US2336683A

US2336683A - Gas lift pump

Info

Publication number: US2336683A
Application number: US342293A
Authority: US
Inventors: George A Hatfield
Original assignee: Nat Supply Co
Current assignee: National Supply Co
Priority date: 1940-06-25
Filing date: 1940-06-25
Publication date: 1943-12-14
Anticipated expiration: 1960-12-14

Description

Dec. 14,v 1943.

GAS

Filed June 25, 1940 HATFIELD LIFT PUMP 4 Sheets-Sheet 1 De@ 14, 1943. G. A. HATFIELD 2,336,683

GAS LIFT PUMPy Filed June 25, 1940 4 Sheets-Sheet 2 Dec. M, 1943u G. A. HATFIELD GAS LIFT PUMP Filed June 25, 1940 4 Sheets-Sheet 3 Dec.

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G. A. HATFIELD GAS LIFT PUMP Filed June 25, 1940 4 Sheets-Sheet 41 zal llll

Nihil! lll nllllyl Hl Il] |r Imi! LUM gfx/verdon Patented Der., i4, 1943 STATES oFFlcs GAS PUMP Application June 25, 1940, Serial No. 342,293

claims. (ci, 10a-24o) This invention relates to gas lift devices for wells, and more particularly to a method and apparatus for elevating well fluid from a Well utilizing gas as the lifting medium.

It is an object of this invention to provide a '5 gas lift method and apparatus for raising liquid from a well in which any back pressure on liquid entering the apparatus is substantially eliminated.

Another object'of this invention is to provideV a method and apparatus for reducing excessive head of fluid in a well to enable normal gas lifting operations to be initiated and carried out.

Another object of this invention is to provide a gas lift pump having a fluid accumulation chamber carried and supported upon a conduit in a well and including a positively operated valve adapted for insertion through the tubing to control theadmission and exhaust of gas to and from the accumulation chamber.

Another object of this invention is to provide a gas lift pump wherein there is included a double-ended valve which includes a singe movable element adapted to contact two seating surfaces.

Other'objects and advantages of this invention it is believed will be 'apparent from the following detailed description of a preferred embodiment thereof as illustrated in the accompanying drawings.

In the drawings:

Figure l is a longitudinal section broken to 4foreshortenl the view illustrating the gas lift pump embodying my invention and illustrating the same positioned within a well bore.

Figure 2 is an enlarged sectional view of the upper portion of the gas lift pump illustrated in Figure l.

Flgure is au intermediate section thereof,

Figure 4 is the lower section thereof.

Figure 5 is a diagrammatic view partly in section illustrating the surface equipment utilized in connection with the apparatus as illustrated in Figure l.

Figure 6 is a diagrammatic view illustrated in vertical section schematically showing the structure as illustrated in Figure 1 and illustrating the parts in the position for that portion of the normal operating gas lift cycle during which the well Y uld is entering the accumulation chamber.

Figure 7 is a view similar to Figure 6 illustratng parts as moved to the position during which the actuating gas is operating to expel the well fluid from the chamber and through the eduction tube.

Figure 8 is a diagrammatic view schematically 55 illustrating the structure as illustrated in Figure 1 and illustrating the method embodied in my invention of initiating gas lift operations when the iluid in the well has reached an abnormally high level, and illustrating the condition existing in the well when the well has accumulated a high static head of liquid.

Figure 9 is a View similar to Figure 8 illustrating the first step in the method of my invention of reducing the excessive head of liquid in the pump prior to the initiation of the normal lifting operations.

Figure 10 is a view similar to Figures 8 and 9 illustrating the further stepof reducing the excessive head of liquid in the pump just prior to the initiation of normal gas lifting operationsA Figure 11 is a sectional end view taken substantially on the line II-II of Figure 3.

In the preferred embodiment of my invention as illustrated in the accompanying drawings, l

t indicates a Well casing within winch thereis positioned a well tubing 2 and a smaller tubing or macaroni 3 which is insertable through the tubing. The three concentric strings of pipe I, 2 and 3, extend from the surface down into the well bore. Extending through the macaroni 3 is a wire line 4 on the lower end of which is carried a weight bar 5. The weight bar 5 is lowered through the macaroni upon the wire line 4 and is provided for the purpose of actuating the control valve 6. l.

Means `are provided for forminga tluid accumulation chamber 'I at the lower end of the tubing 2 and macaroni 3 and within the casing I below the normal iluid level in the well. To provide this uid accumulation chamber I there is carried at the lower end of the tubing 2 a pipe 8 which is of larger diameter than the tubing 2. Within this pipe 8 there is positioned the eduction tube 8 which extends into the iluid accumulation chamber l formed between the pipe 8 and the eduction tube 9. Mounted at the lower end of the pipe 8 is a. standing valve I0 'permitting entry of the well uld into the chamber l and operative to prevent reverse flow therefrom.

The control valve 6 includes a seating member I I and an insertable member I2 and is positioned immediately above the iiuid accumulation chamber l. The seating member I I is secured in positionwithin the tubing 2 and supports the eduction tube 9 at its lower end. The insertable member I2 is carried upon the lower end of the macaroni tubing 3 and is adapted to be moved upon the macaroni 3 through. the tubing 2 into Y its operative position within the central bore it of the seating member II. Means are provided for supporting the insertable assembly in position within the seating member II, which means includes a tapered shoulder I4 formed on the insertable member I2 and a complementary landing seat I5 formed at the upper end of the seating member Il. Spaced packing means are provided between the insertable member I2 and the seating member I I which are operative when the member I2 is resting upon the seat I5. The spaced packings include packing seals I6, I1, I8, i9 and 20.

Means are provided for conducting actuating gas from the tubing 2 to the top of the fluid accumulation chamber 1, which' means includes a passageway 2| formed in the seating member II and communicating with the tubing 2 through a screen 22.

The passageway 2I terminates in the lateral port 23 between packings I8 and I9. The port 23 leads into the bore 24 of the insertable member I2. A second lateral port 25 leads from the bore 24 to the gas passageway 26 which leads downwardly to the top of the accumulation chamber 1. A valve means 21 is positioned in the bore 24 between the

ports

23 and 25 and is operative to control the intervals of now of gas through the passageways as thus deiined.

A further vent port 28 is formed in the insertable member I2 in communication with a vent port 29 formed through the member II and'tubing 2 leading to the space between the tubing 2 and the casing I. The port 28 is formed between the packing members I6 and I1. Passage of fluid through the port 28 and out through the ports 29 is controlled by means of a valve member mounted within the bore 24 of the insertable member I2.

The valve control means 6 includes the valve means 21 and 30 which are mounted at opposed ends of the valve stem 3I in position to seat upon

seats

32 and 33, respectively, of the inserted valve sleeve seat member 34. The valve sleeve seat member 34 is provided with lateral ports 35 communicating with the gas port 25 intermediate the packing I1 and I8.

It will be apparent from the foregoing that the

valve members

21 and 30 are operatively connected so that when one valve member is seated, the other may be open. It will thus be apparent that when the valve member 21 is moved oi from its seat 32, that the flow of gas through the port 23 is through the valve sleeve member 34 and out the port 25 and'down the passageway 26 to the fluid accumulation chamber 1. When the valve member 21 is seated upon the seat 32, the valve member will be raised from its seat 33 and the gasaccumulated within the chamber 1 may be vented up through passageway 26 through the port 25, sleeve 34 and out the

ports

28 and 29 into the space exterior of the tubing 2.

The `flow of Well uid from the' fluid accumulation chamber 1 under the pressure of the lift- -ing gas is up through the eduction tube 9, by the check valve 36, and through the lateral passageway 31 formed in the insertable member I2 and the seating member II, after which Ithe fluid passes up by the seating member II through the by-pass 31a and enters through the port 38 formed above the packing I6 and. into the macaroni 3.

Means are provided for actuating the control valve 6 and

valve members

21 and 30, which means include:

A tubular extension 39 is secured to the upper end of the valve stem 40 which is in turn secured to the uppermost Valve member 30. Mounted at the upper end of the tubular extension is an abutment cap 4I upon which the weight bar 5 may be 4allowed to rest. When the weight bar 5 is resting upon the cap 4 I, the

valve members

21 and 30 are held in position with the Valve member 30 upon its seat 33 and the valve member 21 moved away from its seat 32. When 'the weight-bar 5 is moved into position in engagement with the abutment cap 4I, the valves are moved to this position or are maintained in this their lowermost position.

A starting valve 42, including a ball 43 and a seat 44, are provided in the abutment cap 4I. A lateral port 45 in the abutment cap communicates with the interior of the tubular extension 39 by way of the valve 42 and the ported follower 46. The valve stem 40 is bored to provide communlcation from the end of the sleeve 39 through a port 41 with the vent port 28 from theupper chamber 49 formed above the seat 33 of the upper valve 36.

Means are provided for maintaining the ball 43 against the seat 44, which means includes a spring 5U mounted within the sleeve 39 to act against the follower 46. The force exerted by the spring 50 is predetermined to maintain the valve 42 closed against the effect of the fluid pressure operating under normal conditions and when operating, exerting a force tending to open the valve 42. The action of this starting valve is as hereinafter set forth.

At the surface of the well there is provided means for raising and lowering the weight bar 5 carried upon the Wire line 4. This means includes a stuing box 5I through which the wire line 4 extends. The wire line 4 is connected through the medium of a suitable clamp 52 with the piston rod 53 of a piston 54. The piston 54 ls mounted in a cylinder 55 which is supported in position in any suitable or desirable manner as, for example, by means of a. hook or the like supported from the crown block of the derrick, not shown. Fluid under pressure is supplied to the cylinder 55 to raise the piston 54 therein through a conduit 56. Mounted in the conduit 56 is a two-way operating valve 51 which is connected into the high pressure gas supply line 58 as indicated `at 59. The valve 51 is operated to admit high pressure gas to the cylinder 55 or to exhaust the gas therefrom through a line 60 through the medium of a timing device operative to control the intervals of time at which gas is admitted to the cylinder and during which it is being exhausted therefrom. A diaphragm member 6I is connected with the movable element 62 of the valve 51 and operative to move said element 62 to the position to interrupt ow of gas from the high pressure supply line 58.

A spring 63 provides the means for actuating the element 62 in the reverse direction. The diaphragm member 6I is connected through a conduit 64 to a low pressure gas source. Mounted in this low pressure gas conduit is a timing valve 65 which is adapted to be actuated from a timer 66. The timer 66 is adapted to move the valve element 61 to and from position to interrupt flow of low pressure gas through the conduit 64 and to exhaust the said low pressure gas to the atmosphere. The valve element 61 is moved in the reverse direction by means of the spring 66. Any suitable or desirable means may be provided for driving the rotary element 66.

The casing I is, at the surface of the well.

connected to a casing head 69 having a pair of outlet branches 10 and 1l. The tubing 2 eX- tends through the casing head through a suitable packing element 12 and is supported in any suitable or desirable manner as indicated at 13. The tubing is connected to a tubing head 1li, likewise provided with a pair of fluid conducting branches 'l5 and 16. The macaroni tubing 3 is also suitably connected to a head 11, likewise having a pair of

iiuid branches

18 and 19.

The high pressure gas line 58 is connected to

branches

1I, 16 and 19, respectively. A discharge conduit 80, leading to a suitable trap or other place of disposal of the well fluid andgas, is connected through suitable connections to the

branches

1B, 15 and 18. In each of these connections there is provided a control valve. The control valves numbered 8l, 82 and 83 control the admission of high pressure gas to the

branches

1l, 16 and 19 respectively, while the valves numbered 88, 85 and 88 connect the discharge conduit 38 with the

branches

10, 15 and 18, respectively.

It will be apparent from the foregoing that the uid pressure is utilized to raise the piston d and hence to raise the weight bar 5. Exhaust of pressure in the cylinder 55 allows the piston 54, line and weight bar 5, to drop under inuence of gravity.

During normal operation of the gas lift system embodying my invention, the

valves

82, 88 and 3d are open and valves 8|, 83 and 85 are closed. With the valves thus set, gas under pressure is maintained in the tubing 2 and the well fluid is discharged intermittently through the macaroni 3 and the discharge conduit 80.

A check valve 81 is provided in the conduit connecting the discharge line 80 with the branch 19 to prevent well iiuid from flowing back into the casing l during the discharge of the well iiuid from the well. Ordinarily no back pressure is maintained within the casing l and hence well fluid from the formation may ow into the lower end of the casing l unimpeded.

The normal operating cycle of the device embodying my invention is:

During the filling period when the weight bar 5 is raised from the control valve 6, as schematically illustrated in Figure 6, the pressure of the actuating gas acting on the lower end of the control valve 6 maintains the same in its upper position. During this period the actuating gas is admitted into the lower chamber 88 below the control valve 3 through the passageway 2l and the port 23. During this period gas is prevented from entering the intermediate chamber 89 formed within the sleeve 33. The control valve t remains in its upper position as its upper end projects into the relatively low pressure existing within the macaroni 3 while its lower end is eX- posed to the high pressure of the actuating gas. The middle chamber 99 and the upper chamber i9 are at this time in open communication, and hence an unobstructed passage is provided from the accumulation chamber 1 to the low pressure annulus formed between the casing i and the tubing 2 by Way of the passageway 26 and through the chambers 89. and 49 and exhaust port 28. In this way the gas pressure remaining .in the accumulation chamber 1 from the previ- The ,timing device 66 at the surface of the well is adjusted to meet the characteristics ofthe well, depending upon the type of well fluidin the well, depth of the well, and the flow of Vvvell fluid into the chamber 1. The timing is such that the weight bar 5 is lowered when suiiicient Well iiuid has accumulated in the chamberV 1. When the weight bar 5 is lowered, the control valve 6 admits actuating gas into the accumulation chamber 1, and this marks the beginning* of the discharge period diagrammatically.illustrated in Figure 7.

As the control valve 6 has been moved toits lower position, the upper chamber 49 is isolated and communication is established betweenthe intermediate and lower chambers 89and 88. .Actuating gas under pressure then passes downthe passageway 2l through the lower and

middle chambers

88 and 89 and down through the passageway 26 to the accumulation chamber 1.1

The gas under pressure is impressed onfthe top of the well fluid in the chamber 1, thereby closing the standing valve I0. The gas under pressure displaces the well fluid up through the eduction tube 9 to lift a slug or column of well fluid.

It is of course obvious to those skilled in this device that the timing device v66 may be adjusted so lthat several slugs or columns of well duid are lifted into the macaroni 3 from the chamber 1 before the actuating gas is allowed to` enter the eduction tube 9 in sumcient quantity to lift the combined load to the surface. In such event the check valve 36 functions to prevent return of the well fluid into the eduction tube and chamber 1 between periods of discharge.

The foregoing sets forth the normal cycle of operation of the gas lift pump embodying my invention. However, when starting the gas lift operations for the first time, or after a period of shut down, the static head of the well fluid may, and usually will, have reached an abnormal height in the well. The head of the fiuid in the well, as diagrammatically indicated in Figure 8, may then be so high that the gas pressure availableis lnsuiiicient to lift the abnormally long column or slug to the surface; To overcome this diiculty I have provided a novel method and apparatus for initiating the gas lift. operations and the same is diagrammatically illustrated in Figures 8, 9 and 1Q.

Figure 8 illustrates the condition existing in the well after a period of shutdown and when' the static fluid level has risen to a point such that the normally available gas pressure. is insuicient to initiate normai operations. The method embodying my invention to overcome this condition is: "l

The weight bar 5 is lowered to hold the control valve 6 in its lower position when well fluidglls the chamber 1, eduction tube 9, casing l, tubing 2, and macaroni 3, to the level indicated. As illustrated in Figure 9, gas under pressure is ,then admitted into the tubing 2. The gas under pressure seats the standing valve I0 and forces well uid down through the passageway 2| and the

chambers

89 and 88, passageway 26, through the accumulation chamber 1.and up through the eduction tube 9 into the macaroni 3. The effect of this operation is to transfer this well fluid from the tubing 2 to the macaroni 3. The actuating gas continues to force well fluid into the macaroni 3 until the equilibrium is reached where the head of fluid in the macaroni` balances the pressure of the actuating gas. This condition is diagrammatically illustrated in Figure 9. The

' starting valve 42 remains closed up to this time because the pressure due to the head of the well fluid in the macaroniy is insumcient to open it. When this condition is reached, actuating gas under pressure is then admitted into the macaroni 3 above the column of well fluid, as illustrated in Figure 10. This is accomplished by opening the surface valve 83 and closing the surface valve 86.

The check valve 36 closes preventing return now into the eduction tube 9 and accumulation chamber 1. The combined eilect of the pressure of the actuating gas plus the pressure due to the head of the well duid is now suillcient to open the starting valve 42, with the result that the well fluid in the macaroni 3 passes through the valve 42, sleeve 39, and bore of the upper valve stem 40, out the-port 41, and through the

vent ports

28 and 29 out into the chamber between the tubing 2 and the casing l, raising the iluld level therein. The result of this action 'is to reduce the quantity of well fluid remaining under the influence of the gasY lift pump and reducing the head of the uid on the chamber 1 so as to enable normal gas lift operations to be carried out with the gas pressure available. The actuating gas is then vented from the macaroni 3 by closing the valve 83 and opening the valve 48 at the head of the well. Opening the valve 86 causes the starting valve 42 to close and automatically results in commencement of the normal lifting operations wherein the actuating gas supplied through the tubing 2 displaces well uid from the accumulation chamber 1 into the macaroni 3. The timing mechanism is started to control operation of the weight bar 5, whereupon the normal `pumping cycle is carried out.

Attention is directed to my co-pending application, Serial No.' 312,833, led January 8, 1940.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

l. In a device for raising liquid from a well, having a gas admission conduit and a well Iluid eduction conduit extending into the well and having communication near their lower ends, means for injecting gas under pressure into the gas admission conduit during normal operations for raising well fluid through the eduction conduit, means for expelling well fluid from the eduction conduit to the well space outside both of said conduits when the well fluid level in the eduction conduit has reached an abnormally high level, said means including passage means adapted to establish communication with said well space and with said well iluid eduction conduit at a point above its lower end, and a pressure-sensitive valve operable upon increase in pressure in the eduction conduit to control flow through said passage means.

2. In a device for raising liquid from a well, having a gas admission conduit and a well fluid eduction conduit extending into the well and communicating near their lower ends, the combination of means for injecting gas under pressure into the gas admission conduit during normal operations for raising well uid through the eduction conduit, means for expelling well fluid from the eduction conduit to the well space outside both of said conduits when the well fluid level in the eduction conduit has reached an abnormally high level, said means including passage means adapted to establish communication between said well fluid eduction conduit and with said well space, a pressure operated valve adapted to control flow through said passage, means for injecting gas under pressure into the well uid eduction conduit, the combined effect of such gas pressure and the head of well fluid in the eduction conduit being sulcient to open the valve.

3. In a device for raising liquid from a well, the combination of a gas admission conduit and a well fluid eduction conduit communicating near their lower ends, means for injecting gas under pressure ito the gas admission conduit during normal operations for raising Well fluid through the eduction conduit, a check valve in said eduction conduit, passage means communicating with said eduction conduit at a point above said check valve and with the well space outside both of said conduits, and a starting valve associated with said passage means selectively operable to permit iiow therethroughv vfrom said eduction conduit to said Well space.

4. In a device for raising liquid from a well,

the combination o'f a well fluid accumulation chamber positioned in the well below the normal level -of fluid therein, said chamber having an inlet valve adapted to admit Well fluid from the well space outside said chamber, a well fluid eduction conduit and a pressure fluid supply conduit extending into the well and each communicating with said chamber, a check valve in said eduction conduit, passage means communieating with said Well space and with the eduction conduit at a point above said check valve, and a starting valve associated with said passage means selectively operable to permit ilow therethrough from said eduction conduit to said well space.

5. In a rdevice for raising liquid from a well,v

the combination of a chamber for the accumulation of liquid, a conduit for admitting gas under pressure to said chamber, a conduit for the eduction of liquid Vfrom said chamber, a port for the exhaust of gas from the chamber to the well space outside the chamber, means to control the admission of gas to said chamber and the exhaust of gas, therefrom, and means including a starting valve adapted to establish communication to permit flow from the eduction conduit to the exhaust port.

6. In a device for raising liquid from a well, the combination of a chamber for the accumulation of liquid, a conduit for admitting gas under pressure to said chamber, a conduit for the eduction of liquid from said chamber, a check valve in the eduction conduit, a port for the exhaust of gas from the chamber to the well space outside the chamber, means to control the admission of gas to said chamber and the exhaust of gas therefrom, passagemeans communicating with said port and with the eduction conduit at a point above said check valve, and a starting valve associated with said passage means selectively operable to permit flow through said passage means from said eduction conduit to the exhaust port.

7. A gas lift pump comprising in combination a pair of concentric conduits extending into a well, one of said conduits being adapted to convey a lifting fluid under pressure downwardly therethrough, the other of said conduits comprising an eduction conduit through which well fluid may be raised, an accumulation chamber disposed in the well and provided with a well fluid inlet valve, means whereby each of said conduits may communicate with said accumulation chamber, said means including a service valve adapted to control admission of lifting fluid to said chamber, a lateral passageway extending through the Wall of said eduction conduit above the fluid inlet valve communicating with the well space outside both of said conduits, and a starting valve operable to permit ow from said eduction conduit through said passageway to said well space.

8. In a device for raising liquid from a well, the combination of a chamber for the accumulation of liquid, a conduit for admitting gas under pressure to said chamber, a conduit for the eduction of liquid from said chamber, a port for the exhaust of gas from the chamber to the well space outside the chamber, means to control the admission of gas to said chamber and the exhaust of gas therefrom, said means including a valve having an element thereof movable axially of the eduction conduit, a passage in the movable element communicating with the exhaust port and with the eduction conduit, and a pressure operated valve adapted to permit flow through said passage from the eduction conduit to the exhaust port.

9. In a device for raising liquid from a well, the combination of a pair of concentric pipes secured together and adapted to form an annularV accumulation chamber therebetween, a conduit for admitting gas under pressure to said chamber, a conduit concentric therewith for the eduction of liquid from said chamber, a port for the exhaust of gas from the chamber to the well space outside the chamber, positively operated means to control the admission of gas to said chamber and the exhaust of gas therefrom, said means including a valve assembly adapted to be lowered from the surface through the outer of said conduits into operative position above said annular accumulation chamber.

10. In a device for raising liquid from a well, the combination of a pair of concentric pipes secured together and adapted to form an annular accumulation chamber therebetween, a conduit for admitting gas under pressure to said chamber, a conduit concentric therewith for the eduction of liquid from said chamber, a port for the exhaust of gas from the chamber to the well space outside the chamber, means to control the admission of gas to said chamber and the exhaust of gas therefrom, said means including a valve assembly adapted to be lowered from the surface through the outer of said conduits into operative position above said annular accumulation chamber, and means including a wire line extending from the surface' and adapted to control the operation of said valve assembly.

l1. In a device for raising liquid from a well, the combination of a chamber for the accumulation of liquid, a conduit for admitting gas underpressure to said chamber, a conduit for the eduction of liquid from said chamber, the walls of said chamber being defined by a pair of concentric pipes secured to and supported by the gas admission conduit, a port for the exhaust of gas from the chamber to the well space outside the chamber, positively operated means to control the admission of gas to said chamber and the exhaust of gas therefrom, said means including a valve assembly adapted to be lowered from the surface on the eduction conduit through the gas admission conduit into operative position above said annular accumulation chamber.,

12. In a device for raising uid from a well, the combination of an accumulation chamber for well uid, a conduit for conducting gas under 5 pressure to said chamber. a tube for the eduction of well fluid from said chamber, a seating member secured to said conduit and positioned above said chamber, a port for the exhaust of gas from the accumulation chamber to the well space outside said conduit, a valve assembly insertable through said conduit into operative position within said seating member, said valve assembly andV said seating member cooperating to form three valve chambers, passage means connecting the first of said valve chambers to said exhaust port, the second to said conduit and .the third to the well uid accumulation chamber, said valve assembly having a movable valve element associated with said valve chambers, said valve element in one position being adaptedto establish communication between said first and second valve chambers and in another position to establish communication between the second and third valve chambers, and means including a wire line extending from the surface adapted to control the movement of said valve element.

13. In a device for raising fluid from a well, the combination of a gas admission conduit having a seating member secured thereto, a portion of said conduit below said seating member being enlarged to delne the outer wall of an annular accumulation chamber, an eduction tube secured to said seating member and extending downwardly therefrom within said enlarged portion of said conduit to dene the inner wall of said annular accumulation chamber, means including a passage in said seating memberfor the exhaust' of gas from the chamber to the well space outside the chamber, a fluid delivery pipe within said gas admission conduit having a valve assembly carried on its lower end, said iiuid delivery pipe and valve assembly being insertable axially through said gas admission conduit to bring the valve assembly into operative position within the seating member, cooperating parts associated with the fluid delivery pipe and the seating member adapted to establish communication between said eduction tube and said fluid delivery pipe, additional cooperating parts associated withv the valve assembly and the seating member adapted to dene a gas admission passage for conveying gas from said conduit to said accumulation chamber, and a positively operated valve included in said valve assembly for closing and opening said admission and exhaust passages.

14. In a device for raising liquid from a well, the combination of a chamber for the accumulation of liquid, a conduit for admitting gas under pressure to said chamber, a conduit for the eduction of liquid from said chamber, a port for the exhaust of gas from the chamber to the well space outside both of said conduits, a seating member secured to the gas admission conduit and positioned above said chamber, a valve assembly insertable through the gas admission conduit into operative position within said seating member, said valve assembly and said seating member cooperating to control the admission of gas to said chamber and the exhaust of gas therefrom, a vertically reciprocable valve element operatively included in said Valve. assembly and having a portion thereof projecting into the liquid eduction conduit, said valve element in one position being adap'ted to establish communication between the gas admission conduit and the accumulation chamber, and in another position to establish communication between the accumulation chamber and the exhaust port, means to move said valve element from one position to the other including a weight bar controlled from the surface and adapted to contact the projecting portion of the valve element.

15. In a device for raising uid from a Well,`

the combination of a gas admission conduit having a seating member secured thereto, a portion of said conduit below said seating member being enlarged to dene the outer wall of an annular accumulation chamber, an eduction tube secured to said seating member and extending downwardly therefrom within said enlarged Portion of said conduit to define the inner wall of said annular accumulation chamber, means including a passage in said seating member for the exhaust of gas from the chamber to the well space outside the chamber, a fluid delivery pipe within said gas admission conduit having a. valve assembly carried on its lower end, said duid delivery pipe and valve assembly being insertable axially through said gas admission conduit to bring the valve assembly into operative position within the seating member, cooperating parts associated with the uid delivery pipe and the seating member adapted to establish communication between said eduction tube and said fluid delivery pipe, said cooperating parts including a check valve insertable with the fluid delivery pipe and adapted to prevent retrogression of fluid therein, and additional cooperating parts associated with the valve assembly and the seating member adapted to dene a gas admission passage for conveying gas from said conduit to said accumulation chamber.

GEORGE A. HA'I'FIELD.