a position which is opposite from normal with regard to engagement with the seat, i.e., the disc is continuously urged toward the seat if the valve is normally open and away from the seat if normally closed. Fluid actuated means which can be operated from the surface are employed for selectively securing the valve disc in a normally opened or closed position and for releasing the disc for the automatic movement thereof into or out of the valve seat by the operating means.

Description

United States Patent Rosewald Nov. 26, 1974 1 STORM CHOKE Prima ExaminerJames A. Le ink 7 1 t w. R 1 T PP 1 5] men or Gary sewa Okla Attorney, Agent, or FirmElton F. Gunn [73] Assignee: Cities Service Oil Company, Tulsa,

Okl 22 F1 d 0c 3 1972 [57] ABSTRACT 1 1e Accidental blow out of a producing oil or gas well is PP 294,744 prevented by means of a storm choke located within a production tubing which extends from the surface to a [52] Us. CL 166/72 166/224 A producing petroleum reservoir. The valve disc is [51] Int CL 33/03 E2lb 43/12 equipped with operating means which continuously [58] Field f l66/72224 224 urges the disc toward a position which is opposite 63 from normal with regard to engagement with the seat, i.e., the disc is continuously urged toward the seat if [56] References Cited the valve is normally open and away from the seat if UNITED STATES PATENTS normally closed. Fluid actuated means which can be operated from the surface are employed for selectively Crake ecuring the valve disc in a normally pened or closed g f 1 position and for releasing the disc for the automatic ous r 1 t 3,007,524 11 1961 Pistole et a1. 166/72 movertpem thereof or out of the valve Seat by the 3,078,923 2/1963 Tausch 166/72 Opera mg means- 3,288,221 11 1966 Howard et al.. 166/72 R26,l49 1 1967 Sizer et al. 166/72 11 3 Drawmg F'gures 4 3 v -(l/ I Wow/4% I JLEW 1 1 1 1 1 1 ,1 1 1- 1 1 r 1 1 STORM CHOKE BACKGROUND OF THE INVENTION Due to fire and health hazards, the potential loss of produced fluids, and potential damage to the environment, there has been increased emphasis on use of downhole safety shut-off valves, e.g., storm chokes, for flowing petroleum wells. By means of a storm choke,

the flow of petroleum fluids through the production 1 tubing of a flowing well can be shut off in an emergency, thus providing means for preventing or controlling an accidental blow out.

Most of the storm chokes now used are of three basic types which are installed in the well bore:

1. A valve which automatically closes and thus shuts off flow of fluid when the pressure differential across the valve becomes too great. More specifically, a valve of this type is designed to shut automatically if the flow of fluid through it exceeds a certain limit.

2. A hydraulically activated valve to which hydraulic fluid is pumped from the surface when an emergency arises.

3. A valve through which the fluid will flow only if the pressure in the well bore at the valve is above a pressure at which the valve is preset to close and which closes automatically if the pressure falls below the preset value.

None of the valve arrangements mentioned above has proven to be altogether satisfactory because of total dependence upon fully automatic operating systems which sometimes fail or else because it has not always been possible to complete an action at the surface which is necessary for opening or closing the valve.

It is therefore an object of the present invention to provide a simple and reliable storm choke which can be secured in a normally open or closed condition and which will close or open automatically upon manual or accidental release of the securing means. Other objects and advantages of the invention will become apparent from the following description which is, of course, intended to be illustrative rather than limitative.

SUMMARY OF THE INVENTION The present invention resides in apparatus for controlling flow of petroleum fluids through the production tubing of a flowing well. A valve seat is located within the production tubing between the surface and a producing reservoir. An operable valve disc is also located within the tubing and is adapted to engage and mate with the valve seat. Operating means is provided for urging the valve disc to move toward a position which is opposite from normal with regard to engagement of the disc with the seat. The apparatus can be arranged for either normal engagement or disengagement of the disc and seat, i.e., the valve can be either normally opened or closed. Operation of the valve disc toward or away from the seat can be accomplished by means of a pressurized fluid or a tensioned spring. Securing and releasing of the valve disc for movement can be accomplished with a fluid actuated means which can be operated from the surface to alter fluid pressure which normally holds the valve open or closed, so that upon reduction of the fluid pressure the valve is automatically closed or opened by the operating means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat diagrammatical sectional view of a producing well having one embodiment of the apparatus of the present invention installed therein.

FIG. 2 is a sectional view of an embodiment of the invention wherein the valve disc is operated by means of spring tension.

FIG. 3 is a sectional view of another embodiment of 0 the invention wherein the valve disc is operated by means of a bellows.

DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1, a production well generally indicated at 1 has a string of production tubing 2 which extends from above the surface of the earth 3 through a casing 4 to a petroleum producing reservoir 5.

A storm choke, generally represented at 6, is located within the production tubing between the surface and the producing reservoir, and will be described later in greater detail with reference to FIG. 2. The choke comprises a stem 7 attached to a valve disc 8 and a valve seat 9 affixed coaxially within the tubing to the wall thereof. Spring 10 is compressed and continuously urges upward against a piston 11 affixed to the stem 7, thus urging the disc toward engagement with the seat. However, in the arrangement shown in FIG. 1 the storm choke is normally open, so the disc must be held off the seat to provide a flow path for liquid through the tubing for recovery at the surface through line 12. The choke can be held open by means of a hydraulic cylinder 13 into which fluid is pumped through a hollow, flexible tubing line 14 which extends upward from stem 7 through the production tubing 2 and exits therefrom of the stem 7 which is attached to the piston. Down-.

ward displacement of the piston also compresses the spring 10, but the tension therein is overcome by fluid pressure in the cylinder so that the valve is held open. However, when hydraulic pressure in the cylinder is deliberately or accidentally released, the valve closes automatically by virtue of the spring tension being exerted against the piston in an upward direction. In operation, fluid pressure in the cylinder is thus held at a level which overcomes the tension of spring 10 so that the valve remains normally open. Pressurization of hydraulic fluid in line 14 is effected by means of a pump 15 located in the line 14. The fluid pressure is regulated by means of a shunt line 16 having a flow control valve 17 whereby part of the fluid delivery from the pump is returned to the reservoir via the shunt, i.e., the pressure increases as the amount of shunted fluid is reduced and vice versa. A gauge 19 can be employed in line 14 for determining the pressure therein and thus providing means for ascertaining whether sufficient pressure is being supplied for holding the valve open. Once the desired pressure is reached in line 14, valve 28 can be closed to hold the pressure in the line. Should the pressure gradually fall off, it can be reestablished by reopening valve 28 and repeating the pumping procedure. Pressurization can also be maintained by means of an automatic detector-controller device. As previously indicated, the valve will close automatically when the hydraulic pressure in cylinder 13 falls or is reduced below a value which overrides the tension of spring 10.

For quick closure of the valve in an emergency, relief valve 29 is opened to achieve a rapid bleed-down of pressure in line 14 and chamber 24. The valve will also close automatically should line 14 become broken in a storm, fire or other accident.

FIG. 1 shows use of a wench for applying tension to the hollow, flexible tubing line 14. This is an optical feature for raising the disc 8 into abutment with the seat 9 in the event that automatic abutment is not effected by expansion of spring 10. It will also be appreciated that a flexible hydraulic line such as 14 can be run down the production tubing independently of a separate cable attached to disc 8 and wench 20, thus providing a stouter line for lifting the disc by means of the wench and lessening the possibility of accidentally parting the hydraulic line. For convenience, the line can be wrapped around that part of the cable which extends below the pulley into production tubing 2. As an alternative, a stout tubing or pipe can be run from below the pulley down to the valve disc, thus serving as a mechanical linkage and a conduit for hydraulic fluid. In such a case, a cable can be attached to the upper end of the pipe and extended over to the wench, with hydraulic fluid being pumped into the pipe at a point between the pulley 31 and the seal 30.

In FIG. 2, the cylinder 13 is coaxially aligned within the production tubing 2 and is rigidly attached to the wall thereof by means of brackets 21. The upper end of the cylinder 13 has an end closure 22 and an attached seal 23 for the stem 7 which extends coaxially through the closure and is attached to the disc 8 and the piston 11, the latter being closely fitted to the inner wall of the cylinder 13 to provide a sealed but expansible chamber 24 into which hydraulic fluid can be pumped for displacement of the piston and movement of the disc away from the seat. The piston can be equipped with O-rings to facilitate sealing.

The line 14 is attached to and interconnects with stem 7 which is also hollow. Fluid which is pumped into line 14 enters the chamber 24 through openings 25 in the stem. During operation, hydraulic fluid is pressurized in chamber 24, by pumping, to drive piston 11 downward. This disengages the valve disc 8 from the seat 9 and also compresses spring 10. The valve is thus held open until the hydraulic pressure in chamber 24 is deliverately or inadvertantly released, and in which case the disc is automatically moved upward by spring pressure against the piston.

The lower end of the cylinder 13 serves as a retainer for the spring 10 and is provided with a lower spring rest in the form of a plate 26 which is attached to the cylinder wall. Since the spring rest, the cylinder and the tubing 2 are all rigidly connected together the spring 10 is in effect attached to the tubing 2, so that one end of the spring urges against the tubing while pushing against the movable piston from the other end. As shown in FIG. 2, the valve seat 9 is axially aligned in the production tubing 2 whereas the valve disc is axially aligned with the opening in the seat.

FIG. 3 represents an embodiment of the invention which is basically the same as shown in FIG. 2 except that the piston 11 and, hence, the valve disc 8 are continuously urged upward by means of a compressed fluid contained in a sealed bellows 27 rather than a spring. As can be seen in FIG. 3, the bellows is contained in the lower part of the cylinder 13. The bellows is supported at the bottom by plate 26 while the top thereof abuts the lower end of piston 11. The length of the bellows and the pressure of the fluidtherein is sufficient to drive the piston upward and seat the disc 8 when the hydraulic pressure in chamber 24 is insufficient to hold the valve closed. However, when the chamber is pressurized-following controlled pumping of fluid through line 14, the bellows becomes partially collapsed, further compressing the fluid therein and thus holding the valve normally open. As previously indicated, either deliberate or inadvertant release of pressure from chamber 24 permits automatic expansion of the bellows and closure of the valve. The fluid in the bellows can be any suitable gas such as air, nitrogen, an inert gas or the like.

It will be understood that the bellows 27 is optional since the lower end of the cylinder 13 can be a sealed container for the compressible fluid, but a bellows is preferred since it is an assured means of sealing the fluid. Therefore, a bellows could also be employed for sealing hydraulic fluid in the upper part of the cylinder.

Using valves as shown in FIGS. 2 and 3, hydraulic fluid is normally supplied under controlled pressure to hold the disc 8 off of seat 9 so that flow of petroleum fluids can be maintained through the well tubing. Closure of .the choke can be quickly accomplished merely by opening relief valve 29, the seating of the valve disc 8 being automatically accomplished by expansion of spring 10 or the bellows 26.

FIGS. 2 and 3 illustrate use of storm chokes wherein the valve disc 8 is below the seat 9 and is normally displaced therefrom so that the valve is open. It will be appreciated that the apparatus features of these valves could be easily rearranged so that the cylinder and/or disc is located above the seat, or whereby the valve is kept normally closed and will open automatically upon release of the hydraulic pressure. A normally closed valve can be used, for instance, with a relief well in the same formation as a producing well, but which is opened only during an emergency in order to relieve pressure in theformation.

Although the drawings illustrate use of beveled sealing surfaces on the valve discs and seats, other types of sealing engagements between these members can be employed, e.g., flat surfaces or a ring-and-groove ar rangement.

Once in place, the automatic disc-operating features of the present invention can be quickly and easily tested at any time merely by opening the hydraulic relief valve'29 to accomplish a desired opening or closing of the choke. Whether or not the choke operates properly can then be ascertained by a detected interruption or initiation of flow through line 12. Once tested, the valve disc can then be restored to its normally opened or closed condition by reestablishment of hydraulic pressure.

The present invention has been described with reference to particular apparatus features and arrangements thereof but it will be understood that still other embodiments will become apparent which are within the spirit and scope of the invention defined in the following claims.

What is claimed is:

1. In a producing well having a production tubing which extends below the surface to a producing reservoir, a storm choke which comprises:

a. a valve seat located within the production tubing,

b. an operable valve disc located within the production tubing, the disc being adapted to engage and mate with the valve seat when the disc is operated,

0. operating means for urging the valve disc to move toward a position which is opposite from normal with regard to engagement of the disc with the valve seat, said operating means comprising a cylinder secured to the inner wall of the production tubing, said cylinder having a sealed but expansible chamber therein for a contained fluid, which is relatively compressed when the valve disc is secured in a normal position with regard to engagement with the valve seat and relatively expanded when the disc is released for movement, and

d. fluid activated means in the production tubing for selectively securing the valve disc in a normal position with regard to engagement with the seat and for releasing the disc for movement by the operating means, said fluid activated means comprising a piston within said cylinder, the piston being attached to the valve disc, 21 fluid-conveying tubing which leads from the cylinder and up through the production tubing, and means located at the surface for pumping fluid into the cylinder through the conveying tubing and for controlling fluid pressure in the cylinder.

2. Apparatus as in claim 1 wherein the valve seat comprises an attached valve stem aligned axially with the disc and seat, the piston being attached to the stem, and a compressed spring which urges the piston.

3. Apparatus as in claim 1 wherein the sealed but expansible chamber is a bellows.

4. Apparatus as in claim 1 wherein the sealed but expansible chamber is a cylinder having a fitted piston therein, the cylinder being axially aligned with the valve disc, and the piston being attached to the disc.

5. Apparatus as in claim 4 wherein the operating means for urging the valve disc comprises a tensioned spring.

6. In a producing well having a production tubing which extends below the surface to a producing reservoir, a storm choke which comprises:

a. a valve seat located within the production tubing and aligned axially therewith,

b. an operable valve disc located within the production tubing andaligned axially with the valve seat,

the disc being adapted to engage and mate with the valve seat when the disc is operated,

c. a cylinder located within the production tubing,

the cylinder being closed at one end,

d. a movable piston located within the cylinder,

e. a valve stem which extends through the closed end of the cylinder and is attached at one end to the piston and at the other end to the valve disc,

f. means for supplying a hydraulic fluid at controlled pressure to the cylinder between the piston and the closed end thereof, and

g. means for continuously urging the piston to move in an opposite direction from that which results from supplying fluid pressure to the cylinder.

7. Apparatus as in claim 6 wherein the means for urging the piston to move is a compressed spring.

8. Apparatus as in claim 6 wherein the cylinder is also sealed at the other end, the means for supplying hydraulic fluid at controlled pressure comprises a fluidconveying tubing which leads into a section of the cylinder on one side of the'piston, and the second of the cylinder on the other side of the piston contains a compressible fluid which urges the piston to move toward the section of the cylinder into which hydraulic fluid is supplied at controlled pressure.

9. Apparatus as in claim 8 wherein the fluidconveying tubing is attached to the valve disc and is movable within the production tubing, and further comprising means at the surface for securing and releasing the fluid-conveying tubing for movement within the production tubing.

10. Apparatus as in claim 8 further comprising a mechanical linkage attached at one end to the valve disc and which extends up through the valve disc, and means at the surface for securing and releasing the mechanical linkage for movement within the production tubing.

11. Apparatus as in claim 8 including a mechanical linkage attached to the valve disc which extends up through the production tubing and is adapted for movement therein, means at the surface for selectively securing and moving the linkage within the tubing, and wherein the fluid-conveying tubing extends from the valve up through the roduction tubing, and means at the surface for pumping hydraulic fluid into the fluidconveying conduit and for controlling the hydraulic pressure within the valve.

Claims

1. In a producing well having a production tubing which extends below the surface to a producing reservoir, a storm choke which comprises: a. a valve seat located within the production tubing, b. an operable valve disc located within the production tubing, the disc being adapted to engage and mate with the valve seat when the disc is operated, c. operating means for urging the valve disc to move toward a position which is opposite from normal with regard to engagement of the disc with the valve seat, said operating means comprising a cylinder secured to the inner wall of the production tubing, said cylinder having a sealed but expansible chamber therein for a contained fluid, which is relatively compressed when the valve disc is secured in a normal position with regard to engagement with the valve seat and relatively expanded when the disc is released for movement, and d. fluid activated means in the production tubing for selectively securing the valve disc in a normal position with regard to engagement with the seat and for releasing the disc for movement by the operating means, said fluid activated means comprising a piston within said cylinder, the piston being attached to the valve disc, a fluid-conveying tubing which leads from the cylinder and up through the production tubing, and means located at the surface for pumping fluid into the cylinder through the conveying tubing and for controlling fluid pressure in the cylinder.

6. In a producing well having a production tubing which extends below the surface to a producing reservoir, a storm choke which comprises: a. a valve seat located within the production tubing and aligned axially therewith, b. an operable valve disc located within the production tubing and aligned axially with the valve seat, the disc being adapted to engage and mate with the valve seat when the disc is operated, c. a cylinder located within the production tubing, the cylinder being closed at one end, d. a movable piston located within the cylinder, e. a valve stem which extends through the closed end of the cylinder and is attached at one end to the piston and at the other end to the valve disc, f. means for supplying a hydraulic fluid at controlled pressure to the cylinder between the piston and the closed end thereof, and g. means for continuously urging the piston to move in an opposite direction from that which results from supplying fluid pressure to the cylinder.

8. Apparatus as in claim 6 wherein the cylinder is also sealed at the other end, the means for supplying hydraulic fluid at controlled pressure comprises a fluid-conveying tubing which leads into a section of the cylinder on one side of the piston, and the section of the cylinder on the other side of the piston contains a compressible fluid which urges the piston to move toward the section of the cylinder into which hydraulic fluid is supplied at controlled pressure.

9. Apparatus as in claim 8 wherein the fluid-conveying tubing is attached to the valve disc and is movable within the production tubing, and further comprising means at the surface for securing and releasing the fluid-conveying tubing for movement within the production tubing.

11. Apparatus as in claim 8 including a mechanical linkage attached to the valve disc which extends up through the production tubing and is adapted for movement therein, means at the surface for selectively securing and moving the linkage within the tubing, and wherein the fluid-conveying tubing extends from the valve up through the production tubing, and means at the surface for pumping hydraulic fluid into the fluid-conveying conduit and for controlling the hydraulic pressure within the valve.