US2676547A

US2676547A - Two-stage plunger lift device

Info

Publication number: US2676547A
Application number: US213885A
Authority: US
Inventors: Donald G Knox
Original assignee: Nat Supply Co
Current assignee: National Supply Co
Priority date: 1951-03-05
Filing date: 1951-03-05
Publication date: 1954-04-27
Anticipated expiration: 1971-04-27

Description

April 27, 1954 D. G. KNox Two-STAGE PLUNGER LIFT DEVICE l2 Sheets-Sheet l Filed March 5, 1951 .5 my TM N my V m ma m M M u wA April 27, 1,954

Filed March 5, 1951 D. G. KNox 2,676,547

TWO-STAGE PLUNGER LIFT DEVICE 2 Sheets-Sheet 2 I z g far/ga. s. g I

28 /49 4o /2747 '5' se 5 so 5@ i 48 2 v INVENTOR. I g D 20x/,qm G'. ,eA/0x i BY Y so o, E .a O M Patented Apr. 27, 1954 TWO-STAGE PLUNGER LIFT DEVICE Donald G. Knox, Long Beach, Calif., assignor to The National Supply Company, Pittsburgh, Pa., a corporation of Pennsylvania Application March 5, 1951, Serial No. 213,885

(Cl. ID3- 46) 14 Claims.

This invention relates to apparatus for raising oil or other fluid from wells, and is particularly directed to improvements in plunger lift devices of the general type shown in my United States Patent No. 2,508,174.

The principal object of the present invention is to provide plunger lift apparatus capable of increased production capacity without changing the size of the eduction tubing.

Another object is to reduce the amount of in- `iection gas required per barrel of oil produced.

Another object is to provide a dual or twostage plunger lift apparatus in which a first plunger travels from the bottom of the eduction tubing to a midway point and then returns to the bottom while the second plunger picks up the fluid unloaded at the midway station and carries it to the surface of the ground, with both plungers moving simultaneously.

In plunger lift devices now in use, a single plunger travels the full length of the eduction tubing from the bottom of the well to the ground surface. In present eld practice a single plunger lifting fluid from eight thousand feet can bring up a maximum of about one hundred fty barrels per day. It the depth is ten thousand feet only about one hundred twenty live barrels per day can be produced. The reason for the lower rate of production is that a longer time is required for the plunger to travel the greater distance, and also, at near maximum production rates the number of cycles per day are reduced because of the greater height of fluid column in the eduction tubing that the plunger must fall through each time it returns to the bottom of the fj,

tubing string.

Other factors limiting the production rate are the height, density and viscosity of the fluid column itself. As the plunger travels to the surface with its load of fluid at an estimated average speed of one thousand feet per minute, gas and oil are entering into the lower end of the eduction tubing. It is the slippage or passage of gas through the incoming well iiuid that makes it possible for the plunger to continue its trip to the surface. if the column of iluid in the lower end of the eduction tubing becomes tno high the propelling gas fails to break through and the plunger will slow down or stop. Within limits pressure and volume of the gas supplied from the surface into the well casing can be increased to break through high iiuid columns in order to maintain average plunger speed. The upper limit is approached when flow velocities of the gas operation.

In accordance with my invention, the production rate on deep wells is increased by using a plurality of plungers within the same eduction tube, each of the plungers travelling only part of the length of the eduction tube. Assuming that two plungers are used, the lower plunger discharges its load at a midway station about half way up from the lower end of the eduction tube. The upper plunger carries the load from the midway station to the surface. The cycle time is about one-half that required for a single plunger to complete the round trip from the bottom of the tubing to the surface. The fluid loads for each of the dual plungers is about half the corresponding load for a single plunger, and splitting the load permits a more rapid rate of upward travel of the plungers. Furthermore, the dual plungers take less time to pass down through the shorter fluid columns. The ratio of injected gas to oil produced may be reduced in certain wells where maximum production rates are not required. This may be accomplished because the stored up gas energy that is trapped below the second plunger at the time the well is shut in is fully utilized in lifting a fluid load each cycle.

In the drawings:

Figure la is a side elevation partly in section showing the surface equipment of a plunger lift device embodying my invention and also showing the upper portion of the well casing and eduction tubing.

Figure 1b is a sectional view constituting a continuation of the lower end of Figure la and showing the midway station at the upper end of the travel of the lower plunger and the lower end of the travel of the upper plunger.

Figure 1c is a sectional elevation constituting an extension of the lower end of Figure 1b and showing the lower end of the bore hole and the lower end of the plunger lift device.

Figure 2 is a sectional View taken substantially along the line 2 2 of Figure 1a showing a preierred form of construction of one of the plungers.

Figures 3a and 3b are sectional elevations taken substantially along the lines 3a-3a of Figure 1b. Figure 3b is a continuation of the lower end of Figure 3a.

Figure 4 is a sectional plan view taken substantially along the line t ci of Figure 3a.

Referring now to the drawings, the sectional well casing iii extends into the bore hole and the means of a nipple I@ to the master gate or trap valve I5. The valve i5 is in turn connected to the stack assembly generally designated I6. This assembly i6 includes a spring mounted spear il of the type described in my copending application, Ser. No. 106,579.

The lower` end of the eduction tubing I3 is connected to a footpiece i8 from which is suspended a perforated liner pipe i9. Oil and gas entering the eduction pipe i3 pass inward through the perforations in the liner pipe I9. A lower plunger generally designated 2.@ travels in the lower portion of the eduction tubing i3 while an upper plunger generally designated 2I travels in the upper portion of the same eduction tubing I3. A barrier device generally designated 22 is anchored within the `eduction tubing at a midway station located about hali way from the lower end of the eduction tubing to the surface. barrier device 22 to the surface and returns while the lower plunger 2t travels from the lower end oi the eduction tubing i3 to the barrier device 22 and returns.

The plungers 2e and 2l may be substantially "f plungers each comprise a body 23 having spaced sets of radially movable sealing elements 2d adapted to seal against the inner surface 25 of the eduction tubing E3. For clarity of illustra tion the couplings joining adjacent sections of the tubular eduction pipe are omitted, but it will be understood that the construction of the radially movable sealing devices 24 is such that they pass over1 the joints between adjacent sections of the eduction pipe without interference or possibility of hanging up. The body 23 is provided with a central passage 26 extending from end to end, and this passage may be closed by means of the vertically movable poppet-type valve 2l which has a head 2S adapted to seal against the seat 2S. The lower end of the valve stem 30 projects below the lower end of the body i3. When the valve is in open position as shown in Figure 2, the plunger falls downwardly through the eduction tubing i3, and any fluid in the interior oi the eduction tubing passes upward through the r passageway 2e to permit the plunger to fall through the fluid. When the valve 2 is closed, the plunger is lifted within the eduction tubing i3 by the pressure oi the gas below the plunger, and the lowering of gas pressure above it. lowering of the gas pressure in the eduction tubing occurs when the motor valve (not shown) in the discharge line is opened. A motor valve of this type is shown in my Patent No. 2,503,174, granted May 16, 1950.

The barrier device 22 may be anchored at any selected point within the eduction tubing I3 and may be lowered on a wireline extending from the surface into position. As shown in the draw-v ings, this barrier device includes a tubular mann drel 3l having an externally tapered surface 32. A plurality oi" wedge slips 33 are mounted on the surface 32 and are provided with wicker teeth 34 for engaging the inner surface 25 of the eduction tubing I3. A supporting arm 35 extends downwardly from each of the wedge slips 33. The lower end 36 of each arm is secured relative to a collar 3l. The upper end 38 or a coil spring 39 is xed on the lower extension t0 of the collar 3l'. The lower` end of the spring 39 is fixed to The upper plunger 2i travels from this the line.

4 the upper end of the spear tube lil. From this description it will be understood that the spear iii, spring 3S, and collar 3'! are suspended from the slips 33 which engage the inner surface of the eduction tubing I3.

The tapered mandrel 3i is supported within the tapered bore lli. of the slips 33 and the upper end of the mandrel is provided with a flange or head i3 which is engaged by a plurality of spring iingers lill extending downwardly from the collar '65. Threads G6 connect the collar i5 with a sealing device generally designated il which seals against the inner wall 'E5 of the eduction tubing I3. While any conventional or desirable form of seal may be employed, I have found that one of the sealing units of the type employed on the plungers 2e and 2I may be used to good advantage. Accordingly, the sealing device il includes a tubular body 48 having a plurality of longitudinally extending radially spaced slots i0 and a circumferential groove 5i! intersecting the slots. Radially movable bars 5l are positioned within the slots 9, and ring segments 5E are mounted in the groove 50. The central portions of the bars and the ring segments cooperate to form an uninterrupted circular seal with the interior ol' th-e eduction tubing I3.

Threads 53 connect the upper end or the tubular body d3 to the sleeve 54. The sleeve l is connected by threads 5i? to the valve cage 55. A ball valve 5l is mounted within the cage Eil and normally rests on the upper end of the annular seat 53. A coil spring 59 maintains the valve seat in engagement with the tapered shoulder 35 on the cage 56. The cage is provided with a central chamber 6I. A bar 62 mounted on the cage extends diametrically across the chamber ti to limit upward travel of the ball 52'. An upper extension 63 on the cage pre1" -i mounting for the lower end ttl of the coil s The upper end of the coil spring e5 cai a bumper 6G against which the valve stem 3G on the upper plunger 2l rests when the plunger 2i mounted at the upper end of a Coil spring une the lower end of this coil spring is mounted the support 59 which is detachably connecte the foot-piece I by means of the spring le. The barrier device 22 is lowered into L. tion on a wire line and is preferably lowers two sections in order to reduceY the weight The lower section comprising the in drei 3i, slip assembly, spring 30 and spear di are lowered rst. The slips 33 are set by suddenly increasing the rate of downward travel. The upper section comprising the

bumper

56, 65, valve cage 55, body l? and collar z lowered. The two sections are joined when the spring fingers 44 engage the fishing neck at the upper end of the mandrel Si In operation, well fluid enters the lower end of the eduction tubing ill through the perfor in the liner pipe il Well fluid passes through the interior of the support Eid interior of the eduction tubing. Forma` in the annulus 9 between the easing il e tion tubing i3 forces the column of upwardly within the eduction tubing it. gas pressure within the annelus t may be supplemented by gas pumped into the annulus from the surface through the side outlets in the casing head I I, if desired.

Assuming that the lower plunger 2@ is dropping by gravity through a column of well duid in the lower end of the eduction tubing it, the

plunger continues its downward movement until the valve stem 3B engages the spring mounted bumper 6l. This closes the valve 2l in the plunger 20. The pressure in the eduction tubing below the plunger 2i! thereupon raises the plunger 20 to lift a column of well duid above it. The plunger and its load of well uid continues upward until the spear di extends into the central opening 26 in the plunger and mechanically engages the upper end of the valve head 28 to open the valve. The load of well iluid above the plunger 2li passes upward through the interior of the hollow collal` 3l, hollow mandrel Si, collar 45, hollow body i8 and past the check valve 5l into the eduction tubing i3 above the location of the barrier device 22. The seal aiforded by the bars 5| and ring segments 52 prevents the well iiuid from leaking downwardly around the exterior of the barrier device. When the valve 2l in the lower plunger 2Q is opened, the Iplunge: 2G again drops by gravity downward toward the lower end of the eduction tubing I3 to begin another cycle of operations.

The upper plunger 2l drops by gravity through the upper portion of the eduction tubing and down through the column of well fluid previously raised by the lower plunger 2Q. valve stem 35i engages the spring mounted bumper il@ to close the valve and arrest downward movement of the plunger 2|. Pressure within the eduction tubing I3 below the plunger 2l then raises the plunger upwardly toward the surface, carrying the load of well fluid above it. When the plunger El approaches the surface, the column of well fluid above it passes out through discharge pipes ll and l2 connected to the stack assembly it. The spring mounted spear il mechanically ergages the valve head 23 to open the valve, and the plunger 2l thereupon descends by gravity down toward the barrier device 22 to begin a new cycle. From the above description it will be understood that the upper and lower plunger-s 2li and 2l operate simultaneously, and that each travels back and forth in its respective portion of the eduction tubing i3. While only plungers have been shown and described, more an two can be employed in the same eduction t bing if desired.

ln the event that it should be desirable to reduce the height of the iiuid column above the check valve 5l, gas under pressure can be applied to the interior of the tubing at the well head. When a pressure of suiiiciently great intensity is reached, the spring 59 is compressed, allowing the seat 53 to move away from its sealing shoulder 6E, thereby permitting downwaroL now of duid in the tubing past the check valve.

lf it should become necessary to remove the plungers and barrier device 22 from the well for servicing or cleaning, or for any other reason, the upper plunger 2l may be trapped at the sur-- face by closing the valve l5 and thereafter an overshot device oi conventional forni may be lowered from the surface on a wire line to engage the bumper 65. An upwardly directed force applied to the bumper et raises the spring valve cage 56, hollow body t8, sleeve lid, and mandrel 3i. Raising of the mandrel 3i releases the slips 3S from contact with the inner wall o the eduction tubing iii.l The ring 'i3 which cncircles the slip support arms 35 is fined to the mandrel by means of iingers 'it located between adjacent arms 35. VWhen the mandrel moves upwardly the shoulder l5 on the ring it. engages the abutments 'i6 on the wedge slips 33 so that two the wedge slips 33, collar 31, spring 39 and spear lll are withdrawn from the eduction tubing i3 along with the mandrel 3|.

When the barrier device 22 has been lifted to the surface on the wire line, it may be set aside and the wire line and overshot again run into the hole to engage the bumper 61. An upwardly directed force applied to the bumper 6l by means of the overshot tensions the spring t8 and serves to disengage the spring fingers lil on the support 69 from the footpiece I8. The parts El, 68, 6@ and lil are then withdrawn on the wire line.

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

I claim:

l. in a multiple-stage plunger lift device :for raising well iiuid in an eduction tubing, the combination of: a barrier device adapted to be fixed in said eduction tubing, the barrier device having a passageway extending therethrough, a iirst plunger adapted to travel in the eduction tubing from the lower end thereoic to the barrier device to raise a load of well fluid through sai-l passageway into the eduction tubing above the barrier device, a second plunger adapted to travel in the eduction tubing from the barrier device to a location in the eduction tubing spaced above the barrier device for raising well iiuid upwardly from the barrier device, each of the plungers having a passageway extending longitudinally therethrough and each having an upwardly closing valve for closing the passageway, and means at the lower end of the eduction tubing constituting the sole means for introducing niotive fluid into the eduction tubing.

2. in a multiple-stage plunger lift device for raising well fluid in an eduction tubing, the combination of: a barrier device adapted to be nrqed in said eduction tubing, the barrier device having a check valve preventing low of iiuid downwardly through the barrier device, a rst plunger adapted to travel in the eduction tubing from the lower end thereof to the barrier device to raise a load o well huid through the check valve into the eduction tubing. above the barrier device, a second plunger adapted to travel in the eduction tubing from the barrier device to a location in the eduction tubing spaced above the barrier device for raising well fluid upwardly from the barrier device, each of the plungers having a passageway extending longitudinally therethrough and each having an upwardly closing valve for closing the passageway, and means at the lower end of the eduction tubing constitilting the sole means or introducing motive iiuid into the eduction tubing.

3. In a multiple-stage plunger lift device for raising well fluid in an eduction tubing, the coinbination of: a barrier device in said eduction tubing, means including wedge slips on the barrier device engageable with the inner surface or the eduction tubing for releasably anchoring the barrier device in the eduction tubing, the barrier device having a check valve preventing iow of fluid downwardly through the barrier device, a rst plunger adapted to travel in ihe eduction tubing from the lower end thereof to the barrier device to raise a load or" well fluid through the check valve into the eduction tubing above the barrier device, a second plunger adapted to travel inthe eduction tubing from the barrier device to a location in the eduction tubing spaced above the barrier device for raising well fluid upwardly from the barrier device, each of the plungers having a passageway extending longitudinally therethrough and each having an upwardly closing valve for closing the passageway, and means at the lower end of the eduction tubing constituting the sole means for introducing motive iuid into the eduction tubing.

4. In a multiple-stage plunger lift device for wells, the combination of: an eduction tubing, a barrier device xed in said eduction tubing, the barrier device having a passageway extending therethrough, a first plunger in the eduction tubing traveling from the lower end oi the eduction tubing to the barrier device to raise a load of Well fluid through said passageway into the eduction tubing above the barrier device, a second plunger in the eduction tubing travelling from the barrier device to a location in the eduction tubing spaced above the barrier device for raising well iluid upwardly from the barrier device, each of the plungers having a passageway extending longitudinally therethrough and each having an upwardly closing valve for ciosing the passageway, and means at the lower end of the eduction tubing constituting the sole means for introducing motive fluid into the eduction tubing.

5. In a two-stage plunger lift device for wells, the combination of an eduction tubing, a barrier device fixed in said eduction tubing, the barrier device having a passageway extending therethrough, a lower plunger in the eduction tubing adapted to travel from the lower end oi the eduction tubing to the barrier device to raise a load of well fluid through said passageway into the eduction tubing above the barrier device, an upper plunger in the eduction tubing adapted to travel from the barrier device to the upper end of the eduction tubing for raising well duid to the surface, each of the plungers having a sageway extending longitudinally therethrough and each having an upwardly closing valve closing the passageway, and means at the lower end of the eduction tubing constituting the sole means for introducing motive fluid into the eduction tubing.

6. In a two-stage plunger lift device for wells, the combination of: an eduction tubing, a barrier device iixed in said eduction tubing, the barrier device having a check valve preventing iiow of iiuid downwardly through the barrier device, a lower plunger in the eduction tubing travelling from the lower end of the eduction tubing to the barrier device to raise a load of well fluid through the check valve into the eduction tubing above the barrier device, an upper plunger in the eduction tubing traveling from the barrier device to the upper end of the eduction tubing for raising well fluid to the surface, each ci the plungers having a passageway extending longitudinally therethrough and each having an upwardly closing valve for closing the passageway, and means at the lower end of the eduction tubing constituting the sole means for introducing motive fluid into the eduction tubing.

7. In a two-stage plunger lift device for wells, the combination of z an eduction tubing, a barrier device in said eduction tubing, means including wedge slips on the barrier device engaging the inner surface of the eduction tubing for releasably anchoring the barrier device in the eduction tubing, the barrier device having a check valve preventing ow of uid downwardly through the barrier device, a lower plunger the eduction tubing travelling from the lower end of the eduction tubing to the barrier device to raise a load of well uid through the check valve into the eduction tubing above the barrier device, an upper plunger in the eduction tubing travelling from the barrier device to the upper end of the eduction tubing for raising well fiuid to the surface, each of the plungers having a passageway extending longitudinally therethrough and each having an upwardly closing valve for closing the passageway, and means at the lower end of the eduction tubing constituting the sole means for introducing motive duid into the eduction tubing.

8. In a multiple-stage plunger lift device for raising well uid in an eduction tubing, the combination of: a barrier device in said eduction tubing, means including wedge slips on the barrier device engageable with the inner surface of the eduction tubing for releasably anchoring the barrier device in the eduction tubing, the barrier device having a check valve preventing riow of fluid downwardly through the barrier device, a rst plunger adapted to travel in the eduction tubing from the lower end thereof to the barrier device to raise a load of well iiuid th the check valve into the eduction tubing above the barrier device, a bumper element resll' tly mounted on the barrier device for a ng downward movement of the rst plunger, a second plunger adapted to travel in th euction tubing from the barrier device to a location in the eduction tubing spaced above the barrier device for raising well iiuid upwardly from the barrier device, each of the plungers having a passageway extending longitudinally therethrough and each having an upwardly closing valve for closing the passageway, and means at the lower end of the eduction tubing constituting the sole means for introducing motive into the eduction tubing.

9. For use in multiple-stage plunger lift apparatus employing a plurality of swab plungers travelling freely within a single eduction tubing, the combination of: a barrier device inserta-ble into the eduction tubing from the upper end thereof, means on the barrier device for releasably anchoring it within the eduction tubing, the barrier device having a passageway extending therethrough, a check valve in seid passageway preventing passage oi fluid downwardly in said passageway, a bumper element resilient-ly mounted on the barrier device for arr downward movement of an upper plunger, an element resiliently mounted on the l; device for arresting upward movement ci a lewe plunger.

10. For use in multiple-stage plunger liit apparatus employing a plurality of swab plungers travelling freely within a single eduction tubing, the combination of: a barrier device insertable into the eduction tubing from up end thereof, means including wedge slips on i, o rier device engageable with the inner si face of the eduction tubing for releasably anchoring the barrier device in the eduction tub fr, the

preventing passage of iluid downwardiy passageway, a bumper element mounted on the barrier device for ar downward movement of an upper plunger an element resiliently mounted on the barrier device for arresting upward movement of a lower plunger.

11.For use in multiple-stage plunger lift apparatus employing a, plurality of valved swab plungers travelling freely within a single eduction tubing, the combination of: a barrier device insertable into the eduction tubing from the end thereof, means including wedge slips on the barrier device engageable with the inner sur- `lace of the eduction tubing for releasably anchoring the barrier device in the eduction tubing, means establishing a seal between the barrier device and the inner surface of the eduction tubing, the barrier device having a passageway extending therethrough, a check valve in said passageway preventing passage o fluid downwardly in said passageway, a bumper element resiliently mounted on the barrier device for arresting downward movement of an upper plunger and for closing its valve, and a spear element resiliently mounted on the barrier device for arresting upward movement of a lower plunger and for opening its valve.

12. Multiple-stage plunger lift apparatus having in combination: an eduction tubing, a pair of z b plungers travelling freely within the eduction tubing, a barrier device positioned within the eduction tubing between said plungers, means on the barrier device for releasably anchoring it within the eduction tubing, the barrier device liaving a passageway extending therethrough, a check valve in said passageway preventing passage of fluid downwardly in said passageway, a bumper element resiliently mounted on the barrier device for arresting downward movement of one of the plungers, and an element resiliently mounted on the barrier device for arresting upward movement of the other plunger.

13. Multiple-stage plunger lift apparatus 'naving in combination: an eduction tubing, a pair oi swab plungers travelling freely within the eduction tubing, a barrier device positioned within the eduction tubing between the plungers, means including wedge slips on the barrier device engageable with the inner surface of the eduction tubing for releasably anchoring the barrier device in the eduction tubing, the barrier device having a passageway extending therethrough, a check valve in said passageway preventing passage of fluid downwardly in said passageway, a bumper element resiliently mounted on the barrier device for arresting downward movement of one of the plungers, and an element resiliently mounted on the barrier device for arresting upward movement of the other plunger.

14. Multiple stage plunger lift apparatus having in combination: a single eduction tubing, a pair of swab piungers travelling freely within said single eduction tubing, each plunger eing tubular and having a valve near the lower end thereof adapted to move upwardly to closed position, a barrier device positioned within the eduction tubing between the plungers, means on the barrier device for releasably anchoring it within the eduction tubing, the barrier device having a passageway extending therethrough, a check valve in said passageway preventing passage of iiuid downwardly in said passageway, a bumper element resiliently mounted on the barrier device for arresting downward movement of an upper plunger and for closing its valve, and a spear element resiliently mounted on the barrier device for arresting upward movement of a lower plunger and for opening its valve.

lteferences Cited in the file 0f this patent UNITED STATES PATENTS Number Name Date 971,612 Holliday Oct. 4, 1910 1,547,025 Callahan July 21, 1925 2,001,551 Scott 1 May 14, 1935