US2142485A - Gas-lift pump - Google Patents

Description

Jan. 3, 1939.

J. P. STEPHENS ET AL GAS -LI FT PUMP 2 Sheds-Sheet 1 Filed Nov. lO, 1936 2 Sheets-Sheet 2 ATTORNEYS.

GAS-LIFT PUMP Filed NOV. lO, 1956 Jan. 3, 1939.4 J. P. STEPHENS ET AL Patented Jan. 3, 1939 UNITED STATES GAS-LIFT PUMP James P. Stephens, Francis E. Steele, and William F. Flood, Oklahoma City, and Clarence M. Rader, Tulsa, Okla., assignors to Phillips Petroleum Company, a corporation of Delaware Application November 10, 1936, Serial No. 110,164

11 Claims.

This invention relates to devices for raising fluids from wells.

More'specically, the invention relates to devices for raising liquids from wells in which the actuating medium is a gas under pressure.

An object of the present invention is to provide a device for raising well uids to the surface.

An additional object of the present invention is to provide a device which will operate with a satisfactory gas-oil ratio.

A further object of the invention is the provision of a; device which will be simple, compact, and economical in operation, easy to install and remove, and contain few moving parts.

A still further object of the present invention is the provision of a device operable by varying the operating gas pressure.

Another object of the present invention is the provision of a device operable in accordance with the pressures existing in the liquid eduction column.

Other objects of the invention will be apparent from a consideration of the detailed description, claims and drawings. f

This application is a continuation in part of application Serial Number 32,798, iiled July 23, 1935.

In the drawings, in which like numerals are employed to designate like parts, throughout the same,

Fig. l is a schematic showin a well hole,

Fig. 2-A is a longitudinal section through the lower part of the device of the invention,

Fig. 2-B is a. longitudinal section through the upper part of the device of the invention, omitting the tubing string shown in Fig. Z-A, i

Fig. 3 is a longitudinal section similar to part of Fig. 2B but showing the valve in another position,

Fig. 4 is a longitudinal section similar to part vof the device in of Fig. 2-A but showing the valves in other posithe (Gl. S-231) passages serving to conduct the gas under pressure from the source to the surface of the oil in the accumulation chamber are herein termed gas induction conduits or passages. Those passages serving to exhaust the gas under pressure from the accumulation chamber to the surface of the ground are called exhaust passages. Those passages serving to conduct the oil or liquid from the bottom hole to'the surface of the ground are' termed liquid eduction conduits or passages.

Referring to the drawings, a Well hole is indicated lined with casing II which is cemented to the bore at I2 in the neighborhood of the producing formation. Within casing I'I is a tubing string I3 screw threaded at its lower end to a nipple I l which in turn is screw threaded to an accumulation chamber I5 having its lower end closed by a standing valve I6. This chamber is submerged in the liquid in the bottomhole. The nipple I i has a shoulder or ledge at I'i and exhaust ports at I8 opening into the space I8' formed between the casing and the tubing string. Within the tubing I3 is positioned a flow string 2U which is screw threadedly connected through adapter 2l to a pump indicated generally by reference numeral 22, to form a flow String assembly.

The pump body 22 is composed of two body members joined by nipple 23. The lower body member 24 has extending through it a liquid discharge or eduction conduit 25 screw threadedly connected at its lower end to the discharge tube 26 which is closed at its lower end by a check valve 2l. 'I'he eduction conduit 25 opens at its upper end on the interior of nipple 23. The lower pump body member further includes a bore designated generally at 28, being lined in part by liner 28' formed of hard metal, and opening at its lower end in the top of accumulation chamber l5. Bore 28 includes exhaust ports' 29 which open on space I9 between the iiow string assembly and tubing string in the neighborhood of ports I8 in tubing string It, and intake or induction ports 30 opening on the same space. Slideably mounted in bore 28 is a main valve 3i consisting of a hollow cylindrical member 32 integrally joined through a reduced portion 33 to a piston head 3G. The annular space 35 around reduced portion 33 is in communication with the inside of cylindrical member 32 through openings 36. Movement of this` valve in bore 21 is limited by a stop 31 and a partition formed bythe closed end of cylindrical sleeve 38 which is fixed in the upper end of bore 28. Slidable in cylindrical sleeve 38 is a pilot valve 33 in the form of a piston having 39 and the valve head 40 with the exterior of pump body 24. To achieve a distributed pressure,

while presenting a large impact surface to sleeve 38, valve 3| has a valve face 43 on piston head 34 (see Fig. 4) which is axially bored at 44 and 5 radially bored at 45, 45, the last mentioned bores being in communication with bore 44 and bore 44 registering with orice 4I when the valve 3| is in its uppermost position. An annular space 46 is formed between sleeve 38 and the body of piston head 34 around the valve face 43, bores 45, 45, opening on this space. A port 41 connects this annular space with a bleeder passage 48 which in turn connects with port 49 opening on space I9 (see Figs. 5 and '1). Bleeder passage 48 extends upwardly beyond port 41 to open into port 41' in the upper end of sleeve 38 above the upper face of piston valve 39. The extreme upper end of bore 28 is closed by a cylindrical plug fitting 50 having screw threaded connection therewith. Thus bore fitting 28 from this plug fitting down to stop 31 constitutes a valve chamber. The plug fitting 50 houses a spring 5| which biases pilot valve 39 downwardly through valve stem 52. Spring 5| acts on valve stem 52 by means of a spring retainer 53. The upper end of tting 50 is closed by a plug 54 having a set screw 55 in screw threaded relation therewith. This set screw engages spring 50 through spring retainer 56. A lock nut is shown at 51. The plug 54 is capped at 58. Annular shoulders 59, 60, and projections 6I serve to retain a screen 62 in spaced relation over the various ports in the body member 24. The exhaust ports I8 and 29 are isolated from the upper reaches of space |9 by a packer or gasket comprising a pair of resilient rings 63 held between shoulder 60 and an annular channel member 64 and spaced by a ring 65. The exhaust ports are also isolated from the accumulation chamber by a similar pair of gaskets or packers 66 spaced by ring 61. Below the lowest packer 66 is a ring 68. The packers, rings, and annular channel member are slidably mounted on pump body member 24 for movement below shoulder 59. It will be apparent that the weight of the flow string and pump resting on shoulder or ledge I1 through ring 68 will compress the gaskets 63, 66, into sealing engagement with nipple I4. Annular channel member 64 has openings 69 permitting communication between ports 29 and I8. A ring 10 is screw threaded on the lower extremity of body member 24 to prevent the packer structure from sliding off while the pump is being lowered into position.

The upper body member 1| of the pump has three large passages 12 and one small passage 13 therethrough. The large passages constitute a liquid discharge or eduction conduit and the small one a gas passage, the purpose of which will be later described. A bore, indicated generally at 14, is also located in this body member, terminating at its lowe:` end in a gas passage 15 which opens on space I9 through port 16. The lower portion of bore 14 is lined with a hard metal liner 11 within which a supplemental valve 18 travels. Intermediate its ends piston valve 18 has a reduced portion 19 forming an annular space which in the lowest position of the valve coincides with a port 8| opening into space I9 and a port 82 opening into passage 13. The upper end of liner 11 is closed by a plug 83 having a clearance bore 84 through which passes valve stem 85 of valve 83. In the upper portion of bore 14 is a spring 86 exerting pressure on valve stem 85 through spring retainer 81 and held at its upper extremity by spring retainer 88. The spring is tensioned by a set screw 89, screw threaded into a plug which is itself screw threaded into the open end of bore 14. In the neighborhood of the spring, bore 14 has a port 9| opening into a liquid eduction passage 12. Passage 13 is closed at its upper end by plug 13' and is screw threaded near its lower end to receive gland packing nut 92. A pipe 93 has at its upper end a shoulder 94 between which and the packing gland nut 92 is positioned a packing 95. The lower end of pipe 93 is connected to a passage 96 which in turn opens through port 99 on bore 28 below the closed end of sleeve 38. Valve 3| has a second reduced portion 91 forming a second annular space 98 which when the valve is in its uppermost position registers with port 99. In this position annular space 98 also registers with a port |00 opening into liquid eduction passage 25. A bushing |02 is shown in port 99. An opening |03 is necessary in the wall of this body member to drill port 99. This opening is closed by plug |04. A screen |05 is shown covering the ports 16 and 80 and spaced away from them by projections |06. It is to be understood that nipple 23 completes the liquid eduction conduit through the pump.

At the surface space |9 is closed and connected by pipe |01 to a source of gas under pressure (not shown). In pipe |01 is a control valve |08 and an intermitter |09. Space I8' between tubing string I3 and casing I.I may be open to the atmosphere or closed and connected with a source of gas utilization at low pressure.

In the operation of the device, ywith no gas pressure applied to space |9, herein termed an induction or intake passage or conduit, oil in the bottom hole will ow past standing valve I6 into accumulation chamber |5 due to gravity. Assume that valve 38 will be ln the position shown in Fig. 2-A leaving the accumulation chamber I5 open to the pressure existing in space Il', which is usually around atmospheric pressure, through the exhaust passage or conduit 28, ports 29, openings 69, and ports I8. The oil in chamber I5 will seek the level of the oil in the bottom hole. When the oil in the bottom hole has been given sufficient time to enter the accumulation chamber, the intermitter |09 opens to allow gas under pressure to enter induction or intake passage |9. As pressure builds up in this passage it is applied through port 42 to the lower face of the piston of pilot valve 39. Spring 5I has previously been tensioned by means of set screw 55 so that a predetermined pressure on the lower face of valve 39 is necessary to move it and thus move valve head 40 away from the orice 4I. Upon this happening. the gas pressure will be applied through orifice 4| and bores 44, 45 to annular space 46, forcing the valve 3| down. wardly into engagement with stop 31, as shown ln Fig. 4. Valve 3| in this position closes exhaust port 29 and uncovers intake port 30 so that gas pressure is admitted from induction passage I9 through port 30, annular space 35, openings 36, the cylindrical portion of valve 3|, and the passage or conduit formed by the lower end of bore 28, to the surface of the oil in the accumulation chamber. With this pressure acting upon the oil, the valve I6 closes and the oil is forced past valve 21 and up discharge tube 26, discharge or eduction conduit 25, nipple 23, eduction con- :Ivalve chamber.

duit 12, to the flow string 20. The intermitter |08 continues the application of the gas pressure until all the oil in the accumulation chamber above the lower end of discharge tube 26 is forced out. Usually further pressure is continued until a slug of gas is forced up the discharge tube behind the oil. At this point the intermitter shuts oi the supply of gas pressure and as the pressure in space I9 falls, spring 5I forces valve 39 downwardly to close orifice 4|. The residual pressure in accumulation chamber I5 returns valve 3| to the position shown in Fig. 2-A, the gas trapped above valve 3| bleeding oft' through port 41, bleeder passage 48, and ports 49, 69, and I8 to the exhaust space I8'. Although port 41 is always open it is so small that it does not materially reduce the pressure on piston 3| during the pressure cycle. The same applies to port 41' which allows any gas leaking past piston valve 39 to escape. With valve 3| in its uppermost position against sleeve 38, exhaust ports 29 are opened -allowing gas in the accumulation chamber to exhaust through ports 29, openings 59 and ports |8 to space I8'. As the pressure in the accumulation chamber falls, valve 3| is held in its uppermost position against cylindrical sleeve 38 by the residual pressure at port 30 forcing the valve against the opposite wall of the With the pressure in the accumulation chamber I5 reduced, valve I6 will open toadmit oil into the chamber from the bottom hole and the pump is again ready for the pressure cycle.

When the pump is rst lowered into the well if valve 3| is down against stop 31 as shown in Fig. 4 gas pressure in the accumulation chamber` due to the hydrostatic head of the oil in the bottom hole will raise it. In case it does not, or in the case where the `pump has been in the well not operating and valve 3| is down, gas entering port 30 will build up pressure in the accumulation chamber which will force the valve 3| up since no pressure is being applied to its upper face. v

It is evident that the pump couldbe operated by timing thev intermitter so that the admission of gas to the accumulation chamber and up the flow string behind a slug of oil could be continued until enough gas had been admitted to the. flow string to establish the proper gas-oil ratio. In the applicants present device, however, a supplemental valve is furnished to admit this quantity of gas directly from the gas induction passage |9 to the flow string through liquid eduction conduit 25 while the accumulation chamber I5 is exhausting. This means that the accumulation chamber need be used only for acc umulating oil and forcing the accumulated oil up the flow string,.lnstead of operating a sub, stantial..part of the time as a part of the gas admission circuit. Of course some gas will be forced up the flow string from the accumulation chamber behind the oil slug to force the oil slug past port |00 so that gas entering liquid eduction conduit 25 'from this port during the exhaust cycle will not enter and mix .with the oil to break up the continuity of the oil slug. Admission of this gas into the column during the exhaust cycleallows the accumulation chamber to be filling while the oil slug is being further speeded toward the surface permitting the chamber to fill oftener and preventing deceleration of the oil slug.'

The supplemental valve 18 accomplishes these purposes by the following mode of operation. The

valve is exposed on its under side to the pressure in gas induction passage I9 through port 16 and passage and on its upper side to the pressure in liquid eduction conduit 12 through port 9|. bore 14, and clearance bore 84. 'I'he pressure in eduction conduit 12 is aided by spring 86in opposing upward movement of the valve. Spring .86 is so tensioned that the valve 'I8 is held in its upper position (see Fig. 3) by gas-pressure in gas induction passage I9 until a sufficient head of oil is present in flow string in which case it will be forced into its lower position as shown in Fig. 2B. In this position annular space 8| registers with ports 80 and 82 to permit the gas under pressure to enter passage 13, pipe 93, to passage 96. If valve 3| is in the pressure cycle position (see Fig. 4) port 99 is blocked but if valve 3| is in the exhaust cycle position (see Fig. 2-A) recess 98 connects port 99 and port |00, venting the gas under pressure into liquid eduction conduit 25. 'I'he bore in bushing |02 is designed to have the proper cross section for the condition present. When some oil is-un loaded at the surface, the pressure or head in flow string 20 is decreased and the pressure on the lower or under face of valve 18 overcomes the column pressure plus the spring pressure to move the valve upwardly to cut 01T the flow of gas into the column.

It is to be understood that the form of our invention, herewith shown and described, is to be taken as a preferred example of the same and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from theI spirit of our invention, and further that the theories of operation set out, although believed to be accurate are not to be considered as the sole basis of operativeness of our device but that our device does operate successively, whether or not upon the principles described herein, our invention to be limited solely by the appended claims.

We claim:

1. In a pump comprising a body, a liquid eduction conduit extending through said body, a main valve and a supplemental valve in said body independently movable, said main valve serving to operate said pump, a gas passage extending between said liquid eduction conduit and the exterior of said body, said supplemental valve having a portion coacting with said gas passage to close or open the same.

2. In a gas lift system, a tubing string having a liquid accumulation chamber adjacent its lower end, a flow string within said tubing string and spaced therefrom, terminating in a pump body `valve means operating to cause the gas under pressure to act on liquid in said accumulation chamberto force said liquid up said discharge tube and eduction conduit to said flow string, a passage connecting said space and said liquid eduction conduit, and valve means in said passage exposed on one side to the pressure in said space and lon the other vside to the pressure in said liquid eduction conduit for closing and opening said pasage. y

3. In a pump comprising a body. a liquid eduction conduit extending through said body, a. main valve and a supplemental valve in said body independently movable, a gas passage extending between said liquid eduction conduit and the exterior of said body, said main valve and said supplemental valve each having portions coacting with said gas passage t close or open the same.

4. In a pump comprising a body, a liquid eduction conduit extending through said body, a main valve and a supplemental valve in said body independently movable, a gas passage extending between said liquid eduction conduit and the exterior of said body, said main valve and said supplemental valve each having portions defining a part of said passage in one position, and having further' portions closing said passage in another position.

5. In a pump comprising a body, a liquid eduction conduit extending through said body, a main valve and a supplemental valve in said body independently movable, intake and exhaust ports in said body, said main valve having a portion coacting with said ports to close and open said ports upon movement of said main valve, a gas passage extending between said liquid eduction conduit and the exterior of said body, said main valve and said supplemental valve each having portions coacting with said gas passage to close or open the same.

6. In a pump adapted to be connected at its upper end to a ilow string and at its lower end to a discharge tube, comprising a body having gas induction and exhaust means and a liquid eduction conduit, a main valve movable for controlling induction and exhaust of gas, means including a supplemental valve exposed on one side to the pressure in said liquid eduction conduit, a passage connecting the exterior oi said body with said liquid eduction conduit, said supplemental *valve in one position having means`foiclosing said passage and in another position for opening said passage.

7. In a pump adapted to be connected at its upper end to a ow string and at its lower end to a discharge tube, comprising a body having gas induction and exhaust means and a liquid eduction conduit, a main valve movable for controlling induction and exhaust of gas, means including a supplemental valve exposed on one side to the pressure in said liquid eduction conduit, a passage connecting the exterior of said body with said liquid eduction conduit, said main valve and said supplemental valve each in certain positions having means for closing said passage and in other positions for opening said passage.

8. In a gas lift system. a tubing string having a liquid accumulation chamber adjacent its lower end, a iiow string within said tubing string and spaced therefrom terminating in a pump body having a discharge tube within said accumulation chamber, said pump body including an eduction conduit connecting said dischargeA tube and said ow string, valve means associated with said pump body, a source of gas under pressure connected to the space between said tubing string and said dow string, said valve means operating to cause the gas under pressure to act on liquid in said accumulation chamber to force said liquid up said discharge tube and eduction conduit to said ilow string and additional valve means independently movable relative to said iirst mentioned valve means and cooperating with said first mentioned valve means to periodically admit the gas under pressure directly into said eduction conduit. i

9. In a pump adapted to be positioned within a tubing string, connected at its upper end to a flow string and at its lower end to a discharge tube, comprising a body having a liquid eduction conduit extending therethrough, and a gas induction and exhaust passage opening adjacent one end thereof, said passage having a gas intake port and a gas exhaust port opening on the exterior oi said body and in spaced relation along the length of said passage, sealing means for engagement with the tubing string positioned on the exterior of said body between said intake port and said exhaust port, additional sealing means positioned on the exterior of said body between said exhaust port and said passage opening, a movable valve in said body in one position closing said exhaust port and opening said intake port and in another position opening said exhaust port and closing said intake port, a supplemental valve in said body exposed on one end to the pressure in said eductionconduit, and a passage from the exterior of said body to said eduction conduit, each of said valves acting to block said passage in one position and to unblock said passage in another position.

10. In a pumping system, a tubing string having a seat adjacent its lower end, an exhaust port above said seat, and an accumulation chamber below said seat a flow string assembly positioned within said tubing string and spaced therefrom, comprising a ilow string, a pump body connected lto the lower end of said ilow string, and a discharge tube positioned within said accumulation chamber, connected to the lower end of said pump, an exhaust port in said pump body in the neighborhood of said iirst mentioned exhaust port, an intake port in said pump body above said exhaust port, a sealing member for the space between the tubing string and the flow string assembly positioned between said intake port and said exhaust ports, said space above said sealing member constituting a gas induction conduit, an -additional sealing member for the space between the tubing string and the ow string assembly below said exhaust ports, a liquid eduction conduit in said pump body connecting said discharge tube and said flow string, a valve chamber upon which said intake port and said second mentioned exhaust port open, gas induction and exhaust passage means connecting said accumulation chamber with said valve chamber, a source of gas under pressure connected to said gas induction conduit, a main valve in said valve chamber movable by the gas under pressure to close said second mentioned exhaust port while opening said intake port, a supplemental valve chamber, a supplemental valve movable in said supplemental valve chamber, one side of said valve being exposed to the pressure in said gas induction conduit and the other side being exposed to the pressure in said liquid eduction conduit, movement of said valve taking place due to the presence of a pressure differential, a passage between said gas induction conduit and said liquid eduction conduit. said supplemental valve having a portion which in one position oi said supplemental valve deilnes a part of .said passage and in another posi-.v

tion blocks said passage.

11. In a pumping system, a tubing string having a seat adjacent its lower end, an exhaust port above said seat. and an accumulation chamber below said seat a iiow string assembly positioned within said tubing string and spaced therefrom, comprising a ow string, a pump body connected to thelower end oi said iiow string, and a disama-iss charge tube positioned within said accumulation chamber, connected to the lower end of said pump, an exhaust port in said pump body in the-neighborhood of said iii-st mentioned exhaust port, an intake port in said pump body above said exhaust port, a sealing member for the space between the tubing string and the flow string assembly positioned between said intake port and said exhaust ports, said space above said sealing member constituting a gas induction conduit, an additional sealing member for the space between the tubing string and the ilow string assembly below said exhaust ports, a liquid eduction conduit in said pump body connecting said discharge tube and said flow string, a valve chamber upon which said intake port and said second mentioned exhaust port open, gas induction and exhaust passage means connecting said accumulation chamber with said valve chamber, a source of gas under pressure connected to said gas induction conduit, a main valve in said valve chamber movable by the gas under pressure to close said second mentioned exhaust port while opening said' intake port, a pilot valve for applying the gas under pressure to said main valve. said main valve being exposed to' the pressure in said accumulation chamber and movable thereby when the gas under pressure is not applied to said main valve to close said intake port and open said second mentioned exhaust port, a supplemental valve chamber, a supplemental valve movable in said supplemental valve chamber, one side of said valve being exposed to the pressure in said gas induction conduit and the other side being exposed to the pressure in said liquid eduction conduit, movement of said valve taking place due to the presence of a pressure diilerential, a passage between said gas induction conduit and said liquid educ'- tion conduit, said main valve and said supplemental valve each having a portion which in one position of each said main and supplemental valves dennes a part of said passage and in another position blocks said passage.

JAMES P. STEPHENS. FRANCIS E.s'1EELE. WILLIAM E. ELooD. CLARENCE M.

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