US2245006A - System and apparatus for flowing wells - Google Patents

Description

June 10, 1941. J. D. NIXON SYSTEM AND APPARATUS FOR FLowING wELLs Filed Nov. 9, 1940 A 3 Sheets-Sham*I 1 June l0, 1941. 1 D NlxQ'N 2,245,006

SYSTEM AND APPARATUS FOR FLOWIVNG WELLS ./EDIDYZl/WXON June l0, 1941. 1 D NlxoN SYSTEM AND APPARATUS FOR FLowING WELLS Filed NOV. 9, 1940 3 Sheets-Sheet 3 Parmed June 1o, 1941 SYSTEM AND APPARATUS FOR FLOWING WELLS .Teddy D. Nixon, Houston, Tex., assignor of onehalf to Wilson Supply Company, Houston, Tex., a corporation of Texas Application November 9, 1940, Serial No. 365,024

(Cl. 10S-232) 32 Claims.

This invention relates to new and useful improvements in systems and apparatus for flowing Wells.

One object of the invention is to provide an improved system and apparatus including an automatic or pressure differential operated valve, which while operated by a pressure differential is so controlled as to make for economical, as well as efficient and profitable, use of the lifting fluid, which usually is gas.

It is pointed out that the larger portion of all Wells fluctuate and vary in the quantity of fluid produced, the constituency or composition of the produced fluid and the rate at which the wells produce their fluids. Also, the components or composition of the well fluid, as well as the amount of fluid allowed to be produced, are factors in determining the various producing conditions encountered. In producing fluid from a Well with a pressure or a lifting fluid, the lifting lluid is stored or maintained in an annular space, usually the well casing, and the amount of pressure of the lifting fluid maintained. generally determines the quantity of .well fluid that may be lifted. The length of the flow line from the usual casing head -to the storage tanks or other suitable disposal determines the back pressure that is placed on the fluid traveling through said flow' line and in said well tubing. The longer the flow line is, the greater the back pressure that is set up and this back pressure affects to some extent the lifting of the well' fluid.

It is possible with applicants invention to vary the pressure of thelifting fluid maintained in said well casing to control the amount of the uid lifted, the intervals at which it is lifted and the velocity of the lifted fluid. However, any change inthe Weight of the well fluid due to variance in the composition of said fluid does not affect the operation of the inlet valve nor the surface control mechanism. Although, Ithe different constituents of the well fluid encountered in various installationsl will affect the setting of the surface control mechanism.

It is also possible to change the pressure differential of applicants fluid inlet valve'to obtain the desired opening pressure in order to increase or decrease the velocity of the lifted body or slug of well fluid flowing up the tubing and through the flow line. Furthermore, by changing the opening or operating pressure of the surface control apparatus, diiferent weights and lengths of slugs may be satisfactorily handled, as well as the different back pressures that are set up by the various lengths of flow lines and other operating conditions.

A particular object of the invention is to provide an improved well flowing system and apparatus whereby more uniform flow or periodic discharges of maximum amounts of well fluid are obtained with substantially equal amounts of lifting fluid, thus preventing waste of lifting fluid.

A further object of the invention is to provide for an accumulated column of well fluid, suflicient to assure a pay load of well fluid at each admission of lifting fluid, by maintaining such admission closed until a column of well fluid of the desired amount is built up.

Another object of the invention 'is' to provide an apparatus of the character described wherein the lifting fluid inlet valve is positively opened and closed by spring action, thus preventing sticking of the valve.

Still another object of the invention is to provide a system and apparatus wherein the lifting fluid admitting valve is set to open on a predetermined pressure differential and to be. positively closed when a desired quantity or a predetermined pressure of well fluid reaches the top of the well.

A further object of the invention is to provide an improved lifting fluid inlet valve which may be used as a kickoff valve, a flow valve, or a bottom hole valve.

An important object of the invention is to provide a surface operating device having valve fastening and releasing means also arranged to close the valve, and including an operator on the surface adapted to be actuated by the well fluid that is elevated by the lifting fluid.

Still another object of the invention is to provide a system and apparatus wherein the flow of .the Well fluid is utilized to operate surface equipment which has such connection with one or more lifting fluid admitting valves in the tubing,`as to positively closesuch valves after a suflicient quantity of lifting fluid has been admitted, by -each valve, to carry out the desired lifting or elevating operation.

Still another object of the invention is to provide an improved uid inlet valve that may be so arranged that adjustments may be made to obtain various opening pressures in order to increase or decrease the velocity of the lifted well fluid, whereby the o'pening pressure may be predetermined and setto handle the well fluid in accordance with the well conditions of the particular installation.

It is an important object of the invention toprovide an improved well flowing system and apparatus whereby the'pressure of the lifting fluid may be varied 4to regulate the amount of well uid lifted, the velocity'of the lifted Well fluid, the in- -tervals at which the well fluid is lifted, and to produce the well fluid from a low standing uid level.

A further object of the invention is to provide a system and apparatus so arranged that when the well is flowing or producing the well fluid naturally, that is, without the admission of lifting iiuid,the lifting fluid admitting valve or valves are maintained closed and the waste of lifting fluid is prevented.

A particular object of the invention is to pro` vide a system which may be used as satisfactorily on an Vopen well, without the use of the usual packer as shown in the drawings, or on a closed well, where a packer is used in the well.

A construction designed to carry out the invention will be hereinafter described, together wi-th other features of the invention.

'Ihe invention will be more readily understood from a reading of the following speciiication and by reference` to the accompanying drawings, in which an example of the invention is shown, and wherein:

Figure 1 is a view, partly in elevation and partly in section, showing the vupper portion of a well with a well fluid lifting apparatus, constructed in accordance with the invention, connected thereon;

Figure 2 is a continuation of Figure 1, partly in section and partly in elevation, showing the lower portions of the well casing and the tubing string with a pressure fluid inlet valve, constructed in accordance with the invention, mounted in said tubing and' the operating device therefor; said valve being closed and fastened against automatic actuation;

Figure 3 is a view, partly in section and partly in elevation, showing the upper portion of a well with another form of surface operating means;

Figure 4 is a continuation of Figure 3, similar to Figure 2, and showing the valve released and in position for automatic operation;

Figure 5 isv an enlarged, vertical, sectional view f the automatic valve released and opened for Y the admission of lifting uid;

Figure 6 is a horizontal, -cross-sectional view taken 'on the line 6-6/of Figure 5;

Figure 7 is a transverse, vertical, sectional view of the pressure iluid control valve for the me'chanism shown in Figure 3;

Figure 8 is a partial horizontal, cross-sectional view taken on the line V88 of Figure 5;

Figure 9 is a similar view taken on the line 9 9 of Figure and j Figure 10 is a horizontal, cross-sectional view taken on the line III-I0 of Figure 5.

Inthe drawings, the numeral I0 designates the usual well casing which may be placed in-the well bore in any suitable manner and in accordance.

with the conditions present at the particular well which it is desired to automatically ow. A suitable casing head II is 'mounted on the upper end of the casing I0 in accordance with the practice now in common use,` and this head is provided with a pressure uid inlet pipe I2 in which a cutoif valve I3 is connected. A single string of well tubing I4 is suspended or hung in the casing head I I in any suitable manner and'extends above said casing so that a T I5 may beI connected therein. A well uid discharge pipe I6 leads from the T and has a cut-off valve I'I connected therein.

In Figures 2 and 4, I have shown the tubing -string I4 extending below the casing into the shot hole A and having a perforated bull plug or strainer I8 screwed onto its lower end, but it is to be understood that the tubing may be terminated at any desired point and its relation to the lower end of the casing may be varied to suit the diierent well conditions encountered. It is customary to perforate casing to admit the well uid from the formation and also to use liners and elongated screens. Any of these devices may be employed in connection with the invention.

.One or more valve nipples orbodies I9, each constituting a mounting for an automatic valve,

may be connected in the tubing at any desired elevation. It is customary to connect these valves in said tubing I4 at different elevations, using the uppermost valve as a kick-olf value; however,

The nipple I9 is' provided at each .end with reduced, externally screw-threaded pins 20. These pins .are screwed into reducing, connecting collars 2I which in turn are screwed onto the ends of the adjacent tubingsections I4. The nipple I9 has an axial bore 22, which is smaller in diameter than the boreof the tubing, andthese pins 2D are beveled at 23 at each end of the bore 22, so as to guide tools and other appliances into said bore. In order to provide ample iiow space, ducts 24 are provided longitudinally of the nipple on each side'of thebore 22 thereof, as is best shown in Figure 6.

one side of the nippie is is cut out to form a vertical recess 25, and an upright valve casing or housing 26`is mounted in this recess so as to engage snugly between the shoulders 2l formed at the lower and upper ends of said recess. This valve casing may be secured in the recess in any f itis desired to remove said casing 26. This casing has an inlet chamber 28 at its lower end provided with radial perforations 29, whereby the lifting fluid from the well casing may freely enter said chamber. vThe top of the chamber is formedby a transverse partition 30 above which overhangs an ear 32, formed integralV with the valve casing 26.

The casing 26, as shownin Figures 6, 8 and 9, may be given a nearly semi-circular shape. The lower end of said casing is closed and provided with a screw-threaded and counterbored opening 3| for receiving a plug 33; The partition 30 is provided with a valve seat 34 suitably beveled to receive .a valve head 35 mounted on the lower end of a valve stem 36, that through the seat 34, and also through the ear 32 which forms a guide therefor. The upper end of saidvalve stem is reduced to form' a pilot pin 31 which telescopes into a socket 38 in a cap nut 39 screwed into the upper end of the valve casing.

At the lower end of the pilot pin, the valve stem is formed with a shoulder 40 for receiving a collar 4I which supports the lower -en d of a coiled spring 42, the upper end` of which engages the under side of the nut 39. This spring is a relatively light one and is under a moderate compression. Just below the shoulder 40, the valve stem is provided with screw threads 43 for receiving a stop nut or collar 44. This collar is provided with a set screw 46 (Figure 10) which engages in a key groove 4'I in the valve stem, whereby said extends upwardlyA collar is held against rotation. A sleeve 45, slidably mounted on the valve stem, has its upper end bearing against; the collar. A coiled spring 48 is confined between the' lower end o-f the sleeve 45 and the upperside of said ear 32. This spring is considerably heavier than the spring 42 and is under greater compression, so as to force the sleeve upwardly into engagement with the stop collar, and to hold the valve head 35 on its seat 34.

The sleeve'45 is provided with diametrically opposite slots 49 which receive the yoke 50 of a bell crank lever I, as is best shown in Figures 2, 4, 5 and 8. The lower end of the lever 5I is pivoted between ears 52 provided on the back; wall of the recess on each side of a vertical slot 53 communicating with the bore 22 of the nipple I9.

The upper end of the lever has a small roller 54 journaled therein. When the lbore 22 of the nipple is unobstructed as in Figure 2, the lever 5I is free to swing through the slot into said bore, and this will be its position when the valve is closed; the spring 48 being under sufficient compression to raise the sleeve 45 and swing the lever 5I.

As hereinbefore pointed out, one of the objections to the ordinary automatic valve, which is employed for admitting lifting fluid to the well tubing, is that there is no positive way of controlling the opening and closing of said valve, and particularly the latter. It will be obvious that when the valve is closed, as shown in Figure 2, and the sleeve 45 is elevated so as to engage the collar 44, the spring 48 will not be under as great compression as it will be when the lever 5I is swung outward and the sleeve moved downwardly from said collar, as sho-wn inFigure 4.

When the lever is in the position shown in Figure 2, the valve is fastened or held against operation; whereas,'when the lever is swung outwardly and the sleeve moved downwardly, as in Figure 4, the valve is released for automatic or pressure differential operation.

In order to fasten and release the valve, a suitable operating device must be `provided for the lever 5I I have illustrated a cylindrical, operating bar 55 which has a snug sliding t in the bore 22 of the nipple I9. The ends of this bar are beveled so that it will freely enter the nipple, and also ride upon the roller 54. The bar is suspended by a wire line or'other flexible connection 5B, and has hanging from its lower end a rod 51 which supports a weight bar 58 which latter coacts'with the bar 55 in holding the wire line taut, as well as assuring a proper lowering of the bar 55. Any suitable means may be employed to raise and lower the operating bar 55. When said bar 55 is raised to the position shown in Figure 2, the lever 5I will be freed and permitted to swing through the slot 41 into the'bore 22. In this position `the valve will be fastened against operation.

When the operating bar 55 is lowered, the lower end engages the roller 54 and as the lowering is continued the lever 5I is swung outwardly, whereby its yoke 50is swung downwardly. The downward swing of the yoke 50 slides the sleeve 45 downwardly on the valve stem 36, whereby said sleeve is moved away from the stop collar 44 and further compresses the spring 48, bringing the parts to the position shown in Figure 4. In this position the valve is unlocked, released, or set and ready to be operated. When a pressure differential is built up, by the hydrostatic head of oil or well fluid standing in the tubing I4, which combined with thev expansive force of the upper Figure l.

spring 42 is sufficient to overcome the force of 75 the lifting fluid exerted against the valve head 35, said head will be quickly opened. When this occurs, the valve head 35 and valve stem 36 will be moved downwardly until the collar 44 engages the sleeve 45, as is shown in Figure 5.

In the preferred form of operation, the casing I0, above the fluid level standing therein, is filled with a lifting fluid which is constantly maintained under a head pressure sufficient, when admitted to the tubing, to elevate the body of oil which is picked up thereby, to the top of the tubing. It is pointed out that by this arrangement the chamber 28 is at all times maintained full of lifting fluidA under the aforesaid pressure; and thus, when the valve head 35 is opened, the lifting uid will be immediately admitted in such volume, and under such pressure, as to pick up the oil standing above the valve and carry it to the top of the tubing at a sufficient velocity to prevent slippage, or the lifting fluid channeling through the oil. In order to permit the lifting fluid to freely enter the ducts 24 of the nipple I9, a manifold 59 is provided in the bore 22 so as to communicate with the sl'ot 41.

For raising and lowering the wire line 56, I provide an operator 60 on the upper end of the tubing I4 above the T I5, as is clearly shown in This operator includes a cylinder 6I in which is mounted an annular piston 62 carrying a polish tube 63 which has a snug sliding fit in the collar 64 mounted on the upper end ofthe cylinder. A stuiling box 65 oi' suitable construction is mounted on the upper end of the tube 63 by a coupling collar 66. The wireline is suspended from a clamping block 61 which is seated in a thimble 68 screwed onto the upper end of the stuffing box. It will be seen that as the piston is moved up and down in the cylinder, the polish tube 63 will raise and lower the clamping block 61, whereby the wire line 56 will be raised and lowered and the bar 55 thereby operated.

The piston 62 is designed to be operated by the Well fluid which is discharged into the cylinder 60 when said well fluid is' elevated in the tubing I4.'

The upwardly flowing `well uid will, of course, escape by way of the T I5 and pipe I6, but it will also elevate the piston, thus raising the operating bar 55 (Figure 2) and freeing the lever 5I. slide the sleeve 45 upwardly, whereby the valve head 35 will be closed. By such a means the admission of lifting fluid is positively cut off and waste prevented. It is pointed out that whenever the well fluid is flowing, the piston will be raised and all inlet or flow valves will be closed, because the spring 48 is of sufficient strength to compress the spring 42, after the lever 5I has been released by the bar 55. From this, it will be obvious that the closing of the valve is controlled by the elevationpf the piston and the removal of the operating bar 55 from the path of the lever 5I, so that whenever the piston is elevated by the lifted or the flo-wing well fluid, the operating bar 55 will be withdrawn and the spring 48 will elevate'the sleeve 45, whereby the lever 5| will be swung inwardly to the position shown in Figure 2; and the valve thus positively closed and fastened against operation.

It is important to properly calibrate the springs 42 and 48. It is obvious that fluid pressure in the This permits the spring 46 to expand andv kick open the valve when the hydrostatic head of the column of well fluid, which has, accumulated in the tubing, reaches a predetermined degree. The spring d8 must exert su'cient force to resist the expansive force of the spring 42 and swing the lever 5I outwardly after the removal of the bar 55.

As the pressure in the tubing |111 and flow line I8 is reduced, the pressure in the cylinder 6l and polish tube 63 will be reduced, which permits said polish tube 63 to be lowered and carry the wire line 55 therewith. As this reduction takes place, the actuating bar 55 will again be lowered into the valve body i9, swinging the roller 54, lever 5I and sleeve t5, as shown in Figure 4, which unlocks, releases or sets said valve for automatic operation. The well may be operated from this particular valve, or the actuating bar may be dropped to a lower valve, where the above operation is again carried out. `It will be seen that a semi-automatic valve is thus hadand a control unittherefor, which only will admit lifting uid when there is a suflicient column of well fluid to be lifted and that the admission of lifting fluid is terminated as soon as the lifted charge or slug has sufficient lifting fluid therebeneath to carry it through the flow line i6 to a storagetank, or other suitable disposal (not shown).

vIt is pointed out that the spring 48 is much stronger than the spring 31, so that whenever the bar 55 releases the roller 55, said spring 58 will `lift the sleeve 85, swinging the lever 5I and the roller 5d inwardly. The upper end of said sleeve will already be in engagement with the under side of said stop collar 4d (when said valve head 35 is opened, said stopcollar will drop down on said sleeve) and the valve stem will be lifted andthe valve head 35 seated on its seat 35 to close the port 30 and shut olf the admission of additional lifting fluid from said casing I8 into said tubing it.

Attention is called to the fact that the spring 31 is set for a predetermined compression in order that a pressure differential may be had between the column of well fluid in the tubing and the lifting fluid in the casing. Therefore, the weight or pressure of the column of well fluid plus the compressi n of the spring 31 is the operating pressure to open the valve'IS, when said bar is in said valveto unlock or release the same for actuation. When the pressure of the column of well fluid plus the compression' of said spring 31 becomes greater than the pressure of the lifting fluid in the casing, the valve head 35 will be moved downwardly away from its seat 35 to open -the port 30, whereby lifting fluid will be admitted to expel said column of Well fluid. Thus, by using different springs 31 of different compressions, various differentials or lengths of columns of Well fluid may be had and'various adjustments may thus be obtained in accordancen'ith the well conditions encountered. y

A further adjustment or control of the production.` from the well maybe obtained by varying the pressure of the lifting fluid in the casing. The spring 31 when installed, is known to have va predetermined compression to set up a certain pressure differential and by increasing or decreasing the pressure of the lifting fluid, a number of results may be had. These are: first, the quantity or length of the column of well fluid may be controlled so that a greater or smaller amount of well fluid will accumulate before the valve head 35 is opened; second, the velocity or speed of flow up the tubing of the cut olf column or slug of Well fluid may be regulated; third, the intervals at which the slugs of well fluid are lifted may be spaced farther apart or closer together; and fourth, where wells produce fluid slowly or not very high in the tubing, termed low fluid level wells, this low fluid level or short column of well iluid may be handled or lifted readily and more economically by reducing the lifting fluid pressure in the casing. These four resultsI usually Will handle any producing or well condition presented, either with or without changing the compression of the spring 31. However, in some instances the adjustment of said spring compression may be required in addition to varying the lifting fluid pressure in the casing.

Another operating apparatus is shown in Figures 3 and 7. Instead of the T l5, a cross i5' is mounted on the upper .end of the tubing it, and a nipple 18 is screwed into the top of the cross, while the well luiddischarge pipe l5 is screwed into one side of said cross. A stumng box 1| is mounted in the nipple 10, and the wire line 58 extends through this -box and is suspended from a clamp 12 mounted on the bottom of a piston rod 13 which depends from a piston 15 mounted in a cylinder 16. The cylinder is suspended by a hook 11 from the bottom of a sheave 18 which has a pulley 19 therein over which the wire line 55 passes. When it is desired to manipulate the wire line independently of the operatingapparatus, the clamp 12 maybe loosened to free the line which may then be operated from the sheave 18.

A T is connectedl in the pressure fluid supply line l2 in advance of the valve I3, and a by-pass pipe 8| extends from the T to a valve body 82.- As is shown in Figure 7, the vlave bodyv has a seat 83 for receiving on its upper Side a valve head 85 which is mounted on the upper end of a stem 85. The valve structure is similar to an'ordinary spring-loaded diaphragm valve. A supply' pipe 14 leads from the valve to the bottom of the cylinder 18 for supplying pressure fluid to the cylinder to lelevate the piston 15 when the valve 84 is lifted from its Iseat. The supply `of pressure fluid is suflicient to lift the .piston 15 and thereby raise the wire line, similar tothe piston 62. When the valve head 8d is seated, the pressure fluid therebeyond is trapped and such pressure fluid may -bleed back through a T-shaped passage 86 in a plug 81 screwed into the top of the valve 82; and thusescape to the atmosphere. As the trapped pressure fluidy is bledoff, the piston 15'is lowered, thereby lowering the operating bar 55. By regulating the size -of the passage 88, the rate of descent of the piston may be controlled and the releasing of the Valve head 35 thereby timed, if desired.

The valve stem 85 extends through a stumng box 88 carried on the-bottom of the Valve -body 8 2 vwhich also carries a cage 89. This cage is mounted on a diaphragm bowl 90 into which vis screwed a nipple 8|, extending from a T S2 con nected to a pipe 93 extending from the cross I5 thus admitted to the cylinder 16; whereby the piston 'l5 will be raised and the operating bar 55 elevated to .permit the lever 5I to swing into the nipple I9, thereby raising the sleeve 45 and closing and fastening the automatic valve.

Various changes, alterations and modifications may be made in the size, shape and arrangement of the hereindescribed elements, within the scope of the appended claims.

What I claim and desire to secure by Letters Patent is:

1. The system of flowing wells which includes, a casing provided with a supply of .lifting fluid, a single'string of tubing, a lifting fluid inlet valve mounted in the tubing for admitting lifting fluid from the casing to the tubing, and means controllable from the top of the well for locking said valve, said means being adapted to unlocking said Valve, said valve having elements responsive to pressure differentials between the well fluid and the lifting fluid and operable when the valve` is unlocked.

2. The system as set forth in claim 1 with means at the surface above the well responsive to the well fluids flowing up the tubing for operating said locking and unlocking means.

3. As a new article of manufacture, an inlet valve for a well fluid lifting system which includes, a housing having a fluid inlet and a fluid outlet, a valve seat in the housing between said inlet and outlet, .a valve member engaging said seat, a valve operating element mounted in the housing and projecting therefrom, a spring-impelled element mounted in the housing and operatively associated with the valve member and connected with the operating element and movable therewith, whereby said spring-impelled element functions to fasten and release said valve, anda stop .on the valve member co-acting with said spring-impelled element.

4. As a new article of manufacture, an inle valve for a well fluid lifting system which includes, a housing having a fluid inlet and a fluid outlet, a valve seat in the housing between said inlet and outlet, a valve member engaging said seat, a valve operating -element mounted on the housing and projecting therefrom, a spring-impelled element mounted in the housing and operatively associated with the valve 'member and connected with the operating element and movable therewith, whereby said spring-impelled element functions to fasten and release said valve, a stop on the valve member co-acting with said spring-impelled element, and a nipple adapted to be connected in a tubing string provided with a mounting for the valve housing and having a bore into which the projecting portion of the operating element extends, whereby fluid 'flowing through the valve seat in said housing from said inlet enters the bore of said nipple.

5. The system of flowing wells which includes, a tubing string, an automatic pressure fluid inlet valve mounted in the tubing and normally responsive to a pressure differential between the Well fluid and the lifting fluid to admit fluid into said tubing, and means controlled and actuated from the top of the well for fastening said valve against such differential operation.

6. The system of flowing wells which includes, a tubing string, an automatic pressure fluid inlet valve mounted in the tubing and normally responsive to a pressure differential betweenthe Well fluid and the lifting fluid to admit fluid into said tubing, means controlled and actuated from the top of the well for fastening said valve against such differential operation, and means responsive to the pressure of the well fluid for operating said fastening means.

'7. The system of flowing wells which includes, a tubing string, an automatic pressure fluid inlet valve mounted in the tubing and normally responsive to a pressure differential between the well. fluid and the lifting fluid to admit fluid into said tubing, means for fastening said valve against operation and-for releasing said valve for such differential operation, and means responsive to the pressure of the well fluid elevated in the tubing for operating said fastening and releasing means.

8. The system of flowing wells which includes, a tubing string, an automatic pressure fluid inlet valve mounted in the tubing and normally responsive to a pressure differential between the well fluid and the lifting fluid to admit fluid into said tubing, means for`.fastening said valve against operationand for releasing said valve for such differential operation, a tool movable verticallyin the tubing for controlling the operation of said fastening and releasing means, and means responsive to the pressure of the well fluid elevated in the tubing for operating said tool.

9. The system of flowing walls which includes, a tubing string, an automatic pressure fluid inlet valve mounted in the tubing and normally responsive to a pressure differential between the well fluid and the lifting fluid to admit fluid into said tubing, means for fastening said valve against operation and for releasing said valve for such differential operation, a tool movable vertically in the tubing for controlling the operation of said fastening and releasing means, a flexible line for suspending said tool in the tubing, and means responsive to the pressure of the well fluid elevated in the tubing for operating said flexible connection.

10. In a well flowing apparatus, the combination of, a Well tubing string, a nipple adapted to be connected inthe tubing, a valve housing communicating `with the bore of the nipple and mounted on vthe nipple, a pressure fluid responsive valve in the housing, an operating member connected with said valve and having aportion exposed in the bore of the nipple, means for fastening the valve, and a tool movable in the bore of the nipple to displace the operating member to release the fastening means and free the valve for operation by pressure fluid and movable from said member to permit the fastening means to lock said valve against pressure fluid actuation. 11. In a well flowing apparatus, the combination of, a well tubing string, a nipple adapted to be connected in the tubing, a valve housing communicating with the bore of the nipple and mounted on the nipple, a pressure fluid responsive valve in the housing, an operating member connected with said valve and having a portion exposed in the bore of the nipple, means forfastening the valve, a tool movable in the bore of the nipple to displace the operating member to release the fastening means and free the valve for operation by pressure fluid and movable from said member to permit the fastening means to lock said valve against pressure fluid actuation.

and pressure fluid responsive means at the top of the well connected to the tool for vertically moving the same.

12. In a well flowing apparatus, the combination of. a well tubing and a casing, a lifting fluid inlet valve in the casing connected in the tubv ing for controlling the admission of fluid from the casing into the tubing, a spring co-acting with the hydrostatic pressure of the Well fluid .standing in the tubing for opening said valve, a

-ing in the tubing for opening said valve, a second and stronger spring disposed to overcome the rst spring for closing said valve, means movable independently of the valve for confining the second spring and freeing the first spring for operation, and means operable from the top ofthe well for actuating said movable means.

14. In a well flowing apparatus, the combination of, a well tubing and a casing, a lifting fluid l inlet valve in the casing connected in the tubing for controlling the admission of fluid from the casing into the tubing, a spring co-acting with the hydrostatic pressure of the well uid standing in the tubing for opening said valve, a second and stronger spring disposed to overcome the rst spring for closing said valve, means movable independently of the valve for confiningA the second spring and freeing the first spring for operation, uid pressure operating means at the top of the well responsive to the pressure of the elevated well uid, and a tool suspended in the tubing and operably connected with said operating means for actuating said movable means.

15. In a well flowing apparatus wherein a well casing is provided with a supply of lifting :duid and a well tubing string is mounted therein, the combination of, a lifting fluid invalvewhere it may be operated, said valve having elements responsive to pressure differentials between the well fluid in the tubing string and the lifting fluid in the casing and operable when said valve is unlocked, actuating means on the surface for operating said surface controlled means, and surface control means operated by a pressure fluid for operating 'said actuating means.

18. In a well flowing apparatus wherein a well casing is provided with a supplyof lifting fluid and a well tubing string is mounted therein, the combination of, a lifting fluid inlet valve mounted in the tubing for admitting well and lifting fluid from the casing tov the tubing, means controlled from the surface of the well for locking said Valve against operation or unlocking said valve where it may be operated, said valve having elements responsive to pressure differentials between the well fluid in the tubing string and the lifting fluid in the casing and operable when said valve is unlocked, actuating means on the surface of the well for. actuating said surface controlled means, a flow conduit extending to said actuating means for supplying a pressure fluid thereto to operate said actuating means, and surface control means connected to said oW conduit for controlling the flow of a pressure let valve mounted in the tubing for admitting well and liftinguid from the casing to the tubing, means controllable from the surface of the well for bringing about the closing'andthe fastening of said valve, said means also adapted to,v

release said valve, said valve having elements which are responsive tov pressure differentials between the well uid and the lifting fluid and operable when said valve is released, and surface control means operated by pressure fluid for actuating said surface controllable means.

16. In a well flowing apparatus wherein a wel] casing is provided with a supply of lifting fluid and a well tubing string is mounted therein, thev combination of, a lifting fluid inlet valve mounted in the tubing for admitting well and liftingA fluid from the casing to the tubing, means controlled from the surface of the well for locking said valve against operation or unlocking said valve where it may be operated, said valve having eleme'nts responsive to pressure differentials between the well fluid in the tubing string and the lifting fluid in the easing and operable when said valve is unlocked, and surface control means operated by a pressure fluid for actuating said 'surface controlled means. v

17. In a well owing apparatus wherein a well casing is provided with a supply of lifting fluid and a well tubing string is mounted therein, the combination of, a lifting fluid inlet valve mounted in the tubing for admitting well and lifting uid from the casing to the tubing, means controlled from the surface of the well for locking said valve against operation .or unlocking said fluid through said conduit to control the operation of said actuating means.

19. The system of flowing wells which includes, a well casing for providing asupply of lifting fluid, a Well tubing in the casing for accumulating a quantity of well fluid and serving as a conductor for the well uid, one or more lifting fluid inlet valves connected to the tubing, means for normally fastening the valve or valves against and releasing said valve or valves for operation by a pressure differential between the well fluid and the lifting fluid, means for utilizing the pressure of the elevated Well fluid to controlthe operation of the fastening and releasing means, means for providing a predetermined.

amount of mechanical -energy which when combined with a hydrostatic pressure of a predetermined quantity-.of well fluid c-auses opening of said valve or valves, said fastening means including resilient means for closing said valve or valves, said valves being constructed so that the opening thereof may be controlled by the varying of the pressure of the lifting fluid in the casing.

20. The 'system of flowing wells which includes, a well casing for providing a supply of lifting. fluid, a well tubing in the casing for accumulating a quantity of well fluid and serving as a conductor for `the well fluid, one or more lifting fluid inlet valves connected to the tubing, means for normally fastening the valve or valves against and releasing said valve or valves for operation by a pressure differential between the Well fluid and the lifting fluid, means for providing a predetermined amount of mechanical energy which when combined with a hydrostatic pressure of a predetermined quantity of Well uid causes opening of said valve or valves, said fastening means including resilient means for closing said valve or valves', s aid valves lbeing constructed so that the opening thereof may be' coning the pressure of the elevated well fluid to control the operation of the surface controlling means.

21. The system of flowing wells which includes, a well casing for providing a supply of lifting fluid, a well tubing in the casing for accumulating a quantity of well fluid and serving as a conductor for the well fluid, one or more lifting fluid inlet valves connected to the tubing, means for normally fastening the valve or valves against and releasing said valve or valves for operation by a pressure differential between the well fluid and the lifting fluid, means for providing a predetermined amount of mechanical energy which when combined with a hydrostatic pressure of a predetermined quantity of well fluid causes opening of said valve or valves, said fastening means including resilient means for closing said valve or valves, said valves being constructed so that the .opening thereof may be controlled by the varying of the pressure of the lifting fluid in' the casing, means on the surface of the well for controlling the operation of the fastening and releasing means, and means for utilizing the pressure of the elevated well fluid to control the operation of the surface controlling means, said operating means being adjustable to regulate the operation of said surface' control means.

22. The system of flowing wells which includes, a well casing for providing a supply of lifting fluid, a well tubing in the casing for accumulating a quantity of well fluid and serving as a conductor for the well fluid, one or more lifting fluid inlet valves connected to the tubing, means for normally fastening the valve or valves against and releasing said valve or valves for operation by a pressure differential between the well fluid and the lifting fluid, means for utilizing the pressure of the elevated well fluid to control the operation of the fastening and releasing means, means for providing 'a predetermined amount of mechanical energy which when combined with a hydrostatic pressure of a predetermined quantity of well fluid causes opening of said valve or valves, the amount of mechanicalenergy provided may be varied to control. the quantity of well fluid accumulated to regulate the opening of said valve or valves, said fastening means including resilient means for closing said valve or valves, said valves being constructed-so that the opening thereof may be controlled bythe varying of the pressure of the lifting fluid in the casing.

23. The system of flowing wells which includes, a casing provided with a supply of lifting fluid, a single string ofl tubing, one or more lifting fluid inlet valves connected to the tubing for admitting lifting fluid from the casing to the tubing, said valves adapted to be selectively and intermittently operated, means controlled from the surface of the well for locking said valves against operation, said vmeans being adapted to unlock said valves, said valves having elements responsive to pressure differentials between the well fluid and the lifting fluid which are operable when said valves are unlocked.

24. The system offlowing wells which includes, a casing provided with a supply of lifting fluid, a singlestring of tubing, a plurality of uid inlet valves' mounted in the tubing for admitting lifting flui-dfrom the casing to the tubing, said valves adapted to be selectively and intermittently operated, and means controlled from the surface of the well for locking said valvesagainst operation, said means being adapted to selectively release any of said valves, said valves having elements responsive to pressure differentials between thewell fluid and the lifting fluid which are operable when lany of the valves are released.

25. In a well flowing apparatus wherein a well casing is provided with a supply of lifting fluid Iand a well tubing string is mounted therein, the combination of, a lifting fluid inl-et valve mounted in the tubing for admitting well and lifting fluid from the-casing to lthe ftubing, said valve being adapted to be intermittently operated, means controlled from the surface of the well for bringing about the closing and the fas-tening of said valve, said means also adapted to release sai-d valve, said valve having elements which are responsive to pressure differenti-als between the well fluid and the lifting fluid and operable when said valve is released, and surface control means operated by a pressure fluid for actuating said surface controlled means.

26. In a well flowing apparatus wherein a well casing is provided with a. supply of lifting fluid and a well tubing string is mounted therein, the combination of, a plurality of lifting fluid inlet valves mounted in the tubing for admitting lifting fluid fro-rn the casing to the tubing, said valves adapted to be selectively and intermittently cperated, means controlled from the surface of the well for bringing about the locking of said valves, said means also adapted to unlock said valves, said valves having elements which are responsive to pressure differentials between the well fluid and 'the lifting fluid and these elements are operable when said valves are unlocked, and surface control meansl operated by a pressure fluid for actuating said surface controlled means, said surface control means having regulating means -to control the operation thereof.

27'. A system of flow-ing wells which includes, a well casing provided with a supply of lifting fluid above the liquid therein, a single string of well tubing in said casing, whereby columns of. well fluid may accumulate in the well casing and tubing, means for controllingthe -admission of fluid from the casing to the tubing, means for controlling from the surface of the well the fastening and releasing of the admission controlling means, said admission controlling means when released bein-g actuated by a pressure differential between the well fluid and the lifting fluid to ladmit lifting uid to the tubing to elevate the well fluid to the top of the well, and means for. utilizing the elevated well fluid to control the surface control means to bring about the closing of the admission controlling means to terminate the admittance of lifting fluid and to lock said means against reopening.

. 28. A system of owing Wells which includes, a well casing, a single string of well tubing in said casing, whereby columns of well fluid may accumulate in the well casing and tubing, one-or more pressure differential operated lifting fluid inlet valves mounted inthe tubing. means for no-rmally fastening said inlet valve or valves against operation by a pressure differential, means for releasing sai-d valve or valves for open-ing by a pressure differential, and means for utilizing the pressure of the elevated well fluid to control the releasing and fastening means. i

A2 9. A system of flowing wells which includes, a well casing, a well tubing in the Well casing. a lifting fluid pressure -d'ifferentialoperated valve connected to the well tubing, means for normally fastening the valve against operation by .between the well fluid in or for releasing said Valve for opening by a pressure differential, means for utilizing 'the elevated well fluid to control the fastening and releasing means, and means for providing a predetermined amount of mechanical energy which when combined with a hydrostatic pressure of a predetermined quantity of well fluid causes opening of said valve, said fastening and releasing means including resilient means for closing the valve.

30. In a well flowing apparatus wherein a well casing is provided lwith a supply of lifting uid and a Well tubing ismounted therein, the combination of, a lifting fluid inlet valve connected to the tubing for admitting well and lifting fluid from the casing into the tubing, means controlled from the surface of the well for fastening said valve against operation or releasing said valve where it may be operated, said valve having elements responsive to pressure differentials the tubing and the lifting fluid in the casing andvoperable when said valve is released, and surface control means operated by a pressure fluid for actuating said surface controlled means. v v

3l. |In a well flowing apparatus wherein a Well casing is provided with a supply of lifting fluid and a well tubing string is mounted therein, the combinati-on of, a lifting uid inlet valve connected to the tubing foradmitting Well and lifting fluid from the casing to 'the tubing, means the well for fas-' controlled from the surface of tening said valve against operation or releasing 'said valve where i-t may be operated, said Valve having elements responsive to pressure differentials between the Well uid in the tubing and the lifting fluid in the casing an-d operable when said valve is released, an actuator on the surfa-ce for operating said surface controlled means, and surface control means operated by a pressure uid for controlling the operation of said actuator.

32. In a well owing apparatus wherein a well casing is provided with a supply of lifting uid and a well tubing is mounted therein, the combination of, a lifting uid inlet-valve connected to the tubing for admittingwell and lifting fluid from the casing to the tubing, means controlled from the surface of 'the well for locking said valve against operation or unlocking said valve where it may be operated, said valve having elements responsive to pressure differentials between the well fluid in the tubing and lifting Huid in the casing and operable when said valve is unlockecL' actuating' means on the surface of the well for actuating said surface controlled means, a flow conduit extending to said actuating means for supplying a' pressure fluid 4thereto to operate said actuating means, and surface control means connected to said ow conduit for controlling the flow of a pressure fluid through said conduit to control the operation of said actuating means.

JEDDY' D. NIXON. Y

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