US2258299A

US2258299A - Automatic pumping

Info

Publication number: US2258299A
Application number: US224887A
Authority: US
Inventors: Robert P Miller
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-08-15
Filing date: 1938-08-15
Publication date: 1941-10-07
Anticipated expiration: 1958-10-07

Description

oct. 7, 1941. R, P, MILLE'R A 258,299

AUTOMA'I IC PUMPING Filed Aug. 15, 1958 2 Sheets-Sheet l y ATTORNEY.

Oct. 7, 1941. R. P. MILLER AUTOMATIC PUMPING 2 Sheets-'Sheet 2 Filed Aug'. l5, 1958 INvEryxoR. Robe/2.12? 734; R MDTTORNEY.

Patented Oct. 7, 1941 UNITED STATES OFFICE AUTOMATIC PMPING Robert P. Miller, san Gabriel, Calif. Application August 15, 1931i-,Y serial No.V 224,887 i 10 Claims. (Cl.fi0w3-?,ir) l i Thislinvent-ion Vrelates to automatic pumping of fluid-byfluid pressure the present application being "a, lcontinuation in part of my copending' application Ser. vNo. 56,492, led Dec. 28, 1935,

nowabandoned. The fluidv which is to be pumped is herein referred to as the production fluid; and `the uid under pressure which pumps the production uid is herein referred to as the displace- Inent flid.

The invention isparticularly applicable to petroleum Wells in which the production lluid comprises gaseous` and/or liquid constituents, and the liquid constituents are oil and/or Water. Thedisplacement fluid maybe any suitable 'gas under pressure supplied from any desired source atthe top oi thewell. i In practice, iiow tubing for production liui'dfmay extend through usual well casing to the production zone of the Well, with displacement fluid supplied via the annular spa-ce between the tubing and the surrounding 'casingQor the ilowtubing may surround an inner conduit through Which displacement uid is Supplied. l i i `-The invention relates to that method of pumpin gj'in which a foot valve controls admission of production uid to the flow tubing, `and ahead valve controls admission of displacement iluid for elevating the previously admitted production Pumping `is automatic, the head and foot valves being dependently actuated and alternately opened and closed responsive to pressure diii'erential. At the start of the lling period, pressrein the flow tubing is relieved by disehaigeoff an elevated slug of production iluid 4so thetubingV string and thus creates pressure difierential for opening the foot valve and closing the `head valve. Production iiuid then enters `and risesin the ilow tubing until pressure in the tubing string plus pressure of displacement lluid "'pposing opening of the ifoot valve exceeds formation pressure and thus creates pressure differ- Eenti'al in the` opposite direction for closing the footvalve and opening the head valve. This lnaugurates the discharge period during which displacement fiuid forms a liuid piston for ele# Vating and expelling the production which has been trapped in the flow tubing. As the productien nuid isv elevated and expelled; the displacement iluid expands and thereby relieves pressure in the tubing stringuntil said pressure isagain exceeded by formation pressure for opening the foot valve and closing the head valve to restart the filling period.

that formation pressure exceeds pressure in Cyclic operation is thus dependent upon pres'- 5y Vsure differential inaugrating thelling period,

thisv pressure differential then automatically decea'singuntil there is pressure differential in the opposite direction, thereby terminating 'the filling period and inau'g'urating the discharge perid; and such automatic variation in pressure differential lis dependent upon the relation betvvee'n `tl'ie Wells formation pressure, its productive rate jo'f` lidiid and 'of gas, pressure of displacement fliiid `admitted to `'the flow tubing, pressure of displacement fluid opposing opening of the foot-valve,fpress'ure droppast the open foot valve, and relief of pressure in the new tubing `when production fluid has been elevated and expelled. HCens'eduently, there must be proper relation be'tvveenthese variable factorsfor each particular installation if "automatic cyclic operation is to be maintained.

`F'or example, at each particular installation the relation between Vthese variable factors must be such that: (l) displacement `fluid is admitted at a pressure and in a `quantity suiiicient to elevate-that volume of production fluid which has been trapped in the llow tubing; (2) displacement iluid is admitted at a rate not in excess off discharge capacity of the ow tubing (since otherwise e'iqsiul's'in' of production iluid would notisuilciently relieve pressure in the flow tubing te permit yiecpeining-l` er thereon-valve) and` 3) 'pressure drop past the open' foot valve and/or `pressure of displacement fluid opposing opening of thel foot valve His such as to reverse the direction of pressure differential (for closing the foot valve and opening the head valve) when the volume of production iluid which has entered the tubing string is such thatthe displacement 'ui'diwhioh is thenadinitted to the tubing Will elevate this productionllluid as a slug, Without blb'wing threugh't'h'e column 'of production fluid and Without delay in inaugurating the discharge period, Furthermore, ii automatic cyclic operation is to bel maintained'asvwell conditions change during the producing life of the Well, the relation betyvee the elforementi'oned variable factors must be adjusted in accordance-with the changed `ivell conditions. Fer example, as the Wells formation pressure4 and/or its productive rate of liquid and/or 'gas changes 'during the producing life of the fv'vell, pressure drop past the open foot valve and/or pressureof displacement fluid opposing opening of the foot valve must be adjusted in order toA maintain that relation to formation pressure which will `close the foot valve and open the head valve' after a lling period of desired time interval; and if there has been a change in discharge capacity of the flow tubing (resulting from employment of a different length and/ or diameter of tubing'string) it may be necessary to change the rate of admission of displacement fluid in order to maintain necessary relationship to discharge capacity of the flow tubing.

It is the object of the invention to rst determine Well conditions at each particular installation, and then install a pump so proportioned that rate of admission of displacement fluid, pressure drop past the open foot valve and/or pressure of displacement fluid opposing opening of the foot Valve are such as to maintain autmatic cyclic operation in accordance with condi-A tions at the particular well.

n is a further objectV of the inventiqnt -ad- Y just the pump subsequent to initial installation, as well conditions (when employing this type of pump) are more accurately determined and/or as well lconditions change during the life4 of the well, sothat the aforementioned operatingfactors may be adjusted in accordance with par-` ticular well conditions. f .i Vlitkis a -still further object of the invention to adaptfthe pump to a particular installation by interchangeably employing pump structures havingtheir parts variously proportioned so as to provide diierent relationships between the aforementioned operatingfactors; and to adjust such apump to changed well conditions by pull'- ing thentubing string and installing a different pump assembly. A Y Y v It fis a still further object of the invention to Aadapt the pump for adjustment from the earths surface while the pump is in the well, so as to avoid the necessity of pulling the tubing string in order to adapt the pump to particular well conditions. i

It is a still further object of the invention to provide 4for adjustment by a combinationA of interchangeable parts and adjustment from the earths surface, whereby adjustments to meet transientconditions may be made without pull ing the tubing string, while adjustments to meet changed conditions which are liable to be more permanent maybe made by pulling the tubing string and substituting interchangeable parts.

Itis'a still further object of the invention to arrange the dependently actuated'foot andvhead valves of the pump as ,ar simple but reliable valve mechanism. Y

YIt is a still further object of the invention to arrange' the pump so that it is particularly applicable to an installation wherein the displacement fluid is supplied via the annular space between the flow tubing and a surrounding well casing withY a packer in said annular space coniining the displacement fluid; and with the valve mechanism adapted for installation at 'any desired level adjacent or appreciably below the packer and arranged whereby an extremely sim'- ple assembly connects the valve mechanism with the annular space above Vthe packer, with said assembly offeringonly'minimum restriction to discharge capacity of the flow tubing.

Further objects of the invention will be readily understood from the following description of the accompanying drawings, in which:

Fig. 1 is a vertical section through the upper portionA of a well in which the pump is installed, showing the adjusting mechanism at the earths surface. i 1 j l Figi. 2 is aA similar section through the lower portion of the well, showing the pump assembly.

Fig. 3 is a detail axial sectiony through the pump structure,

Fig. 4 is a transverse section on the line 4-4 of Fig. 3.

Fig. 5 is a detail side elevation of actuating mechanism for adjusting the pump.

By way of example, the invention is illustrated and described in connection with the pumping of petroleum wells, the pump being installed in flow tubing A which in the present embodiment of the invention is surrounded by well casing A' so that the annular space 3 between the tubing and the casing forms a supply conduit for the gas under pressure which constitutes the displacement fluid. The displacement fluid may be supplied to the space 3 from an upper gas zone l of thel well or from a conduit 2 at the earths surface leading from any source of supply; and

by means of a packer I the annular space 3 is n shut off from the production fluid which enters the well casing from the productionl zone of the well. The production'fluid enters the well casing viaa perforated casing section 2a which is below the packer 4 and flows thence through an oil screen 5 at the lower end of the flow tubing, seeking its static or working level inthe flow tubing. l 1

Valve mechanism comprising a Ydependently actuated head and foot valve is mounted in the flow tubing. The foot valve B controls admission ofproduction fluid to that portion of the `flow tubingwhich is above the screen 5 and the head valve C controls admission of displacement fluid from the annular space 3 to that portion of the now tubing which is above the `foot -valve B.

The valve mechanism B-C is adapted yfor mounting in thev flow tubing A at any `desired distance below the packer 4, .whereby the pump may be operated `at a level appreciably below the packer or may be operated at a level ad jacent the packer. Means for supplying displacement fluidpfrom the annular space 3 above the packer, to the head valve C below the packer, is arranged for4 simplicity and economy of construction and so as to offer minimum obstruction to elevation of production fluid via the flow tubing A. n As an instance of this arrangement, a section Y of the flow tubing may be ported for admitting displacement fluid from the space 3 to a sleeve 'I which is concentrically mounted in the section I and which is surrounded by passageways 8 opening longitudinally through said section; and a conduit 9 may be detachably suspended from the sleeve 'I concentrically within the flow tubing. A section II) of the flow rtubing is detachably suspended from the section 6, and is in turn detachably connected to a section II of the flow tubingY from which the screen 5 is suspended, with the section II forming a housing for the valve mechanism BC. The upper portion of the housing II has a sleeve I3 mounted therein, with the valve mechanism B-C suspended from said sleeve and with passageways- I4 open longitudinally through the housing H around the sleeve. Y

The packer 4 is positioned' below the ported section 6, preferably adjacent the upper endv of the section I0; and sections I0 of different length may be interchangeably incorporated in the ow tubing so asvto position the housing II and the valve mechanism B-C either a short distance or any desired appreciable distance below the packer 4. A conduit I2 is detachably connected to theA conduit 9 and `to the bore of the sleeve I3I whereby conduits @L -:l2 of'fdiierent `loor'e, and/,or ofi: different lengthdepending upon' the lengthl oij the section lo, may beinterchangeelnyerh oyejd forfapurpose hereinafter/described."j In the usr trated embodiment, the conduits 9j-I2 areijtrele'- scopi'cally connected with suitable packing vI'5 'at their telescopio joint. fl j' l Displacement iiuid for operating"thefpump; is Supplied Via the conduits Q -l2' to the' bore of the sleeve I3 andV thence to the communicating head valve C; `This supply orndisplacementyfluid need have only a Vrelativelysmall cross-sectional area compared 4 with theA cross-sectional fare'a "of -tliefflowf tubing A.y Consequently, by positioning the` eoidii-its 5 1! 2' within the flow tubingJ the requi 'ci eressfseeticnai area 'iorjthe displacement iiiiizi: cbtaineq'wiiiieempibying conduits 9;!2 wijten are ci reitiveiy `sriiaii diameter; tnererjiy qiiirin'gconduits er ne great wail 'sttengtngin order to` withstand pressure in "said` Lc'nduits, and with seid conduits oirenrig but. iittiel re'strie` tion` to How through the surrounding tubing string A. f' For. a purpose hereinafter described, the rate of" admission of displacement fluid via the ported 'seetion 6 may be adjusted.` For this purpose, a series of longitudinally spaced lateral parts 49 iiiay open throughthe section 6 from the space 3 to the interior of the sleeve1, with each successively lowerport of increased diameter; and e. plug 4l may be rotated in the sleeve 1 for selectively opening' communication between the re spective ports 4d andthe conduits 9-l2. As an "instance of this arrangement, the plug 4I has an aiial bore 42l communicating at its lower end Withfthe conduit 9. Above said lower end, the liore"`42 is of progressively reduced diameter in transverse alinement with the `respective ports `40;` and in transverse. alinement with each of said' ports the bore 42` has the saine diameter as said port, with the upper end of the bore closed at a level above the uppermost port. Radial lporlts 443 are formed in the plug 4I in longitudie "iiallyspaced `relation so as to provide communieation between the respective ports 4U and their `repective transversely alined portions of the bere 42,"andeach of the ports 43 has thesame diameter as its corresponding portion of the bore 'f42 and its Icorresponding port 4d.

lTl'ie radial ports 43V are relatively arcuatelyv spaced, preferably equidistantly, whereby in one .rotatably adjusted position of the plug 4l the iipp'ermost port 43 provides communication oe-f .tween its cooperating port it and the here 42 While the other ports'40 are closed by the plug "4l (as shownl at Figs. 3 and a). As the plug 4l "is' rotated step-by-step, communication. is successively established via the respective successively lower cooperating ports4U--43, while closing communication via the remainder` of said cooperating ports; and after communication has been established via the lowermost ports lid-43 the next step-by-step rotation of the plug '4l Areestablishes connection via the uppermostA ports MLM for repeating `the cycle of adjustment. `evince each pair of the" successively lower cooperatingports 40-4`3are of increased diameter, step-bystep"rotation of the plug 4l provides an `afdjustment for successively increasing the cross fsctionalareaofthe displacement iiuid which is admit-ted to the' bore 475;` andthence to the coni nuits. `sie-tz.

The plug 4-I may beffrotated step-by-s`tep, by

'depressing an actuatingheadM. As an instance wardl'yffroin tli'ef plug 4l, Vwith the act-iiatingV head' 4,41` fyieldably projectedgrelative to; theA stem' 4 5-while'xed`for rotationl with said stern. For this' purposethe stem 45 is sl-idalole `in' a looie"` 4G oi` a'sleeve,V 41 .which depends from the actuatingv head 454, `with saidstern and bore oi 'corre' spondjirig` 'polygonal cross-section and with a spring`m4l8 inouritedgin said lior'e between the stem 45""ahd th'efactuating; head 44..` Thesleeve41 arid thestelmli yare rotatable in an extension 1aor thejsleeve 1; there being an voperating conneetion `between the sleeve 41 'and then sleeveY V1at whereby depressionjof fthe head 44 rotates the4 sleeve 41 and the stem 45 for turn-ing the plugr 41' throughfoneoi itsystep-by-step arcs of rota"- tion. L fAs,an instance'of this operating connection', the outer periphery of the sleeve 41 is grooved; and pins 5l]A project from the sleeve 1a" into said groove; The groove comprises a pluralit'yfof groove elements `equi-distantly circumferentially spaced around the 'sleeve- 4'1 and corresponding in'number to the number of cooperating ports 40'-43. Each groove' element comprises"coope'ri` being cui-ved' at its lower end `as shov'viiat `53 soY as to form a space 54,` with this space later ally "offset witlrrelation tothe groove 51. The groove 52 project'sfupwardly from' the spaceI 5:4 with `tlreylowe'r end' of said groove in longitu'ole nal 'alinement with `said space as shown'at' 55, and jwith saidfgroove` then inclinedrelative to tnefgro'cvel" and terminating at its upper end in a spacei. The spac'eli of each of the' groove elements isfin longitudinal alinem'enttwith` andi formsthe' upper. end of the groove 51 of the next' groove element. y

when the` hee-d 4i:- and. its eieeve. n arenevvardlyspring-projjcted with relation tothe stein 4`5'and the sleeve 1 as shown at'Fig. 3; each pin 50 is in the space 54' of Aone of the groove elements 5|-:52'. The pinis thus in longitudinal alinementwth the entrance: 55 to the groove 52 pif said groove element 'and' is laterally offset rela-Y tive tothe" groove 5| of said groove element. Wherithe 'head 44 and the sleeve 41 are` longi tudinall'y depressed against the tension of spring 48,tl'ie pin 50" enters and' then `moves upwardly along the inclined groove 52 and into the space 56, so that When the head 44 iscthe'n released for springelevation of `tl1"e sleeve 41..relativ`e to the sleeveV 1a,` the p in r50 enters and. rnov'esv d'ow'n wardly alongv the groove 51 of `Ythe next one of tlielgroove elements 5|.'52, and thence along the curved' surface Av53` and 'intothe space 54 of said ii'ext'groove"element,y Since the pins-5l) project from thesleeve 1a which is xed against rotation, the sleeve 41 is turned relative tothe sleeve 1'a by this" movement of the pin 50 along an inclined groove `52 and then along the curvedlower end (inthe IieXt grOOjvt-Y 5|, withV the stem 45 and the plug 4'li` turning with the sleeve J41.- This turning of theplug' MV moves the` saine from: a position alining one of the pairs of cooperating ports "40; tagte e positionV aiming the next "pair of 'said cooperating ports. In similar manner, when the heady` 44 is again depressed and 'then lreleasedA for" y Anext groove 52 and then along the next groove" ,51;

neirt'pair of cooperating ports'4ULS-43l The displacement fluid whieh'is' admitteoviaa pair of"c'ooperating"ports S40- 43' and supplied `cef 'via conduits` 9-`-|'2` to the borefoffytlie Ve I'3', isy admitted l'O the holsing livi'the forftiirning the plug 4l to a position alining the lhead valve C. The head valvemay be of the type disclosed andV claimed in my copending application Ser. No. 334,856, led May 13, 1940; and is illustrated as comprising a cylinder 20 suspended from and communicating at its upper end with the bore of the sleeve I3, with the lower end of the cylinder closed by a bushingZI, and with a valve sleeve 22 projecting upwardly from a cage 26 and adapted for reciprocation on the cylinder 20. When thesleeve 22 is in its upper position as shown at Fig. 3 it closes lateral'ports 23 in the wall of cylinder 20 and thus shuts off admission -ofdisplacement fluid to the housing I I, and when in its lower position it uncovers the ports 23 so as to admit displacement uid to the housing II. A replaceable baie 24 may reciprocate with the sleeve 22 so that the displacement fluid which isdischarged` via the ports. 23 strikes the baffle, instead of impinging directly. against the wallV of the housing I I,` as might prematurely cut-out the housing.

When the head valve is closed, pressure of displacement fluid supplied via 9--I2 preferably tends to open the valve, and for this purpose a pin 2l may project from the cage 26, through the bushing 2| and into the `cylinder 20. Pressure of displacement iiuid is thus directed against the end of the pin 2l, thereby exerting a force tending to lower thersleeve 22 so as to uncover the ports 23,v and the force which is thus exerted is dependent upon the pressure of the displacement Y fluid supplied via 9-I2 and the pressure area of the pin 2l. The pin 2l is preferably detachably supported by the cageV 26 ywhereby pins having different pressure areas may be interchangeably employed for a purpose hereinafter described; yand the Vbushing V2| through which the pin 21 f projects is also detachable so that a bushing may be employed having a bore adapted for snug sliding reception ofthe particular diameter of pressure pin which is being used.

The head valve C is adapted for dependent actuation with the foot valve B, so that when. the footvalve is closed the discharge ports of the head valve are uncovered and kwhen the foot valve is openl the discharge ports of the head valve are closed. For this purposea valve stem 28 depends from the cage 26 of the reciprocating head valve and is connected to the. valve headof the foot valve. Y l i j p The foot valve B controls admission to .the housing II ofv production fluid which enters the lower portion of the tubingstring via thescreen section 5. 'I'he Vfoot valve comprises a valve head 3l!V suspended from valve steml 28V and acooperating valveseat 3|. The valve seat is fixed in the lower portion'zof the housing I I and has an axial bore 32 and a transverse seating surface 33. The cooperating valve head 30 is adapted for recipro- I cation in the bore 32 and has an annular iange '34 adaptedto seat on the surface 33 for, closing the foot valve. Opening movement of the valve head is preferably limitedV so that when the foot 'valve has been opened to its limit ofmovement as shownat Fig. 3, the head 30 is'not clear of the bore 32 but stilloifers some restriction tofree Vflow of fluid'through the open valve; andfthe valve' head is of such diameter as to providea The valve head 30 is detachably'mountedon its valve-'stem and for this purpose athreaded bushing 354y may detachably connect the valve head to the valve stem 28,l preferably with the connection adapting the valve head for rotation relative toits stern. Valve heads of different di- Operation of the structure thus far described, l

is as follows:

Formation pressure tends to open the foot valve B and close the dependently actuated head valve C. This pressure is opposed by pressure of displacement fluid against the pressure pin 2l. These opposing pressures are such that when pressure in the flow tubing is relieved by elevat-y ing and expelling a slug of production fluid, pressure differential opens the foot valve and closes the dependently actuated head valve. Produce tion uid is thus admitted to the housing II via the open foot valve B and rises in the flow tub-` ing, seeking its static or working level.

At first the rate of admission of production fluid is comparatively -slow since its entrance is opposed by back pressure of that column'of 'dis' placement fluid which'is in the flow tubing. and which has expelled a slug of production fluid but which has not yet been completely discharged at the top of the well. As this displacement fluid is expelled, thereby relieving back pressure, the rate of admission of production fluid increases until all of the production fluid which has ac# cumulated in the well during the preceding discharge period hasentered the flow tubing. Then the -rate of admission of production uid equals the productive rate of the well, and diminishes asthe Aproductive rate decreases as aresult of the increasing back pressure of the rising column of production iiuid. o

During this varying rate of intake of vproduction fiuid theV open' foot valve partially restricts ilow so as to maintain pressure drop past the open valve. VThis pressure drop is so great that in spite of the rising column of production fluid and pressure of displacement fluid against the pin 2l, pressure diierential (for retaining the foot valve in open position) is maintained until the production uid stands in the flow tubing at that level which provides aV column of such vmaximum volume that lthe subsequently'admitted displacement uid will be capable of elevating and expelling the same but of such minimum sure drops past the open foot valve'is not so excessive but that as soon as thel production fluid reaches the aforementioned level, pressure of the column of fluid plus pressure'of displace# mentifluid against the p-in 2 exceedsformation pressure and thereby immediately closes the foot valve and opens the dependently actuated head valve.

Displacement uid is then admittedv to the housing I I via the Vopen head valve C, at a pressure and in quantity suicient to elevate that volume of production fluid which is now trapped in the flow tubing above the closed foot `valve* B. rlhe displacement fluid thus elevates 'the produc# tion fluid as a slug, and discharges the same'atY the top of the Awell.` .The raterof admission-of displacement uuid issueh that it does not exceed cuscharge Vcapacity of the iiow tubingi. e. it is such that whenv production vfluid is expelled,VVV

pressure inthe flow tubing is relieved rather than being maintained bythe incoming displace@ Y ment fluid. Due to this relief of pressure, formation l pressure in the well again exceeds pressure in the ilow tubing` plus pressure of displacement fluid against the pin 21, so that resulting pressure differential reopens the foot valve and closes the dependently actuated head valve, thereby restarting the lling period.

Automatic cyclic operation is thus dependent upon thepump having its parts proportioned in accordance with Well conditions of each particular installation, i. e. discharge capacity of the tubing string and formation pressure and productive rate of each particular well. Consequently, before installing a' pump well conditions at that particular installation arefsurveyed to determine these variable factors.

Thepump, as then installed, is provided with a foot valve B which will insure a predetermined restriction to flow past the openvalve as it approaches closed position, i. le. as the valve head 30 moving into the bore 32 further restricts the annular `space between thel valve head and the surrounding bore., For this purpose, the Valve head which is mounted on the valve stem 28 is of such diameter as tcprovide a predetermined restricted passageway between .the Valve head and the surrounding bore 32, with opening movement of the valve head so limited by abutment of the cage 26 againstthe bushinggZl that when the foot valve is open it still maintains a pre- D determined restricted passagewaybetween the valve head and its cooperating seat. VThis restricted passageway is determined with relation to (l) productive rate of gas` and of liquid and formation pressure of the particular well, (2).

pressure of displacement fluid admitted to the flow tubing, and`(3) pressureof displacement fluid opposinggopening' ofjthe foot valve. AIn accordance with `these ,factorsr the restricted passageway provides such pressure drop past the open foot valve as it approaches closed position that (l) formation pressure is notexceeded: by opposing pressure tending to close the foot valve for terminating the llingperiod, ,until production iiuid has been admitted in such volume that the subsequently admitted displacementuid will not blowthrough the column of production fluid but will elevate and expel the same as a slug, and (2) formation pressure is exceeded by said opposing pressure (thereby closing the foot valve) as soon as said volume of production iiuid has been admitted.

Furthermore, the pump is arranged so that displacement fluid supplied via conduits 9|2 exerts predetermined pressure opposing opening of the foot valve. selected pressure arealis mounted on. the cage 26 for projection intov the` cylinder 202 `This' pressure` area is determined with) relation to (al) pressuresofdisplacement fluid supplied` via conduitsQ-H and-'(2)' pressure drop past the open foot valve, so that the force exerted at said pressure area in cooperation Witnpressure `drop past `the open foot valve is- (l) exceeded by formation pressure for maintaining the foot valve open until thedesired Volume `of productionfluid has been admitted to the ow tubing, and (2) `exceeds formationpressure for closing the foot valve as soon as the desired volume of production fluid has been admitted.

Furthermore, the pump is arranged so as to provide a predetermined rate of admission of displacement fluid. ForV this purpose,the displacement luid may have a predetermined cross-sectional area` of admission, or therate of admission For this purpose, a pin v2T of may be controlled by imposing frictional resist- 'ance through .different lengths of `admission con'- duit, or a combination' of such regulating means may be employedjV For example-the rate of admission of displacement uid maybe regulated by employing a conduit 9-|2 of selected'crosssectional area, with the tubing section I0 'of such longitudinal dimension that the conduit 9-I2 is telescoped to a selected length. Furthermore, the rate of admission of displacement fluid may be regulated by depressingand then releasing the head 44 thedesired number of times before installing the pump in the well, so as to turn the plug 4l foralinement of those cooperating ports 4D-43which provide desired cross-sectional area for admission od fluid. A combination `of the Iaforementioned adjusting means may also be employed.` The selected rate of admission of displacement iiuid is determined with relation to 1) pressure of displacement fluid supplied to the annular space 3,`and (2)` discharge capacity of the tubing string (as determined by length and bore'of the tubing string and back `pressure maintained on the Well by a gas trap or .the like), so that the rate of admission of displacement fluid will not exceed the dischargecapacity of the tubing string. This-is toinsure relief Vcf vpressure and opening of the foot .valve and closing of the dependently actuated head Valve as soon as a slug, of production fluid has beenl elevated` 'and expelled. lf the rate of admission ofdsplacement fluid exceeded discharge capacity of the tubing string, pressure would be maintained in the flow tubing after `elevation and expulsion of the slug of pro-` duction fluid, thereby tending to maintain the foot valve closed and the head valve open.` If the input of displacement uidto the annular space 3 were so great as to'maintain this pressure, the pressure in the flow tubing would never be sufcientlyl relieved to ,restart the lling period, 'and the pump wouldV lbecome inoperative with displacement fluid continuing toenter the flow tubingvi'a the open head valve and flowing thence v'iaitheflow tubing for escape at the top of the well. On the/other hand, if the input of displacement iiuid to the annular space 3 wereso restricted as: to reduce the pressure insaid annular spaceas a result of the displacement fluid continuing to ow via the open head valve for escape viathe flow tubing, the pressure in the annular space 3 and in the tubing would eventually berelieved to the extent necessary to restart the filling period. But this would only occur after an appreciable delay in restarting the filling period,

duringwhich displacement fluid would` continue to' escape, and therewould also be appreciable delay'vin restartingthe next following discharge period, since it would be necessary for the pressure to again build up in the annular space 3 before it `would be suflicient to elevate the slug of production fluidwhich had been trapped in the now tubing during the preceding filling period.

Furthermore, when the pump has been installed and is ready for operation, the pressure at which displacement fluid is supplied to the space 3 is regulated with relation to volume of production fluid which Yis admitted to the flow tubing during the lling period, land with relation tothe pressure area of the pin 21, so that the foot valve will be automatically closed and the dependently actuated head valve opened at the end of the desired filling period, with thepressure of the i displacement fluid (which is then admitted to tive rate of gas and/or liquid or appreciable change in formation pressure or appreciable change in discharge capacity of the tubing string,

will destroy the predetermined relation between the various operating factors.

Therefore as the productive rate of the Well decreases or yits formation pressure diminishes, the foot valve B may be provided with a head 3ll of greater diameter providing a greater restriction to flow andconsequently an increased pressure drop past the open foot valve as it approaches closed position; thelhead 3l) which is selected being such as to provide `a pressure drop which with relation t` the changed Well conditions Will restore the previously described operating cycle.

In lieu of, or in conjunction with adjustment of pressure drop past the open foot valve as it approaches closed position, a pressure pin 21 o-f smaller pressure area may be installed when productive rate or formation pressure of the Well decreases. This reduction in pressure area will be that required for restoring the proper relation between the various operating factors for continuing automatic cyclic loperation under the changed Well conditions.

In similar manner, if changing Well conditions make it advisable to supply displacement fluid to the annular space 3 at a different pressure or if the discharge capacity of the tubing string changes, the rate of admission of displacement fluid is restored to. its proper relation t0. discharge capacity of the tuibing string, by substituting a different bore and/or length of conduit 9-I2, and/or rotating the plug 4| for alining a different pair of cooperating ports 4ll-43.

It is thus possibleby one or morerof the aforementioned adjustments, to restore that operating relationship in accordance with changed Well conditions, which will continue automatic cyclic Voperationof the pump.

The adjustments which have been described are made by pulling the tubing string A when it is desired to change the valvehead 3U or the pressure pin 21 or the conduits 9--I2, or when it is desired to turn the plug 4I for alining a different pair of cooperating ports d70-43. The inventon also provides for adjusting the pump to particular Well conditions without pulling the tubing string.

ForV this purpose, means may be provided at the earths surface for building up pressure in the tubing string A during the Vfilling period of the pump, lWith this pressure relieved during the discharge yperiod of the pump. Consequently, without changing the valve head 3D so as to provide different restriction to 110W past the Open foot valveY B and/or without changing the pressure pin 21 so as to provide different pressure of displacement uid -opposing opening of the foot valve, such pressure may be built up in the tubing string during the filling period as will insure terminating the lling'period and inaugurating the discharge period for maintaining lautomatic cyclic operation in accordance With theparticular' Well conditions at each installation.V

` As in instance of this arrangement, the tubing string A may be provided with an usual manually controlled valve 60 at the earths surface (with said valve open during operation of the pump) ,and may also be provided at the earths surface with Va valve 6l which is respectively opened and closed during discharge and lling periods of the pump and which may be automatically timed. The valve 6I is open during the discharge period of the pump so that at the end of said discharge period pressure in the tubing string is relieved. (as previously described) and formation pressure thereby opens the foot valve B to inaugurate the lling period; vand. fthe valve 6l 'is closed fora desired intervall during the filling period of the pump so as Yto build up pressure in the tubing string for insuring said pressure exceeding formation pressure and thus closing the foot valve and inaugurating the discharge period as soon as the desired volume of production fluid has entered the iiovv tubing.

Automatic timing of the valve 6l may be by a diaphragm control 62, the valve being opened by a spring (not shown) when pressure against the diaphragm is relieved via a bleeder line 63, and being closed by pressure against the diaphragm When the bleeder line is closed. Pressure for actuating the diaphragm may be supplied via a line 64 which may be a branch of the conduit 2 which supplies displacement fluid to the annular space 3 and which may have suitable pressure regulating means 64a; and the line B4 may have a branch leading therefrom 4and forming the bleeder line 63. 'I'he bleeder line 63 may be alternately opened and closed by a valve 65 Which may be actuated by a usual clock mechanism.4

For example, a clock mechanism 66 may rotate a disc 6l, and the valve 65v may be mounted on a lever 68 which Arideslon the periphery of the rotating disc. The periphery Aof the Adisc yhas alternate high and low spots 69 and 10, whereby engagement of the lever by a high spot opens the valve 65, and engagement of the lever by a low spot closed the valve as shown at Fig. 1.

The disc 61 is readily detachable from the shaft of the clock mechanism whereby discs may be interchangeably employed having alternate high and lovv spots of different length.` A disc is` selected having its alternate high and loW spots of such relative length as tov open and close the-bleeder line 63 and thereby open and close the valve 6I for desired timeintervals during the discharge and filling periods of the particular pump, so as to build up pressure for terminating the filling period and inaugurating the discharge period in accordance with operating factors of the particular installation.

A by-pass 'H is preferably provided around the Valve 6l and is normally closed by a pressure relief valve 12. I, through any mechanicalv defect the valve 6I fails to open at the proper time and excess pressure is thus built'up' in the fiow tubing A, the valve 12 automatically opens to relieve said excess pressure via the by-pass, so that only the desired pressure is built up in the flow tubing, l

If, While the valve 6| is closed during the filling period,` pressure of production fluid in the tubing string A is insucient to build up the desired pressure, additional fluid pressure may be supplied to the tubing string. For this purpose, aline 13 may supply fluid pressure to the flow tubing A and may be a branch line leading from the conduit 2 which supplies displacement fluid to the annular space 3. The line 13 may be controlled by a valve `1li at the earths surface with this `valve respectively opened and closed while the valve 6| is closed and open respectively.

Y Automatic timing of the valve 14 in synchronism with the valvefglmay be by a diaphragm control 15, the valve 14 being closed by a spring (not shown) when pressure against the da,- phragm l5 is relieved, preferably via the previously described bleeder line 63, and the, valve "I4` being opened by pressure against the diaphragm when the bleeder line is closed. For this purpose, a branch line 'I6 4may connect the line 64 with the diaphragm 15. The clock mechanism 66 thus actuates the valves 6I and 1 4 in synchronism, whereby fluid pressure is supplied via the line 13 to the tubing string A while the valve 6I is closed, in order to build up desired pressure in the tubing string, and the supply of fluid pressure via the line 'i3 is shut off while the valve 6| is in open position for discharging production fluid from the tubing string.

When the pumpis to be operated Without uid pressure being supplied via the line 13, a valve 11 in the line l5 is` closed at a time when the valve '14 is in its closed position, i. e. at a time when the valve S5 is in position opening the bleeder line E3. The closed valve 11 thus prevents iiuidpressure being subsequently supplied via the line 'I6l for opening the valve 14, and ad-` mission of fluid to the tubing string via the line 13 is thus shut oir.

f The line T31 may also be employed for kickover at the start Vof pumping operations, i. e. for supplying :fluid pressure via the tubing string A and thence via` the open head valve C to the annular space 3 for discharge from said space at `the earths surface. `lor 'this purpose a line Si! having a manually controlled valve 8l may lead from the annular space 3 and may communicate `with the by-pass il." 1 During pumping operation vthevalve 8l is closed for preventing escape of 4pressure via the lineltl; ut for kick-over at `the start of pumping operations a valve 82 in the supply conduit 2 is closedand the valve 8l in the line 80 is opened, and the'bleeder line 83 is closed .and thevalve 'V is opened so that the valve'ld'is l opened by Vpressure against its` diaphragm l5,

while` the valve iii is closed by pressure against its diaphragm'l; l

Pressure Huid supplied `via the open 4valve 14 thus flows downwardly through the tubing string A so as to close the foot valve B and open the dependently actuated head valve C, wherebyls'aid nui-d is discharged via conduits ll--IZ andthe ported section 6 to the annular space 3, from whence it is discharged via the line' Silandthe f"- determined, and in accordance with these particular conditions a pump is installed providing predetermined restriction to flow past the open foot valve B as it approaches closed position and I.'

`having a pressure pin 2li 'of predetermined pressure area and providing a.predetermined rate of admission of displacement fluid via ported section 6 and conduits 9-I2, so as vto insure auto'- matic cyclic operation as previously described.`

However, as soon as the pump is installed it maybe found that while production rate of liquid is as has 'been determined by prior survey of well conditions, productive rate of gas is appreciably increasedwhen operating the pump, due to the pump functioning with its foot valve B closed during the discharge period and thus preventing back pressure against the formation..` Such increase in productive rate of gas changes the particular relationship between the various operating factors for which the pump has been proportioned, i. e. the unforeseen increased now of gasv may increase pressure drop past the open foot valve B as it approaches closed position so that pressure in the tubing string will not exceed formation pressure (for closingthe foot valve) at the end of a desired filling period.

Furthermore, it is preferable when iirst installing the pump to employ avalve head `3i! of greater diameter than required for proper functioning of the pump, since reduction in productive rate of the well during its producing life will eventually make necessary a larger valve head 30 in orderto provide greater restriction to flovv past the open foot valve as it approaches closed position for maintaining desired pressure drop in accordance with changed well conditions, and initial installation of a valve head 5B of greater diameter than required will thus postpone the necessity of substituting a larger valve head as well conditions change. But such initial use of a valve head of greaterldiameter than required,

will-initially produce excesspressure drop past the open footjva-lve B as it approaches closed position Vso that the foot valve will not close at the end of a desired filling period.

.Furthermore` decrease in productive rate an-d/orformation pressure of the well during its producing life, will eventually destroy the .desired` relationship between `the various operating factors so that pressure in the tubing string plus pressure of displacement iiuid against the pin' 2l' and opposing opening of the foot valve will no longer exceed formation pressure at the end of a desired filling period, consequently there `vvill be undue delay in closingthe` foot valve to inaugurate the ldischarge period.

To compensate for the aforementioned conditions and thus maintain automatic cyclic operation without pulling the tubing string and substituting a different valve head 3E and/or a different pressure pin El', the valve Elis automatically opened and closed at selected time intervals during operation of the pump. For this purpose, a dischi' is selected which will provide a desired time interval during which the valve 54 isopen, followed by a desired time interval during which the valve is closed.

lfjhe selection of a disc El is such that the valve cl remains open during `the discharge period of the pump, untilvthe slug of production fluid which has been discharged via the open valve and pressure of displacement fluid which has elevated the, slug has been so relieved via the open valve, that formation pressure again exceeds pressure in the tubing string plus pressure of displacement iluid againstthe 2l for opening-'the foot valve and cl.. ing the dependently actuated head valve to inaugurato the filling period. i

The selection of avdisc 6l is also such that during thefilling period the valve (il is closed for such time interval asto build up pressure in the tubing stringA, so that if the diameter of the valve head 3i) and/or the pressure area of the pin 2l are not such as to provide necessary pressure in the tubing string for closing the foot valve at the end of a desired iilling period, the :additional pressure built up as a result of closing the valve 6| will insure the desired pressure in excess of formation pressure for closing the foot valve at the desired time. The selection of a disc 61 is also such that the Valve 6| is again opened as soon as the foot valve has closed for terminating the lling period and inaugurating the discharge period.

If suiiicient pressure is not built up by closing the valve S I the valve 14 may be operated in synchronism with the valve 6| so as to admit additional iiuid pressure via the line 13 while the valve El is closed, thereby insuring the desired pressure being built up in the tubing string for terminating the filling period and inaugurating the discharge period.

` Means may also be provided at the earths surface for adjusting the rate of admis-sion of displacement fluid to the head valve C via the conduits 9-l2, Without pulling the tubing string A. For this purpose, and without pulling the tubing string to substitute conduits 9|2 of different length and/or bore, and without pulling the tubing string to permit access to the head 44 for adjusting the plug 4l so as to aline a different pair of cooperating ports 441-43, the head 44 may be actuated from the earths surfacewhile the tubing string is still in th'e well.

As an instance of this arrangement, a line S which is weighted at its lower end as shown at 9|, may be reciprocated through the tubing string A by a suitable operating connection (not shown) at the learths surface. By lowering the line 9U its weight 9| depresses the head 44 against the tension of the spring 48, and by then elevating the line and its weight the head 44 is elevated by its spring. This movement of the head 44 rotates the plug 4| as previously described, so as to aline a different pair of cooperating ports 40-43; and by lowering and then elevating the line 90 any desired number of times Ythe plug 4I is rotated for alining a desired pair of the cooperating ports.

lOperation when rotatably adjusting the plug 4| from the earths surface is as follows:

In accordance with particular well conditions,

v the pump is initially installed so that during operation of the pump displacement fluid is admitted via the port'ed section 6 and the plug 4| to the conduits 9|2, with the rate of admission of displacement fluid regulated by the plug 4| having been rotated to aline a select-ed pair of the cooperating ports 4|]-43 and/or by conduits S-IZ of selected length and/or bore having been installed in the pump. c

During operation of rthe pump a diiferent rate of admission of displacement fluid may become necessary in order that it shall not exceed discharge capacity of the tubing string A. This may be due to changing discharge capacity of the tubing string resulting from substitution of a diierent bore and/or length of tubing string, or resulting from different lback pressure being maintained in the tubing string at a gas trap or the like with which the tubing string communicates. In order to maintain the desired rate of admission of displacement fluid it may also be necessary to change the cross-sectional area of admission in accordance with change in pressure of the displacement fluid. For example, if .the displacement uid is not supplied via the conduit 2 which leads from a source of supply having constant pressure, but is supplied from an upper gas zone of the well, the pressure of said fluid will vary in accordance with changing formation pressure at said upper Zone.

Admission of displacement fluid is adjusted in accordance with the aforementioned Variable factors so as to provide desired rate of admission of displacement fluid for maintaining automatic cyclic operation of the pump. In order to make said adjustment without pulling the tubing string for inserting dinerent conduits 9-l2 or for rotating the plug 4| by direct engagement of the head 44, the line 9U is reciprocated from the earths surface while the tubing string is still in the well, so as to aline that particular pair of cooperating ports 40--43 which has a crosssectional area insuring desired rate of admission of displacement fluid, in accordance with particular well conditions, for maintaining automatic cyclic operation of the pump.

rIhe invention thus provides for automatic operation by installing the pump in accordance with well conditions at each particular installation, so as to insure pressure diierential for inaugurating the filling period, followed by decrease of said pressure differential until the pressure differential is in the opposite direction for starting the discharge period, with displacement fluid admitted during said discharge period so as to elevate and discharge the trapped production fluid, and with discharge of the'produlction iiuid relieving pressure so as to restart the iilling period.

The invention also provides for adjusting the various operating factor-s during the producing life of the well and as well conditions change, so as to restore the proper relationship for continuing automatic cyclic operation.

The invention also provides for making such adjustments by pulling the tubing string for substituting interchangeable parts, or for making said adjustments from the earths surface without pulling the tubing string. Adjustments to meet particular 'conditions which cannot be accurately determined until the pump is in operat1on or to meet changed conditions of a transient nature may thus be made from the earths sur face, while adjustments to meet changed conditions which are of a more permanent nature may be made by pulling the tubing string and substituting interchangeable parts. l

I claim:

1. In a tubing string, well tubing, an extension suspended from the well tubing, a housing suspended from the extension, the extension being detachably connected to the well tubing and to the housing whereby extensions of different length may be interchangeably employed, an intake for displacement iluid leading to the interior of the tubing string, a valve controlling admission of displacement iluid to the housing, a conduit in the tubing string providing communication between said intake and said Valve, said conduit being detachably supported so that conduits of different bore may be interchangeably employed, said conduit comprising telescopic sections whereby it may telescopically adapt itself to the length of the particular extension which is employed, and a valve controlling admission of production fluid to the housing, the said valves being adapted for dependent automatic operation responsive to pressure differential for admitting production fluid to the housing while shutting olf admission of displacement fluid and then trapping production nuid assenso in the housing andadmitting displacement fluid for` elevating the trapped production fluid and then repeating the `cycle of operation.`

l2. In a tubing string, a housing, an intake for displacement fluid leading to the interior ofthe tubing string, a valve -controlling admission of displacement ilu'id to the housing, a conduit in the tubingstring providing communication between said" intake and said valve, said `conduit comprising telescopic sections whereby it may be adjusted to a length providing predetermined rate or".v flow of displacement fluid with `relation tolldiscl'large` capacity of the` tubing string, and a valvecontrolling .admission` of production fluid tothe housing, the said valves being adapted for dependent automatic `operation responsive to pressure :differential for admitting production `fluid to. the'housingwhile shutting ofi admission of'` displacement fluid and then trapping production fluid in the housing` `and admitting displacement for elevating the trapped production fluid and then ,repeating the cycle of operation.

3. In a tubing string, a housing, an intake for displacement fluid leading to the interior oi the tubing string, a valve controlling admission of displacement fluid to the housing, a conduit in the tubing string providing communication between said intake and said valve, said conduit being detachably supported so that conduits of different bore may be interchangeably employed, said conduit comprising telescopic sections whereby it may be adjusted to a length so that the conduit is of a length and bore for predetermined rate of ilow of displacement fluid with relation to discharge capacity of the tubing string, and a valve controlling admission of production fluid to the housing, the said valves being adapted for dependent automatic operation responsive to pressure differential for admitting production lluid to the housing While shutting off admission of displacement lluid and then trapping production fluid in the housing and admitting displacement fluid for elevating the trapped production fluid and then repeating the cycle of operation.

4. In combination, a tub-ing string, a valve controlling admission of displacement fluid to the tubing string, a valve controlling admission of production fluid to the tubing string, the said valves being adapted for dependent automatic operation for admitting production iluid to the tubing string while shutting off admission of displacement fluid and then trapping production fluid in the tubing string and admitting displacement fluid for elevating the trapped production fluid for discharge via the tubing string and then repeating the cycle of operation, a valve controlling discharge of the elevated production iluid from the tubing string, and means for respectively closing and opening the last mentioned valve during opening and closing oi" the second mentioned valve.

5. In combination, a tubing string, a valve controlling admission of displacement fluid to the tubing string, a valve controlling admission of production fluid to the tubing string, the said valves being adapted for dependent automatic operation for admitting production luid to the tubing string while shutting off admission of displacement lluid and then trapping production fluid in the tubing string and admitting displacement fluid for elevating the trapped production fluid for discharge via the tubing string and then repeating the cycle of operation, a valve controlling discharge ofthe elevated production iluid from the tubing string, and means for automatically opening and closing the last mentioned valve at predetermined time intervals.

6. In combination, a tubing string, a valve controlling admission of displacement fluid to the tubing string, avalve controlling admission of production fluid to the tubing string, the said valves being adapted for dependent automatic operation for admitting production fluid to the tubingl string .while shutting off admission of displacement fluid' and then ltrappingproduction fluid in the tubingstring and admitting. displacement iluid for elevating the trapped production fluid for `discharge via Athe tubing stringand then repeating the'cycle of operation, Ya valve controlling discharge of the elevated production iluid from the tubing string, means for automatically opening and closing the last mentioned valve atpredetermined time intervals, and means for independently adjusting`V the time intervals during which-said last mentioned valve is open and closed respectively.

7. In combination, a tubing string for a well bore, means for admitting production fluid from the Well bore to the tubing string, valvular means in the well rotatably movable through a plurality of open positions to permit various rates of admission of displacement fluid to the tubing string, an actuator engaging said valvular means so that the actuator is adapted for reciprocation relative to the valvular means but rotates the valvular means through its plurality of open positions responsive to step-by-step rotation of the actuator, a pin and slot operating connection for rotating the actuator step-by-step responsive to successive reciprocations of the actuator, and means controlled from the earths surface for reciprocating the actuator.

8. In combination, a tubing string for a Well bore, a valve in the well bore controlling admission of displacement fluid to the tubing string, a valve controlling admission of production fluid to the tubing string, the said valves being adapted for dependent automatic operation responsive to pressure differential for admitting production fluid to the tubing string while shutting off admission of displacement fluid and then trapping production fluid in the tubing string and admitting displacement fluid for elevating the trapped production fluid and then repeating the cycle of operation, valvular means in the well rotatably movable through a plurality of open positions to permit various rates of admission of displacement fluid via the open displacementfluid-admitting valve, an actuator engaging said valvular means so that the actuator is adapted for reciprocation relative to the valvular means but rotates the valvular means through its plurality of open positions responsive to step-bystep rotation of the actuator, a pin and slot operating connection for rotating the actuatorstepby-step responsive to successive reciprocations of the actuator, and means controlled from the earths surface for reciprocating the actuator.

9. In combination, a tubing string, a valve controlling admission of displacement fluid to the tubing string, a valve controlling admission of production fluid to the tubing string, the said valves being adapted for dependent automatic operation for opening the second mentioned valve and admitting production fluid to the tubing string, While closing the first mentioned valve and shutting oil admission of displacement fluid, and then closing the second mentioned valve string, while opening the rst mentioned valve and admitting displacement fluid for elevating the trapped production fluid for discharge via the tubing string, and then repeating the cycle of operation, a valve controlling discharge of the elevated production iiuid from the tubing string, Y and means for alternately opening and closing the last mentioned valve, so that said last mentioned valve is opened for discharge of said elevated production fluid, and is closed at a time at which the second mentioned valve is open, for increasing the pressure in the tubing string so as to close the second mentioned valve.

10. In combination, a tubing string, a valve controlling admission of displacement fluid to the tubing string, a valve controlling admission of production iiuid to the tubing string, the said valves being adapted for dependentautomatic operation for opening the second mentioned valve and admitting production fiuid to the tubing string, while closing the first mentioned valve and shutting off admission of'displacement fluid, and then closing the second mentioned valve and trapping production fluid in the tubing string, While opening the rst mentioned valve and arimitting displacement fluid for elevating the trapped production iiuid for discharge via the tubing string, and then repeating the cycle of operation, a valve controlling discharge of the elevated production fluid from the tubing string, means for alternately opening and closing the last mentioned valve, so that said last mentioned valve is opened for. discharge of said elevated production fluid, and is closed at a time at which the second mentioned valve is open, auxiliary means controlling admission of fluid pressure to the tubing string, and means for closing said auxiliary means while said last mentioned Valve is open, and opening said auxiliary means for a time interval While said last mentioned valve is closed, for increasing the pressure in the tubing string so as to close the second mentioned valve.

ROBERT P. MILLER.