US2142484A

US2142484A - Gas-lift pump

Info

Publication number: US2142484A
Application number: US108275A
Authority: US
Inventors: Gerald P Jennings
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1936-10-29
Filing date: 1936-10-29
Publication date: 1939-01-03
Anticipated expiration: 1956-01-03

Description

Jan. 3, 1939.

G. P. JENNINGS GAS-LIFT PUMP 2 Sheets-Sheet l Filed Oct. 29, 1956 2 2 9 2 2 B 0 0 a M 2 5 3.. ,1 ,H H F ///V///r////// 5 6 l 0 2 l 6 W. 5 M 5 5 5 5 M m 4 7 M M 3 INVENTOR. GERALD P. JENNINGS -ATTORNEYS.

Jan. 3, 1939. G. P. JENNINGS GAS LIFT PUMP Filed Oct. 29, 1936 2 Sheets-Sheet 2 INVENTOR. GERALD P. JENNINGS YZ M 7? M A TTORNEYS.

Patented Jan. 3, 1939 PATENT OFFICE GAS-LIFT PUMP Gerald P. Jennings, Bartlesville, Okla assignor to Phillips Petroleum Company, a corporation of Delaware Application October 29, 1936, Serial No. 108,275

14 Claims.

This invention relates to devices for raising fluids from wells.

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

In wells such as oil wells, after the drilling operation is completed the well either flows naturally in which case the gas pressure in the producing strata or the bottom hole pressure is sufficient to force the liquid to the surface, or

the pressure will be sufficient only to force the liquid into the hole to about where the hydrostatic head will balance the bottom hole pressure. In wells which flow under their own pressure it is of course unnecessary to employ additional means to raise the liquid. As the well flows, however, the bottom hole pressures gradually become lower until such time when it is insuflicient to sustain natural flow or until such flow is no longer the most economical mode of production. In such event, extraneous measures must then be employed as in those wells which fail to-fiow naturally at the outset.

In some cases the gas-lift method is utilized,

f in which gas under pressure is introduced to a point in the liquid eduction conduit to aerate or lighten the liquid column and thus enable the existing bottom hole pressure to flow the well. Eventually, however, the bottom hole pressures become too low to make this practice feasible, in which case some form of pumping device must be employed, such as sucker-rod pumps, electrically driven centrifugal pumps or gas-lift pumps.

Objections to the sucker-rod pump include,

among others, the fact that expensive and bulky equipment is required at the surface to .reciprocate the long sucker rod, which in many instances may be thousands of feet in length. The stretch inherent in the material of the rods, as well as expansion and contraction, insert difliculties hard to-overcome.

Aside from the fact that the electrically driven pumps require a source of electrical energy, they are adapted primarily to wells 'of considerable production and the initial cost is high.

pump of greater capacity in the same limited space. Further no spring is used on the main valve to oppose the force of the gas pressure, leaving the full force effective for moving the valve. This feature is desirable to overcome possible sticking of the valve due to dirt, pipe scale, etc.- The arrangement is such that the travel of the exhaust is short and direct, cutting down back pressure and making possible more rapid exhaust of the accumulation chamber.

An object of the present invention is to provide a device for raising well fluids 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 for raising liquids which will be simple 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 invention is the provision of a device operable in accordance with pressures existing in the liquid eduction column. 5

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

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

' Fig. 1 is a view illustrating schematically the application of applicant's invention in a well hole,

Fig. 2 is a longitudinal section of applicant's device in a well hole,

Fig. 3 is a cross sectional view taken on the line 3-3 of Fig. 2,

Fig. 4 is a cross sectional view taken on the line 44 of Fig. 2,

Fig, 5 is a cross sectional view taken on the line 5-5 of Fig. '2,

' Fig. 6 is a longitudinal section of another embodiment of the applicants invention.

Fig. 7 is a cross sectional view taken on line 1'l of Fig. 6,

Fig. 8 is a cross sectional view taken on the line 8-8 of Fig. 6,

Fig. 9 is a cross sectional view taken on the line 99 of Fig. 6, and

Fig. 10 is a schematic showing of the embodiment shown in Fig. 6, in a well hole.

Referring to Figs. 1 to 5 inclusive, a well hole is indicated lined with casing II which is cemented to the bore at l2 in the neighborhood of the producing formation. Within the casing II is a tubing string |3 screw threaded at its lower end to a nipple l4 which in turn is screw threaded to an accumulation chamber I5 having its lower end closed by a standing valve |5. The nipple H has a seat i1. formed on its interior surface having therein a recess |8 opening at intervals through ports |9 to the exterior, the purpose of which will be later herein described. Within the tubing string I3 is positioned a fiow string 20 adapted to be connected at the surface of the ground with an oil storage or utilization point. This flow string 28 is screw threaded through adapter 2| to a pump barrel formed of a nipple 22 and a body member 23. Extending through the body member 23 is a liquid discharge or eduction conduit 24 screw threadedly connected at its lower end to discharge tube 25 which is closed at its lower end by a check valve 26. The

.eduction conduit 24 opens at its upper end on the interior of nipple 22 and flow string 20. The pump body further includes a bore designated generally at 21, opening at its lower end in the top of the accumulation chamber. Body member 23 is reduced in cross section at its lower end so as to make an hermetic seal with seat H on nipple |4 above and below recess l8. Bore 21 isopen to recess |8 through exhaust ports 28. Above the seat IT in nipple I4 is a recess 29 defining the end of the space 58, formed between the inner string, made up of flow string 29, nipp1e'22, and pump body 23, and the outer string made up of tubing string l3 and nipple 4. Bore 21 is open to recess 29 through intake or induction port 38. Slidably mounted in bore 21 is a main valve 3| consisting of a hollow cylindrical member 32 iiitegrally joined through a reduced portion 33 to a piston head 34. The annular space 35 around the reduced portion 33 is in communication with the inside of cylindrical member 32 through openlugs 35. Movement of this valve in bore 21 is limited by a stop 31 and a portion formed by the closed end of cylindrical sleeve 38 which is fixed in the upper end of bore 21. Slldable in cylindrical sleeve 38 is a pilot vlave 39 in the form of a piston, having a valve head 40 adapted to close an orifice 4| in the closed end of cylindrical sleeve 38. A port 42 connects the space between the valve piston 39 and the valve head 40 with the exterior of pump body 23. To achieve a distributed .pressure, while presenting a large impact surface, valve 3| has a valve face 43 on piston head 34 (see Fig. 4) which is axially bored at 44 and radially bored at 45, 45, the last mentioned bores being in communication with bore 44 and bore 44 registering with orifice 4| when the valve 3| is in its uppermost position. Thus an annular space 45 between the partition 38 -and the body of piston head 34 is formed. A

port 41 connects this annular space 48 with a bleeder passage 48 which in turn connects with port 49 opening on recess l8. Bleeder passage 48 extends upwardly beyond port 41 to open into port 41' in the upper end oi. cylindrical plug 38 above the upper face of piston valve 39. The extainer 56 on its lower extremity. A lock nut is shown at 51. The plug 54 is capped at l2.

From recess 29 to the surface of the ground, the concentric tubing string and flow string with their terminal fittings define a continuous anriular space 58 as mentioned above, which is closed above the surface at 59. A source supplies gas under pressure, air or gas, through pipe 60 controlled by a hand operated valve 8| and an intermitter 62 to the space 58. The intermitter may be of any well known form. The entire bore or well hole is open up to the surface of the ground from the bottom hole 54 through the space 63, defined by the tubing string I3 and the casing H.

In the operation of the device of Figs. 1 to 5 inclusive with no gas pressure applied to space 58, herein termed an intake or induction passage or conduit, oil in the bottom hole 64 will fiow past standing valve l6 into accumulation chamber l5 due to gravity. Valve 3| will be in the position shown in Fig. 2 leaving the accumulation chamber open to atmospheric pressure through an exhaust passage or conduit formed by bore 21, ports 28, recess |8 and ports l9. Thus the oil in chamber 5 will seek the level of the oil in the bottom hole. When the oil in the accumulation chamber has been given sufficient time to enter, the intermitter 62 opens to allow gas under pressure to enter induction or intake passage 58. 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 5| by means of set screw 55 has previously been tensioned so that a predetermined pressure on the face of valve 39 is necessary to move it and thus move valve head 48 away from orifice 4|. Upon this happening, the gas pressurewill be applied through orifice 4|, and bores 44, 45 to annular space 46, forcing the valve 3| downwardly into engagement with stop 31. It is apparent that valve 3| in this position closes exhaust port 28 and uncovers intake or induction port 38 so that the gas pressure is admitted from recess 29 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 21 to the surface of the oil in the accumulation chamber. With this pressure acting upon the oil the valve |6 closes, the oil is forced past valve 26 and up discharge tube 25, discharge or eduction conduit 24 to flow string 20. The intermitter 62 continues the application of the gas pressure until all the 011 above the lower end of discharge tube 25 is exhausted from the accumulation chamber. Usually further pressure is continued until a slug of gas is forced up the eduction conduit behind the oil. This slug of gas by its expansion keeps the oil moving upward. At this point the intermitter 52 cuts off the flow of gas and the exhaust cycle commences. The pressure in passage 58 begins to decrease. When it gets to the point at which pilot valve 39 can no longer be held open against the action of spring 5|, the pilot valve closes, closing orifice 4|. The gas trapped between the piston head 34 and orifice 4| bleeds off through port 41 passage 48, port 49, recess l8, and ports |9 to space 53 which is substantially at atmospheric pressure. 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. This also applies to port 41 which allows any gas leaking past the pilot valve piston to escape. Considering again the valve 3|, as the gas pressure beand ports I9 to space03'. When the exhaust from I2 and port 41' shown chamber|5 is completed and the pressure in the chamber approaches atmospheric pressure, valve 3| is prevented from falling down against stop 31 by the residual gas pressure at 30 forcing the valve against the opposite wall of the chamber. With the pressure in the accumulation chamber reduced, valve will open to admit oil into the chamber and the pump is. again ready for the pressure cycle.

It is evident that the pump can be so operated that the oil being carried up theflow string 20 after valve "has closed for the exhaust cycle may still be in motion due to the expansion of the gas slug, when the valve 26 again opens during the pressure cycle. Thus the inertia of the oil in the flow string need not be overcome with each pressure impulse. It is further evident that due to a substantial head of oil in the well hole, rapid operation of the intermitter with accompanying rapid action of the valves, that pressures in the accumulation chamber and exhaust passages during the exhaust cycle may be above atmospheric pressure without reducing the efficiency of the pump. Throughout this specification by the term gas", I refer to any expansible fluid.

In Figs. 6 to 10 inclusive a modification of the device is shown in which the need for an intermitter at the surface is dispensed with and some of the elements are shown in a more practical embodiment. The cylindrical fitting 50 is apertured at IOI subjecting the upper face of the pilot valve piston 39 to the pressure present in nipple 22 which is the flow string'pressure. Cap

in the preceding embodiment can be eliminated. Pump body 23 has annular recesses I02formed on its exterior surface closed by a screen I03. Port 42 and port 30 open on two of these receses I02, ,a third port I04 opening on the third recess. This latter port I04 opens interiorly of pump body 23 on an annular 'gr'oov I05 formed in pistonhead 34, when the valve 3| is in the exhaust position. When the valve 3| is in the intake or induction position.

port I04 is closed by extension I06 of piston head 34, annular groove I05 in the exhaust position of valve 3| communicates with discharge or eduction conduit 24 through port I01. When valve 3| is in the induction position port I01 is closed by piston head bore 21 traversedby valve 3| is shown lined by a suitable hard metal liner I 08 to improve, the wearing qualities of the pump. Instead of the seating arrangement I1 and recess I8 of Figs. 1-5 inclusive a modified structure is shown. Nipple I4 carries at its lower end a shoulder or ledge I09 upon which shoulder IIO of pump body 23 rests. A shoulder III is formed on pump body 23 above exhaust ports 28. Gaskets or packings ||2 spaced by spacer 3 are positioned on pump body 23 above ports 28 and gaskets or packlngs ||4 spaced by spacer II5 below ports 23 in the reduced portion formed between shoulders H0 and III. These gaskets make an hermetical seal on both sides of ports 20 with nipple I4. An annular channel IIG with openings III spaces the gaskets H2, 4 from the ports 23 at the same time allowing communication between ports 28 andports II in nipple I4. Elements 0, H2, H3,

extension I06. That portion of the H4, H5 and II! are slidably mounted on pump body 23. Thus the weight of the flow string assembly expands the gaskets or packers to form the above mentioned seal with the nipple I4. At the surface a pressure reducing valve is shown at III! for applying constant pressure to space 50. Obviously if the gas in pipe is at constant pressure, device 3 may be omitted. In this embodiment accumulation chamber I5 is attached directly to and supported by the pump barrel at II9. This makes it possible to inspect and repa r the entire pump system by pulling only the flow string.

The operation of this embodiment is the same as that previously described with the exception of the manner of operating the pilot valve 39 and the addition of gas path I04, I05, I01.

With constant gas pressure in space 59, the pilot valve in the position shown in Fig.6, and a column of oil of the proper height in the flow string, gas will enter port 42 forcing pilot valve 39 into its uppermost position. This will open orifice 4| allowing the gas pressure to be exerted on the face of valve 3| moving that valve into its lowermost or gas induction position. The gas pressure will then be applied to the surface of the liquid in accumulation chamber I5 forcing the liquid past valve 26 into eduction or discharge conduit 24 and up the flow string 20. This operation will continue until sufllcient oil has passed the apertures IN to build up the pressure or hydro-static head at this point due to the entire column of oil and gas which head acting upon the upper face of the piston of pilot valve 39 and aided by spring.50, will force the valve down despite the gas pressure acting on the lower face of the piston. It is to be noted that two forces act on the valve 39 from below. The first is the result of the gas pressure on the piston, less the area of orifice 4| when the valve is down. The second is the result of the gas pressure on the entire area of the piston when the valve is up. Thus valve 39 raises at a lower pressure in eduction conduit 24 than it will take in the same conduit to close it. This insures that a reasonable length slug of oil will pass apertures IOI before pilot valve 39 is closed. valve 39 closes orifice 4|. This starts the exhaust cycle which is the same as that in the previous embodiment with the added feature that gas under pressure in space conduit 24 through port I04 groove I05 and port I0'I to keep the oil column moving upward. It is to be understood that this injection of gas is not always necessary and that the feature may be om ted. When enough oil has been unloaded at the surface, the pressure in the oil column will.

be lowered to the extent that with spring 50 it can no longer hold valve 39 down against the pressure from space 58. Valve 39 rises and the pressure cycle in the accumulation chamber is again started. Thepressure in the oil column is always less than the gas pressure due to the.

fact that the spring 50 aids the pressure in the column. Therefore any leakage past the piston of valve 39 will be fromihe gas side.

Obviously an intermitter could be used with this embodiment in which case the tension of spring 5| could be considerably reduced or the spring could even be eliminated since the pressure in the flow string tends to return the pilot valve to close orifice 4|.

It can be seen that whether or not an intermitter is used,- a sufllcient head of oil must be built up in the flow column to produce a proper The lowering of pilot 5s flows into eduction pressure at port llll for forcing the pilot valve down into position to close orifice 4! against the pressure existing at port 42. One Way of obtaining this condition is set out below. A valve (not shown) on flow string 20 at the surface is closed. Valve 6| is opened. If valve 3| is in its lowermost position, the pressure will be admitted directly into chamber l5. If valve 3| is in its uppermost position, valve 39 will be raised and valve 3| will be forced into its lowermost position. The oil in chamber l will be forced up the flow string 20 until, due to flow string 20 being closed atthe surface, pressure will build up in the flow string sufliciently to force valve 39 down, valve 3| will rise, exhausting chamber l5, which will then fill with oil. The flow string 20 will then be bled at the surface valve sufficiently to cause valve 39 to rise. These steps can be repeated until the height of oil in the flow string 20 is suflicient to operate valve 39 at which time the valve at the surface in flow string 20 is left open.

In both modifications the tension of spring 50 and the relative sizes of the parts of the pump can be designed to meet any specific well conditions to be encountered.

It is to be understood that the form of my 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 the spirit of my 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 the operativeness of my device but that my device does operate successfully whether or not upon the principles described herein, my invention to be limited solely.

by the appended claims.

I claim:

1. In a gas-lift pump including a liquid ac cumulation chamber, a valve chamber havinga portion in communication with said accumulation chamber, gas admission and exhaust ports in said valve chamber, a main valve in said valve chamber slidable to open one of said ports while closing the other, a source of gas under pressure, a pilot valve in said chamber in communication with said gas under pressure and responsive to said gas pressure to control the pressure on one side of said main valve, the other side of said main valve being exposed to pressure in said chamber.

2. In a pump, a barrel, gas pressure input and exhaust ports formed in said barrel, a valve chamber within said barrel connecting with said ports, a valve having a body portion in movable close fitting relation to the walls of said valve chamber, said body portion having a recess opening at one end thereof, a gas pressure conduit in said barrel, opening on said valve chamber and in continuous communication with the recess in said body portion, in one position of said valve, said input port, said valve chamber, said body recess, and said gas pressure conduit constituting a continuous gas pressure input passage, in another position of said valve, said exhaust port, said valve chamber, and said gas pressure conduit constituting a continuous exhaust passage.

3. In a pump, a barrel, gas pressure'input and exhaust ports formed in said barrel, a valve chamber within said barrel connecting with said ports, a valve having a body portion in movable close fitting relation to the walls of said valve chamber, said body'portion having an opening in one end and side joined to form a passage therethrough, a gas pressure conduit in said barrel, opening on said valve chamber and in continuous communication with the body portion passage in said body portion, in one position of said valve said input port, said valve chamber, said body portion passage and said gas pressure conduit constituting a continuous gas pressure input passage, in another position of said valve, said exhaust port, said valve chamber, and said gas pressure conduit constituting a continuous exhaust passage.

4. In a gas pressure pumping system, a tubing string terminating in an accumulation chamber, a seat in said tubing string adjacent said chamber, a flow string disposed within said tubing string and forming a space therebetween, said fiow string terminating in a pump body, said pump body contacting said seat to close said space, a liquid discharge conduit in said pump body connected to said flow string and terminating in a discharge tube having a check valve adjacent the lower end thereof, a source of gas under pressure connected to said space, said pump body including a pilot valve, a main valve, an intake port and an exhaust port, said pilot valve in one position operating to apply said gas at a predetermined pressure to said main valve for movement thereof, said intake port connecting said space and the accumulation chamber upon said movement, and means whereby with said pilot valve in another position, the main valve is moved by the gas pressure in said accumulation chamber to connect said accumulation chamber and said exhaust port.

5. In a gas pressure pumping system, a tubing string terminating in an accumulation chamber,

a flow string disposed within said tubing string and forming a space therebetween, said flow string terminating in a pump body, a liquid discharge conduit in said pump body connected to said flow string and terminating in a discharge said space, said pump body including a pilot 0 Z'alve, a main valve, an intake port and an exhaust port, said pilot valve in one position operatingto apply said gas to said main valve for movement thereof, said intake port connecting said space and the accumulation chamber upon said movement, and means whereby with Said pilot valve in another position, the main valve is moved by the gas pressure in said accumulation chamber to connect said accumulation chamber and said exhaust port.

6. In a pumping system in which gas under pressure is applied to liquid in an accumulation chamber, forcing the liquid through a discharge conduit and in which the pressure is automatically reduced by movement of a main valve in accordance with the pressure in the discharge conduit, in combination, a main valve for controlling the application of the pressure gas to the accumulation chamber, a, pilot valve in the form of a piston, one end of said pilot valve being exposed ly reduced by movement of a main valve in accordance with the pressure in the discharge conduit, in combination, a main valve for controlling the application of the pressure gas to the accumulation chamber, a pilot valve in the form of a piston, one end of said pilot valve being exposed to said gas under pressure'the other end being exposed to said discharge conduit, said pilot valve having spring biasing means opposing said fluid pressure.

8. In a pumping system in which gas under pressure is applied to liquid in an accumulation chamber, forcing the liquid through a discharge conduit and in which the pressure is automatically reduced by movement of a main valve in accordance with the pressure in the discharge conduit, in combination, a main valve, 9. pilot valve in the form of a piston, one end of said pilot valve being exposed to said gas under pressure, the other end being exposed to said discharge conduit, said main valve in one position presenting means for introducing the gas under pressure directly into the discharge conduit.

9. In a pumping system in which gas under pressure is applied to a liquid in an accumulation chamber forcing the liquid up a flow string, the application of the gas under pressure being controlled by a main valve in accordance with the pressure in the flow string, comprising, a main valve, a pilot valve mounted for movement in accordance with the differential pressure between the gas under pressure and the pressure in the flow string, said movement of the pilot valve controlling the operation of the main valve and means whereby the gas under pressure is admitted directly to the flow string when the main valve isolates said gas from the accumulation chamber.

10. In a device for raising liquids from a well including a chamber for.the accumulation of liquid therein and a liquid eductionv conduit, a valve unit placing said liquid eduction conduit in communication with said chamber. gas admission and exhaust ports in said unit, a pressure operated piston valve in said unit for alternately closing and opening said ports; a pilot valve in said unit for controlling the operation of said pressure operated valve, ports in said unit adapted to place said pilot valve in communication'with a source of pressure and the liquid eduction conduit, said pilot valve being operable in accordance with the pressure difierential therebetween, and means for adjusting the pressure diflerential required to operate said pilot valve.

11. In a device for raising liquids from a well,

a tubing string extending into said well and provided with a liquid accumulation chamber at one end thereof, a second tubing string within said first tubing string and in communication with said chamber for the eduction of liquid therefrom, a source of gas under pressure in communication with said chamber through said first named tubing string, valvemeans to control the admission of gas to said chamber responsive to variations of pressure in said liquid eduction tubing. 7,

12. In a device for raising liquids from a well, a chamber for the accumulation of liquid therein, a conduit in communication with said chamber for the eduction of liquid therefrom, a conduit for the induction of gas to said chamber, gas operated valve means in said gas induction conduit for controlling the flow of gas therethrough, pilot valve means in communication with said gas induction conduit andsaid liquid eduction conduit and operable by the pressure differential between the same to control the admission of operating gas to said gas operated valve.

13. In a pump system for wells, a tubing string having an exhaust port adjacent its lower extremity, a flow string within said tubing string carrying at its lower end an accumulation chamber and a pump barrel above said accumulation chamber, said pump barrel having an exhaust port opening adjacent said first mentioned exhaust port and a resilient gasket above and below said exhaust ports between the tubing string -said shoulder, an exhaust port in said tubing string, an exhaust port in said flow assembly, a plurality of packing members, the space between said tubing string and said flow assembly being closed above said exhaust ports by one of said packing members and below said exhaust ports by another of saidpacking members.

. GERALD P. JENNINGS.