US2469225A - Means for flowing wells - Google Patents

Description

May 3, 1949. V o. EQDEMPSEY 2,469,225

' umus FOR FLowme WELLS Filed Feb, 4, 1946- s Sheets-Sheet 1 a re Patented May 3, 1949 UNITED STATES PATENT OFFICE MEANS FOR FLOWING WELLS Oscar E. Dempsey, Tulsa, Okla., asslgnor to Dempsey Pump 00., Tulsa, Okla., a corporation Oklahoma Application February 4,1946, Serial No. 645,305

11 Claims.

strata into a lower filling chamber and is displaced by input pressure fluid controlled through the operation of a valve mechanism in the lifting unit. The displacement operation is dependent upon overcoming a differential pressur across a lower liquid discharge valve which is moved relative to an outlet passageway for allowing discharge of fluid from the filling chamber to a reservoir located at a higher level. Movement of the liquid discharge valve is through the full length of its stroke or travel which in turn will effect an operation of the valve controlling mechanism to close ofi the supply pressure fluid regardless of whether all of the production fluid in th lower filling chamber is displaced or not. Furthermore, actuation of the valve mechanism by the discharge valve to shut off supply of pressure fluid simultaneously provides for the exhaust for all residue supply pressure fluid present in the filling chamber and connecting passageways to eliminate any counteracting pressure against the sand pressure of the production fluid. This provides for a constant emission of fluid into the filing chamber except for the momentary interruption during the displacement operation. 4

The present invention differs from applicant's co-pending application supra in that the structure in the lower portion of the lifting unit controlling the discharge of the production fluid from a lower filling chamber to the reservoir has been improved to assure a more positive and substant ally complete displacement of the productionfluid present in the lower filling chamber prior to actuation of the valve controlling mechanism for closing off the motivating supply pressure fluid as well as the bleeding ofi of the exhaust pressure.

It is, therefore, an important object of this invenion to provide a lifting unit for the disp acement of fluid from a well which progressively lifts quantities-of the fluid from a lower collection chamber to a reservoir disposed at a higher level, said lifting unit having a valve mechanism for controlling the discharge of supply pressure fluid into the lower chamber wherein a portion of the displaced fluid acts as a snubber 5 to maintain said valve mechanism in an open position for the discharge of the input pressure fluid until substantially all of the production fluid from the lower chamber is displaced.

Still another object of this invention is to 10 provide a lifting unit for displacing oil from a well by progressively lifting quantities of fluid from the lower collection chamber to a reservoir disposed at a higher level, said lifting unit having a valve mechanism controlling the input of sup- 15 ply pressure fluid into the lower chamber for displacing the fluid as well as the exhausting of the residue supply pressure fluid after displacement of the fluid from the lower chamber.

And still another object of this invention is to provide a lifting unit for displacing fluid from a well having an automatic valve mechanism controlling the discharge of supply pressure fluid into the well for displacing the well fluid and the exhaust of residue supply pressur fluid after displacement of the fluid, wherein the control mechanism prevents exhaust of supply pressure fluid during the displacement of the well fluid and similarly prevents the supply pressure fluid fromdisplacing the well fluid during exhaust of residue supply fluid after displacement.

Another object of this invention is to displace oil from a well in such a manner to conserve the bottom hole pressure of the well in order to maintain a substantially constant emission of well fluid from the sand strata whereby oil can be continually emitted into the eduction tubing without regard to intervals of time.

And still another object of this invention is to bleed off residue supply pressure fluid from a small section of the well depth from which oil from the sand strata is displaced therefrom, said bleeding allowing expeditious and repetitious flow of oil from the strata into said displacement chamber, thereby eliminating considerable intervals of time which oil may be displaced.

And still another object of this invention is to allow escape of formation gas to the well surface at all times except a momentary period when oil is being displaced or slugged to the top of the well.

And an additional object of this invention is the economic use of small volumes of gas in cubic feet fOr progressively lifting small amounts of fluid into a reservoir to be intermittently slugged in predetermined quantities, thereby eliminating the well bore.

the use of large volumes of gas to slug small amounts of entrapped oil all the way through the tubing string.

Other objects and advantages of the invention will be evident from the following detailed description read in conjunction with the accompanying drawings which illustrate my invention.

In the drawings:

Fig. l is a fragmentary sectional view showing part of the lifting unit disposed in a well bore.

Fig. 2 is an extension of Fig. 1 showing in elevation the lower portion of the lifting unit disposed in the well bore.

Fig. 3 is a fragmentary sectional elevational view shown schematically and slightly enlarged for clarity of the liftin unit disposed in the well casing with the valve mechanism shown in one position before displacement of the well fluid.

Fig. 4 is a view similar to Fig. 3 showing the position of the valve mechanismof the lifting unit h in a stage of operation.

Fig. is a similar view showing another position of the valve mechanism for the lifting unit during the displacement of the well fluid.

Fig. 6 is a similar view to Fig. 5 showing the final position of the valve mechanism for the lifting unit upon completing the operation of displacing the well fluid.

Referring to the drawings in detail particularly Figs. 1 and 2 reference character 2 represents a string of tubing disposed in spaced relation to the well casing 3 extending to the sub-surface producing strata of the well. A packing assembly 4 is connected to the tubing 2 by a collar 5, and comprises an outer cylindrical housing 6 having its outer periphery provided with a plurality of spaced annular packing glands 1. Below the packing glands the housing 6 is provided with a pair of diametrically opposed belly springs 8 having serrated slips 9 securing the assembly in the well casing. The springs are secured to the housing 6 by welding or the like. The cylindrical housing is provided with a longitudinal port Ill providing communication with the chamber ll between the housing 6 and easing 3 for the discharge of production and formation gas as will be hereinafter explained. A ball check valve I2 is provided in the upper portion of passageway in for formation gas discharging therethrough to the interior of the tubing 2. A string of tubing I3 is disposed in the housing 6 in spaced relation thereto. Packing I4 is interposed between the tubing [3 and inner periphery of housing 6.

A plurality of annular spaced apertures I5 provide communication between a chamber l6 conpressure fluid into the lifting unit l8 as will be hereinafter explained. The tubing I3 is connected by a collar I9 to a lower tubing string of larger diameter extending downwardly and secured to a supportingmember 24 as will be hereinafter set forth. Extending from the lowermost portion of housing 6 is an intermediate string of tubing 23 arranged in spaced relation between casing 3 and tubing 20. The tubing 23 extends downwardly from the housin 6 to the bottom of position is provided with an inwardly projecting ing shoulders 25 adapted to cooperate with an outwardly projecting flange 26 provided in the central portion of the cylindrical housing 22.

The tubing 23 at a predetermined Packing rings 21 surround the housing 22 at the jointure of the tubings 20 and 23 with the member 24. The lowermost end of the tubing 23 is provided with a perforated plug or gas anchor 28 for a purpose as will be hereinafter set forth. A cylindrical tubing 29 extends downwardly from the lowermost portion of the housing 22. An apertured plug 36 is secured to the lower end of tubing 29 and is anchored in the gas anchor 28 by packing rings 3 I.

The upper portion of the housing 22 is provided with a plurality of vertical bores 32 and '33 for receiving a differential valve unit 34 as will be hereinafter set forth. The housing 22 is further provided with a valve bore 35 communicating with a chamber 36 which in turn communicates with chamber 31. l The valve bores and chambers contain an automatic valve mechanism similar to the valve mechanism disclosed in applicants copending application heretofore-mentioned. The lowermost portion of the housing 22 is provided with a bore 38 communicating with a lower chamber 39 which houses a cylindrical piston having a main body portion or circular flange 4| provided with oppositely extending cylinders 42 and 43.

Referring now to the main valve unit 44 (Figs. 3 to 6, inclusively), a loosely disposed elongated valve 46 is disposed in the bore 35. A substantially cylindrical slide valve 41 is disposed in chamber 36. Wholly confined within the slide valve, and movable therein, is a piston valve 48. A pair of latch members 49 are loosely secured on studs 50 anchored in the chamber 36. A valve locking pushrod 51 is disposed in the chamber 36 immediately below the valve 46 and comprises an upper shaft 52 and a lower shaft 53. The rod 5! extends between the latch members 49 and into the interior of valves 41 and 48. A sleeve 54 loosely surrounds the lower shaft 53 and is provided with a groove 55 for a purpose as will be hereinafter set forth. The lower face of sleeve 54 is provided with a shoulder 56 for anchoring one end of a helical spring 51 having its opposite end resting on a surface 58 of valve 48. The valve 48 is provided with a transverse port 59 communicating with vertical ports 68 in .turn communicating with chamber 36. The outer valve 41 is provided with a port 6| and immediately below is a second port 62 for a purpose as will be hereinafter explained. The upper central portion of the housing 22 is provided with a passageway 63 communicating with an annulus 64 which in turn communicates with a plurality of circumferentially spaced apertures 65 providing communication with the inlet chamber II. In similar manner a vertical passageway 66 communicates with an annulus 61 provided in housing 22, which in turn communicates with a plurality of circumferentially spaced apertures 68 communicating with the exhaust chamber i I.

From the foregoing, it will be apparent that the above-described structure is similar to that of applicants co-pending application heretofore-mentioned; however, the lower portion of the housing 22 is constructed as to provide the piston unit 40 and complementary structure I tends in spaced relation through an aperture III 3 provided by inwardly projecting shoulders H of the cylinder 29 to'a position below the shoulders and into a chamber 12 provided in the lowermost portion of cylinder 29. The lower end of cylinder 43 is provided with a cage 13 in which is disposed a ball check valve 14 cooperating with an aperture 15. The cylinder 29 is provided with a plurality of circumferentially spaced apertures 18. A second set of circumferentially spaced apertures 11 are provided in the cylinder 29 in vertically spaced relationship to apertures 16. The plug 38 is provided with a ball check valve 19 cooperating with an aperture 18.

The upper end of piston cylinder 42 is provided with a plurality of apertures 88 for a purpose that willl be hereinafter explained. A pistonextension rod 8| comprising an upper shaft 82 and a lower shaft 83 cooperates with piston cylinder 42. The lower shaft 83 extends through a centrally disposed aperture 88 of cylinder 42 and is provided with a projection 83 of increased diameter confined within the interior of piston cylinder 42. The upper shaft 82 extends through an aperture 84 provided by inwardly projecting shoulders 85 of housing 22. The shaft 82 is provided with a circular flange 88 adapted to contact the shoulders 85 and maintain the upper portion of shaft 82 in chambers 31 and 38. The flange 4| is provided with a plurality of circular packing cups 88 preventing leakage past the piston flange into the chamber 39.

It will be apparent that the sand pressure of the well will cause fluid from the production strata to flow through the plug 28, aperture 18, past valve 19, and through apertures 18 and 11, thereby filling chambers 12 and 98 with production fluid. It will be apparent from Fig. 3 that the oil builds up in these filling chambers for displacement to a reservoir located at a higher level.

Motive fluid pressure tained in the well from a surface compressor or like equipment (not shown) into the chamber l6 and discharges into the inlet passageway I1, port 83, into constant communication with upper valve units'34 and 44. Referring now to the valve unit 44, with production fluid standing in the lower filling chambers 12 and 98, Fig. 3, it will be understood that production fluid is also present above the piston flange 4| in chambers 39, bore 38, and the reservoir due to a previous displacement operation of fluid from the lower filling chambers as will be more fully set out. The input motive pressure discharges from port 83 into a bleed port 92 provided in main valve 48 and leaks between the valve 48 and its bore into the chamber 38. It is to be understood that the fit of the valve 48 in its bore 35, especially the lowermost end of the valve below the horizontal leg portion of the bleed port 92, is such that the input pressure fluid discharging from port 92 is allowedto leak between the outer periphery of valve 48 and its bore into the chamber 38. The small amount of pressure fluid constantly leaking through port 92 into the chamber 38 is not suflicient to warrant any displacement of liquid in the filling chambers 12 and 98. With the mechanism of the lifting unit l8 in the position as shown in Fig. 3, the leakage pressure flowing into chamber 38 with the aid of tension spring 51 will cause downward vertical movement of valve 48 until the port 59 moves past the port 8|, thereby closing off the chamber 38 from exhaust passageway 88. The downward movement of valve 48 contacts the base 93 of valve 41 and conis constantly maintinned leakage of supply pressure fluid into chamber 38 will build up the pressure therein, moving valve 41 downward out of contact with the locking latches 49. The valve 41 is held by friction and does not'move downward of its own weight during the preliminary movement of valve 48. Furthermore, during the preliminary movement of valve 48, the sleeve 54 is prevented from moving downward by thetension of spring 51. As s0on-as the top of valve 41 moves below the shoulders 94 of the locking latches 49, the latches are free to swing transversely outward in the chamber 38 (Fig. 4), thereby releasing the locking pushrod 5|. The rod 5| is then moved downward by valve 48 actuated by input pressure fluid. Movement of valve 48 downwardly (Fig. 4) opens passageway 95 to input pressure fluid which is directed therethrough and into chamber 31 below the chamber 38.

A passageway 98 provides communication between chamber 31 and chamber 39 at a position below the piston flange 4|. With the production fluid displaced by a previous operation to a position above the piston flange 4| as shown in Fig. 4, discharge of input pressure fluid below the flange at a greater pressure than the static pressure of the production fluid in chamber 39, bore 38, and reservoir 9| will move the piston 48 vertically upward; however, upward movement of the piston is limited due to a decrease in volume of oil in chamber 39, whereby the oil present in chamber 39 acts as a snubber to momentarily retard upward movement of the piston 4| and prevent actuation of the valve mechanism until substantially all of the fluid is displaced from the filling chambers. With the snubbing action momentarily precluding further upward movement of the piston 48, the input pressure is then directed through port 18 and outlets 16 into contact with the well fluid in the chambers 12 and 98. As soon as the input pressure fluid increases sufliciently greater than the static pressure of the fluid in the filling chambers, it will cause displacement of the fluid from the chambers 12 and 98 through the ball check valve 14 and into the interior of piston 48. The production fluid being displaced through the interior of piston 48 discharges through apertures 88, bore 38, outlet aperture 89, and into the reservoir 9|.

It will be apparent that simultaneous with the displacement of thefluid from the chambers 12 and 98, the input pressure fluid continues to act against the underface of piston flange 4|. With the production fluid displaced through piston 48, the input pressure fluid discharging through annulus 18 also flows through the interior of piston 48, apertures 88 and into bore 38, causing a complete displacement of liquid into the reservoir 9|.

The diameter of outlet aperture 89 is greater than the annulus 18 formed by the spaced relation of cylinder 43 and shoulder 1|, which provides for,

a faster discharge of the input pressure fluid through the outlet orifice 89 than the discharge thereof through the smaller annulus 18. This results in a decreased pressure condition in bore 38, allowing the oil in chamber 39 surrounding the piston cylinder 42 to be discharged into the annulus 99, bore 38, and the outlet 89. The annulus 99 is formed by the spaced relation of the cylinder 43 to the bore 38. The displacement of fluid from chamber 39 above the piston is due to input pressure fluid contacting the underface of piston flange 4| and it will be apparent that the snubbing action of the fluid above the piston flange and tubing 2 to the top of the well.

has been relieved, thereby causing the input pressure fluid to move the piston 40 to completion of its upward stroke as shown in Fig. 6. The final upward vertical movement of piston 40 causes the top portion of piston cylinder 43 to contact the larger shaft 02 of piston rod 8| (Fig. 6), thereby moving the rod 8| upwardly through the apertured base 93 to'causevertical upward movement of valve 48 and position ports 59 and 60 into communication with port 8|, thereby exhausting the pressure in chamber 38 into passageway 68. Simultaneous with upward movement of valve 48, there is a vertical upward movement of pushrod causing the upper shaft 82 to move out of contact with the locking latches 49 so they may swing transversely inward into the V-shaped groove 55 of sleeve 54, at which time the rod shoulder 86 and supply fluid pressure in chamber 31 contacts the underface of valve base 93 to move valve 41 vertically upward. The movement of rod 5| is assisted by tension spring 51. Vertical upward movement of rod 52 causes movement of valve 46 upward against the input pressure fluid to close of! the passageway 95.

In this position (Fig. 6), the locking latches 49 have been swung inwardly to lock the rod 5| and valve 46 in closed position. The movement of the valve 41 vertically upward positions the port 52 into communication with exhaust passageway '68.

The residue input pressure fluid in passageways 95, 96, and chamber 31, as well as chambers I2 and 90, is allowed to exhaust through the apertured base 93, port 82, to the exhaust passageway 63, chamber II, passageway I0, valve I2, With the input pressure fluid cut off from passageway 95 and the oil displaced from the chamber 90, it will be apparent that the production strata can flow through the apertured plug 28 without interference from residue input pressure fluid. Furthermore, the static head of displaced fluid standing in reservoir 9| falls back through outlet port '89, bore 38, and this pressure with the assistance of gravity moves the piston 40 vertically downward in chamber 39 to a position shown in Fig. 3.

It will be understood that the relationship of pressures is commensurate with the areas "with the various valves, pistons, and bores and the ratio between them is a matter of choice dependent upon a particular well. Furthermore, the length 'of tubing providing the reservoir 9| is much longer than the tubing for the filling chambers I2 and 90 in order to provide a larger storage chamber or reservoir. In practice it has been found that a ratio of 10 to l is satisfactory. It will also be understood that the formation gas from the production strata is liberated from 'the well through chamber II along with the exhaust or residue supply pressurefluid exhausting through the passageway 65.

The upper portion of housing 22 is provided with the differential valve unit 34 which functions to allow discharge of supply pressure fluid into the reservoir 9| for slugging the stored fluid onto the top of the well as will now be fully explained. The valve unit 34 communicates with the inlet passageway 63 through a conduit I00 of valve I04 from passageway 83 and simultaneously flowing through passageway I00 into bore '32 and port I03, it will be apparent there is an equal pressure on both sides of valve I04 whereby a tension spring I05 maintains valve I04 in closed position as shown in Fig. 4. A passageway I06 provides communication between the reservoir 9| and the underface of valve I0'I.

With a sufficient increase in hydrostatic head in the reservoir 9| complementary with an increase in pressure beneath the valve IOI assisted by the tension spring I02, the constantly maintained supply pressure fluid acting against the top of valve IOI is overcome, causing the valve to move vertically upward and close off port I03 and open a port III'I communicating between the port I03 and the underside of valve IOI. With the valve |0 in upward position, supply pressure fluid in chamber 33 is bled oil through the ports I03 and I01 into the chamber 32 below the valve IOI, thereby unbalancing valve I04 by relieving pressure on one side thereof. With the unbalancing of valve I04, supply pressure fluid discharging from passageway 63 moves valve I04 upwardly to open a port I08, allowing discharge of supply pressure fluid directly into the reservoir 9| for displacing the fluid in the reservoir 9| upward to the top of the well.,

As is clearly shown in Figures 1 and 2, the

housing in 22 is provided with a fishing neck IIO,

affording means for receivin any suitable hook and cable for lowering or lifting the lifting unit into and out of the well respectively. It will be apparent that the unit I8 is of such size to easily pass through the tubings I3 and 2.

From the foregoing, it will be apparent that the invention contemplates the intermittent lifting of small quantities of oil from a lower filling chamber to a higher reservoir, and functions in such manner to prevent any supply pressure fluid utilized for displacing the oilfrom counteracting the sand pressure of the well, so that there is always a constant emission of fluid from the production strata except for the momentary period during the displacement operation. Furthermore, thelifting unit comprises an automatic valve mechanism for controlling the supply pressure fluid into the displacement chamber, and assures that substantially all of the production fluid is displaced from the filling chamber prior to shutting ofl. the supply pressure fluid. This ,is accomplished by utilizing a portion of the production fluid as a snubber against the supply pressure fluid in the displacement to exhaust all the residue supply pressure fluid and formation gas remaining from the displaceso that the supply pressure fluid is constantly ment of the production fluid in order to prevent a counteracting pressure against the sand pressure of the well. The lifting apparatus will operate successfully in either deep or shallow wells, providing either high or low sand pressure, and will displace the well fluid with a minimum of supply pressure fluid in the most economical and efficient manner.

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown in the drawings, it

being understood that any modification in the precise embodiment of .the invention may be made within the scope of the following claims without departing from the spirit of the invention.

What is claimed is: 1. In an apparatus for lifting fluid from a 9 well including a filling chamber, means for introducing constantly maintained motive pressure fluid into the filling chamber for displacing the fluid emitting therein from the production strata, means for receiving the displaced fluid, means actuated by the motive pressure fluid to move the first mentioned means to a position preventing introduction of motive fluid into the filling chamber and permitting exhaust of residue motive fluid therefrom, said last mentioned means including a piston responsive to previously displaced well fluid disposed above the piston to provide a snubbing action to limit the actuation of the said means until substantially all the production fluid in the filling chamber is displaced, and means independent of the first mentioned means and responsive to the hydrostatic head of well fluid in the receiving means for introducing motive fluid thereto to slug the well fluid to the top of the well.

2. In an apparatus for lifting fluid from a Well comprising an automatic valve unit communicating with an inlet passageway having a constantly maintained motive pressure fluid therein, an accumulation chamber for well fluid emitting irom the production strata, a reservoir communicating with the valve unit and the accumulation chamber, a main valve in the unit and moveable by motive pressure fluid to open position for directing motive pressure fluid into the accumulation chamber for displacing well fluid therefrom, piston means operably connected with the valve unit and moveable in response to motive pressure fluid to close the main valve against motive pressure fluid after displacement of the well fluid from the accumulation chamber to the reservoir, said piston means having previously displaced well fluid standing on one side thereof to snubber the movement of said piston means and prevent closing of the main valve until substantially complete displacement of the well fluid from the accumulation chamber, and means independent of the main valve and responsive to the hydrostatic head of well fluid in the reservoir for introducing motive pressure fluid thereto to slug the well fluid to the top of the well. a

3. In an apparatus for lifting fluid from a well having an eduction tubing and a well casing, said apparatus including a reservoir communieating with the eduction tubing, a filling chamber communicating with the well casing and the reservoir, an automatic valve mechanism operable in one position to direct constantly maintained motive pressure fluid from the casing into the filling chamber for displacing well fluid therefrom, said mechanism operable in another position to bleed ofi residue motive pressure fluid after displacement of well fluid from the filling chamber, fluid means for snubbing the movement ot'the mechanism in the last mentioned position until substantially all the well fluid is displaced from the filling chamber, and means independent or the valve mechanism and responsive to the hydrostatic head of well fluid in the reservoir for introducing motive pressure fluid thereto to slug the well fluid to the top of the well. I

4. In. an apparatus for fitting fluid from a well including a filling chamber, a main valve mechanism controlling the introduction. of constantly maintained motive pressure fluid into the filling chamber for displacing the well fluid emitting therein from the production strata, a reservoir well receiving the displaced fluid, a cylindrical piston operably connected with the valve mechanism and responsive to supply pressure fluid for actuating the valve mechanism to shut off the supply pressure fluid from the filling chamber after displacement of the well fluid therefrom, said piston responsive to displaced well fluid standing above the piston for limiting the movement of the piston in one direction until substantially complete displacement of the well fluid from the filling chamber, and means independent of the main valve and responsive to the hydrostatic head of well fluid in the reservoir for introducing motive pressure fluid thereto to slug the well fluid to the top of the well.

5. In an apparatus for lifting fluid from a well including a filling chamber communicating with an eduction tubing, a main valve mechanism communicating with constantly maintained motive pressure fluid in the eduction tubing and moveable in response thereto for directing the motive pressure fluid into the filling chamber for displacing well fluid therefrom, a cylindrical piston operably connected to the valve mechanism and responsive to the motive fluid pressure to move the valve to a position preventing introduction of motive fluid pressure into the filling chamber, said piston cooperating with previously displaced well fluid in the filling chamber and standing above the piston for retarding the action of the motive pressure against the piston until substantially all the well fluid therein is displaced from the filling chamber, means in the valve mechainsm permitting exhaust of residue supply pressure fluid after the displacement of well fluid from the filling chamber, and means independent of the main valve and responsive to the hydrostatic head of well fluid in the reservoir for introducing motive pressure fluid thereto to slug the well fluid to the top of the well.

6. In an apparatus for flowing wells including a filling chamber, a removable lifting unit for introducing constantly maintained motive pressure fluid into the filling chamber for displacing oil emitting thereto from the production strata, a reservoir above the filling chamber for receiving the displaced oil, said lifting unit comprising a main valve movable in one position to open a communicating passageway directing motive fluid into the filling chamber, means in the lifting unit movable in response to the displacement of oil from the filling chamber to allow .bleeding on of residue motive fluid therefrom, fluid means for snubbing the movement of the last mentioned means until substantially all the well fluid is displacedfrom the filling chamber, and means independent of the valve means and responsive to the hydrostatic head of well fluid in the reservoir for introducing motive pressure fluid thereto to slug the well fluid to the top of the well.

7. In a lifting apparatus for lifting fluid from a well including a filling chamber and a reservoir, means for periodically introducing constantly maintained motive pressure fluid into the filling chamber for displacing fluid emitting therein from the production strata to the reservoir, said means allowing bleeding oiT of residue motive fluid utilized in the displacement of the well fluid from the filling chamber and simultaneously preventing the introduction of motive pressure fluid during the bleeding off of the residue motive fluid, and piston means cooperating with previously displaced well fluid to snub the action of said first mentioned means and prevent the bleeding off of the residue fluid until substantially all the production fluid in the filling ll chamber is displaced therefrom, and means independent of the first mentioned means and responsive to the hydrostatic of well fluid in the reservoir for introducing motive pressure fluid thereto to slug the well fluid to the top of the well.

8. In a lifting apparatus for lifting fluid from a well including a filling chamber and a reservoir, means for periodically introducing conatantLv maintained motive pressure fluid into the filling chamber for displacing fluid emitting therein from the production strata to the reservoir, said means allowing bleeding of! of residue motive fluid utilized in the displacement of the well fluid from the filling chamber and simultaneously preventing the introduction of motive pressure fluid during the bleeding 01f of the residue motive fluid, an apertured piston disposed in the filling chamber and permitting discharge of the well fluid therethrough, said piston having a flange co-operating with previously displaced well fluid standing thereabove for snubbing the action of the first mentioned means for preventing bleed oil of the residue pressure fluid "until substantially all the well ,fiuid in the filling chamber is displaced therefrom.

9. In a lifting apparatus for lifting fluid from a well including 'a filling chamber and a reservoir. means for periodically introducing constantly maintained motive pressure fluid into the filling chamber for displacing fluid emitting therein from the production strata to the reservoir, said means allowing bleeding off of residue motive'fluid utilized in the displacement of the wellfluid from the filling chamber and simultaneously preventing theintroduction of motive pressure fluid during the bleeding of! of the residue motive fluid, an apertured piston disposed in the filling chamber and permitting discharge of the well fluid there-through, said piston having a flange co-operating with previously displaced well fluid standing thereabove for snubbing the action of the first mentioned means for preventing bleed oil. of the residue pressure fluid until substantially all of the well fluid in the filling chamber is displaced therefrom, and means independent of the first mentioned means and responsive to the hydrostatic head of well fluid in the reservoir for introducing motive pressure fluid thereto to slug the well fluid to the top of the well.

10. In a lifting apparatus for the intermittent lifting of fluid in a well to different stages of 12 elevation including a filling chamber and a hither reservoir chamber, means for directing constantly maintained motive pressure fluid into the filling chamber for displacing well fluid therefrom, said means allowing bleeding oil of residue motive fluid utilized in the displacement of the well fluid from the fillingchamber and simultaneously preventing the introduction of motive pressure fluid during the bleeding oil of the residue motive fluid, an apertured piston operably connected with the first mentioned means and having a passageway for discharge of the displaced fluid from the lower portion of the filling chamber to an upper portion of the filling chamber above the piston, said piston co-operating with displaced fluid standing above the piston for retarding the action of the first mentioned means and preventing bleed off of the residue fluid until substantially all the well fluid in the lower portion of the filling chamber is displaced therefrom.

11. In a lifting apparatus for lifting fluid to difierent stages of elevation in a well including a filling chamber and 'a higher'reservoir cham-,

ber, means for directing supply pressure fluid into the filling chamber for displacing well fluid therefrom, said means allowing bleeding oil of residue motive fluid utilized in the displacement of the well fluid from the filling chamber and simultaneously preventing ,the introduction of motive pressure fluid during the bleed oil of the residue fluid, control means operably connected with the first mentioned means, means for discharging the fluid from the filling chamber to a position above the control means, said control means co-operating with the displaced fluid above said control means for retarding the actuation of the first mentioned means and preventing bleed ofi of the residue fluid until substantially all the well fluid is displaced from the filling chamber.

OSCAR E. DEMPSEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Dempsey Mar. 5, 1946

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