US3861464A

US3861464A - Safety valve for wells

Info

Publication number: US3861464A
Application number: US410418A
Authority: US
Inventors: George I Boyadjieff; Ben A Otsap
Original assignee: Varco International Inc
Current assignee: Varco International Inc
Priority date: 1973-10-29
Filing date: 1973-10-29
Publication date: 1975-01-21
Anticipated expiration: 1992-01-21

Abstract

A safety valve to be lowered into a well and actuated from a location near the surface of the earth by a flexible line or the like extending downwardly into the well, and having a reversing mechanism acting to convert upward movement of the actuating line to downward movement of a valve opening part in the well, with the reversing mechanism including two pistons or other parts exposed to a common body of confined fluid in a relation causing downward displacement of one of the parts in response to upward movement of the other part.

Description

United States Patent Boyadjieff et al.

[451 Jan. 21, 1975 [73] Assignee: Varco International, Inc., Los

Angeles, Calif.

22 Filed: Oct. 29, 1973 211 Appl. N01; 410,418

[52] US. Cl 166/224 A, 166/72, 251/63.6 [51] Int. Cl E2lb 43/12, E2lb 33/03 [58] Field of Search 166/72, 73, 224, 274 A,

[56] References Cited UNITED STATES PATENTS 5/1933 Otis 166/72 7/1940 Toney..... 8/1944 Erwin 166/72 3,078,923 2/1963 Tausch 166/224 S 3,351,133 11/1967 Clark et al.... 166/72 3,411,585 11/1968 Page 166/73 3,675,718 7/1972 Kanady 166/224 S Primary Examiner-James A. Leppink Attorney, Agent, or Firm-Wil1iam P. Green [57] ABSTRACT A safety valve to be lowered into a well and actuated from a location near the surface of the earth by a flexible line or the like extending downwardly into the well, and having a reversing mechanism acting to convert upward movement of the actuating line to downward movement of a valve opening part in the well, with the reversing mechanism including two pistons or other parts exposed to a common body of confined fluid in a relation causing downward displacement of one of the parts in response to upward movement of the other part.

18 Claims, 7 Drawing Figures "n "Elli t PATENTED JANZ 1 I975 SNEU 10F 2 SAFETY VALVE FOR WELLS CROSS REFERENCE TO RELATED APPLICATION Certain features of the apparatus disclosed in the present application have been shown and claimed in our prior copending application Ser. No 252,808 filed May 12, 1972 on Remotely Operated Well Safety Valves, which was a continuation in part of application Ser. No. 203,142 filed Nov. 30, 1971 and now abandoned.

BACKGROUND OF THE INVENTION This invention relates to improved well safety valves for closing off the flow of well fluid at a location deep within a well, and adapted for remotely controlled actuation and control from the surface of the earth.

Our above identified prior copending application Ser. No. 252,808 shows a remotely controlled safety valve which is actuated from a location near the surface of the earth by actuation of a flexible line extending downwardly within the well to the location of the valve. The line or cable is preferably maintained under tension when the valve is open, so that any release of that tensioned condition, either intentionally or accidentally, will automatically close the valve and shut off further escape of well fluid therefrom. Thus, the valve will close if adverse conditions develop which in some way break the cable, or break the supply of energy to an actuating unit at the surface of the earth which maintains the line in tension. This actuating unit may be a piston and cylinder mechanism located within an upper portion of the well and held in a line-tensioning condition by the force of a pressurized control fluid.

SUMMARY OF THE INVENTION The present invention provides a safety valve unit which can be controlled remotely in a manner similar to the valves of my above discussed copending application, but in which the structure and functioning of the valve mechanism are different from, and for certain situations or installations preferable to, the valves of that prior application. One feature of particular importance to the present invention relates to the provision of a unique type of force reversing mechanism, which can be actuated by force applied to the mechanism in a first vertical direction through the flexible line or other actuator, and which will function to reverse the direction of that force to produce a valve operating force in the opposite vertical direction. Consequently, if a first of these forces is applied to the reversing mechanism by a flexible line of the above discussed type in an upward direction tensioning that line, the reversing mechanism can then apply to the valve or a valve operator a downward force for opening the valve, and holding it open until the tensioned condition of the flexible line is released. The force reversal is effected by a fluid type system, in which a confined body of fluid is exposed to and acts against two different movable parts, both of which may be considered as pistons, in a relation such that movement of one of the parts or pistons in a first direction acts through the fluid to cause movement of the other part in the opposite direction. Desirably, both of these pistons are tubular to provide within the interior of the pistons a relatively open vertical passageway through which the production fluid of the well can flow upwardly without substantial restriction to the surface ofthc earth. a portion of one of these parts may actuate the safety valve proper from a closed position of extension across the fluid passageway in the device to a laterally deflected open position. In that open position, a portion of the tubular piston element may extend vertically past the valve element, in a manner protecting or shielding it from contact with and deterioration by the upflowing stream of well fluid.

Another feature of the invention relates to a novel arrangement for actuating an equalizer valve, which functions to place the interior of the valve unit in communication with its exterior at a location above the main safety valve element proper just prior to opening of the main valve element, in order to eliminate or decrease the pressure differential across the main valve and thereby facilitate its opening movement. More particularly, this equalizer valve controls the flow of well fluid through an aperture or apertures in the wall of the valve unit body, at a location above the main safety valve element, and is actuable to open condition by initial upward movement of the actuating line. To assure opening of the equalizer valve before the mechanism attempts to open the main valve, a lost motion connection is provided which upon upward movement of the actuating line first opens the equalizer valve, and only after that valve has been opened commences actuation of the mechanism which opens the main valve element. A spring may yieldingly resist this lost motion, and a second and opposed spring may resist relative motion of the parts in an opposite vertical direction in a relation opening the equalizer valve during lowering of the tool into the well.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiment illustrated in the accompanying drawings, in which:

FIG. 1 shows somewhat diagramatically a well containing safety valve equipment constructed in accordance with the invention;

FIG. 2 is an enlarged vertical fragmentary section through various portions of the apparatus of FIG. 1, showing the main safety valve element in its open condition;

FIG. 3 is a view showing the lower portion of the FIG. 2 apparatus, but with the safety valve in its closed condition;

FIG. 4 is an enlarged vertical section through the equalizer valve mechanism in its FIG. 2 condition;

FIG. 5 is a view similar to FIG. 4, but showing the equalizer valve closed, as in FIG. 3;

FIG. 6 is an enlarged fragmentary vertical section taken in the area of the circle 66 of FIG. 3 and;

FIG. 7 is an enlarged vertical fragmentary section showing a portion of the main valve, in the region of the cricle 77 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows at 10 a well containing a casing 11 within which a string of production tubing 12 extends downwardly, in spaced relation to the casing. A conventional well head represented at 13 is connected to the upper end of the casing, and appropriately suspends the tubing string 12. Production fluid from the formation surrounding the well enters the lower end of the tubing string at the production zone 14, and ultimately discharges from the upper end of tubing 12 into a storage tank 16 or appropriate distribution line past a suitable control valve 116. The tubing 12 may be formed in conventional manner of a series of tubing sections connected together by threaded couplings 15. In lieu of the typically illustrated type of well drilled directly into the surface of the earth, it is contemplated that the present well safety apparatus may also be utilized in the drilling of underwater wells, as from a barge or ship floating on the surface of a body of water, with the well casing and its contents extending downwardly through the water to the ocean floor or the like, and then into the earth at that location.

The safety valve unit proper is designated generally by the number 17 in FIG. 1, and is set in fixed position within the lower portion of tubing string 12 by a landing and sealing unit represented at 18. Unit 18 may be constructed integrally with valve unit 17, or may be a separately formed attached conventional landing and sealing unit as illustrated, rigidly connected to the upper end of the valve unit 17 by a threaded connection 19 (FIG. 2). The safety valve is actuated and controlled by an elongated flexible line 20, preferably of the type commonly referred to as a wireline. This line or cable extends upwardly to the surface of the earth for control by a powered operating mechanism designated generally at 21. The line 20 may be any conventional or known type of flexible cable or the like, including elements of this type formed of either a single wire or strand, or a number of wires or strands interwoven or wound together.

The landing and sealing unit 18 is typically and somewhat diagramatically illustrated as of the same conventional key-type shown and described in our above identified copending application. Specifically, this unit 18 may include a tubular body member 22 connected at its lower end to the upper end of body 23 of valve unit 17 by the previously mentioned threaded connection 19, with an annular seal ring 24 of rubber or other elastomeric material clamped between shoulders on

elements

22 and 23 as seen in FIG. 2 for annular engagement with the inner surface of tubing 12 to form a fluid tight seal therewith preventing upward flow of fluid about the outside of

elements

22 and 23 at the location of seal 24. Disposed about body 22, the landing and sealing unit 18 includes a sleeve or mandrel 25 containing apertures through which a number of circularly spaced locking keys or dogs 26 project radially outwardly for interfitting reception within a mating locating groove or plurality of grooves 27 formed in a coacting locating or landing nipple 28 connected into tubing 12. As is conventional in this type of device, keys 26 may be spring pressed radially outwardly relative to sleeve 25 for automatic reception within the groove or grooves 27 when they reach the location of the groove, with the keys then being locked in their outer holding positions in conventional manner by predetermined manipulation of body 22 from the surface of the earth. For example, the keys may be locked in their outer positions by a rapid vertical jarring movement of body 22 serving to shear a connection between the body and sleeve 25 and thereby move a looking or camming portion of the body into a position behind or radially inwardly of the keys. After being set by this type motion, the keys thereafter positively lock sleeve 25 and body 22 against both upward and downward movement relative to section 28 of the tubing, to thereby positively retain the valve unit 17 in its FIG. 1 position in the lower portion of the tubing string. Any other type of conven tional landing equipment may of course be substituted for the particular key-type device typically illustrated in FIG. 2, such as for example a type having slips designed to be forced outwardly against the tubing in frictional holding relation, or having lugs which are receivable between the ends of successive lengths of the tubing 12, or any other known or usable type of apparatus controllable from the surface of the earth for holding the valve unit 17 in a fixed vertical setting.

The actuating unit 21 located near the surface of the earth preferably takes the form of an annular piston and cylinder mechanism, to which the upper end of the flexible line 20 is connectible, and through which a central vertical passage 29 is formed for passing production fluid upwardly through the interior of this actuating unit. The cylinder 30 of the piston and cylinder mechanism 21 is an essentially tubular element having a vertical cylindrical internal surface 31, and contains a piston 32 which is movable upwardly and downwardly along the vertical axis 33 of the well. The piston 32 has an upper enlarged diameter portion 34 slidably received within and sealed by an O-ring 35 with respect to the inner cylindrical surface 31 of cylinder 30. An annular hydraulic cylinder chamber 36 is thus formed between the cylinder and piston, acting to force the piston upwardly relative to the cylinder in response to the injection of pressure fluid into the chamber 36. The lower end of chamber 36 is closed by provision of a reduced diameter portion 37 of the cylinder, having an internal surface 38 slidably engaging and receiving the lower reduced diameter portion 39 of the piston, and sealed with respect thereto by an annular O-ring 40. Pressure fluid is introduced into the lower end of cylinder chamber 36 through a small fluid inlet line 41, connecting into the cylinder chamber at 42.

The upper end of piston 32 carriesa a spider 43, which supports a tubular element 44 at a central location within the piston, so that the flexible line 20 may extend upwardly through this tubular portion 44 and be attached to an upper enlarged head element 45 shaped to serve as a fishing neck, for engagement with a fishing tool to pull the flexible line upwardly if and when desired. Upward movement of the piston acts to displace head element 44 and the connected flexible line upwardly, to open the valve unit 17 and maintain the flexible line under tension.

The piston and cylinder mechanism 21 is preferably suspended in the well from the well head 13, from which the usual main flow control valve assembly or Christmas Tree projects upwardly, the lower portion of this valve assembly being represented at 46 in FIG. 2. To suspend the actuating piston and cylinder mechanism from the well head, there is desirably provded between

elements

13 and 46 an adapter flange or ring 47, suitably secured to the flanges of

elements

13 and 46, and appropriately sealed with respect thereto as by rings represented at 48 and 49. The upper end of cylinder 30 may be connected threadedly at 50 to a short suspending tube 51, sealed with respect to the cylinder at 52 and 53, and annularly sealed with respect to flange 47 at two vertically spaced

locations

54 and 55. One or more locking dogs 56 may be threadedly connected into element 47 for projection into an annular external groove 57 formed in part 51, to suspend that part and the connected piston and cylinder mechanism in the illustrated position within the well. Actuating pressure fluid may be supplied to the piston and cylinder mechanism through an inlet passage 58 communicating through small passages 59 and 60 in

elements

51 and 30 respectively with the previously mentioned line 41 extending downwardly to the lower end of cylinder chamber 36. A fishing neck 61 may be connected onto the upper end of part 51, for engagement with an appropriate fishing tool to enable removal of the unit 21 upwardly from the well when desired. The actuating pressure fluid is supplied to passage 58 from any appropriate source represented diagramatically at 62 in FIG. 1, under the control of a manually or automatically operable three way valve or other valve represented at 63, for selectively either applying pressure to or releasing pressure from the hydraulic cylinder chamber 36.

The novelty of the present invention is particularly concerned with the structure of the safety valve unit 17 at the bottom of the well. Referring particularly to FIG. 2, the previously mentioned outer body 23 of this valve unit may be a vertically elongated rigid tubular struc ture formed sectionally to include a first upper section 64 threadedly connected at 66 to a second section 65 in fluid tight annularly sealed relation, with an annular bottom section 67 being threadedly connected at 68 to the lower end of section 65. The main safety valve element is a flapper type valve 69, mounted pivotally at 70 for swinging movement between the closed horizontally extending position of FIGS. 3 and 5, disposed transversely of vertical axis 33 of the well and tool, and the open position of FIG. 2, in which the valve 69 extends essentially vertically within an annular pocket or recess 71 formed in section 65 of the body 23. The pivotal axis 72 of valve 69 (see FIG. 7) is disposed horizontally in the illustrated position of the tool, to lie in a plane extending transversely of vertical axis 33. In its closed position of FIGS. 3 and 7, the circular valve disc 69 has its annular peripheral surface 73 (FIG. 7) in annular sealing engagement with a seal ring 74 carried by a radially inwardly projecting annular shoulder 75 formed within the interior of part 65, to positively close off all upward flow of production fluid through the valve unit and past element 69.

The valve element 69 is actuated to its open position by downward movement of a tubular part 76 whose upper portion 77 may function as part of a reversing mechanism 78 acting to displace part 76 downwardly in response to upward movement of flexible line and a connected element 79 forming a second portion of the reversing mechanism. Part 79 functions as an annular piston element, having a tubular straight cylindrical portion 80 slidably received within and engaging an internal cylindrical surface 81 formed in part 64 of body 23, and sealed with respect thereto by an O-ring 82. Beneath the location of O-ring 82, part 64 contains and enlarged diameter internal cylindrical surface 83, defining the outer wall of an annular vertically extending cylinder chamber 84 within which a body of pressure fluid is contained in confined and hermetically sealed condition. At its lower end, the element 79 has an annular radially outwardly projecting piston head 85.

Portion 77 or part 76 is shaped as a vertical tube functioning as a second annular piston having parallel internal and external cylindrical surfaces centered about axis 33. The outer surface of portion 77 of part 76 slidably engages internal surface 83 of part 64, and is sealed with respect thereto as by an O-ring 86. The

internal surface of portion 77 slidably contacts piston head 85 of the upper piston element 79, being sealed with respect thereto by an elastomeric ring 87 at its upper end. Portion 77 of part 76 may threadedly carry an annular part 88, which may have a portion 89 extending across the end of portion 77, and an axially ex tending portion 90 projecting radially inwardly from and beyond the internal surface of portion 77 of part 76, to define with the outer surface of piston element 79 an annular restricted passage 91, which provides restricted communication between and has a radial width smaller than two upper and lower annular

fluid com partments

92 and 93 forming portions of the previously discussed closed fluid chamber 84. This chamber and its two

compartments

92 and 93 are filled with fluid in any suitable manner, as by injection through one or more inlet passages 94 which, after injection of the fluid, may be closed and sealed by plugs 95 or otherwise. Desirably, the fluid within chamber 84 is a liquid, to render the actuation of the reversing mechanism as positive and controllable as possible.

At the lower end of the piston portion 77 of part 76, this part has an annular portion 192 of increased radial thickness, defining a shoulder 193 against which a compression spring 194 bears upwardly to yieldingly urge part 76 upwardly toward the FIG. 3 closed valve condition thereof. Beneath the level of shoulder 93, part 76 has a reduced diameter tubular portion 195, which slidably contacts an internal cylindrical surface in shoulder portion 75 of body part 65, and which has an annular beveled lower end surface 96 engageable annularly with an upwardly facing surface 97 formed on part 67 in the open position of valve 69, to thereby close off access of the production fluid within the interior of

part

67 and 76 to the open valve 69. Thus, the valve is protected against erosion by or other damage from contact with the moving production fluid. An opening 98 in the side wall of part 65 beneath shoulder 75 allows fluid flow into and out of the annular valve receiving compartment 71, to avoid any tendency for restriction of movement of the parts by entrapment of fluid in this compartment.

At its upper end, the upper piston part 79 of the reversing mechanism 78 is connected to flexible line 20 through an equalizing valve assembly 99 and a landing weight 100. The landing weight 100 may be connected in an suitable manner to the lower end of flexible line 20, and carry a downwardly projecting essentially rigid vertical rod 101 which is detachably connectible to the upper end of equalizer valve assembly 99 by a quick disconnect connection 102. As seen best in FIGS. 4 and 5, this connection 102 includes a part 103 disposed about the lower portion of rod 101 and forming a series of downwardly projecting circularly spaced spring fingers 104 whose lower enlargements 105 are receivable within a socket recess 106 formed in the upper chuck portion 107 of body 108 of the equalizer valve assembly 99. The part 104, rod 101 and weight 100 are not lowered into the well until after the valve unit 17 and landing unit 18 have been set therein. At that time,

parts

100, 101, and 103 are lowered into the well in a condition in which a lower camming enlargement 109 carried by rod 101 is located downwardly beneath the level of enlargements 105 on spring fingers 104, as represented by the broken lines 109' in FIG. 4. With the parts in this condition, enlargements 105 of the spring fingers 104 can move downwardly into the socket recess 106, and then spring radially outwardly in that recess, and be retained in the FIG. 4 full line connecting position by upward movement of enlargement 107 rela tive to the fingers and to a position between and blocking inward movement of the fingers. Thereafter, the connection 102 secures the rod 101 to body 108, with sufficient strength to withstand forces applied by the flexible line 20 in the FIG. 2 open position of valve 69, and unless and until the cable 20 is forceably pulled upwardly with excessive force sufficient to shear a pin 110 which initially extends through and is carried by rod 101 in the position of FIG. 4, but which upon exertion of an upper jarring force is sheared off to allow upward movement of rod 101 and its enlargement 109 from the FIG. 4 position to the FIG. position in which fingers 105 are free to move radially inwardly for release from chuck 107.

The equalizer valve assembly includes a tubular slide valve element 111 (FIGS. 4 and 5), which slidably engages the inner cylindrical surface 112 of body part 64, and which in the normal closed position of FIG. 5 to which it tends to return blocks fluid flow through one or more apertures 113 formed in the side wall of part 64. When the valve is open, these apertures 113 place the interior of body part 64 in communication with its exterior, to apply the same pressure to the upper side of main valve element 64 as to its underside.

The body part 108 of equalizer valve assembly 101 is a vertically extending tubular part, which rigidly carries sleeve valve element 111, as by provision of a series of circularly spaced radially extending web elements 114 connecting parts 108 and 111 but allowing upward flow of production fluid between elements 114. Internally, part 108 has a chamber 115 beneath the upper chuck recess 106, and within which two upper and lower compression springs 116 and 117 are received above and beneath an upper radial flange portion 118 carried at the upper end of a rigid rod 119 which projects upwardly from and is rigidly attached to the upper piston element 79 of the reversing mechanism 78. A seen in FIGS. 2 and 3, rod 119 may be connected to part 79 by providing the latter with an upper reduced diameter portion 120 attached to the main tubular portion of part 79 by a web structure 121 containing circularly spaced apertures 122 through which the production fluid can flow upwardly from the interior of part 79 to the space about rod 119.

To now describe a cycle of use of the disclosed apparatus, the first step to be followed in placing the equipment in operation in a well is to lower valve unit 17 and landing and sealing unit 18 into the well and to a production zone location as represented in FIG. 1. At this time, the flexible line and all parts connected thereto above chuck 107 are not attached to the

units

17 and 18 which are lowered into the well. An appropriate running tool lowers these

units

17 and 18 and then actuates the unit 18 to lock itself and unit 17 in fixed position in the well. Thereafter, the flexible line 20 and connected parts are lowered into the well, and fingers 105 are actuated to form a connection with chuck 107 as seen in FIG. 4. The actuating mechanism 21 is appropriately positioned in the upper portion of the well, and the upper end of flexible line 20 is passed through part 44 and connected to upper element 45 in an appropriate setting. Before application of pressure to the actuating unit 21, the

springs

116 and 117 retain element 108 and sleeve valve 111 in the FIG. 5 closed position of the equalizer valve, and spring 194 holds the part 76 in its FIG. 3 position in which the main valve 69 is also closed. When it is desired to open the safety valve to allow production of fluid from the well, control 5 fluid under pressure is applied to actuating unit 21 through

passages

58, 59 and 60, and line 41, to force piston 32 upwardly to the FIG. 2 position, and thereby apply upward tensioning force to cable 20 moving that cable upwardly to its FIG. 2 position. The initial upward movement of the cable moves outer body 108 of the equalizer valve assembly upwardly relative to rod 109 and its head 118, against the tendency of spring 117, and to a position in which sleeve valve element 111 is in its broken line position of FIG. 5 relative to part 64, to thereby open the equalizer or bleed passages 113. The strength of spring 117 is not sufficient to cause upward movement of rod 19 and its connected parts during this initial upward movement of part 108. However, when slide valve element 111 reaches its broken line position of FIG. 5, the spring 117 is in its fully compressed condition and therefore transmits further upward movement of part 108 to rod 119, to correspondingly move piston 79 upwardly relative to part 64, to thereby force liquid from compartment 93 through the restriction 91 and into the upper compartment 92 of chamber 84. The increased amount of liquid in upper compartment 92 forces the lower piston 77 downwardly in response to the upward movement of piston 79, to thereby displace the lower portion 195 of part 76 downwardly to its FIG. 2 position opening main valve 69. The narrow dimension of restriction 91 limits the rate at which this motion of the pistons can occur, to prevent damage to the pistons and/or valve and other related mechanism by too rapid motion. While the well is producing, the flexible line 20 is continuously maintained in this upwardly displaced tensioned condition of FIG. 2 by the actuating unit 21, to hold valve element 69 in its opened condition.

If any adverse condition develops during production which breaks cable 20, as by an earthquake or the like, the tensional force exerted by that cable is immediately released, and the main valve and equalizer valve are permitted to return to their normal closed positions, under the influence of

springs

194 and 1 17. A coacting spring 123 associated with element 169 may yieldingly urge that valve to its closed position pivotally about its axis 72, to urge the valve closed upon upward movement of part 76. The pressure fluid itself will of course normally assist this closure of valve 69, and maintain it positively closed by virtue of the pressure differential at the opposite sides of the valve when the equalizer valve element 111 is closed.

The second spring 116 within the equalizer valve assembly 99 is provided for permitting opening of the equalizer valve 1 11 during lowering of the

units

17 and 18 into the well. During such lowering, the running tool which installs these units in the well may displace part 108 downwardly relative to part 119 against the tendency of upper spring 1 16, and downwardly beyond the FIG. 5 position of part 111, to move part 111 out of blocking relation with respect to apertures 113 while the apparatus is being installed, and thereby allow fluid flow upwardly past seal element 24 and prevent the fluid in the well from resisting downward movement of the equipment.

While a certain specific embodiment of the present invention has been disclosed as typical, the invention is of course not limited to this particular form, but rather is applicable broadly to all such variations as fall within the scope of the appended claims.

We claim:

1. In well safety apparatus, including a valve unit to be lowered into a well and located therein, and a member extending upwardly toward the surface of the earth for actuating said valve unit; the improvement comprising formation of said valve unit to include means containing and enclosing a confined body of fluid, said means including a first element connectible to said member for actuation upwardly thereby and exposed to and acting against said confined body of fluid in a manner displacing a portion of said fluid in response to said upward movement of said element, and a second element exposed to said confined body of fluid and actuable downwardly by the pressure of the fluid upon said upward movement of said first element, said valve unit including also valve means operable by said downward movement of said second element.

2. The improvement in well safety apparatus as recited in claim 1, in which said two elements are pistons exposed to said body of fluid.

3. The improvement in well safety apparatus as recited in claim 1, in which said two elements are two concentric annular pistons movable in opposite vertical directions.

4. The improvement in well safety apparatus as recited in claim 1, in which said elements are two telescopically interfitting oppositely movable piston elements exposed to said confined fluid, one of said elements having a portion contacting said fluid which is thicker radially than an adjacent portion of said one element and which defines a restricted passage extending between and narrower than two compartments containing said confined fluid and between which said confined fluid must flow upon relative movement of the two elements.

5. The improvement in well safety apparatus as recited in claim 1, in which said valve means include a valve element mounted to swing downwardly and radially outwardly from a closed position blocking off the flow of production fluid upwardly through the well to an open position permitting such flow, said second element having a portion positioned to engage said valve element and deflect it downwardly and outwardly to said open position upon downward movement of said second element.

6. The improvement in well safety apparatus as recited in claim 1, in which said second element has a tubular lower portion through which production fluid flows upwardly in the open position of said valve means, said valve means including a valve member mounted pivotally for downward and outward swinging movement by downward movement of said tubular portion of said second element and from a closed position to an open position of reception radially outwardly of said tubular portion.

7. The improvement in well safety apparatus as recited in claim 1, in which said valve unit includes a body through which production fluid flows upwardly when said valve means are open, and equalizer valve means operable upon upward movement of said first element to place the exterior of said body in communication with its interior at a location above said first mentioned valve means.

8. In well safety apparatus including a body to be lowered into a well and located therein; a main valve member carried by said body and actuable between an open position passing production fluid upwardly into the interior of the body and a closed position blocking off such fluid flow; an equalizer valve element movable be tween an open position for passing fluid through a bleed passage formed in a side wall of said body and placing the exterior of the body in communication with its interior at a location above said main valve member, and a closed position; an elongated member extending upwardly toward the surface of the earth and operable by upward movement to open both said main valve element and said equalizer valve element; means for exerting upward force on said elongated member from a location near the surface of the earth; and a lost motion connection between said two valve elements acting to open said equalizer valve element upon initial upward movement of said elongated member and to then open said main valve element upon further upward movement of the elongated member.

9. The improvement in well safety apparatus as recited in claim 8, including spring means yieldingly resisting movement of said equalizer valve element independently of said main valve element.

10. In well safety apparatus, including a valve unit to be lowered into a well and located therein, and a member extending upwardly toward the surface of the earth for actuating said valve unit; the improvement comprising formation of said valve unit to include a first element connectible to said member for actuation upwardly thereby and exposed to and acting against a confined body of fluid in a manner displacing a portion of said fluid in response to said upward movement of said element, a second element exposed to said confined body of fluid and actuable downwardly by the pressure of the fluid upon said upward movement of said first element, and valve means operable by said downward movement of said second element, said valve unit including a tubular vertically extending body defining a side wall of a chamber containing said con fined fluid, one of said elements being an annular piston having a tubular wall defining a second side wall of said chamber.

11. In well safety apparatus, including a valve unit to be lowered into a well and located therein, and a member extending upwardly toward the surface of the earch for actuating said valve unit; the improvement comprising formation of said valve unit to include a first element connectible to said member for actuation upwardly thereby and exposed to and acting against a confined body of fluid in a manner displacing a portion of said fluid in response to said upward movement of said element, a second element exposed to said confined body of fluid and actuable downwardly by the pressure of the fluid upon said upward movement of said first element, and valve means operable by said downward movement of said second element, said valve unit including a tubular body defining a radially outer wall of a cylinder chamber containing said confined fluid, one of said elements being tubular and defining a radially inner wall of said cylinder chamber and having a piston head acting against the confined fluid at an end of the chamber.

12. In well safety apparatus, including a valve unit to be lowered into a well and located therein, and a member extending upwardly toward the surface of the earth for actuating said valve unit; the improvement comprising formation of said valve unit to include a first element connectible to said member for actuation upwardly thereby and exposed to and acting against a confined body of fluid in a manner displacing a portion of said fluid in response to said upward movement of said element, a second element exposed to said confined body of fluid and actuable downwardly by the pressure of the fluid upon said upward movement of said first element, and valve means operable by said downward movement of said second element, said valve unit including a vertically extending tubular body defining a radially outer wall of a cylinder chamber containing said confined fluid, one of said elements being a tubular part defining a radially inner wall of said chamber spaced radially from said outer wall and having a piston head acting against the confined liquid at an end of the chamber, the other of said elements being an annular piston element extending telescopically into said chamber and between said inner and outer walls thereof and slidably engaging said piston head in sealed relation.

13. In well safety apparatus, including a valve unit to be lowered into a well and located therein, and a member extending upwardlytoward the surface of the earth for actuating said valve unit; the improvement comprising formation of said valve unit to include a first element connectible to said member for actuation upwardly thereby and exposed to and acting against a confined body of fluid in a manner displacing a portion of said fluid in response to said upward movement of said element, a second element exposed to said confined body of fluid and actuable downwardly by the pressure of the fluid upon said upward movement of said first element, and valve means operable by said downward movement of said second element, said valve unit including a vertically extending tubular body defining a radially outer wall of a cylinder chamber containing said confined fluid, one of said elements being a tubular part defining a radially inner wall of said chamber spaced radially from said outer wall and having a piston head acting against the confined liquid at an end of the chamber, the other of said elements being an annular piston element extending telescopically into said chamber and between said inner and outer walls thereof and slidably engaging said piston head in sealed relation, said second element having a portion within said chamber which is thicker than an adjacent portion of said element and defines with said radially inner wall of said chamber a restriction between two compartments in the chamber controlling the rate of displacement of said elements.

14. In well safety apparatus, including a valve unit to be lowered into a well and located therein, and a mmeber extending upwardly toward the surface of the earth for actuating said valve unit; the improvement comprising formation of said valve unit to include a first element connectible to said member for actuation upwardly thereby and exposed to and acting against a confined body of fluid in a manner displacing a portion of said fluid in response to said upward movement of said element, a second element exposed to said confined body of fluid and actuable downwardly by the pressure of the fluid upon said upward movement of said first element, valve means operable by said downward movement of said second element, said valve unit including a tubular vertically extending body having a first smaller internal diameter portion and having therebeneath a larger internal diameter portion defining an outer wall of a cylinder chamber containing said confined fluid, said first element being an annular first piston having a tubular portion slidably received in and sealed with respect to said smaller internal diameter portion and forming a radially inner wall of said chamber and having a lower annular radially outwardly projecting piston head, said second element being an annular second piston projecting upwardly telescopically about said piston head and in engagement therewith and telescopically within said chamber and in engagement with the interior of said larger diameter portion of said body in a relation causing downward movement of said second piston element relative to the body in response to upward movement of said first piston element relative to the body, said second element having a downwardly projecting tubular portion movable downwardly therewith, a valve seat carried by said body and facing downwardly and past which said lower tubular portion of said second element is movable upon downward movement of the second element, said valve means including a flapper valve element mounted to said body for swinging movement downwardly and outwardly by said lower tubular portion of said second element and from a closed position of engagement with said seat to a downwardly projecting open position of reception in the body at the outside of said lower tubular portion of said second element, and spring means yieldingly urging said second element upwardly relative to said body.

15. The improvement in well safety apparatus as reicted in claim 14, in which said second element has a portion received within said chamber in contact with said confined fluid and projecting radially inwardly farther than an axially adjacent portion of said second element and into close proximity with said first element to define therewith a restricted passage narrower than two upper and lower compartments of said chamber, there being an upwardly facing annular seat surface carried by said body, and engageable annularly with the lower extremity of said lower tubular portion of said second element in the lowermost position. thereof to close off access of production fluid therepast to said valve element.

16. In well safety apparatus including a body to be lowered into a well and located therein; a main valve member carried by said body and actuable between an open position passing production fluid upwardly into the interior of the body and a closed position blocking off such fluid flow; an equalizer valve element movable vertically between two different open positions in which it passes fluid through a bleed passage formed in a side wall of said body and places the exterior of the body in communication with its interior at a location above said main valve member, and a vertically intermediate closed position; an elongated member extending upwardly toward the surface of the earth and operable by vertical movement to open both said main valve element and said equalizer valve element; and a lost motion connection between said two valve elements acting to open said equalizer valve element upon initial vertical movement of said elongated member and to then open said main valve element upon further vertical movement of the elongated member, said lost motion connection being constructed to enable movement of said equalizer valve element both upwardly and downwardly from said closed position and to both of said open positions without opening movement of said main valve element.

17. In well safety apparatus including a body to be lowered into a well and located therein, a main valve member carried by said body and actuable between an open position passing production fluid upwardly into the interior of the body and a closed position blocking off such fluid flow, an equalizer valve element movable between an open position for passing fluid through a bleed passage formed in a side wall of said body for placing the exterior of the body in communication with its interior at a location above said main valve member, and a closed position, an elongated member extending upwardly toward the surface of the earth and actuable vertically to open said main valve element and said equalizer valve element, and a lost motion connection between said two valve elements acting to open said equalizer valve element upon initial vertical movement of said elongated member and to then open said main valve element upon further vertical movement of the elongated member, said lost motion connection including a part operatively connected to said main valve element for opening the latter in response to upward movement of said part, a coacting part actuable by said elongated member and operable by both upward and downward movement relative to the body to open said bleed passage, and two springs yieldingly resisting upward and downward movement respectively of said coacting part relative to said first mentioned part.

18. The improvement in well safety apparatus as recited in claim 17, in which said first mentioned part is a hollow vertically elongated element connectiblc at its upper end to said elongated member and carrying externally said equalizer valve element for movement upwardly and downwardly therewith, said coacting part including a rod projecting upwardly into the interior of said first mentioned part and operatively connected to said main valve element and having an enlargement received vertically between said two springs.

Claims

8. In well safety apparatus including a body to be lowered into a well and located therein; a main valve member carried by said body and actuable between an open position passing production fluid upwardly into the interior of the body and a closed position blocking off such fluid flow; an equalizer valve element movable between an open position for passing fluid through a bleed passage formed in a side wall of said body and placing the exterior of the body in communication with its interior at a location above said main valve member, and a closed position; an elongated member extending upwardly toward the surface of the earth and operable by upward movement to open both said main valve element and said equalizer valve element; means for exerting upward force on said elongated member from a location near the surface of the earth; and a lost motion connection between said two valve elements acting to open said equalizer valve element upon initial upward movement of said elongated member and to then open said main valve element upon further upward movement of the elongated member.

10. In well safety apparatus, including a valve unit to be lowered into a well and located therein, and a member extending upwardly toward the surface of the earth for actuating said valve unit; the improvement comprising formation of said valve unit to include a first element connectible to said member for actuation upwardly thereby and exposed to and acting against a confined body of fluid in a manner displacing a portion of said fluid in response to said upward movement of said element, a second element exposed to said confined body of fluid and actuable downwardly by the pressure of the fluid upon said upward movement of said first element, and valve means operable by said downward movement of said second element, said valve unit including a tubular vertically extending body defining a side wall of a chamber containing said confined fluid, one of said elements being an annular piston having a tubular wall defining a second side wall of said chamber.

13. In well safety apparatus, including a valve unit to be lowered into a well and located therein, and a member extending upwardly toward the surface of the earth for actuating said valve unit; the improvement comprising formation of said valve unit to include a first element connectible to said member for actuation upwardly thereby and exposed to and acting against a confined body of fluid in a manner displacing a portion of said fluid in response to said upward movement of said element, a second element exposed to said confined body of fluid and actuable downwardly by the pressure of the fluid upon said upward movement of said first element, and valve means operable by said downward movement of said second element, said valve unit including a vertically extending tubular body defining a radially outer wall of a cylinder chamber containing said confined fluid, one of said elements being a tubular part defining a radially inner wall of said chamber spaced radially from said outer wall and having a piston head acting against the confined liquid at an end of the chamber, the other of said elements being an annular piston element extending telescopically into said chamber and between said inner and outer walls thereof and slidably engaging said piston head in sealed relation, said second element having a portion within said chamber which is thicker than an adjacent portion of said element and defines with said radially inner wall of said chamber a restriction between two compartments in the chamber controlling the rate of displacement of said elements.

18. The improvement in well safety apparatus as recited in claim 17, in which said first mentioned part is a hollow vertically elongated element connectible at its upper end to said elongated member and carrying externally said equalizer valve element for movement upwardly and downwardly therewith, said coacting part including a rod projecting upwardly into the interior of said first mentioned part and operatively connected to said main valve element and having an enlargement received vertically between said two springs.