Safety Valve Assembly

Abstract

Opening and closing of a subsurface safety valve is regulated by the pressure communicated to the valve through a tubing string which extends to the well's surface. The valve is retrievable through the tubing string and well production is through a casing string which surrounds the tubing. Control fluid in the tubing string is maintained at or above a predetermined pressure and a drop to a lower pressure due to wellhead damage or the like causes the valve to automatically close. The control fluid may be injection gas used to artifically produce the well. In the latter modification, the valve remains open so long as a predetermined injection gas pressure is maintained.

Parent Case Text

The present invention is a continuation-in-part of U. S. Pat. application Ser. No. 173,360, filed Aug. 20, 1971, entitled "AUTOMATIC CHOKE."

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to valving means for controlling the flow of fluids through fluid conductors. In an exemplary, specific description of the preferred form of the present invention, the field of the invention relates to retrievable, surface operated safety valves designed to be employed at a subsurface location within an oil or gas well where well production is through the well casing. The primary purpose of the valve is to automatically terminate the flow of high pressure petroleum fluids from the well in the event of damage to or inoperability of the restraining structure at the well head.

As used herein, the term "fluids" is intended to include both liquids and gases and the term "casing" is intended to include any fluid conduit through which a smaller fluid conduit extends axially.

2. Brief Description of the Prior Art

The majority of prior art devices which are intended to automatically terminate the flow of high pressure petroleum fluids from a well in the event of well structure damage or inoperability are subsurface valves which close in response to either a drop in the pressure of the petroleum fluids or to an increase in the rate of flow of the fluid through the well. The subsurface position of the valve protects it from surface damage and the valve functions as a safety device which prevents a well "blowout" in which petroleum fluids flow uncontrollably from the well.

Many of the prior art safety valves of the type being considered herein are "retrievable" in that they are designed to be positioned in and retrieved from the production tubing while the tubing is in place. These retrievable valves normally include a control mechanism which, depending on the type involved, senses a drop in production fluid pressure or an increase in flow rate and employs the potential energy of a compressed spring or a gas charged chamber to effect movement of valve closure elements which terminates flow through the production string. Normally, also, the production string is a string of tubing which is surrounded by a larger casing string. Conventional packing means are usually positioned between the tubing and casing strings at a subsurface location so that all well fluids are forced to flow through the central production string. Most of the prior art safety valves are designed to be employed in the typical well configuration where production is through the central tubing string.

Since the conventional, self-contained safety valves close only on the occurrence of either a low pressure or an increased flow rate, it is often impractical to test the valve when it is in its subsurface location. In the typical well, production fluid is normally being fed into a restraining pipe line or storage tank under controlled pressure and flow conditions and the only time when the well fluids drop below the closure pressure or move at a rate greater than the closure rate of the safety valve is when control of the well has been lost. In any event, even if the desired low pressure or high flow rate conditions for the production fluid could be provided at the well surface for purposes of testing the downhole valve, the equipment required to complete the test and the danger associated with the test would likely render testing of the downhole valve impractical.

In some cases, it is desired to close the subsurface safety valve and also to close the well with valves at the wellhead. Simultaneous closure of both the wellhead valve and the subsurface valve is desired for example, where off-shore platforms are being readied for a threatened hurricane which might damge or destroy the confining wellhead structure. Where self-contained pressure or flow rate responsive valves are employed, such valves cannot normally be closed with the wellhead valves closed since the pressure and flow rate values under these conditions are not adequate to cause closing of the subsurface valve. Because of the amount of time required and the expense involved, it is impractical to retrieve the self-contained valve in each well and replace it with a plug or other suitable device each time a hurricane threatens. If the subsurface valve is not closed before the hurricane strikes, there is a danger that malfunction will prevent the subsurface valve from automatically closing and that damage to the wellhead structure will result in a blowout.

Another prior art safety valve which overcomes several of the shortcomings associated with self-contained flow responsive or pressure responsive safety valves employs a small control line which extends from a subsurface valve to the well surface. The control line is filled with a pressurized fluid which keeps the valve open. Loss of pressure in the line releases the closure elements of the subsurface valve which permits the valve to close and terminate all flow through the tubing string.

In systems of the foregoing type, the control line is normally a relatively small conduit which must be accommodated between the tubing string and the surrounding well casing. The need for a third conduit in addition to the casing and tubing string is undesirable in many applications and the small control line is subject to breakage or crimping which would prevent proper operation of the safety valve. Moreover, the small control line and the tubing string must be inserted into the well simultaneously and special equipment is needed for this purpose.

In the self-contained safety valves described previsouly, pressure responsive valves cannot normally be employed where the well must be artifically produced by gas lift techniques because of the low pressure present in the production fluid column of the gas lifted well. Moreover, neither of the prior art safety valves described previously is adapted for applications where the well fluid is to flow to the wellhead through the casing rather than the tubing string.

SUMMARY OF THE INVENTION

The present invention provides a surface controlled, subsurface safety valve designed to be employed in an oil or gas well in which the petroleum fluids are carried to the wellhead through the well casting. The valve is retrievable and may be run in a conventional tubing string which extends through the casing and functions as a control string. Operation of the valve is regulated by the pressure of the control fluid contained within the tubing string which in turn may be surface regulated.

In the preferred form of the present invention, a drop in the control fluid pressure causes the valve to close. Surface control is thus effected without the need for a separate control line extending between the tubing and casing. Since the valve is surface controlled, it may be tested and it may also be closed even when the well is closed at the wellhead. The valve may be retrieved without having to remove the tubing string from the well. This feature of the present invention permits the valve to be easily recovered for replacement or repair or for changing operating pressure values.

The assembly of the present invention may also be used in a gas injection system where pressurized gas is injected int the casing through the control string. When used in an injection system, the valve is held in open position so long as the injection gas pressure remains above a predetermined value.

A landing nipple receives the valve and holds it at its subsurface location. The nipple is equipped with a blast collar which prevents abrasive well fluids from abrading and eventually cutting through the casing string wall. The valve may be positioned within or recovered from the landing nipple by pumping it through the tubing string or with the use of conventional wireline tools and techniques. Anchoring and seal means are provided along the external surface of the valving means to provide sealing engagement and releasable anchoring with the landing nipple.

The foregoing as well as other features and advantages of the present invention will be more readily appreciated from the following specification, claims and related drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical section schematically illustrating the valve of the present invention in open position;

FIG. 2 is a view similar to FIG. 1 illustrating the valve in closed position;

FIG. 3 is a vertical elevation, partially in section illustrating details in the construction of the valve assembly of the present invention;

FIG. 4 is a view similar to FIG. 3 illustrating the valve in open position;

FIG. 5 is a vertical section schematically illustrating a modified form of the present invention designed for use in gas lift assemblies; and

FIG. 6 is a view similar to FIG. 5 illustrating the valve in closed position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The safety valve assembly of the present invention is indicated generally at 10 in FIG. 1. The assembly 10 is illustrated in position within a well casing C which extends between a subsurface location (not illustrated) and a surface wellhead (not illustrated). A conventional tubing string T extends axially within the casing C and conventional packing means P forms a fluid-tight seal between the tubing and casing. A retrievable valve indicated generally at 11 is illustrated in position within a landing nipple 12 which forms a portion of the tubing string T. The assembly 10 includes valving means indicated generally at 13 which cooperate with radial ports 14 formed through the landing nipple 12 to povide a closable flow passage between the valve's upstream side U in the tubing T and its downstream side D in the casing C. Fluid flow through the open valve is in the upstream to the downstream direction as depicted by the arrows A.

The valving means 13 includes a stationary seat 15 and an axially movable stem 16. A coil spring 17 urges the valve stem 16 toward closed, seating engagement with the seat 15 against the opening force exerted by the pressure of the petroleum fluid acting at the valve's upstream side U.

Upper and lower packing means 18 and 19, respectively, provide a fluid-tight seal between the retrievable valve 11 and the surrounding landing nipple 12. Releasable anchoring dogs 20 are provided at the upper end of the valve 11 to provide anchoring engagement with the landing nipple 12. The upper end of the valve 11 is equipped with a fishing neck 21 by which the valve is moved into position within and subsequently retrieved from the landing nipple 12.

Well fluids flowing in the direction of the arrow A travel from a subsurface point downstream of the packer P through the lower portion of the control conduit 12 and up into the flow passages of the valving means 11. As the fluid exits the radial openings 14, it strikes a blast collar 22 which deflects the flow to protect the surrounding casing wall from the abrasive action caused by fluid carried particles. Once the fluids are on the downstream side U within the annular area between the control tubing 12 and the surrounding casing C, they are directed upwardly to the wellhead where they are carried away by a pipeline or deposited in suitable storage containers.

In FIG. 2 of the drawings, the valve closure element 16 is illustrated seated against the valve seat 15. In the latter position, fluid flow through the valving assembly is completely terminated. As will be further described hereinafter, movement of the closure member 16 is regulated as a function of the pressure of a control fluid contained at T-1 within the control conduit T, above the valve 11. In the preferred form of the invention, when the pressure of the control fluid at T-1 drops below a predetermined value, the closure member 16 is automatically moved by the spring 17 into the seated position illustrated in FIG. 2.

Referring now to the detailed illustration of the valving assembly 10 shown in FIGS. 3 and 4 of the drawings, FIG. 3 illustrates the valving means 11 in closed position. The landing nipple 12 is threadedly engaged at its upper and lower ends to tubular conduits which form a portion of the control tubing string T. Above and below the landing nipple 12, the tubing string T is formed of conventional, tubular pipe with the upper pipe section extending to the wellhead and the lower section extending below the packer P. Well fluids are admitted into the internal portions of the well conduit T below the packing P by any conventional means (not illustrated).

The landing nipple 12 is restricted at its lower end 23 to provide a lower limit of travel for the valve 11. The valve 11 includes a centrally ported shoe 24 threadedly engaged to the lower end of a tubular housing section 25. The shoe 24 is externally tapered to assist in guiding the valve downwardly through the tubing string T during initial positioning of the valve. The lower packing 19 which is secured between an outwardly extending housing section shoulder and the upper end of the shoe 24 provides a slidable, fluid tight seal between the lower valve end and the nipple 12. Flow passages through the open valve are formed by radial ports 26 opening through the housing section 25 and by a central opening 27 extending axially through the lower portion of the housing. The valve seat 15 is formed adjacent the upper end of the opening 27.

A control housing section 28 is threadedly engaged to the upper end of the valve housing 25. An externally tapered collar 29 threadedly engaged about the upper end of housing 28 cooperates with an outwardly developed shoulder on the housing to secure the upper packing 18 in position. The packing 18 is formed by chevron type packing overlying a thin metallic support ring 18a which in turn overlies a resilient O-ring seal 18b. The packing seal 18 and components 18a and 18b cooperate to provide a fluid-tight seal between the outer surface of the control housing 28 and the inner surface of the landing nipple 12. The control housing 28 includes an upper bellows housing section formed in part by a bellows support member 30 threadedly engaged to the upper end of the housing 28. A tubular bellows valve housing 31 is threadedly engaged to the upper end of the member 20. A tubular bellows dome housing 32 is threadedly engaged to the upper end of housing 31 and a dome cap member 33 is threadedly engaged into the upper end of the housing 32. The member 33 is centrally ported for removably carrying a conventional gas valve 34 and the upper end of the ported opening is sealed by a threadedly engaged plug 35.

The upper end of the member 33 is threadedly engaged to a spreader member 36 which provides a connecting structure between the main body of the valve 11 and the tubular fishing neck 21 and cooperates with the dogs 20 to anchor the valve 11 in place. The upper end of fishing neck 21 includes an outwardly extending shoulder 21a by which the entire assembly may be grasped by a suitable placement or retrieval tool. A dog retaining collar 37 is slidably carried over the fishing neck 21 and is employed to support a plurality of the anchoring dogs 20. The upper end of the collar 37 is equipped with an outwardly developed shoulder 37a and the lower end is provided with a skirt 37b. An inwardly developed shoulder 37c in the skirt 37b is adapted to engage an outwardly directed shoulder 20a formed at the upper end of each of the dogs 20 to prevent axial separation of the collar and dogs while simultaneously permitting limited pivotal motion of the dogs. The upper end of the spreader member 36 is externally tapered at 36a to provide a wedging surface which cooperates with internally tapered surfaces at the lower end of each of the dogs to pivot the lower dog ends outwardly when the dogs are moved downwardly over the tapered spreader surface. The lower dog ends include anchoring projections 20b which are adapted to pivot outwardly into a nipple recess 38 when the retaining collar 37 is moved axially downwardly over the fishing neck 21. As will be more fully described, the illustrated construction permits the valving assembly 11 to be locked into the landing nipple 12 where it is firmly maintained until being released by a suitable retrieving means.

Opening and closing of the valve 11 is regulated by the pressure existing in the tubing or control conduit T above the point of the packing seal 18 at T-1. The pressure at T-1 is communicated through a plurality of ports 39 extending through the connecting member 36, into an annular area 40 between the valve 11 and the surrounding nipple 12, and into the bellows housing 28 through openings 41. Internally of the housing 28, a tubular bellows section 42 of conventional construction extends axially between the lower end of the bellows support 30 and an externally developed shoulder on an actuator 43. The bellows 42 cooperates with other seals illustrated in the drawings to maintain a fluid tight seal between an external bellows area 44 and an internal bellows area 45 while permitting axial movement of the actuator 43. The upper end of actuator 43 engages an axially movable bellows valve 46 which is adapted to move between upper and lower sealing surfaces 47 and 48, respectively. As will be seen, axial movement of the bellows valve 46 functions to isolate the lower internal bellows area 45 from an upper internal bellows area 49. Upper and lower O-ring seal 50 and 51, respectively, are carried by the bellows valve to provide sealing engagement with the upper and lower seats 47 and 48, respectively.

The primary valve member 16 adapted to regulate the flow of petroleum fluids through the assembly is a substantially tubular piston adapted to be moved axially within the central bore of the valve housing 25. Annular packing 52 extends about the upper end of a main body section 53 of the member or piston 16 to provide a continuous sliding seal between the piston and the walls of the surrounding housing bore. The seal 52 is held in position by a threadedly engaged upper end piece 54. The lower end of the piston 16 includes a centrally apertured body piece 55 secured to an internal shoulder of the main body section 53 by threaded engagement with a retaining collar 56.

An alignment stem 57 extends axially through the center of the collar 56 and end piece 55 and is threaded at its upper end to a tubular spring guide 58. A restricted pressure communicating input passage 59 is formed between the stem 57 and the end piece 55 and collar 56. Pressure existing within the tubing string at the valves upstream end U is communicated through the passage 59 into a control pressure area 60 acting behind the piston 16. A pressure relief passage extends between the pressure area 60 and the downstream side D of the valve 11. The relief passage is provided by a flow passage 61 formed through the control housing 28, an axially extending flow passage 62 formed between the member 28 and the outer surface of the actuator 43, radial passage means 63 extending through the member 28 and radial openings 64 formed in the nipple 12. Axial movement of the actuator 43 causes annular O-ring seals 65 and 66 to open and close the radial passages 63 to provide valving of the relief passage. Because of the restricted size of the passage 59, a pressure drop occurs between the upstream side U and the pressure control area 60 when the pressure relief passage is open. When the actuator is in its upper position as illustrated in FIG. 4, the passage 63 is opened to permit communication with the passage 61 through the axial passage 62. A lower O-ring seal 67 cooperates with the seal 66 to provide upper and lower seals for the passage 62. Pressure openings 28a shown in dotted line prevent the development of a pressure lock which would hamper movement of the actuator 43.

OPERATION

In an exemplary application of the present invention, a conventional tubing string T equipped with the landing nipple 12 is lowered into the well casing C in a well known manner. The nipple 12 is lowered to the desired subsurface location which, for offshore wells, is normally at a point below the water bottom. A conventional packer P is set below the nipple 12 to provide a fluid-tight seal between the casing and tubing. The valve ing means 11 is thereafter inserted into the tubing string T at the well surface and lowered through the string by any suitable means. During the lowering procedure, the dog retaining collar 37 is held at its upper axial position over the fishing neck 21 so that the enlarged portions 20b of the dogs 20 are free to pivot inwardly to their radially innermost position along the fishing neck 21. When the valve 11 is properly located in the nipple 12, the shoe 24 engages the restriction 23 to prevent further downward movement. The dog retaining collar 37 is then lowered about the fishing neck 21 which moves the lower ends of the dogs 20 downwardly over the tapered surface of the spreader member 36. This spreading movement pivots the enlarged ends 20b radially outwardly into the nipple recess 38. Any upward movement of the valve caused by pressure induced forces or otherwise tends to spread the dogs outwardly which maintains the locking engagement between the recess and the dogs. The setting mechanism may be retrieved from the well once the valve 11 has been properly positioned.

The lower internal bellows area 45 is filled with an incompressible fluid such as a light weight oil or other suitable fluid. The oil is filled to a level which extends into the upper chamber 49. The oil displaces any compressible fluid such as air contained within the internal bellows chamber 45. The upper chamber 49, above the oil level, is charged through the valve 34 with a suitable gas. Suitable seals are provided through the valve construction to prevent leakage of the oil and gas contained within the internal bellows area 45 and the upper bellows chamber 49. As will be seen, the gas pressure in the chamber 49 is one of three pressure values which determines the opening and closing operation of the valve.

Once the valve 11 has been latched into position within the nipple 12, a control pressure is supplied to the tubing string T from the wellhead. The fluid providing the control pressure may be either a gas or a liquid. The control fluid in the string T enters the openings 41 and acts against the bellows 42 in the external bellows area 44. When the control fluid pressure exceeds the pressure of the gas in the bellows chamber 49, the bellows 42 is foreshortened causing the actuator 43 to move axially upwardly from the position illustrated in FIG. 3. When the actuator is in its upper postion illustrated in FIG. 4, the control pressure area 60 is in pressure communication with the fluid at the downstream end D of the valve. The pressure of the petroleum fluids acting against the lower end of the closed valve stem piston 16 at the upstream side U moves the piston upwardly against the biasing force of the spring 17 to open the valve flow passages. So long as the relief passage extending between the control pressure area 60 and the downstream pressure at D remains open, the pressure in the area 60 is lower than that acting against the bottom of the piston at the valve's upstream side U and the resulting pressure differential maintains the valve piston 16 in its upper, open position.

In the event the control fluid pressure decreases below a predetermined value as would occur for example if the wellhead were ruptured or damaged, the external bellows pressure at 44 is reduced permitting the gas charge in the upper bellows chamber 49 to expand the bellows and move the attached actuator 43 axially downwardly. The downward movement seals the radial passage 63 as illustrated in FIG. 3 to terminate communication between the pressure control area 60 and the downstream side of the valve. With the relief passage closed, the upstream pressure acting through the restricted passage 59 brings the pressure in the control area 60 up to that existing at the upstream side of the piston 16. When both pressures are substantially equal, pressure induced forces tending to move the piston are reduced to the point necessary to permit the spring 17 to force the valve stem downwardly into its closed position.

Overcompression or overexpansion of the bellows 42 is prevented by action of the bellows valve 46. When the valve is in its lower position illustrated in FIG. 3, the pressure existing within the upper bellows chamber 49 is isolated from the internal bellows area 45 to prevent further expansion of the bellows. When the valve member 46 is in its upper position as illustrated in FIG. 4, the incompressible fluid in the lower bellows area 45 is prevented from escaping the area so that the pressure existing in the outer bellows area 44 is prevented from overcompressing the bellows. By this means, the bellows element 42 is protected from damage caused by overexpansion or overcompression.

Retrieval of the valve from its set position within the nipple 12 is effected by lowering a suitable retrieving mechanism down to the nipple and latching onto the shoulder 37a provided on the dog support member 37. The member 37 is pulled upwardly while the fishing neck 21a is held stationary. This permits the dogs 20 to pivot inwardly and disengage the surrounding nipple wall. The valve may then be retrieved to the surface for inspection, replacement or repair.

In testing the valve, it will be appreciated that presusre within the tubing string T need only be lowered and the production flow from the well monitored. If the production flow terminates, the valve is functioning properly and may be reopened by simply repressuring the control fluid.

A modified form of the invention is illustrated in FIGS. 5 and 6 where the valving assembly has been equipped for use in a gas injection system. The modification in FIGS. 5 and 6 in similar to the invention as already described with the exception that gas lift valves V are provided along the tubing string T to permit gas lifting of the well. In operation, the valve 11 remains open to permit petroleum fluids to flow through the valve so long as the gas injection pressure within the tubing string T' is maintained above a predetermined value.

It will be appreciated that if desired, the safety valve assembly of the present invention may be modified so that the valve automatically closes when the control fluid pressure increases above a predetermined value. Thus, for example, the control pressure fluid may be a suitable gas maintained at subatmospheric pressure. Upon an increase in pressure produced by a rupture or damage to the control conduit, the pressure relief passage would be automatically closed to permit closure of the valve. The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the invention.

Claims

I claim:

1. A safety valve assembly comprising:

a. fluid conductor means for conducting fluids between first and second spaced points;

b. control conduit means extending axially within said conductor means between said first and second points for containing a control fluid;

c. flow passage means opening into said conductor means adjacent said first point for conducting fluids into said conductor means;

d. valving means including:

i. a downstream and an upstream side, said valving means connected with said control conduit means and movable between open and closed positions for respectively opening or closing said flow passage means as a function of the pressure of said control fluid, said valving means being movable through said control conduit means between said first and second points and including remotely actuated anchoring means for anchoring said valving assembly in operative position within said control conduit means;

ii. sealing means for forming a fluid-tight seal between said conduit means and said valving means;

iii. remotely operable release means for releasing said valving means from anchored engagement with said conduit means whereby said valving means may be released and moved through said conduit means from said first to said second point;

e. pressure responsive control means included in said valving means and communicating with said control fluid for maintaining said flow passage means open while the pressure of said control fluid is within a predetermined range of values and for closing said flow passage when the control fluid pressure is outside of said range, said control means including:

i. biasing means tending to move said valving means into closed position against pressure induced forces exerted against the upstream side of said valving means;

ii. a control pressure area for exerting pressure induced forces tending to move said valving means in a direction opposite to the valving means movement caused by said pressure induced forces exerted on the upstream side of said valving means;

iii. pressure relief passage means extending between said control pressure area and the downstream side of the said valving means;

iv. actuator means for opening and closing said pressure relief passage means as a function of said control fluid pressure; and

v. pressure input passage means extending between said control pressure area and the upstream side of said valving means for forming a pressure differential across said valving means tending to maintain said valving means open when said relief passage means is open and for terminating said pressure differential when said relief passage means is closed whereby said biasing means may move said valving means to closed position.

2. A safety valve assembly as defined in claim 1 wherein:

a. said control means includes a bellows area confined within said valving means and separated from said control fluid by movable bellows means; and

b. said actuator means is connected for movement with said bellows means for opening said pressure relief passage means when the pressure of said control fluid is above a predetermined value and for closing said relief passage means when said control fluid pressure drops below said value.

3. A safety valve assembly as defined in claim 2 wherein:

a. said bellows area includes first and second chambers separated from each other by bellows valve means;

b. said bellows valve means is operable between open and closed positions by movement of said bellows means;

c. an incompressible fluid is contained within said first chamber and at least a portion of said second chamber; and

d. said bellows valve means is closed by movement of said bellows means beyond a predetermined amount in a given direction to confine said incompressible fluid within said first chamber to prevent further bellows means movement in the same direction.

4. A safety valve assembly as defined in claim 3 wherein:

a. said fluid conductor means includes a tubular well conduit for conducting oil or gas from a well;

b. said second point is adjacent the wellhead and said first point is adjacent a subsurface location in said well;

c. said control conduit means includes a tubular well conduit extending axially within said conductor means between said subsurface location and said wellhead; and

d. said valving means includes pressure responsive control means communicating with said control fluid for maintaining said flow passage means open while the pressure of said control fluid is above a predetermined value and for closing said flow passage when the control fluid pressure drops below said valve.

5. A safety valve assembly as defined in claim 4 further including:

a. packing means extending between said control conduit means and said well conduit for forming a fluid-tight seal therebetween;

b. fluid inlet means opening into said control conduit on the upstream side of said packing means;

c. fluid outlet means included in said flow passage means and opening out of said control conduit on the downstream side of said packing means whereby fluid at the downstream side of said packing means entering said inlet means is confined to move through said control circuit means and out of said outlet means into said fluid conductor means; and

d. said valving means includes cooperating valve closure means for terminating flow between said inlet and outlet means.

6. A safety valve assembly as defined in claim 5 wherein:

a. said biasing means includes a coil spring;

b. said valve closure means includes piston means movable axially within a tubular valve housing;

c. said outlet means includes radial openings through said valve housing and said control conduit means; and

d. said sealing means includes axially spaced packing carried externally of said tubular housing and disposed above and below said radial openings for providing a fluid-tight seal between said housing and said control conduit means.

7. A safety valve assembly as defined in claim 6 further including shielding means disposed between said outlet means and said fluid conductor means for preventing fluid flowing from said outlet means from striking said fluid conductor means whereby abrasion or wear of said fluid conductor means is prevented.

8. A safety valve assembly as defined in claim 7, wherein said control conduit means includes gas lift valve means between said spaced points for injecting control fluids from said control conduit means into said fluid conduit means.

9. A safety valve assembly as defined in claim 1 wherein said control conduit means includes gas lift valve means between said spaced points for injecting control fluids from said control conduit means into said fluid conduit means.