US2649738A - Control for plunger lifts - Google Patents

Description

g- 1953 H. c. TAIT 2,649,738

CONTROL FOR PLUNGER LIFTS 2'Sheets-Sheet 1 Filed May 22, 1952 i g Q 5 Q a I] N Ham/Po a. m/r,

( "my 1 -0' Wm INVENTOR.

w n !I M! ATTaP/VAVS Aug. 25, 1953 H. c. TAIT 2,649,738

CONTROL FOR PLUNGER LIFTS Filed May 22, 1952 2 Sheets-Sheet 2 :r x INVENTOR.

Patented Aug. 25 195 3 UNITED STATES PATENT OFFICE CONTROL FOR PLUNGER LIFTS Howard C. Tait, Pittsburgh, Pa., assignor to The National Supply Company, Pittsburgh, Pa., a corporation of Pennsylvania Application May 22, 1952, Serial No. 289,277

Claims. (01. 103 -52) This invention relates to plunger lift apparatus and is particularly directed to improvements over devices of the type shown in the copending application of Donald G. Knox, Serial No. 106,579, filed July 25, 1949, for Plunger Lift."

The principal object of this invention is to provide a simplified control system for regulating the action of the plunger which travels the full length of the eduction tube in the well.

An important object of this invention is to provide improved means for closing the main valve in the well fluid delivery pipe leading from the well head, when the plunger reaches the upper end of its stroke.

Other and more detailed objects and. advantages will appear hereinafter.

In the drawings:

Figure 1 is a view in diagrammatic form, partly in section, showing a preferred embodiment of my invention. The parts are shown in the position they assume when the plunger is at the upp r end of its stroke, with the main control valve in the act of closing.

Figure 2 is a. view similar to Figure 1 showing the parts in the position they assume when the plunger is rising in the eduction tubing.

Figure 3 is a sectional elevation of the control valve assembly which is positioned in the well fluid discharge pipe.

Figure 4 is a side elevation, partly in section, showing the plunger which travels the full length of the eduction tubing.

Referring to the drawings, the well head generally designated in is mounted at the upper end of the casing I I. The eduction tubing I2 xtends through the head and is connected to the body of the shut-ofi valve l3. A passageway in the valve 13 establishes communication from the eduction tubing I2 to the stack nipple M. A bumper spring housing I5 is mounted at the upper end of the stack nipple and is provided with a removable cap IS. The well fluid delivery conduit generally designated I1 includes the shut-01f valve [8 and the nipple l9 which connects to a side outlet in the bumper spring housing l5. The main control valve 20 is mounted in the well fluid delivery conduit l'l downstream from the shutofi Hi. When this valve 20 is closed the well is shut in. The valve 20 includes a vertically movable valve stem 2| which is moved by means of a diaphragm 22 acting against th action of a coil spring 23. When pressure is applied to the space 24 above the diaphragm 22 the stem 2| is lowered to open the valve, and when the pressure is vented from the space 24 the coil spring 23 acts to raise the stem 2| and close the valve.

A lateral outlet 25 on the well head is connected by means of a nipple 26 to the shut-off valve 21. Gas under pressur is injected into the pipe 28 and passes through the valve 2! and nipple 26 into the interior of the casing ll.

In the general scheme of operation the control valve 20 remains closed while the plunger 29 is at the lower end of the eduction tube I2. During this period the well fluid enters the eduction tube above the plunger, and casing pressure builds up as the gas is injected through the pipe 28. When the pressure reaches a predetermined magnitude the valve 20 is opened. This action serves to reduce the pressure of the gas in the eduction tube abov the plunger 29. The plunger is then moved upward through the eduction tube, lifted by the pressure of the gas in the casing which continues to enter the lower end of the eduction tube as the plunger rises. A load of well fluid above the plunger is carried to the surface and is discharged through the pipe I! and the valve 20. When the plunger 29 enters the stack nipple l4 the valve 20 closes, again shutting in the well. The plunger 29 drops down through the eduction tube l2 to the lower end thereof and the cycle is repeated.

In order to carry out this cycle of operations I provide an improved control mechanism which causes the control valve 2|] to open when the .casing pressure builds up to a predetermined magnitude, and which causes the valve 20 to close when the plunger 29 comes to rest within the stack nipple I4. In accordance with my invention I provide a trigger 30 which is pivoted on the stack nipple at 3| and which extends through a port 32 in the side wall of the stack nipple I4. A movable arm 33 connected to the trigger 3i} actuates a vent valve 34. When the plunger 29 is not in the stack nipple M, the spring 35 moves the trigger 30 and arm 33 to the position shown in Figure 2. In this position the vent valve 35 is closed. When the plunger 29 enters the stack nipple hi it contacts the trigger 30 and swings it to the position shown in Figure 1, thereby opening the vent valve 34 to bleed the pressure in the line 36.

The control instrument generally designated 3'1 comprises a casing having a number of parts of the control mechanism positioned therein. Among these parts, are the pilot valve 38, the relay valve .39, the bellows assembly 40, the Bourdon tube 4!, and the valve assembly 42. Pilot supply gas at relatively low pressure, for example, 20 p. s. i., is supplied through conduit 43 to the terminal 44 of the relay valve 39 and to the terminal 45 of the pilot valve 38. This pilot supdiaphragm 22 of the control valve 20, and this I line 48 connects to the terminal 49 of the pilot valve 38 and to the terminal 50 ofthebellows as-- sembly 40. The trigger line, 36; connects to the valve assembly 42 and also t9 the terminal-til and 54 of the relay valve 39. The terminal :525 on the pilot valve 38 connects through line 55 with the terminal 53 on the relay valve '39.

The spring 35 normally acts to hold theyent valve 34 against the seat 56 and thereby prevent escape of pressure .fluid from the line 6, The :stem 51 of the valve 34 projects through seal ring 58 into the chamber 5.9 which is sealed with respect to the interior of. the eduction. tube 12. When the plunger ,29 reaches the upper end of its travel and enters the (stack nipple 14,,it contacts the trigger arm .30 andcauses the arm 33 to engage the lowerend oflthe-valve stern 5 a nd lift the valve 3.4:.away .from its-seat 56.. The pressure in the line at then vents t atm phe e through vent port 5!]. V

The relay valve shown diagrammaticall #1139 employs a ball 6;! which engage either an upward facing seatifiz-or adownwardiae ngsea 63. seattzitelosesomthe rampart-1:54.. .Adi nh a xn 65 p ratesa enl n rtefiwmhieh ma enga e the ball =61 and movesitnnward am fr s at. .62 and into contactiwith SQ9$3- 12125811116 fluid-aslmitted through. terminal .54 ronerates the di-' aphragm 6.5.. Arestriction .68. located for convenience within-theerelay. valve-3 9., rconnects tenminalsM and .5.l.:.and.henee establishes communication between .the :pressnre .flm'd. supply line .43 and the trigger line. 36.

The pilot valve shown diagrammatically, ats38 is provided with a "valve :spool .69 which :moves exially within .apylindrical :bore 10. .An annular groove .H in .the spool :69 .cohnects the terminal 49 with either :the terminal .45 or .the vent .port 12, depending upon. the axial position of the .spool .39. Acompression-spring J3 acts resiliently to move .the spooli$9 inone directiQmand-such movement is resisted Lby fluid pressure in the chamber 'Mbelow the:spool'69.

The Bourdon tube l-l has its moving end connected to the crank'arm of the fiapper-valve l5, pivotally mounted at H. A nozzle "18 engages the underside of the-flapper valve-'16 'to form a seal. The nozzle 18 -is also movably mounted, and as shown-diagrammatically-in the drawings, the nozzle is carried on an arm IQ-pivotally supported at 8'0. A'link 8| is p v d i one end to the arm 79-andat-theother endto'the post 82 fixed on the end wallof -thebellow'sflll. When the pressure in the bellows -chamberfljin- V creases, the-nozzle T8is-movedtoward-the flapper One-or more loops Win the nozzle'fe'ed'w flapper vaIve-re is swung toward the nozzle 18..

Thenozzle'18 andjlapper .valve 16 are collectively referred to. asthe vent valve. '42.

In the position of :the names shewnjnjig- When the ball 6! rests :zhy gravit upon th .sure builds .upxto .a. predetermined .-value.

4 ure 1, the plunger 29 is in the stack nipple l4 and the vent valve 34 is open. The trigger line 35 is therefore vented to atmosphere through vent port 80. If desired, a dash-pot mechanism, not shown, can be employed to prevent too rapid closing of the vent valve 34 in the event that the plunger as should descent out pf contact with the trigger 39 pefore a ny gonsigerable pressure drop occurs in pipe 36. The release in pressure below the diaphragm in the relay valve 39 allows the plunger 66 to drop, and the ball 61 restsenseat 62, closing 01? vent port 64. Eressure ironnthe pilgt supply line 43 then passes the vy aly e 39 through terminal 4-4, out through terminal-:53, through pipe 55, and into the mamber L4 in the pilot valve 38 through terminal 52'. The spool 69 moves up against the action-of the spring 13 to close off terminal 45 and to connect the terminal 49 with the vent port 2- Tee tant a-1 his; i -thus ve t d t nowhereand thwg t on press e in t pace-.2; ebeve. thed g e ni .2 n the motel" valveaseemhly 29 Perm ts h series 2.3 t li the stem 2! ;to glo sethe valve heads .5 against the va Yeeai.-.. l l

heatin a he. =9Q l10l h r ih u h vent pa t1? intheiletee 3&- to efie 9 i of theeentr l ve te disses; .ip th @bPTCQ a also a ts tada rease t e-erasure the be chemis 333,. al ews 13 i9 swin ab ut 112 rivet ames were t en zle 8 away from the flap e g e 5- .e ha el? 5 t a vents the line 85 and trigger pipe 35 to atmosphere eren theseh pressu e has s ne stantly supplied thIQJ1lQTllQll $33 from. the pilot supply pipe 43. A reductg n casing pressu e reaeasi mnlzb passa .Q a lth oush t .c ntrolyalvege during its ppgnneri dduct on innressure-is reflec ed y. action. of the Bqurdon tube. indntingrtheflapneryalve .16 .away 1mm the nozzle 518... The plun er 2.9..drons back through the eduction tube llgtmthe lower end thereof inthe welL. Elie control .valve 2 0 remainsclosedmith :the mall "fshut in! The plunger 29 memainsatjtheglower end of the .eductiontube lfl inthe well .until thenasing -pres- The increase in casing pressure ishlffll ht about either by entry .of formation .gas into the .casing ,H at then-lowerv end .thereofor .by admitting gas under pressure through pipe 28, or both. When the pressure-inrthe casing builds-up .to a predeter- :mined intensity the Bourdon tube 4| lowers the flapper valve lit-into contact with the nozzle 18, to close off the nozzle 18 and substantially prevent escape of pressure fluid therefirom.

Pressure :fiuid supplied through restriction 68 then builds up pressure in the -lineand trigger pipe 36. The diaphragm =65 in the relay valve 39 is raised; causing the-pllm er-fifi to seat the ball -6l against the seat -93. This action vents line $5 through port 64 and allows the spring 73 inthe-pilotvalve 38 to shift the spool 69 to a position to close off the vent port '12 and to con- -nect terminal-s5 with terminal 49. Pressure fluid thenpasses-from the pilot. supply line 123 into the control pipe #8, and into the gbellows chamber 83. The various parts of the device are now in the position shownjp figure 2; I

when the' prjessui ejnthe control pipe 4.8 builds up sumeientl :it gctson the diaphragt'n 22 .to overcome the jo'rpeof the spring 23 andopen the control valve 29. The gasunder pressure in the eductiQ tu 12 then p sse u tnr e the discharge pipe II. The consequent reduction in pressure in the eduction tube l2 above the plunger 29 causes the plunger to be driven to the surface by pressure fluid from the casing H. A slug of well fluid is lifted by the plunger 29, and this well fluid passes out through discharge pipe I! and control valve 2o before the plunger 29 reaches the stack nipple Hi. When the plunger 29 reaches the stack nipple l4 it engages the trigger 3i and opens the vent valve 34, and the cycle repeats. A valve 2% in the plunger 29 opens and the plunger drops back down the eduction tube l 2 into the Well.

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:

1. In a plunger lift device having a valved plunger adapted to travel freely under pressure substantially the full length of an eduction tube in a well, the combination of a well head assembly connected to the upper end of the eduction tube, a discharge .pipe leading from the well head assembly, a control valve for controlling flow of well fluid through the discharge pipe, re silient means for closing the control valve, power means for opening the control valve against the action of the resilient means, a trigger element movably mounted on the well head assembly to be actuated when the plunger reaches the upper end of its travel, a vent valve mounted on the well head assembly, a pipe connected to said vent valve, means whereby the trigger element may open the vent valve to vent the pipe, a supply pipe for supplying pressure fluid to said control pipe, and means operable to deenergize said power means to permit the resilient means to close the control valve upon opening of the vent valve by the trigger element.

2. In a plunger lift device having a valved plunger adapted to travel freely under pressure substantially the full length of an eduction tube in a well, the combination of 5 a well head assembly connected to the upper end of the educion tube, a discharge pipe leading from the well head assembly, a control valve for controlling flow of well fluid through the discharge pipe, resilient means for closing the control valve, pres sure operated means for opening the control valve against the action of the resilient means, a control pipe connected to said .pressure operated means, a trigger element movably mounted on the well head assembly to be actuated when the plunger reaches the upper end of its travel, a vent valve mounted on the well head assembly, a second pipe connected to said vent valve, means whereby the trigger element may open the vent valve to vent the second pipe, a supply pipe for supplying pressure fluid to said control pipe and to said second pipe, and means operable to vent the control pipe when said vent valve vents said second pipe to permit the resilient means to close the control valve.

3. In a plunger lift device having a valved plunger adapted to travel freely under pressure substantially the full length of an eduction tube in a well, the combination of: a well head assembly connected to the upper end of the eduction tube, a discharge pipe leading from the Well head assembly, a normally closed control valve interposed in the discharge pipe, pressure operated means for opening the control valve, a control pipe connected to said pressure operated means, a trigger element movably mounted on the well head assembly to be actuated when the plunger reaches the upper end of its travel, a vent valve mounted on the well head assembly, a second pipe connected to said vent valve, resilient means for closing the vent valve, means whereby the trigger element may open the vent valve against the action of said resilient means to vent the second pipe, a supply pipe for supplying pressure fiuid to said control pipe and to said second pipe, and means operable to deenergize the pressure operated means upon opening of the vent valve by the trigger element to permit the resilient means to close the control valve.

4. In a plunger lift device, the combination. of: a well casing, an eduction tube therein, a valved plunger adapted to travel freely under pressure substantially the full length of the eduction tube, a well head assembly connected to the upper end of the casing and eduction tube, a discharge pipe leading from the well head assembly, a control valve for controlling fiow of well fluid through the discharge pipe, resilient means for closing the control valve, pressure operated means for opening the control valve against the action of the resilient means, a control pipe connected to said pressure operated means, a trigger element movably mounted on the well head assembly, a second pipe connected to said vent valve, resilient means for closing the vent valve, means whereby the trigger element may open the vent valve against the action of said resilient means to vent the second pipe, a supply pipe for supplying pressure fluid to said control pipe and to said second pipe, a second vent valve connected to said second pipe, a Bourdon tube connected to open said second vent valv upon increase in pressure therein, means establishing communication between the interior of the casing and said Bourdon tube whereby the second vent valve is closed upon increase in casing pressure beyond a predetermined intensity, and means operable to vent the control pipe to permit the resilient means to close the control valve upon opening of the vent valve by the trigger element.

5. In a plunger lift device having a valved plunger adapted to travel freely under pressure substantially the full length of an eduction tube in a well, the combination of: a well head assembly connected to the upper end of the eduction tube, a discharge pipe leading from the well head assembly, a control valve for controlling flow of well fluid through the discharge pipe, resilient means for closing the control valve, pressure operated means for opening the control valve against the action of the resilient means, a control pipe connected to said pressure operated means, a trigger element movably mounted on the well head assembly and actuated by the plunger at the upper end of its travel, a vent valve mounted on the well head assembly, a second pipe connected to said vent valve, resilient means for closing the vent valve, means whereby the trigger element may open the vent valve against the action of said resilient means to vent the second pipe, a supply pipe for supplying pressure fluid to said control pipe and to said second pipe, and means operable upon venting of the second pipe to vent the control pipe and permit the resilient means to close th control valve.

HOWARD C. TAIT.

No references cited.

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