US3804167A

US3804167A - Automatic shut-in of down hole well production

Info

Publication number: US3804167A
Application number: US00266882A
Authority: US
Inventors: S Swift
Original assignee: Cities Service Oil Co
Current assignee: Cities Service Oil Co
Priority date: 1972-06-28
Filing date: 1972-06-28
Publication date: 1974-04-16
Anticipated expiration: 1991-04-16

Abstract

Accidental blow out of producing oil or gas wells is prevented by means of a storm choke which shuts off flow of the produced fluid automatically in response to an increasing of pressure within the casing of the well. Shut down of production through the tubing string thus occurs quickly and automatically if either the casing, tubing, or wellhead equipment fails above the choke or if the packer below the choke fails.

Description

[ Apr. 16, 1974 United States Patent 1191 Swift ye 14 0/2 66 NW6 0 .Tmm mmm u 7 am Bf m o m PGHL 9062 6667 9999 1111 9 0 1 11 76 6 0329 7 86 7589 ,92 3233 Assignee: Cities Service Oil Company, Tulsa Okla Przmary Exammer-Bobby R. Gay

Assistant Examiner-Albert A. Hafer [22] Filed:

Attorney, Agent, or Firm-Elton F. Gunn June 28, 1972 21 A LN 266 882 l 1 PP ABSTRACT Accidental blow out of producing oil or gas wells is prevented by means of a storm choke which shuts off flow of the produced fluid automatically in response 90 NN7 63 1 332 2 7 1 3 S NR4 6 .2 6 2 l u amR R m4 4 2 2 n a N6 6 "6 6 l u. mmh N .r "8 "a "u .I "f. C d S.Ld

l U h F ill. 2 8 555 [ll to an increasing of pressure within the casing of the well. Shut down of production through the tubing string thus occurs quickly and automatically if either the casing, tubing, or wellhead equipment fails above the choke or if the packer belowthe choke fails.

8 Claims, 3 Drawing Figures PATENTEHAPR] 6 m4 3804.1

sum 1 OF 3- AUTOMATIC SHUT-IN OF DOWN HOLE WELL PRODUCTION BACKGROUND OF THE INVENTION pressure which constituted an emergency condition.

Because of a restricted oil flow at a failed surface location for example, the pressure at the storm choke was not low enough to activate the choke. Use of down hole chokes which can be hydraulically activated from the surface has generally been avoided since the expense for such an installation is relatively high.

SUMMARY OF THE INVENTION This invention pertains to blow out prevention in deep production wells and more particularly pertains to storm chokes installed in deep wells which have a casing which extends below the surface, a string of production tubing within the casing, and a sealed annulus between the casing and tubing which extends from the surface to a deeper location within the well.

In accordance with the present invention there is installed within the well a storm chokewhich comprises a movable valve disc located within the tubing, the disc being activated by an elevation of pressure within the annular space between the well casing and tubing, and a valve seat located within the tubing which is adapted to receive the valve disc when it is activated. Upon mating of the valve disc with the seat, the flow of fluid through the production tubing is obstructed, thus preventing run-away conditions at thesurface should the tubing rupture or the packer between tubing and easing fail below the location of the choke.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents an embodiment of the invention wherein the valve disc of the choke is moved upwardly into the valve seat by means of a collapsable bellows.

FIG. 2 is a departure from the apparatus shown in FIG. 1 only in the sense that the activating mechanism for seating the valve disc is located downstream of the seat rather than upstream, and

FIG. 3 shows use of a piston for seating the valve disc instead of a bellows.

DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1, a well casing 1 extends downwardly from the surface represented at 2 toward at producing formation, notshown. A string of production tubing represented at 3 extends through the casing to the producing formation, and produced fluids are removed therefrom at a location above the surface. Far below the surface, a packing 4 is placed between the tubing and the casing of the well, thus permitting controlled production through the tubing string. A seal 5 is also placed across the tubing and the casing toward the top thereof and thus creating a sealed annular space 6 between the tubing and casing.

At a location above the packing 4, the storm choke resides .within tubing 3. The choke comprises a valve seat 7 axially disposed within tubing 3 and adapted to receive the disc 8 of the valve upon upward movement thereof. A valve stem 9 is attached to the'valve disc and extends into a pressurizable chamber 10 through a stem guide and seal represented at 1 l. A pressurizing port 12 extends through the wall of the tubing 3 and communicates with the annular space 6. As illustrated in FIG. 1, a collapsable bellows 13 is attached to the valve stem 9, so that upon increase of pressure in annular space 6, the pressure is transmitted through port 12 to chamber 10, thus causing collapse of bellows 13 and a consequent insertion of valve disc 8 into seat 7 by means of the thrust exerted on the valve stem by the bellows. Upon mating of the valve disc and seat in this manner, upward flow of fluid through the tubing 3 is stopped. It will be understood that the valve disc 8 can be moved against the seat 7 merely by pressure against the stem 9 alone, but it will also be appreciated that thrust of the stem by this pressure can be greatly multiplied by use of a bellows, piston, etc.

The pressure within the annular space 6 can be maintained relatively low by use of a gas to fill the void, and the bellows 13 can be preset for collapse at a higher pressure in the event that pressure in the annulus is substantially increased by invasion of a foreign fluid, e.g. sea water which results from casing failure on an off shore well, or oil or gas in the'event of packing failure or tubing failure above the packing.

FIG. 2 shows a storm choke like that illustrated in FIG. 1 except that the pressurizing chamber 10 is 10- cated above the valve seat 7 rather than below it, whereupon collapse of the bellows 13 the valve disc 8 is pulled rather than pushed against the seat.

FIG. 3 illustrates use of a piston instead ofa bellows as a pressure multiplier for augmenting thrust upon the valve stem. In the illustrated case chamber 10 is a cylinder and the piston 14 is tightly fitted therein but is adapted to move upward upon pressurizing the cylinder. A spring 15 isfitted within the chamber 10 and prevents the disc 8 from being pushed upwards against the seat 7 during normal operation, i.e. the disc is only moved upward and mated with the seat in the event of abnormal pressure presented to the bottom of the piston through pressurizing port 12.

As in FIG. 2, the cylinder-piston arrangement of FIG. 3 can also be turned upside down and located above the valve seat 7, in which case the spring 15 can either be dispensed with or else retained for the purpose of maintaining the valve always open until reaching a preset pressure as determined by the tension of the spring.

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

What is claimed is:

1. In a producing well having a casing which extends below the surface, a string of production tubing within the casing, and an elongated annular space between the casing and tubing which has a seal member at each end and which extends from the upper end of the well to a deeper location therein, the improvement of an automatically activated storm choke which comprises:

a. a movable valve disc located within said tubing which is activated by an elevation of pressure within said annular space, and

b. a valve seat located within said tubing, said seat being adapted to receive the disc of the valve upon pressure activation of the valve and to obstruct the flow of fluid through said tubing when the valve disc and seat are mated.

2. Apparatus as in claim 1 in which said valve comprises I a. a pressurizable chamber having a pressurizing port which extends through the wall of the tubing and communicates with the annular space between the tubing and casing, and

b. a valve stem attached to the valve disc and which extends into said chamber, said stem and disc being movable by thrust applied to the stem from within the chamber by elevation of pressure therein.

3. Apparatus as in claim 2 wherein the valve seat and valve disc are axially aligned with repect to said tubing.

4. Apparatus as in claim 2 and further comprising a pressure responsive thrust multiplier located within said chamber and adapted to apply thrust to the valve stem upon response to pressure.

5. Apparatus as in claim 4 wherein the thrust multiplier is a bellows.

6. Apparatus as in claim 4 wherein the thrust multiplier is a piston.

7. Apparatus as in claim 3 wherein the valve seat is located above the valve and the valve disc is thrust upwardly upon activation of the valve.

8. Apparatus comprising a tubing which contains a flowing fluid, a casing which surrounds the tubing, an annular space between the tubing and the casing, said annular space having a seal member at each end, a movable valve disc located within said tubing which is activated by an elevation of pressure within said annular space, and a valve seat located within said tubing, said seat being adapted to receive the disc of the valve upon pressure activation thereof and to obstruct the flow of fluid through said tubing when the valve disc and seat are mated.

I ll l

Claims

1. In a producing well having a casing which extends below the surface, a string of production tubing within the casing, and an elongated annular space between the casing and tubing which has a seal member at each end and which extends from the upper end of the well to a deeper location therein, the improvement of an automatically activated storm choke which comprises: a. a movable valve disc located within said tubing which is activated by an elevation of pressure within said annular space, and b. a valve seat located within said tubing, said seat being adapted to receive the disc of the valve upon pressure activation of the valve and to obstruct the flow of fluid through said tubing when the valve disc and seat are mated.

2. Apparatus as in claim 1 in which said valve comprises a. a pressurizable chamber having a pressurizing port which extends through the wall of the tubing and communicates with the annular space between the tubing and casing, and b. a valve stem attached to the valve disc and which extends into said chamber, said stem and disc being movable by thrust applied to the stem from within the chamber by elevation of pressure therein.

5. Apparatus as in claim 4 wherein the thrust multiplier is a bellows.

6. Apparatus as in claim 4 wherein the thrust multiplier is a piston.