US2669936A - Apparatus for pumping wells - Google Patents

Description

1954 L. E. ELKINS ET AL APPARATUS FOR PUMPING WELLS 2 Sheets-Sheet l v Filed May 7, 1952 INVENTORS ATTORNEY FIG. 1

Feb. 23, 1954 E. ELKINS ET AL 2,669,936

APPARATUS FOR PUMPING WELLS v Filed May 7, 1952 N 2 Sheets-Sheet 2 I 1 IO\ l f FIG. 5 1i 2s g i'r N FIG. 8 j i I a I7LB |9 U L g 1 I6 1 r I LLOYD E. ELKINS RENIC P. VINCENT 1 HENRY SCHAEFER I INVENTORS FIG. 2

ATTORNEY Patented Feb. 23, 1954 APPARATUS FOR PUMPING .w Ls

Lloyd Elkins,. ;Renic P. Vincent, and Henry Schaefer; Tulsa; Okla., assignorswto stanolind- OiLand Gas, Company, Tulsa, Okla, aicorporaru; ion o l-De aware AP HQ i9 MeYF l'lria Nos 28-6516:

Figure 4 isa cross-sectionalview of -the plungershown in Figure-3 having; the skirt portion of 13116; plungerncompressewto the same outside d-imenw sions as the solid headportion Figure-5' is a cross-sectional view taken= -on-= line 5--'-5' of Figure 4 showing the skirt portion :of- If the plunger-in its deformed position as :it wouldm A system-ofthistype-is disclosed in U. S. Patent 1,932,496"'Wellensiek-. a copending application, United states application; Serial Numben 261;714 Vincent'filed-December- 14, 1951, variousimprovements v in the :We1lensieksystem have beeni proposed-'wherebythe lifting gas/oil: ratio of suclm-ipu-mping systems may: be materially decreased-.1 Inthe improved: method and apparatust the a power tubing string is I temporarily-- pluggedcat theloottom onceeach' cycle so that the gas remainingcin the-.power-tubingafter the well fluids havelbeen dischargedfro'm the production tubing: is inotirwasteds That is,- in: this improvement; onlytabouthalf of the gasin the system after. a slug. of lwelltfiuids is produced-"is wasted. Biithismeans the pressure in-theproduction tubingcis periodically'reduced'. to substantially 'atmospheric pressure, thereby' facilitating the flow of r well fluiclstinto..-.the.. production tubing. without; at thesame; time, unnecessarilywasting gas;

It-ris an ,objecti'of zthist invention to provide an.

improvement; in, thescycling. 1 gas ilift g plunger or freespiston systemsby Which-the capacity ofsuch l systems can be increased; particularly where-ai well isgequipped witha smallsizeacasing: It is a, 1

more aspecific; objectof .thistinvention to provide.

an ;improvedxcyclinggas lift plunger-nsystem in,-

which the quantity of gaszin thegasaccumulation chamber: or power tubing cana be; varied: overma;

wider-range.

It; is .;still 2 a more; specific: object-10f this. in vention to prgw-ideain,a,,cycling ;gaszliftc; plunger system, power, tubing; 'andzproductionq tubing, strings-of different-sizes ;and ;to-,.prov ide ,a

ycl n gas lift plunger-which will operatein power tubing and production tubing 1 strings of; diflierent size. invention'will become'apparent from the following description;v Inthis descriptionrefez ence will be made to thelaccompanying; drawings in which:

Figure 1 isof a cross-sectional view of wellhead apparatus suitable forusein the herein-described cycling gaslift plunger system;

Figure 2. is across-sectional view of that part of the apparatus located invthe Well which isused. inthis system;

Fi ure. 3 isa cross sectional viewpiatypigal These and other 1 objects of j this be if passed through-a conduit having a diametere of, the same size as -the head portion. of the:

plunger;

Figure 6is-a cross-'sectional view-of a modificasl l tion of- -the plunger shown vain Figure '3 invwhich':i the skirt: portionof the plunger is extended bym the'addition of a cylindricalsleeve; t

Figure '7 is a cross-sectional view of a' -still:fur.-1li 131C131: modification'of the plunger showniin Figures: 3 and l 6 wherein-the; plunger is equippeds with a;

head. andxtail'portion-uand with alcenter skirt oril:

body portion disposed b'etweenithelhead and tall;

and,

Figure 8 is acrossesectional. View of ia'nealterl-s natel plunger showing.::.a head: and: skirt. cone. structed of different'materials. l

Inxthis inventiomwhich; as indicated'above; isl:

an. improvementiuponx-the-cycling gaslift:plunger; K

system, theproductionvand-apower tubing. strings;

are; of different-1nominal-internal1diameteri and the; gas i lift plunger: cycles; down-l: through; the: power tubingnndup:throughathe productiontubs ing, The plunger providesiaa. seal." oredividem in 1 theilarger: tubing-and preferablyseals bothk tub ing; strings :to -,preventfifiuid1from-,byepassing 171165,: plunger .ineither; strings -Ref erri ng news-specifics;

ally to Figures L and 2 foriamore-deta-tiled descrip" tion. of :the: invention;:a wellwis lequippedwithlaz i casingalflm'havingla tubingaheadigl l 1 Thisvtubinga.

head hasdzwo openings-I 2 and 3 whichyaresealedc as; by: weldinggaroundi: a' power tubing 1.4 and" ar:- production; tubing 15;; respectively-:1 .Bothap we tubingwl ligand productionztubingjstrin l izexten downintog-the-welland casing?! 0 tea depth gbel the working fluid 1 levelagof the well- 1 Typi al the two'strings extendltmtheiibottom ofrtheawell and are connectedcby a low-ent ced; |;5;:;f,ormin g as continuous, conduit within: they, well. At the;;,

. lower end of "the :tubing; 6 preferably int thew-head;

gas lift plunger for use in a, cycling gaszliftz; I

plims iv stem empl ng row r ubin ;andmrc:

ductiontubing of difierent sizes;

I h n u s. provided w tha el fiuidrin et 1 H. In some cases it is desirable -;to use a stand s v 1ve I n he we l :fiuid nletqto' prev nt 171K135; well .fiuids in. the conduit: from being; displaced ackli tothew l w n re u e isan l l. the conduitto lift thewellfiuids it 'Ifhi s;,sjzancl ing a ve maylbe-of ithe'remoyaple typ hat a e ed utt ush e-pr m etub n. ac d: epa d; t; e i aied r e l i. ch: i l Qfi-ds heed-1 6'. niiiecn x ass o the; s

contour of the opening in the head may form part of the standing valve cage to facilitate removal of the standing valve. This perforated plate prevents plungers from falling into the standing valve opening in the head and directs the plunger up the production tubing. In some cases it may be desirable to leave out this perforated plate, and the system will operate satisfactorily, since the plunger tends to follow the well fluids around the U-bend in head l5 when standing valve i3 is used to prevent these fluids from flowing out through well fluid inlet 51. j

As disclosed in the above-mentioned copending application Serial Number 261,714 Vincent,

it is generally desirable to place a constriction 2! near the lower end of the power tubing. This constriction, as explained in greater detail hereinafter, holds the plunger in the power tubin'g' as the gas pressure abovejthe constriction and plunger increases up to a predetermined amount. By this means the lifting gas/oil ratio of the well may be decreased. While our gas lift system which employs power tubing and production tubing of different sizes may be operated without the constriction and retain some of the desirable characteristics of the system, we prefer such a constriction. This constriction is placed in the power tubing several joints above the lower end, preferably at about the working fluid level of the well. By this means the capacity of the con duit below the working fluid level is increased. An orifice 22 connecting the power tubing and the production tubing immediately below the com striction' allows the liquid level in both tubing strings to equalize, thereby additionally increasing the capacity of the conduit below the working fluid level so that more fluid can be lifted each lifting cycle. The lower ends of power tubing I 4 and production tubing l5 thus provide an accumulation chamber 23 in which well fluids accumulate between cycles of the plungers. Other means for providing'a large volume accumulation chamber are disclosed in the abovementioned copending application Serial Number 261,714 and can be incorporated in this system.

At the surface a plunger injector apparatus is provided to control the injection of gas into the power tubing and to insert plungers into the gas stream as desired. The plunger injector apppa ratus also separates plungers from the fluids pro- 1 duced from the well and reinjects them into the power tubing. The upper end of the production tubing l5 contains a U-bend 24 which directs well fluids and plungers down into a plunger hopper 25. The plungers may also be inserted into the hopper and withdrawn therefrom through an opening 27 which is plugged with a removable cap 28. The hopper 25 consists of a' perforated'tube 26 which has substantiallythe same internal diameter as'the nominal diameter of. the power tubing. This perforated tube has a flared top 29 which flts in riser 3i; Riser'iil has the same nominal diameter as production" flow line. The lifting gas may be separated from the well fluids in the separator and the lifting gas may be returned to the well to be reinjected and lift additional well fluids. plungers in tube 26 is driven down by the well fluids into a plunger injecting valve 35. This One of the (iii valve comprises a long piston having a diametrical bore 35. The plunger injecting valve is urged to the right, the closed position, by a spring 37 so that the dia-metrical bore 35 is normally in registry with perforated tube 26. When the valve is in this normal'position the gas inlet port 38 from gas supply line 39 is closed preventing gas from entering the power tubing 14. When the plunger injecting valve is in the left, the open positiorrthe diametrical bore 36 registers with port'38 and power tubing I4 permittinglifting gas to flow from the gas supply line 39 into power tubing i4. As this valve moves to the left it carries the bottom plunger ii in the plunger hopper with it in the diametrical bore 36. When this bore is in registry with gas inlet port 38 the lifting gas in gas supply line 39 drivesthe plunger into power tubing 5 l ahead of the lifting gas charge and displaces the plunger down the power tubing. j

The plunger injecting valve-is opened periodically by applying a pressure fluid throughline d! .to the chamber 512. This pressure fluid then acts on the valve head-43w displace the valve to the left. As the valve is displaced to the left, the lower end of perforated tube 26 is cov ered by the long piston on the valve so that the plungers in the tube cannot move downwardly.

The valve is held to the leftagainst the force .of spring 37 by the continued application of pres-v sure in line ii until a predetermined amount of gas pressure is built up inpower tubing I' l, untila predetermined amount of gas has been injected time cycle injector. be controlled by hand-operated'means or by any other means; When the pressure in line 4| 'is eventually removed; the valve returns toits nor:

mal or closed position causing diametrical bore 36 to register again with perforated tube 26 and at the same time closing gas inlet port 38 so that gas will not flow into power tubing 24. As

diametrical bore 35 registers with perforated tube 26 an additional plunger is forced by the pro ducticn tubing pressure down into diametrical bore 36. A perforation id may be provided in the valve housing to-relieve the pressure in diametrical bore 36 so that'well' pressure will force the plunger into position. This perforation is then closed by the bottom plunger as' it comes into position so that we'll fluids are not wasted;

Obviously; the plunger injector and'the gas in jection may be controlled separatelyas by providing a separate control valve on the gas supply line 39 which may be opera'ted by these/me or:

some other control means.

In operation, gas supply line 39 is connected to a source of high pressure gas which maybe a high pressure gas well or a gas compressor dis charge line. 'A number of plungers lil are then inserted into the plunger hopper through open ing 2? and the plungers ar'e forced down so that the bottom plunger is lodged in diametrical bore 3d and the other plungers are resting in series, one above the other, in perforated tube'25. Pressure is then applied through line M to valve head 43 displacing plunger injecting valve 35 to the left against compression spring 37 and injecting the bottom plunger into the power tubing ahead of the gascharge as above described. The flow of gas through diametrical bore 36 which registers with gas inlet port 38, continues by holding plunger injecting valve 35 in the left hand position 4 Referring nowto Figures 4. and 5, the plungeriis' shown in its-deformed position which is its condition as it is driven through the power tubing or the smaller of the two tubing strings. In this condition the skirt does not provide a seal in the tubing but the head portion does since it has the 1 same diameter as the diameter of the smaller I tubing. That is, the skirt portion of the plunger is folded as shown in Figure and being folded it does not provide a continuous seal aroundthe outside with the inside of the small tubing. A modification of the plunger above described is shown in Figure 6. In this alternate embodiment the-head portion 53 is cylindrical, i. e., longer in the axial dimension of the plunger than the head portion of the plunger shown in Figure 3. This longer head is sometimes desirable in order to keep the-plunger pr'operly oriented in the pro-" duction or larger tubing string. The skirt 'of this plunger is like the skirt in the above-described embodiment except that it is extended by a sleeve 54which has an outside diameter substantiallyi equal to the maximum diameter of the skirt 5| and which is also substantially equal to the maximum drift diameter of the larger tubing string. This additional length of skirt is sometimes desired to reduce the slippage of well fluids past the plunger as the plunger is raised through the production tubing. The maximum cross-sectional area of the cylindrical portion of the skirt on any plane perpendicular to the axis of the plunger is,

like the conical portion, less than the cross-sectional area string.

'Still another alternative plunger design is shown in Figure 7. In this embodiment the plunger has a head portion 55 and a tail portion 56. The diameter of the head and tail of this plunger embodiment is substantially equal to the diameter of the smaller tubing. A" central expansible or body portion 51 of the plunger has an outside diameter substantially equal to the nominal diameter of the larger tubing string. The

total cross-sectional area of the resilient material on any plane perpendicular to the axis within the central expansible portion is also preferably less than the cross-sectional area of the head or tail The thin wallsof the central expansible portion form a cavity 58 which portion of the plunger.

may be filled with air so that the outside diar'njeter may be varied substantially to accommodate,"

changes in the inside diameter of a conduit'. Al ternatively a passage 59 may be provided through the tail portion 56 so that when the Plunger is placed in a well the cavity 58*bjecomes filled with well fluids. By inserting this plunger'in the con tinuous conduit so that the tail portion 55 is 'exfi posed to gas pressure as the plungerrise's' through the production tubing, the pressure in cavity 5 8'] becom'es'greater due to friction than the pressure on the outside of the body portion and thus this plunger produces a good seal with the inner surface of the production tubing and reducesthe by passing of well fluids around the plunger.

As indicated above, in the preferred embodiment, a constriction is placed in the lower end of the power tubing so as to reduce the lifting gas/ oil ratio. However, this invention is not limited to the use of such a constriction. Without a constriction it is sometimes unnecessary to use a resilient material in the head portion of a plunger.

Sincethe power tubing and the. productiontubing are of different sizes, howeveiya means isprovidedfor a portion of the plunger to be expansible. As shown in Figure-8 a plungerfora oyof the opening in the'smaller tubing power tubing.

cling gaslift plunger system may be made of a. 1 hardhead portion-6| and aresilient skirt:"'62'.z- The-head may be constructed of, for. example,-

wood, metal, or the like.v The skirt'which 18-1' silient,.as discussed above, is then connected tothe head by any suitable means such as a bolt .63.

The skirt may be disc-like, as indicated, or it may be conical, as discussed above. The plunger .em-

bodiment, as indicated, is adapted for use normally only ina cycling gas lift plunger system which does not employ a constriction. It may be used in a system employing a constriction provided the"- such as constriction is made of resilient material synthetic rubber or the like.

From the foregoing it "can be seen that "we' have shown by various examples how a'cycling'" gas lift plunger system can be operated when the production tubing and power tubing are of differ-= ent-sizes. As stated, it is often considered desir able for a number of reasons to usepower tubing-- and production tubing strings of different size. In the preferred embodiment this invention has been described withthe larger string generallyconstituting the production string. It will be ap parent that in some cases the reverse might be preferred. Various other modifications 'o'f-the apparatus and system of operation will be apparent to those skilled in this art. This inven tion should 'not therefore be construed to be limited to the above description. It should be limited only by the scope tubing extending into said well below the working fluid level therein, said production tubing and;

said power tubing being of substantially different sizes, means at each end for connecting saidpower tubing and said production tubing together as a continuous elongated conduit, 9. constriction said power tubing at about said working fluid level of said well, an inlet for Well fluids below said constriction for admitting well fluids intosaid conduit within said well, a standing valve in said inlet, a multiplicity of plungers in said conduit.

a plunger injector for delivering said plungers in series into the upper end of said power tubing,

means to inject lifting gas into said power tubing:

behind each of said plungers and means at the upper end of said elongated conduit forseparat-' ing said plungers from said well fluids and discharging said well fluids from said conduit. I

2. A pump according to claim 1 in which said plungers comprise a'first relatively rigid part hav-' ing a diameter-about equal to the diameter of the smaller of said production tubing and said power tubing and a second relatively flexible parthaving adiameter'about'equal to the diameterffof the larger of said production tubing and-said- 3. .An apparatus according tubing togethen -an inlet for admitting wellfluids of the appended claims. 1 We claim: V

1. A pump for lifting well fluids froma wel comprising parallel production tubing and power to claim 1 in'which the diameter of said constriction is in the range between about 0.5 and 0.9 of the nominal diameinto said head, a standing valve in said inlet, plunger injecting means comprising hopper and valve means at the upper end of said production tubing and said power tubing, said head and said plunger injecting means connecting said production tubing and said power tubing together and forming a continuous elongated conduit, said hop per means separating said plungers from the well fluids and discharging said well fluids from said conduit as said well fluids are lifted through said production tubing by said plungers, said valve means being adapted to admit lifting gas inter" mittently into said power tubing, and upon opening to discharge a plunger from said hopper into said power tubing ahead of said lifting gas, and a multiplicity of said plungers in said conduit, each of said plungers comprising a solid part having a diameter about equal to the diameter of said power tubing and a skirt part having a diameter about equal to the diameter of said production tubing.

5. In a cycling gas lift plunger pumping system for wells including a producing tubing and a power tubing of different sizes connected together at the bottom to produce a continuous conduit in a well, a plunger comprising a head having substantially the same diameter as the smaller of said production tubing and said power tubing and a skirt having substantially the same diameter as the larger of said production tubing and said power tubing, said skirt being adapted to be deformed so that it is as small as said head whereby said plunger may be cycled through said conduit and will seal both said production tubing and said power tubing.

6. In a pumping apparatus for wells including a production tubing, a power tubing, means at each end for connecting said production and said power tubing together as a continuous elongated conduit, an inlet for Well fluids at the lower end of said elongated conduit, 9, plunger injector for delivering a series of plungers into the upper end of said power tubing, means for injecting lifting fluid behind each of said plungers, and means at the upper end of said elongated conduit for separating said plungers from said well fluids and discharging said well fluids from said conduit, the improvements comprising production tubing and power tubing of different nominal diameters and a plunger having a first part adapted to seal the smaller of said production tubing and said power tubing and a second part adapted to seal the larger of said production tubing and said power tubing.

7. In an apparatus for gas lifting a well with plungers including parallel production tubing and power tubing extending into said well below the working fluid level therein, said production tubing being larger than said power tubing, means at each end for connecting said power tubing and said production tubing together as a continuous elongated conduit, a constriction in said power tubing, an inlet for well fluids at the lower end of said elongated conduit, a plunger injector for delivering a series of plungers into the upper end of said power tubing, means for injecting lifting fluid behind each of said plungers, means at the upper end of said elongated conduit for separating plungers from said well fluids and discharging said well fluids from said conduit, and a cycling gas lift plunger comprising a resilient head having substantially the same diameter as said power tubing and a skirt having substantially the same diameter as said production tubing, said skirt being adapted to be deformed to pass through said power tubing and to expand and seal said production tubing.

8. A plunger for lifting well fluids in a well equipped with a cycling gas lift plunger system having a relatively large production tubing and a relatively small power tubing comprising a cylindrical head having a diameter substantially equal to the nominal diameter of said power tubing and a skirt coaxial with the axis of said head and having a diameter substantially equal to the nominal diameter of said production tubing, said skirt being adapted to be deformed to pass through said power tubing and to expand and seal said production tubing.

9. In an apparatus for lifting well fluids in a well equipped with a cycling gas lift plunger system having a relatively large production tubing and a relatively small power tubing connected together at both ends to form a continuous elongated conduit with well fluid inlet means at the bottom and with well fluid discharge means and gas injection means at the surface, said power tubing having a constriction near the lower end, a plunger comprising a resilient cylindrical head having a diameter substantially equal to the nominal diameter of said power tubing and a conical skirt, the apex of said skirt being connected coaxially to said head, said skirt having substantially the same diameter as said production tubing and being adapted to be deformed to pass through said power tubing and to expand and seal said production tubing.

LLOYD E. ELKINS. RENIC P. VINCENT. HENRY SCHAEFER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,790,450 Torrance Jan. 2'7, 1931 1,815,364 Ricker July 21, 1931 1,932,497 Wellensiek Oct. 31, 1933 2,029,367 Geyer Feb. 4, 1936

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