US2815764A

US2815764A - Balanced gas lift valve

Info

Publication number: US2815764A
Application number: US352943A
Authority: US
Inventors: Thomas E Bryan
Original assignee: Otis Engineering Corp
Current assignee: Otis Engineering Corp
Priority date: 1953-05-04
Filing date: 1953-05-04
Publication date: 1957-12-10
Anticipated expiration: 1974-12-10

Description

Dec. l0, 1957 v T. E. BRYAN BMANGEDv GAS LIFT VALVE:

2 sheets-sheet 1 Filed May 4, 1953 .rl/ Ll l i I fr INVENTOR.

BY f

' WU W Tho/770s Bryan A rok/VE y T. EL BRYAN BALANCED GAS LIFT VALVE Dec. 10, 1957 2 Sheets-Sheet 2 Filed May 4, 1953 4 Il lll l/l/. l l/ Il In Thnmasf. Bryan I INVENTOIL BY wu).

A TTORNE-Y BLNCED' GAS LIFT VALVE Thomas E. Bryan, Fort Worth, Tex., assignor tovOtis Engineering' Corporation', Dallas, Tex., n corporation of eras ApplicatiouMay 4, 1953, Seriall No. 352,94'3

4 Claims'. (Cl. 137-155) The present invention relates to an: improved gas lift valve construction.

In' the artificial lift method of ll'owin'g or pro ducingl wells,. such as oil wells, it is' necessary' to admit an' unloading pressure fluid from the well casing into' the tubing; whereby the well liquids' are thus tiowed up through the tubing. Also, the wellE may be produced by' admitting the unloading pressure linid into the' tubing and discharging it` into the casing where liquid'sin the well are' accumulated, whereby such well liquids may be flowedor produced throughl the casing.

The efficiency of gas lift operation may be considered or determined in terms ofthe amount or volume of gas used to produce a given quantity ofoil'.

l-tseems obvious that in actual operation only a necessary amount of gas needs be used to unload or produce the well'. lfadditional pressure fluid, such as gas, is used over and above this necessary amount, without gaining any benefit therefrom, then the overall eicienc'y of.A the gas lift' operation is materially reduced and the gas is thus wasted.

The present invention provides a Valve construction which is designed so as to admit the amount. of pressure fluid necessary to produce the well, under given conditions, but which will prevent the' flowing of excess pressure uid` into the well liquid. One manner i'n which thel present' construction. accomplishes this is by provid'- ingV a construction whereinthe effect ot backpressure due to well' fluid' or' liquids on the valve iseliminated so that the valve construction, after it has been operatedl to admit the necessary amount of pressure unloading Huid to flow the well may close and prevent the passage of. additional pressure fluid therethrough.

By way of further example only, and notto serve= as any limitation, it may be assumedr that the valve con? struction ofthe present invention is mountedinra well so as to admit unloading pressure huid4 from the well casing into the tubing., whereby the well. fluids ther-ein` may be lifted to the surface. If. the valveAv is setto` operate at say 350 pounds pressure, then when the pressure of` the unloading. fluid in the casing: exceeds this, the valve will open` and admit the unloading pressure iiuid to the tubing. I`f the back. pressure effect. inl the tubing. maintains the valve open so as to continue to admitthe unloading pressure Huid then more pressure fiuidwill be admitted' than that necessary to produce the welL It can be seen, that under. certain circumstances additionall unnecessary quantities off pressure fluid will be drained from the casing so thaty prior to operation of the valve ony its next cycle, it is necessary to replace this drained` gas. However, inthe present construction the effect ofV this. back pressure is eliminated lso that when the pressure applied on the valve in the casing: by the unloading pressure fiuid falls below the opening pressure of 35'0. pounds, then the valve will snap shut. l

n' then other hand, in present valve'` constructions where the back pressure eiectv may maintain the valve open so as to continue the injection of the unloading lpressure through the valve, many thousands' ofv cubic feet of pressure huid may be unnecessarily wasted. As a matter of fact,- every unnecessary pounds ofl pressure drained from a 7 inchcasing may amountv to1 several thousand cubic feet of gas which must be replaced before reop'e'ratien of the valve.

lf the unloading pressure fluid is condi-'ictedl through the' tubing' tothe casing, then the gas in: the tubingv must be replaced before reoperation of the valve.

n object of the present invention is to provide a gas lift valve construction in which the effect of back pressure is eliminated in the operation of the valve. u

A further' object is to provide a v'alve construction in which a selected pressure medium acts to operate' the valve.

Still another object of the invention is to' provide a valve construction which is operated by the well' liuids or liquids t'o adinit an unloading pressureI fluid from the tubing tothe casing so as to flow the' well liquids therein upwardly through the casing.

Stilll another object of the invention is to' provide a valve construction which may be operatedV by the well fluids or liquids so as to admit a pressure uid from the casing to the tubing to` flow the well liquids upwardly through the tubing.

A still further objectv of the invention is to provide a valve' construction which may be pressure or gas operated soasto admit pressure unloading fluid toY ow the liquid in the well upwardly through the tubing.

A still further object of the invention is to provide a valve' construction which may be pressure or gas operated so as to admit pressure unloading hui-d to flow the liquid in the well upwardly through the casing.

Yet a further object is to provide a valveI construction which may be gas or pressure operated to admit such pressure into the liquids in the well so as tofow orproduce such well liquids;

Another object of the invention is' to provide ai valve construction which may be operated by thev well` liquids t'o' admit a pressure unloading Huid tothe well liquids so as to produce or ow such well liquids.l

Still another object of thel invention is to provide a valve wherein the effect of a selected pressure medium acting on the valve isy nullied, whereby ity may be o`p` erated by another existing pressure.

A still further object of the invention is t'oprovide a valve construction which will admit'V a pressure fluidi, but which will shut after it hasadmitted the pressure' fluid so as to prevent the flow of additionalt pressure fluid therethrough.

Yet a further object of the invention is toprovide a valve construction for wells to admit a'n unloading.- pres` sure fluid?- including a bellows, a housing'l about said bellows forming a closed chamber about the bellows; which chamber is charged with gas` at a4 predetermined pressure, a valve member carried by said! bellows; an entry for pressure uid to first act on'said valve member to operate said valve, whereby an unloading pre's'surelu'id isthen admitted to unload the Well.

Still another object of the invention is'to provide a' gas lift valve',L which is pressure charged, wherein" thel pressure medium acting to open the valve is admitted t'o the valve tohrst act on a valve member to operate the valve;

Still" another object of the invention is to provide a valve including a piston member which is subject tothe back pressure effect of a selected pressuremedium; such eiecton opposite sides of the piston b'eingcounterbalanced;

WithY the foregoing andl other anu addition'aif objects and advantages in mind, attention is directed to the drawings wherein:

Fig. 1 illustrates a schematic arrangement showing one manner of employing gas lift valves for flowing awell;

Fig. 2 is a vertical sectional View illustrating an embodiment of the invention;

Fig. 3 is a vertical sectional view of an embodiment of the invention illustrating a slightly different modification;

Fig. 4 is a horizontal sectional View taken on the line 4 4 of Fig. 2;

Fig. 5 is a horizontal sectional view taken on the line 5 5 of Fig. 2;

Fig. 6 is a horizontal sectional view on the line 6-6 of Fig. 3; and

Fig. 7 is a partial vertical sectional view showing a modiication of the form of the invention illustrated in Fig. 2.

Attention is directed to Fig. 2 of the drawings wherein an embodiment of the invention is illustrated. The valve consists of a housing denominated generally by the numeral 3, which housing may be made up of several component parts as illustrated in the drawings. Any suitable manner of joining the component parts together may be used, and as illustrated the valve housing components may be threaded together whereby various parts can be easily replaced. A bellows or diaphragm element 4 is mounted in the housing and the housing forms a chamber 5 about the bellows which may be charged with gas at a predetermined pressure by means of the adapter illustrated generally at 6. It is not believed necessary to give a detailed description of the manner of connecting the bellows in the housing and of charging the chamber with gas at a predetermined pressure, since this procedure is well known in the art. Carried by the bellows 4 by means of the valve stem 7 extending through the housing to the opposite end 8 thereof is a valve member denominated generally by the numeral 9. It is to be noted that the valve stem 7 is secured at one of its ends 10 to the bellows 4 whereby the chamber 5 about the bellows is closed olf from the interior of the bellows.

The valve member 9 is provided with a valve head 11 for seating on the seat 12. The seat 12 is provided with an opening 13 whereby communication therethrough is controlled by means of the valve member.

The valve member includes a piston member 14 on the valve stem 7, which piston member is adapted to sealably 't in the housing to prevent or inhibit the passage ofd pressure from one side of the seal ring 15 to the other s1 e.

It should be understood, of course, that any suitable type seals may be arranged on the piston member 14 so as to engage the inner periphery 16 of the housing and form a sliding sealed connection therewith. The inner periphery 16 of the housing 3 thus joins a cylinder in which the piston member 14 is mounted for reciprocatory motion. The upper end of this cylinder defines an end wall thereof having the valve seat 12 formed therein.

The valve housing as shown in Fig. 2 is provided with

inlets

17 and 18 above and below the piston member 14 respectively, whereby a pressure medium may act on top of the valve head 11 on one side of the piston 14, and also act on the opposite side of the piston member 14 by exerting a pressure inside of the bellows 4 and on the exposed surfaces on the valve stem 7 and piston member 14 below the seal ring 15. The area affected by pressure flowing through the opening 17 above the seal ring 15 and the areas atfected by pressure flowing Ithrough the opening 18 into the housing below the seal ring 15 offset and counterbalance each other.

As may be seen in Fig. 2, the pressure introduced through opening 18 exerts an upward force on piston 14, and a downward force on the diaphragm end wall 10.

The piston 14 has a larger cross-sectional area than does the diaphragm end wall 10, and therefore the upward force on the piston is greater than the downward force on the diaphragm to thus bias the valve member 9 to a closed position. It is this resultant upward bias, due to the pressure introduced through opening 18 and acting on the diaphragm end wall and piston which offsets and counterbalances the downward force which is exerted on the top of valve head 11 by the tubing pressure introduced through the opening 17; otherwise, if this resultant upward bias were not present, the tubing pressure would tend to force the valve member 9 open against the bias of the pressure charged chamber 5. As is obvious, the cross-sectional area of the piston, on which the tubing pressure acts to close the valve member 9, must equal the cross-sectional areas of the diaphragm end wall 10 and the valve seat 13, on which the tubing pressure acts to open the valve member 9, for the effect of the pressure introduced through

openings

17 and 18 to be exactly offset and in true counterbalance.

An additional opening 19 is provided in the housing whereby a pressure fluid or the operating pressure medium may pass thereinto to first act on the valve member to operate the valve, whereby communication through the opening 13 is established for unloading the well. By admitting the pressure uid or the operating pressure medium so as to act on the valve member instead of on the bellows, distortion of the bellows is eliminated.

It should be noted that the operating pressure medium to actuate the valve may be the unloading pressure fluid or it may be the well fluids or liquids, depending upon the type installation desired.

The valve construction illustrated in Fig. 3 is identical with that shown in Fig. 2, however, the inlets above and below the piston are arranged differently, with the inlet for conducting a pressure fluid or pressure medium to operate the valve being shown as arranged in a different position as illustrated at 20. The inlet 17A is shown at the top of the housing in Fig. 3 with the inlet 18A being illustrated in a different position from that shown in Fig. 2.

Fig. 7 illustrates the valve shown in Fig. 2 with the check valve assembly 23 removed. In this connection it should be noted that while the check valve assembly is provided for inhibiting or preventing back flow of well liquid through the valve, it will, for all practical purposes, not alect the equalization of pressure on the piston member 14 above and below the seal ring 15. In other words, practical experience has shown that no check valve under normal well operating conditions will provide an absolute seal so as to prevent the passage of well liquid therearound so as to exert a force on the valve head 11. The invention may be practiced with or without the check valve so far as the back pressure effect on the piston member 14 is concerned. However, with that form of the invention shown in Fig. 7, the check valve assembly is removed in order that the well may be produced in a slightly different manner to be described hereinafter.

It will now be assumed that the valve comprising the invention is mounted on a tubing string 24 extending down into a well, which well has been previously provided with a casing 25 and may be provided with a packer 26 to ll the space between the tubing and the casing so as to form a casing annulus 27.

The valve is connected to the tubing by means well known in the art, and it is not believed necessary to give a detailed description of the manner of connection. However, the tubing is provided with an opening 24' wbereby communication between the valve and tubing, and between the casing and tubing is established by means of the

openings

13 and 19 in the valve. With the form of the invention illustrated in Fig. 2 or Fig. 7, the valve may be gas operated, tubing ow. In other words, well liquid in the tubing 24 will exert a pressure through #fthe opening 17 and through the opening 18, .on `oppo- Asite sides of the piston1'4, whereby the back pressure existing y'in the tubing is counterbalanced. If the chamber 5 has been charged with gas at a predetermined ceeds the loaded pressure tending to maintain the valveI head 11 on seat 12, the valve will open whereupon the unloading gas pressure ows through opening 1.3 and through opening 17 into the tubing.

As the oil in the tubing is being elevated by means of the charge of gas admitted through the opening 17, its weight plus the friction developed by the ow creates a back pressure in the tubing. The effect of this back pressure acts equally on opposite sides of the piston member 14 through

openings

17 and 18 so that it is neutralized. In other words, the back pressure does not maintain the valve open an unnecessary length ot' time so as to drain unusable quantities of gas from the casing annulus 27.

It can be appreciated that only a certain amount of gas is required to lift a certain amount of oil. If the back pressure keeps the valve open and allows it to flow additional unnecessary quantities of gas from the casing, it will be necessary to recharge the casing annulus at the time that the valve is again operated. Also a much larger quantity of gas has been used for producing a given quantity of oil. The excessive amount of unloading gas or pressure admitted through the valve is wasted since it only entered because the back pressure maintained the valve open and it was not necessarily needed to aid in unloading the well.

If the unloading pressure fluid is admitted in a manner so as to aerate the column of well liquids in the tubing the effect of back pressure is relatively unimportant. However, where the quantity of gas flow through the valve into the tubing is great so that a piston of gas is formed to force a piston of oil out, then the back pressure weight of the oil becomes important and unless it were counterbalanced as provided by the construction herein described it would act on valve head 11 to maintain it open and continue the injection of unloading pressure duid.

Fig. 2 not only illustrates the form of the invention suitable for a gas operated, tubing flow manner of flowing a well, but it also illustrates a valve construction which could be used in an oil operated, casing flow" manner of producing the well. If the valve is to be used in this manner, then, of course, the unloading pressure is injected down through the tubing 24, whereupon it exerts a pressure above and below the piston, which pressures oifset each other. The oil which collects in the casing annulus 27 by a means well known in the art would then exert a pressure on the valve member through the opening 19 to rst operate the valve and then the unloading pressure would be admitted through the opening 13 to the casing to unload the well through the casing. When the valve is to be used as an oil operated, casing ilow type of valve the check valve assembly is eliminated, as shown in Fig. 7, for obvious reasons.

Fig. 3 illustrates the form of the invention when the well is to be produced by oil operation, tubing ilow. In the construction illustrated in Fig. 3, and when the well is to be thus produced, the gas unloading pressure in the casing again acts through the

openings

17A and 18A on opposite sides of the seal member 15 of the piston member 14 and exerts counterbalancing effects. The oil or well liquid would then act on the valve member to first operate the valve, whereupon the unloading gas pressure would be admitted from the casing annulus through the valve housing by means of inlet 17A and 6 v "through inlet I3 and thence through port y19A into the tubing,.and then to unload the well.

The form .of the invention illustrated in Fig. 3 could also be used where the well vis to be gas operated, cas- "ing ow `In this manner of producing the well with vention, it seems readily obvious that a valve is provided which includes a housing with an entry, whereby a pressure medium may first act on the valve member to operate the valve and then admit unloading pressure duid to unload the well.

Whether the pressure medium to operate the valve be the well liquid or the unloading pressure uid itself, it is admitted to first act on the valve member and not the bellows. Also, when the valve is used as an oil or well liquid operated type of valve, the unloading pressure uid has no effect on the opening of the valve, since the valve construction is provided with means whereby this pressure acting on the valve member is offset.

Also, where the valve is a pressure or gas operated type of valve, the valve construction is such that the pressure etect of well liquids thereon is eliminated.

From the above statements it is seen that a balanced .valve is provided; that is, one wherein the effect of a selected pressure medium is counterbalanced or nulliiied.

It should be pointed out that the valves and valve seats of the present invention are formed of a carbide construction. Also, a seal ring 30 is provided on the valve stem 7 so that after the valve stern moves a predetermined distance the interior of the bellows will be sealed oif for a well known purpose.

Broadly, the present invention relates to a valve construction which eliminates the effect of back pressure so as to obtain more efficient operation.

What is claimed is:

1. In a balanced valve, a housing forming a cylinder, an end wall formed at one end of said cylinder, a valve seat formed on one side of said end wall, a valve disposed within said cylinder and adapted to seat within said valve seat, a flexible diaphragm enclosing the other end of said cylinder, a piston mounted for reciprocatory motion in said cylinder, said piston having a larger crosssectional area than said valve and also having a larger cross-sectional area than said diaphragm, means connecting said piston to said valve, means connecting said piston to said diaphragm, means forming an inlet in said cylinder between said piston and said diaphragm, means placing said inlet in Huid communication with the other side oi said end wall, means biasing said diaphragm toward said end wall whereby said valve will normally seat in said valve seat, and means forming an opening in said cylinder between said piston and said valve seat whereby fluid under pressure may be introduced into said cylinder to force said piston against said biasing means to open said valve, thereby allowing said fluid under pressure to pass through said valve seat.

2. In a device as set forth in claim 1, wherein said biasing means comprises means forming a chamber surrounding said cylinder at the end provided with said diaphragm, and an elastic uid under a predetermined pressure carried in said chamber.

3. In a device as set forth in claim 1 wherein a second seat is formed in said end wall in fluid communication with said first valve seat, a second valve on the other side of said end wall adapted to seat within said second 7 valve seat, and means biasing said second valve to closed position.

4. In a device as set forth in claim 1 wherein the crosssectional area of said piston is equal to the sum of the cross-sectional areas of said valve seat and said diaphragm. 5

References Cited in the file of this patent UNITED STATES PATENTS 914,587 Longstreet Mar. 9, 1909 10 8 Bryant Oct. 29. 1940 Jensen Aug. 1, 1950 Garrett etal Dec. 9, 1952 Garrett et a1 Dec. 9, 1952 Peters Aug. 10, 1954 Canalizo Dec. 28, 1954