US2391542A - Gas lift pumping apparatus - Google Patents

Description

Dec. 25,1945v J, L. BENARD GAS LIFT PUMPING APPARATUS Filed Feb. '3, 1944 4 Sheets-Sheet l Dec. 25, $945. J. BENARD v GAS LIFT PUMPING APPARATUS 4 Sheets-Sheet 2 Filed F'eb. 5, 1944 25, 1945. J. L. BENARD 2,391,542

I GAS LIFT PUMPING APPARATUS Filed Feb. 5, 1944 4 Sheets-Sheet 5 Inventor j. .wuudf by Af. ,ivi-M:

.11 ttorney.

Uec- 25, 1945. l J. BENARD 2,391,542

GAS LIFT PUMPING APPARATUS Filed Feb. 3, 1944 4 Sheets-Shee 4 Patented Dec. 25, 1945 Application February 3, 1944, Serial N0. 520,887 In Great Britain November 24, 1942 (Cl. S-,231)

8 Claims.

The invention relates to gas-lift pumping appai-agus for raising liquids to an elevated delivery pom The invention has among its objects automatically and intermittently to admit into a displacement chamber. charged with the liquid to be raised, equal volumes of gas or air under pres-4 rsure under similar operating conditions without regard to the timing of the intervals, and without affecting the pressure conditions in the pressure gas supply system during the operation.

A further object of the invention is to use small diameter pressure-gas supply lines, while avoiding the use of gas reservoirs or capacity headers, `which are 4necessary in the use of mechanically operated timing devices for smoothing out the pressure drop in the pressure supply 'lines during Y the operation.

A further object ofthe invention is to avoid the use of timing devicesand control stations that are liable to get out of order and thereby cause production losses. f

A further object of th'e invention in its application to oil wells is to avoid exhausting into the casing oi the well, lpartzofitlfie, operating pressuregas admitted into the displacement chamber, and' fully to utilise the Venergy available in the.-.pres- 'ates to open the pressure-gas inlet valve to admit into the upper part of the liquid displacement receptacle, pressure gas derived from the pressuregas space or receptacle, thus raising the liquid through an eduction pipe extending downward into the liquid displacement eceptacle, and` thence through eduction conduits within the lower part of th'e rising main and throughthe main to the delivery point.

The invention while ofparticular application 'to oil'wells, is of general application in pumping liquids to. an elevated delivery point in such an intermittently operating gas-lift pumping apparatus. 1

The invention is hereinafter described with reference to the accompanying drawings, in which: l

Figure 1 is a diagrammatic vertical section of sure-gasto raise to the delivery point the liquid I charged into the displacement chamber.

A further ob.i eci i 'o t v the invention is to provide I means for raising'tlie liquid from small producing, or stripperpwells by means of gas supplied from the casingheads of wells producing quantities of gas, against a determined back-'pressure without affecting the back-pressure conditions of the wells supplying the gas. A E v A further object of the invention is to provide means for raising a, maximum quantity of liquidwith a minimum practicable quantity of pressure-gas. f

According tothe invention pressure gas at consecutive intervals and in controlled quantity is intermittently charged into a closed pressure-gas space or receptacle to a determined operating pressure, the pressure-gas space or receptacle being disposed in position above and in fluid tlg'ht relation with the liquid displacement receptacle charged with\the lquid from an outside source 'such as an oil well, whereby the liquid is held within the liquid displacement receptacle, the lower part of the rising main being disposed within the pressure-gas receptacle and being' equipped with automatically operating mechanism comprising aplctvalve. apistondevice and a pressure-gas :niet valve, tile pilot valve being apparatus provided for raising liquid, oil or water from an oil well.

Figure 2 similarly illustrates the valve operating mechanism on a slightly larger scale than in Figure 1.

Figures 3a, 3b and 3c are partial views of a. construction of apparatus similar to that illustrated diagrammatically in Figure 2 and together presenta substantially'complete vertical section of th'e apparatus on a larger scale.

Figure 3a shows shows the upper part, Figure 3b the middle vpart and Figure 3c the lower part of anapparatus generally corresponding with the respective upper, middle and lower parts of the apparatus diagrammatically represented in Figure 2 separated on the lines a--a and b--b indicated in that figure.

Figures 4 to 9 illustrate the housing of the main gas-inlet valve employed in the construction illustrated in Figures 3b and 3c, in which,

Figure 4 is a vertical section of the line d-d (Figure 5) of the main gas-inlet valve housing shown in the lower part ofFigure 3b and in the upper part of Figure 3c.

to one construction diagrammatically illustrated y in Figures 1 and 2 of the accompanying drawings, the casing 2 of the oil well, that may as usual comprise a number of connected length sections of the casing, is provided at its lower end with a perforated part 3. Suspended within the casing 2 is a tubing string 4 serving as the external wall of the pressure-gas receptacle, the tubing string comprising, as usual a number of connected tube length sections, having at the lower end an enlarged and advantageously cylindrical receptacleforming a liquid displacement chamber 5. At the bottom of theA liquid displacement receptacle 5 is an inwardly opening check valve 1, which permits the oil or the liquid at the bottom of the well or bore-hole to enter and to accumulate in the liquid displacement receptacle 5, but prevents the return of gas or uid into the casing or bore-hole or the operating pressure gas exerting an excessive pressure on the bore-hole or well formation.

Above the liquid displacement receptacle 5 and in the tubing string 4 a conical seat 6 is provided upon whlch the lower part of the rising main or casing 9 enclosing the automatically operating valve mechanismis supported, the casing 9-serving as an eduction conduit or lower part of the rising main through which the liquid passes upwardly. Extending downwards through the tubing 4 is the casing 9 and the rising mainv 8, the lower end of which is connected to or integral with the upper end of the casing 9. A gas-tight seal is thus maintained at the conical seat 6 of the lower end of the casing in the use of the interposed lead 'ring III. Beneath the casing 9 the eduction pipe II of a small bore extends downward, and may reach a position immediately above the inwardly opening check valve 1.

The automatically operating 'valve mechanism of the gas lift displacement pump apparatus as illustrated in Figure 2 consists of the casing 9 provided near its lower end with a gas inlet valve housing 20 .within which a mushroom pressuregas inlet valve I1 is mounted. The valve I1 has an upwardly extending valve stem 2| on which a guide 22 is mounted, which maintains the valve I1 and valve stem 2| centrally in the bore I8. The valve I1 has a downwardly extending valve stem 24 which freely movesin a bore 25 in the valve housing 20. The valve I1 is pressed upward into close contact with its seat 21 by means of a helical spring 26, and also by 'pressure of Ithe gas which enters below the valve I1, through the port 28 in communication with the annular 'pressure space I3.

In the gas-inlet valve housing 20 a port 29 is provided which communicates at its lower end with the liquid displacement receptacle 5, and through the bore I3 with the casing 3.Y The port The lower end of the valve housing 29 is applied on the conical seat 6 at the lower end of the closed tubing string 4, in position directly above the liquid displacement receptacle 5, a lead ring I0 being interposed. On the full weight of the casing 9, enclosing the valve mechanism of the gas-lift displacement device being applied on the lead sealing ring I0, an eiective seal is made between the receptacle 5 and the annular pressure-gas space or receptacle I3,

The casing 9 is provided with a pilot-valve housing 32, integral with which is a downwardlyy .depending cylinder 34 which accommodates a close iitting sliding piston 35. A piston rod 3i is connected to the piston 35 and carries at its lower end the mushroom valve 31, which is adapted to be applied upon the seat 3| and to close the valve passage I8.

In the upper part of the cylinder 34, a concentric bore-hole I6 is provided which can be sealed oi by the conical pilot valve I5 hereinafter referred to. A small transverse orifice 38 establishes communication between the bore-hole I9 and the casing 9.

'I'he pilot-valve housing 32 is shown diagrammatically in Figure 2 as integrally Aformed with the casing 9 and with an upward extension 39 which is divided into a lower compartment 40' and an upper compartment 4I. The lower compartment 40 communicates with the annular pressure-gas space or receptacle I3 through a radial port 48 in the pilot valve body 3 2. and contains a metal bellows 42 to the lower part of which the stem 43 of the pilot-valve I5 is secured. The metal bellows 42 is hermetcally secured at its upper end to the partition 39a, which divides the compartments 40 and 4|, and at the lower end the bellows is hermetically secured upon a base block 44, carried upon the pilot-valve stem 43 by a collar and gland nut 5|. When the bellows 42 is compressedythe pilot-valve stem V43 can freely move through the opening 45 in the partition 39a between compartments 40 and 4|. At the lower end of the stem 43 the pilot-valve I5 is mounted, which shuts off any flow of gas through the bore-hole I5 when sufllcient pressure is applied by means of the compression spring 46 ln the-compartment 4I. 'Ihe spring 46'abuts on the disc 41 mounted at the upper end of the pilot-valve stem 43, and the pressure applied by the spring may be adjusted by the adjusting screw 49. The screw 49 is packed oil gas-tight by means of the stuiling box 50, so that no gas or liquid can enter the compartment 4I.

In operation pressure-gas from the gas supply system I2 (Figure 1) is admitted through a simple needle or timing valve I4 into the annular space I3 between the tubing string 4 andthe casing 9 and rising main 8. This gas cannot escape because the annular pressure-gas space or receptacle I3 is sealed ofi at the bottom of the casing 9 by the lead sealing ring I0 on the tapered seat 6, the valves I1 and I5 being in the closed position (Figure 2).v Consequently gas pressure 30 provides communication between the eduction ,I

pipe II, and the space 9c, and the valve body 20 has at the upper end of the bore I9a'con1cal seat 3| upon which the valve 310i the cylinder and piston device 35, 35 may seat.

` tends to compress the metal bellows 42 and raises surface.

the pilot-valve I ci! its seat. This tendency however is opposed by the pressure -of the spring 46.1

When a determined pressure hasbeen reached, that may be controlled by the adjustment of the spring 46, the valve I5 being a diierential valve, suddenly rises from its seat and gas iiows through the orifice I6 into the cylinder 34. The pressure After the liquid has been removed from the liquid displacement receptacle 5 and has reached the surface or delivery point above, a certain quantity of gas still remains in the receptacle 5, and also ,gas might enter the receptacle 5 from the sourceof supply or the oil' well through the check-valve 1. If no precautions are taken this is now transmitted to the top of the piston 35,

which is forced downward, and the valve 31 makes contact with the valve stem ZI opens the pressuregas inlet valve I 1. The area of the piston 35 beinggreater than the area shut'oi bythe valve I1, the latter is forced oil its seat 21. At the lsaine time the valve 31 is forced on to its seat 3l and prevents gas iiowing from the annular space I3,

entering the inner space 9c by way of the bore rising main 8 tothe surface gas/liquid collecting system or other delivery point above.

`As the rate of ow from the pressure-gas annular space or receptacle I3 through the valve I1 and the ports I8 and 29 into the chamber 5 is pressure gas supplysystem I2 through the adjustable flow or'timing valve I4, a drop in presgas might create a gas-lock in the receptacle 5 .v and prevent or obstruct the inow'of liquid from the well into the receptacle 5. To avoid such a gas-lock being created in the chamber 5, the gas present in, or entering-the receptacle 5 is ex hausted into the communicating chambers 3c and 9d of the casing '3 forming the lower part of the rising main 8 and thence into the rising main 8 through the port 29, the bore I8 and the orifice uncovered by the valve 31. `This valve 31 rises from its seat 3l directly the valve I1 returns to its closed position. The pressures in the rising main 8 and liquid displacement receptacle 5 are therefore equalised at whatever pressure is main- Cil ' much greater than the vrate of iiow from the sure in the annular pressure-gas space orreceptacle I3`follows. Simultaneouslywiththe pressure dropin the annular pressure-'gas space or re'- .ceptacle I3 the pressure belqwgthej-metal bellows 42 and upon the piston 35 falls. Ona determined pressure drop, depending on the diameter of the vorifice I 8, the pilot valve I5 returns'to its seat in the orifice I6, under pressure of the springv 4Ii. When the pilot valve I5 is properly seated, no

further gas is supplied above the piston 35, and the gas which still exerts pressure upon the vpiston 35, exhausts through the upon the piston 35 are equalised. The pressure ofthe spring 25 all'orice V38 into the I casing 9, until the pressure Yin thel casing 9 and` and the kinetic tained in the gas/liquid collecting system.

It will -be understood thatv during the gas-lift pumping operations, pressure-gas is exhausted from the annular pressure-gas space or receptacle I3 only, and no appreciable increase in iiow takes place through timing valve I4 during this period.r The pressure in the gas supply system I2 is consequently not affected to any extent and the use of large capacity gas supply lines and gas reservoirs or capacity headers is avoided.

Y Furthermore in case of -small producing or "stripperl wells. gas can be supplied' from the casing heads.of producing wells, yielding smallv quantities of gas against a back pressure, without affecting the back-pressure conditions o f the well supplying, the gas. Full use may thereforey be madeofthe energy of the gas which otherwise f would` beglostinthe gas vvcollectionpipe-.dine

gasrspace or'receptacle I3 at each operation is energy of the vgas flowing through',v the hereA ,I8 j overcome the gas pressure on the piston;3,5, jivliiche` Ais equal to the pressure in the casing, 8,'and` the valve I1 returns to its seat 21, forcing thepiston, 35 into its upper position and closing thejsupply constant for any given operating condition, and

not -affected by the interval between., operations. @Thel intervals can be regulated by the valvey I4 f ,untill'the optimum condition )is reached, that is the maximum quantityn of liquid which can be f raised by the volumeiof gas exhausted from the annular pressure-gas space or'rec'eptacle I3 is attained.

e Asthe'pressure in the gas supply system I2 is ofgas to the liquid displacement receptacle5. f

The gas in the liquid displacement receptacle 5 and rising main 8 further expands and forces the "slug of liquid inthe risirigmain 8 to the from the annular pres?V notiniluenced to any appreciable extent during Y th Period gas'is admitted into the liquid disthrough the adjustable timing '.valvek I4 again.

builds up pressure in the annular space I3 to a maximum operating pressure, and the described cycle is repeated. y Y, v

It follows that the number rof operations or cycIqsuper hour, or per dayfdepend' on 'the rate. of ilow through theadjustable timingV valve I4,4

and therefore the number of operations per day can be regulated by reducing or increasing the iiow of gas through valve I4'. The number of operations per day depend' on the quantity of liquid produced by the source of supply or the oil well, and by the quantity of liquid which can be raised by the quantity of'gas supplied from the annular pressure-gas space or receptacle .I3 for the pressure drop for which the device has beenregulated.

placement receptacle' 5. several automatic gas-lift displacement pumps can be operatedsimultaneously withinthe capacty of the lscurce of gas supply, without danger of interference, or of wells going of! production.

Timing devices or control stations which might get out of order, or cause production losses are thus unnecessary, the operating cycles being regulated by a simple needle valve.

In the constructional form of the apparatus ii lustrated in Figures 3a, 3b and 3c, the rising main 8 (Figure 3a) is connected by the screw-threaded tubular fitting 9a with the upper part of the casing 9 serving as the lower part of the rising main 8, which in these :figures for convenience of illus- 'f tration is shown in three separated parts, namely the upper part in Figure 3a, the middle part in Figure 3b. and the lower part in Figure 3c, respectively separated on the lines a-a, and b-'b asindicated in those figures, at positions similarly denoted by theA lines a-a and b-b in the diagrammatic section of Figure 2, the casing 3 being formed of connected lengths oi pipe sections. the lowermost section being connected to the housing 24 of the maingas-inlet valve I'Izwhile the housing 20 at its lower end is .adapted for the screwthreaded connection of the supporting ring 20c (Figure 3c) which has an external conical shape at its lower end for accommodation within a corresponding internal conical seat in the internally screw-threaded coupling sleeve 4a. The sleeve 4aI at its upper end is applied upon the reduced lower externally screw-threaded end of the tubing 4 servingas the external wall of the pressure-gas space or receptacle I 5, and at the lower end the tubing is adapted for the connection of the coupling sleeve 4a for the suspension of the liquid displacement receptacle 5, through which extends downwardly the eduction pipe I I to a position near the bottom of the receptacle, a lead ring I being interposed between the ringA 20c and the conical seat in the coupling sleeve 4a.

The apparatus illustrated in Figures 3a, 3b and 3c comprises the pilot valve I5 and equipment (Figures 3a and 3b) mounted concentrically within the upper part ol' the casing 9 serving as the lower part of the rising main, and the main gasinlet valve I1 and equipment (Figures 3b and 3c) the gas-inlet valve l1 being mounted concentrically within a seating sleeve Ita (Figures 3b, 3c

4 .and 10), set within the main gas-inlet valve housing 20 (Figures 3b and 3c.

The respective pilot valve I5 and main gas-inlet valve I1 as illustrated in Figures 3a and 3b and 3c are supported in a construction many of whose parts are correspondingly numbered with equivalent parts indicated in Figures l and 2. Thus in those figures the helical spring 45 and bellows 42 andthe pilot valve l5 are respectively mounted within the tubular housings 4I and 40, the hous.-

ing 4I serving to enclose the helical spring 46 and piston 41, andthe housing 40 serving to enclose the bellows 42.

The bellows 42 is advantageously provided in known manner of corrugated longitudinal section and formed of alternate ridges and furrows of circular shape from thin metal having an elastic characteristic.

The tubular housing 4I (Figure 3a) has applied at its upper end a screw-threaded socket fitting' 55, through which passes the adjusting screwthreaded spindle 45, that extends into the housing 4I for variation ci' the compression applied to the enclosed helical spring 46. The upper cylindrical part of the adjusting screw-threaded spindle 45. An internally screw-threaded socket.

fitting h is applied 'upon and beneath the lower reducedA and externally screw-threaded part of the bush a, and the latter is packed to ensure fluid tightness. The undertace of the socket ntting 40h .has the upper end of the bellows 42 her- 70 metically secured to it, and at the lower end the bellows is similarly secured to a cylindrical base block 44, carried upon the pilot valve spindle 4l by a collar secured upon the spindle and a gland i nut 5I.

` to slide having a downwardly extending piston .rod 55. at the lower end of whichA a mushroom The assembly comprising the tubular housings 40 and 4I (Figures 3a and'3b) is supported upon a bush 52, that is externally 'screw-threaded at its ends respectively for engagement with an internal screw-thread at the lower end of the housing 40 and at the upper end of the pilot valve housing 32 whereby the latter is connected to the lower' end of the tubular housing 40; the bush 52 having an axial bore through which the pilot valve spindle 43 of smaller diameter than theaxial bore, may freely pass, and through which also the pressure gas is accessible to the housing 40 from below.

The pilot valve housing 32 is also screw-threaded externally at its respective ends, for the connection of adjacent lengths of the casing 5, and is provided with a radial port 48 for admission of the pressure gas from the annular pressuregas space or receptacle I3 within the surround-l ing tubular casing 4; the pressure gas being accessible from the central cavity or bore 40e in the pilot valve housing 32, through the axial bore in the bush 52 to the housing 40 within which the bellows 42 is enclosed. Thus the bellows 42 is rendered subject to the pressure prevailing in the annular pressure-gas space or receptacle I3.

The pilot valve housing 32 (Figures 3b, 11 and l2) is also provided with three vertical throughway passages 33, to permit of the free upward passage therethrough of the liquid from the liquid displacement receptacle 5 and the pressure gas by which itis raised.

The pressure gas derived from the pressure-gas space or receptacle I3, acting on the piston 35 passes through the radial port 48 into the centrally disposed bore or valve chamber 40e. and is thus accessible externally of the bellows 42 above, whereby the latter is contracted and the pilot valve I5 thusvraised from its seat on the pressure rising above the opposed pressure of the helical spring 45. The liquid under the pressure of the pressure gas ilows through the passages 33 and thence through the annular spaces between the housings 40, 4| and the casing 5 into the rising main I.

The pilot valve I 5 has at its lower end a conical face whereby it is adapted to seat upon the upper end oi' va nipple 53 having a central bore of small diameter, the nipple being centrally secured upon a bush 54 having a central bore l5 of a diameter greater than the bore of the nipple above it, and a radial bore-hole 35 extending outward from the central bore I5, open to the casing 9. The borehole 58 is advantageously of larger diameter at the outer part of its length. The bush 54 is externally screw-threaded at its upper and lower ends respectively to enter the internally screwthreaded lower end of the central bore of the pilot valve housing 32, and the internally screwthreaded upper end of the cylinder 34.

Within the cylinder 34 a piston 25 is adapted valve 51 is mounted, that in its lower position is adapted to close upon the seat 3| formed at the upper end of the seating sleeve Ila of the main gas-inlet valve I1, and to contact and to depress the upper stem Ila of the valve I1, whereby the valve I1 is opened against the action of the hellcal lsprint.r 25 (Figure 3c). Thus on the opening of the pilot valve I5, the pressure gas passes downward through the nipple 53 and into the cylinder 34. whereuponthe piston l5 descends. carrying with it the valve Il, vwhereby the upper r'I5 stem I'Ia. and the valve Il (Figure 3c) descend against the action of the helicalv spring 26. and against the pressure gas admitted through the port 28.

The cylinder 34 (Figure 3b) at-its lower end is internally screw-threaded for the reception of the externally screw-threaded upper end of a tubular ttng 55, having in a mid position in its length an outwardly extending circular ange that contacts with the lower end of the cylinder 34, and having a downwardly extending cylindrical part adapted to have a sliding lit within the' upper end of the tubular part 56 that is adapted for the enclosure of the mushroom valve 31 mounted at the lower end of the'piston rod 36. By such means the adjacent ends of the parts 34 and 56 are held together and maintained in alignment without connection.

The part 56 is screw-threaded internally at its lower part and secured at its lower end upon the upper externally screw-threaded end of the seating sleeve I8a of the main gas-inlet valve I1 (Figures 3b and 10), the part 56 being also open to the casing or duction'pipe 9 through the ports 56a, whereby the underside of the-piston 35 is subject to the pressure there prevailing.

The valve seating sleeve I8a of the main gasinlet valve II (Figures 3c and 10) is provided beneath the head I8b, with an external screw thread, whereby the sleeve Illa may be secured within the central cavity in the upper part of the main gas-inlet valve housing 20 (Figures 3b, 3c and 4 to 9) and at its lower` end the valve seating sleeve I8a is reduced in diameter and provided with radial holes I8c, whereby a perforated wall 4is provided aording communication between the annular port Id and the passage I8, while an external shoulder I8e is provided near the lower end of the seating sleeve adapted to lit upon the internal shoulder 20d beneath in the valve hous' ing 2i! (Figure 3c) In the main gas-inlet valve housing 20 three vertical ports 39, 29 and 30 are provided of arcuate form in transverse cross-section (Figures 4 to 9), and a radial port 28 (Figures 3c, 6 to 9). The ports 36 serve for the upward passage of the liquid from the eduction pipe I I 'into the eduction pipe 9. The ports 30 unite at a position 20h (Figure 3c) immediately above the upper end of the eduction pipe II, and beneath the bottom guide block 20e for the lower valve Astem Hb. In the guide block 20e a central bore is providedfor the accommodation of the lower stem IIb of the valve. The central bore at the lower end communicates with the lower ends of a number of holes of smaller diameter spaced apart in the guide block, to extend upward to the top face thereof in order to ensure freedom of movement of the valve in case of any liquid accumulation in the lower part of the central bore.

The valve I1 (Figure 3c) may be inserted into position upon removal of the guide block 20e, and the helical spring 26 may be applied upon the lower valve stem l'Ib, and be held in position by f the guide block.

The valve I1 may be adapted at its upper end ,to be guided in its vertical movements as by the radially or diametrically extending parts 22 (Figure 3b) The port 29 is the gas-inlet port into the upper part ofthe liquid displacement receptacle 5, and terminates at the inlet side inthe annular recess opposite to the radial holes I8c (Figure 3c) The radial port 28 serves on opening of the valve I1, for the admission of the pressure gas from the annular space I3 through the passage I8, port entrance 29a and port 29 into the liquid displacement receptacle 5.

The oppositely disposed lateral ports 30 of arcuate cross-section are at the lower. ends directly accessible to the eduction pipe Il (Figures 3c, 8

. and 9) that extends to the lower part of the liquid displacement receptacle 5, the latter being at its lower end provided (as illustrated in Figure 1) with a non-return valve 1.

The operation of the apparatus illustrated in Figures 3a to 12 is substantially the same as the apparatus diagrammatically shown in Figures 1 and 2.

Thus after the pressure gas has reached its maximum operating pressure in. the annular space or receptacle I3 the main gas-inlet valve I1 is opened on the operation of the pilot valve I5 and piston 35. The high pressure gas then ows into the liquid displacement receptacle 5 and pressure lstiius applied on the liquid tiiat iias accumulated in that receptacle. As the liquid canfonly escape from the-chamber 5 through the eduction tube II, the-liquid rises in the tube. On the liquid reaching the top of the tube II the liquid column divides into two columns on enteling the ports 20D and then rises through both passages 30 into the annular space between the tubular enclosure 56, cylinder 34 and the lowei1 part ot the casing 9. The liquid thereupon rises through the passages 33 in tne pilot valve housing 32 and enters tile annular space between thecasings 4u and 4| and the upper part or' the casing 9. The liquid continues to now through this annular space between bushing 4ua, casing b9, stuning box 50a and eduction casing 9, until it reaciies the eduction rising mam 8.

The quantity oi' gas passing from the annular 'pressure-gas Space I3 into tlie liquid displaceinent receptacle 5 and the rlsing'main 8 siiould be suflicient to bring the "slug or column of liquid to the surface at the delivery point. Trie quantity of gas should be approximately equivalent to the 4capacity oil tne receptacle 5, plus tne capacity of the rising main 8, and should ne at a iinal pressure when the top ol' tne slug or column of liquid reaches the surface, equivalent to the hydrostatic pressure oi' tile blug or column of liquid in tne rising main 8.

The operation of the apparatus illustrated in Figures sa, 3o and 3c is hel-einaiter described by way of example, and approximate ngures are given winch are illustrative of tne conditions that may be employed, and involve no limitation.

1f for example the maximum operating pressure in the annular space I3 is anu los/square inch and the length. of the column of liquid of specific gravity web', is 227 feet, trie internal diameter of trie rising main 8 is 1-i/2 inches, the depth of theoil weil is Z,l0u feet and the capacity oi' the liquid displacement receptacle 5 is o cubic feet, the required quantity or pressure gas. and the pressure drop in the annular pressure-gas space or receptacle .I3 to bring the slug or column oi liquid tothe surface are readily caisure gas which enters through the port 48 from the annular pressure-gas space or receptacle I3 exerts a pressure on the bellows 42 and the pilot valve I5. This pressure is static until the maximum operating pressure has been reached in the annular pressure-gas space or receptacle When this pressure has been reached the pilot valve I5 opens, and a small quantity of pressure gas flows through the bore IB into the cylinder 34 upon the piston 35. 'I'he piston is forced downward andthe main gas-inlet valve I1 isl opened. As the cylinder 34 has only one outlet 38, of small diameter (about alfinch) the gas ow which takes place through the bore 48 after the valve I5 has opened, ls equivalent to the amount of gas which can iiow through orifice 38 at the pressure in the annular space I3. This amount is extremely small and is approximately 3 cubic feet per minute at a pressure of 200 lbs/square inch. It is therefore only necessary that the port48 be slightly larger than the diameter of the orice 38 and a diameter of 1/8 inch is more than necessary.

The port 48 serves to establish communication between the annular space I3 and the space below the main gas-inlet valve Il (after the main gas-inlet valve I'l has been opened) through largeA as is practically possible; this also applies to the perforated grid wall Ic and the ports 29a and 29 (Figures 3c, 6, 7 and 10).

Before the apparatus is passed into the oil well it is rst decided whether to produce the liquid by raising a fairly large quantity of liquid per shot" at long intervals, or a small quantity per shot at short intervals between shots.

`Whether large or small quantities of liquid are to be raised per s hot does not make any diierence to the ultimate quantity of gas required to raise the same quantity of total liquid per day. Thus, if for example 40 gallons of liquid require 400 cubic feet of gas to raise this liquid to the delivery point, 20 gallons of liquid will require only 200 cubic feet of gas. In the rst case the pressure d rop in the annular space I3 must be greater, because 400 cubic feet are required per shot, whereas in the latter case the quantity passing from the annular pressure-gas space or receptacle I3 is 200 cubic feet per shot only, and consequently the pressure drop ln the annular space I3 is appreciably less. The overall input gas to liquid ratio in both cases is the same,'namely 40%() or 209o=10 cubic feet gas to 1 gallon of liquid. Therefore, if the capacity of the oil well be 4,000 gallons of liquid per day, the

quantity of gas required when the well is producing at theQ/te of 40 gallons per shot would .be 40000 400 ubic feet of gas, or 40,000 cubic feet of gas; whereas ifthis quantity of liquid were produced at .the rate of 20 gallons per shot, the required amount of gas would. be 4"""JoXZOO cubic feet of gas, or 40,000 cubic feet of gas, which quantities are identical.

When the operating pressurefand quantity of liquid to =beraised per shot has been decided upon, the pressure drop in the annular space I3 is calculated for the quantity of gas passing from the annular space I3 into the receptacle 5 to raise this liquid to the surface or delivery point. The apparatus is then adjusted for this pressure drop before it is passed into the oil well.

After the apparatus has been passed into the well, and properly seated on the tapered seating with the lead ring I0 interposed, the needle valve I4 is fully opened, and gas admitted into the annular pressure-gas space or receptacle I3. When the operating pressure to which the apparatus has been adjusted has been reached,-the pilot valve I5 opens, and the pressure gas flows into the cylinder 34, the piston 35 thus forced being downward. After the Valve 31 makes contact with the valve stem 2I, the main.gasinlet valve I'I opens, and the valve 31 is seated upon the seating 3|, and the pressure gas from the annular pressure-gas space or receptacle I3 flows into the liqvuid displacement receptacle 5, whereby the liquid that has collected in this receptacle is forced upward to the delivery point.

When the pressure drop for which the apparatus has been adjusted has taken place in the annular pressure-gas space or receptacle I3, the pilot valve I5 closes and the valve I'I again closes, and no further gas is supplied to the liquid displacement receptacle 5, until the operating pressure has again been reached in the annular pressure-gas space or receptacle I3.

As the timing valve I4 is fully| open, the time to replenish the annular pressure-gas space or receptacle I3 is comparatively short, and if this Valve were left fully open, the liquid in the well would soon be exhausted, and only small quantlties of liquid would be raised with the constant quantities of pressure gas passing from the annular pressure-gas space or receptacle I3. Consequently the pressure gas to liquid ratio would increase to above the normal quantity of gas required per gallon of liquid. As this is undesirable, the timing valve I4 is gradually or parinterval betweenv tially closed whereby the shots is prolonged. This partial closure of the needle valve I4 is continued until the quantity yof liquid which is raised to the delivery point per shot is approximately the theoretical quantity which can be raised by the volume of gas passing from the annular pressure-gas space or receptacle I3. When this condition has been reached the timing or needle valve I4 is left in that position, and the apparatus now continues to operate automatically, raising each time the maximum quantity of liquid possible for the volurne of pressure gas injected into the chamber 5.

As the pressure drop in the annular pressuregas space or receptacle I3 is the same for each shot, and as the capacity of this annular space is constant, it follows that the quantity of pressure gas derived from the annular space I3 is always the same, and consequently the volume of pressure gas necessary per gallon of liquid raised to the surface is always the same for any given operating condition.

Thus for a given operating condition the volurne of pressure gas passing from the annular pressure-gas space or receptacle I3 is always constant, as long as the gas pressure in the gas supply lines is higher than the operating pressure of the apparatus. Thus the pressure in the annular pressure-gas space or receptacle I3 cannot build up to a pressure higher than the operating pressure ofthe apparatus.

Assuming that at an opening pressure of 250 lbs/square inch, .and a closing pressure of 200 iba/square inch, 200 cubic feetof gas passes from the annular space I3 into the liquid displacement receptacle 5 to raise 20 gallons of liquid to the delivery point, and that this quan- 5 tity of liquid is -raised at intervals of one hour, the average rate of flow at which the gas ows through the timing or needle valve I4 isv then 20%0, or 3.33 cubic feet per minute.

When the pressure in the annular pressure-gas I timing valve I4 is slightly higher than when the` l5 pressure reaches 250 Iba/square inch in the annular pressure-gas space or receptacle I3. This is due to the increased dierential between the up-.stream and down-stream side of the needle valve I4. This difference in that the pressure drop due to this increased flow rate cannot be measured with an ordinary pressure gauge connected in the gas supply line near the timing valve I4. This very small pressure drop during the of gas supply pipes of small diameter, so that large diameter pipes which are commonly used to reduce the pressure drop in the supply pipes, when other types of displacement pumps are used, are unnecessary. p

In the example hereinbefore described, the flow rate through the timing valve i4 is 3.33

cubic feet of gas per minute, and the interval between the on period or By increasing shots is one hour. the now rate feet per minute on slightly opening the needle valve I4, the interval between shots becomes 3i3/4 X 60 or 50 minutes'. In the rst case the number of shots per day would be 1,44%() minutes or 24 shots, l#Pw/5u minutes or 28.8 shots per 24 hours. If on the other hand the rate of ow were decreased to 2 cubic feet per minute the number of shots per day would be or 14.4 "shots per day.

Thus by increasing or decreasing the average 50 whereby the determined operating pressure is e5 the pressure-gas.

there attained, an inner casing within said pressure-gas receptacle, a pressure-gas inlet valve housing at the lower part of said inner casing, said housing having a vertical passage-way, a

pressure-gas inlet valve normally closed under 70 upward spring pressure, and mounted within said passage-way, a radial port in said housing extending from said pressure-gas receptaclel to a cavity in said `housing beneath said pressuregasinlet valve, a pressure-gas inlet port extend- I5 flow rate is so small on period permits of the use 25 from 3.33 to 4 cubic 35 disposed at the ing upward in the said housing from its lower face. and communicating with said vertical passage-way ata position immediately above said pressure-gas inlet valve, an outlet port for the liquid raised from the said liquid displacement receptacle, extending from top to bottom of said Ihousing, an eduction pipe depending from said housing into said liquid displacement receptacle to the lower part thereof. and communicating with said outlet port, and automatic means mounted within said inner casing adapted under the determined operating pressure'or` the pressure-gas, comprising a pilot valve and a cylinder piston and valve device, whereby the pilot valve is 'opened to admit the pressure-gas into the cylinder of said cylinder, piston and valve device, whereupon the valve of said cylinder, piston and valve device descends and opens the pressuregas inlet valve. and closes said vertical passageway at the upper end, pressure-gas being thus admitted to the upper end of the'liquid displacement receptacle, the liquid discharged from the liquid displacement receptacle passing upwardly through the eduction pipe, and thence through the inner casing and the rising main to the delivery point, the valve of said cylinder, piston and valve/ device being raised from its seat on the closure of said pressure-gas inlet valve, at the conclusion of each operational cycle and pressure-gas receptacle re-charged with pressure-gas and the liquid displacement receptacle with liquid.

2. A gas-lift pumping apparatus as specified in claim l in which a central axial bore-hole is upper end of the cylinder, piston and valve device, which is sealed olf bythe pilot valve at the end of each cycle, and

a small transverse radial passage disposed be` tween the central axial bore-hole and the exand in the latter case 40 ternal wall of the cylinder at its upper end, communicating between the central axial bore-hole, and the inner casing, whereby on the closure of the pilotvalve at the end of a cycle, the gasv remaining in the said cylinder exhausts through 'the said transverse radial passage into the lower part of said inner casing until the pressures in the inner casing and upon the said piston are equalised.

3. A gas-lift pumping apparatus as specied in claim l, in which the pilot valve equipment comprises a smaller casing disposed lengthwise within the inner casing, the smaller casing being divided by a transverse annular partition into an upper and a lower compartment, the latter communicating with the pressure-gas receptacle through a radial port, an expansion spring disposed lengthwise in the upper compartmentl and adapted normally to apply slight axial pressure upon the upper end of the stern of the pilot (j valve for its closure, a metal bellows within said lower compartment corrugated in its length in alternate annular ridges and furrows and being thus adapted for lengthwise contraction under the determined ,operational pressure of the respective upper and lower ends of said metallic bellows being hermetically 1 secured to said transverse annular partition at the upper end, and to a base part mounted near l -.the lower end of the pilot valve stem, whereby on the endwise contraction of the metal bellows at the determined operational pressure, the pilot valve is adapted to open and to rise from its seat against the downward axial pressure applied by said expansion spring.

4. A gas-lift pumping apparatus for periodically raising from an outside source to an ele- -vated delivery point successive charges of liquid ing pressure of the pressure-gas, comprising a pilot valve and a cylinder piston and valve device, whereby the pilot valve is opened to admit the pressure-gas into the cylinder of said cylinder, piston and valve device, whereupon the valve of said cylinder, piston and valve device descends and opens the pressure-gas inlet valve, and closes said vertical passage-way at the upper end, pressure-gasl being thus admitted to the upper end of the liquid displacement receptacle,

the liquid discharged from the liquid displacel ment receptacle passing upwardly through the eduction pipe, and thence through the inner casing and the rising main to the delivery point, the valve of said cylinder, piston and valve device being raised from its seat on the closure of said pressure-gas inlet valve, at the conclusion of each operational cycle and pressure-gas receptacle re-charged with pressure-gas and the liquid displacement receptacle with liquid.

5. A gas-lift pumping apparatus as specified in claim 1, in which the pilot valve stem is extended upward into the upper compartment of the smaller casing in the lower compartment of which the metal bellows is mounted, in which an expansion spring is interposed between an abutment plate mounted on the upwardly extending end of the pilot valve stem, and an abutment plate mounted on the upper end of said expansion spring, and a screw mounted at the'rupper end of said smaller casing, adapted for contacting at its lower end the upper abutment plate as meam for the adjustment of the pressure applied to said expansion spring.

6. A gas-lift pumping apparatus as specified in claim l, in which the expansion spring, the metal bellows, the pilot valve, the cylinder piston and valve device and the pressure-gas inlet valve and its housing are mounted in their order in alignment within tubular parts connected together by tubular connecting parts that accommodate the respective valve stems, and in which the connected tubular parts are mounted and supported within a surrounding tubular inner casing forming an annular space surrounding said connected tubular parts, that at the upper end discharges into the rising main, while at the lower end `the said inner casing serves for the suspension of the eduction pipe that extends downward into the lower end of the liquid displacement receptacle.

7.' A gas lift pumping. apparatus as specified in claim 1, in which the pilot valve equipment comprises a smaller casing disposed lengthwise Within the inner casing, the smaller casing being divided by a transverse annular partition into an upper and a lower compartment. the latter communicating with .the pressure-gas receptacle through a radialport, an expansion spring disposed lengthwise in the upper compartment and adapted normally to apply slight axial pressure upon the upper end of the pilot valve for its closure, a metal bellows within said lower compartment corrugated in its length .in alternate annular ridges and furrows and being thus adapted for lengthwise contraction under the determined operational pressure of the pressure-gas, the respective upper and lower ends of said metal bellows being hermetically secured to said transverse annular partition at the upper end, and a basepart mounted near the lower end of the pilot -valve stem, whereby on the endwise contraction of the metal llows at the determined operational pressure, the pilot valve is adapted to open and to rise from its s eat against the downward axial pressure applied by said expansion spring, and means for adjustment of the pressure applied by the expansion spring upon the stem of the pilot valve, consisting of an adjustable screw passing centrally thro-ugh the upper end of the smaller casing, the said screw abutting at its lower end against a contact plate secured at the upper end of said expansion spring, the lower end of the expansion, spring engaging the contact plate upon the upper end of the pilot Valve stem.

8. A gas lift pumping apparatus a's speciiied in claim l, in which the expansion spring, the meta bellows, lthe pilot valve, the cylinder piston and valve device and the pressure-gas inlet valve and its housing are mounted in their order in alignment within tubular parts connected together by tubular connecting parts that accommodate the respective valve stems, and in which the connected tubular parts are mounted and supported within a surrounding tubular inner casing forming an annular spacesurrounding said connected tubularA parts, thatiat the upper end discharge into the .rising main, while at the lower end the said inner casing serves for 'the suspension of the eduction pipe that extends downwardly'into the lower end of the liquid displacement receptacle, and in which the inner casing is surrounded by a cylindrical outer casing forming between the outer casing and the inner casing an annular space serving as pressure-gas receptacle, at the lower end of which the liquid displacement receptacle is suspended.

JAN LAMBERTUS BENARD.

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