US3851997A

US3851997A - Dual string automatic gas lift valve

Info

Publication number: US3851997A
Authority: US
Inventors: B Douglas
Original assignee: Dresser Industries Inc
Current assignee: Dresser Industries Inc
Priority date: 1974-03-01
Filing date: 1974-03-01
Publication date: 1974-12-03
Anticipated expiration: 1991-12-03

Abstract

An automatically operated, pressure responsive gas lift injection valve for use in a dual zone string utilizes a pressure operated switching valve for delivering injection gas to the tubing string having the highest column of fluid. The switching valve is responsive to the tubing pressure in each of the two production strings and, sensing the higher of the two tubing pressures, opens that string to lift gas injected through the casing annulus.

Description

llnited States Patent [1 91 Douglas 1 Dec. 3, 1974 DUAL STRING AUTOMATIC GAS LIFT VALVE Inventor: Bobby L. Douglas, Houston, Tex.

Dresser Industries, Inc., Dallas, Tex.

Mar. 1, 1974 Assignee:

Filed:

Appl. N0.:

US. Cl 417/112, 417/116, 417/117, 137/119 Int. Cl. F041 1/18, GOSd 11/00 Field of Search 137/119; 417/116, 117, 417/112, 113

References Cited UNITED STATES PATENTS 1'1/1959 Bryan 417 112 3,348,503 10/1967 Sidles 137/119 X Primary Examiner-C. J. l-lusar Assistant ExaminerRichard E. Gluck Attorney, Agent, or FirmMichael J. Caddell [57] ABSTRACT An automatically operated, pressure responsive gas lift injection valve for use in a dual zone string utilizes a pressure operated switching valve for delivering injection gas to the tubing string having the highest column of fluid. The switching valve is responsive to the tubing pressure in each of the two production strings and, sensing the higher of the two tubing pressures, opens that string to lift gas injected through the casing annulus.

15 Claims, 3 Drawing Figures i l 36 5 23 i I 4 DUAL STRING AUTOMATIC GAS LIFT VALVE BACKGROUND OF THE INVENTION In a dual zone completion well wherein the formation pressure is insufficient to force formation fluids to the top of the wellbore from either of the producing formations'and the well is particularly suitable for gas lift operations, the method of producing such a well normally involves utilizing dual string production equipment with gas lift valving apparatus in each production string.

When both injection valves are supplied with gas through the casing annulus, a problem arises in controlling the gas lift operation since both valves may tend to open at the .same time. Since the fluid levels in the two tubing strings are seldom at the same height, one string may be receiving too much gas and the other may be receiving too little gas. Alternatively, when such simultaneous opening occurs itis possible that neither string will receive sufficient gas to provide the gas lifting operation desired. This results in highly inefficient production and greatly increases the cost of the fluids recovered. This is due to the fact that a certain amount of gas is required to bring the well fluids to the surface and when the strings are opened'to the annulus at the same time, they tend to -rob each other and neither ends up with sufficient gas to lift the fluid column.

The present invention solves this problem by providing an alternating intermittent gas lift valve that is responsive to fluidpressure in the two strings to allow injection gas to go only into the production string having the highest column of fluid and therefore in greatest need for injection gas.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I illustrates a dual production string in a well having multiple producing formations.

FIG. 2 illustrates a cross-sectional schematic view. of the apparatus of this invention.

FIG. 3 represents a top cross-sectional view looking down on the apparatus from section line 33 in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. I a dual productionstring is located in the borehole l1 and communicates with two producing formations. the upper formation 12 and a lower formation 13. The dual production tubing string 10 has a primary conduit 14 communicating with the upper formation 12 via opening 15 in the bottom end of the tubing,

and a secondary string 16 communicating with the lower producing formation 13.

- A packer 17 is located in the annulus between the production string 10 and the borehole 11 above the producing formation 12 to seal off the annulus above the packer from that below it. A second packer 18 is located in the annulus below the upper formation to isolate the formations from each other.

The automatic, intermittent gas lift valve 20 is located in the dual producing string 10 between the primary and

secondary conduits

14 and 16, above packer l7.

A closer view of the gas lift valve is shown in the cross-sectional view of FIG. 2 in which the valve is shown as comprising two

tubular adapter conduits

21 and 22 placed in parallel configuration and arranged to align coaxially with the dual production strings l4 and 16 respectively. The

tubular adapters

21 and 22 may be threadedly joined to the production conduit or may be joined by use of connector collars 23 as shown in the figure.

The gas lift valve apparatus utilizes a substantially solid body portion 24 in which has been formed dual

primary valving chambers

25a and 25b, dual

backflow checkvalve chambers

26a and 26b, gas

lift flow passages

27 and 28a and 28b, and

gas injection ports

29a and 29b.

Gas lift passage 27 is substantially centrally located in the upper portion of body portion 24 and passes downward generally parallel with

conduits

21 and 22 whereupon it intersects dual

gas flow passages

28a and 28b which branch generally outward and then turn downward.

Passages

28a and 28b pass downward generally parallel to conduits 21 and 22 and flow into

backflow checkvalve chambers

26a and 26b.

Spring loaded checkvalves 30 and 31 are located movably up and down in

chambers

26a and 26b respectively and are continuously urged upward into sealing engagement with the bore openings of

passages

28a and 28b by

coil springs

32 and 33 respectively.

The lower portion of

chambers

26a and 26b communicate with the

primary valving chambers

25a and 25b via

central openings

34b and 34a located therebetween.

Primary chambers

25a and 25b are separated by an inwardly projecting wall 35 having an opening located substantially in the center thereof. A sliding valve member 37 is located slidably in the opening in wall 35 and a sleeve seal 36 is located in the wall opening abutting valve member 37 in sealing engagement to prevent fluid or gas communication between the primary valving chambers.

The opening in wall 35 is arranged so that it is substantially aligned with opp'osingports 29a and 29b in body 24 so that valve member 37 can move laterally from closing one port to closing the opposite port. As illustrated in the figure, valve member 37 is in the position of opening port 29a and closing port 29b.

Ports 29a and 2% correspond with matching ports through the wall of

conduits

21 and 22, respectively, thereby forming channels of communication from the inner bores of the conduits to the primary valve chambers.

Injection gas is supplied to the main flow passage 27 via a standard gas injection valve .38 having a tubular threaded connection adapter 39 which engages the upper portion of body 24 and communicates with pasof body 40. Body 40 also forms a gas chamber 46 which contains an inert compressed gas which gas also fills the inner portion of bellows 41. An interconnecting cap 47 is sealingly attached to the top of body member 40 enclosing gas chamber 46 and is securedly attached by means such as welding at each end to conduits 21 and 22. Likewise, body 24 is similarly attached to

conduits

21 and 22 at each side.

FIG. 3 illustrates a top view of the gas lift valve assembly as it is located substantially centralized in the wellbore casing 48. Gas passage down the annulus 49 easily flows around the apparatus and has access to ports 45 in the upper lift valve 38.

In typical operation, referring to FIGS. 1 and 2, pressurized injection gas is pumped into the well annulus through means such as piping 50. The gas enters the upper gas valve 38 through ports 45, thereby compressing bellows 41, moving valve element 43 upward out of bore 39a and allowing gas to flow down

passages

27, 28a and 28b.

Meanwhile, prior to the opening of element 43, formation fluid has accumulated in the

conduits

21 and 22 and the fluid in the conduit having the highest level (conduit 21 in the case illustrated) applies the greatest hydrostatic pressure force on the slidable valve member 37 through

ports

29a or 29b thereby moving the member into blocking position over the opposite port. This allows the pressurized injected gas to move the spring loaded checkvalve 30 or 31 downward and moves the gas past the valve 37 and through whichever port is opened. The next pulse of pressurized gas may move out through the opposite port depending upon the rate of build-up of the two different fluid levels in the conduits and also depending upon the time required for the injection gas in the annulus to build-up sufficient pressure again to open the upper gas injection valve 38.

As an alternative, a pressure cycling device containing a timer may be used at the surface to apply intermittent pressure applications to the annulus gas should the rate of fluid build-up in the conduits be too slow to efficiently utilize a constant annulus gas pressure.

A distinct advantage of this apparatus is that it automatically injects gas into the column of fluid having the greatest need for the gas, i.e. the highest column, regardless of which column received the preceding gas charge. This provides the highest possible gas lifting efficiency, particularly when one of the formations is considerably higher flowing formation than the other.

Although a specific preferred embodiment of the present invention has been described in the detailed description above, the description is not intended to limit the invention to the particular forms or embodiments disclosed therein, since they are to be recognized as illustrative rather than restrictive and it will be obvious to these skilled in the art that the invention is not so limited. For example, the valving member is illustrated as elongated and may be cylindrical, polygonal or other configuration in cross-sectional shape. Also other type checkvalves than those shown could be utilized. The invention is declared to cover all changes and modiflca tions of the specific example of the invention herein disclosed for purposes of illustration which do not constitute departures from the spirit and scope of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A dual string, gas lift injection valve assembly comprising:

body means adapted to engage two strings of conduit;

passage means in said body arranged to communicate with the strings of conduit;

checkvalve means in said passage means adapted to allow fluid flow through said passage means in one direction only;

pressure responsive valve means in said passage means communicating with the conduit strings, said pressure responsive means arranged in said passage means to receive fluid pressure from the conduit strings and to move responsively thereto to open and close said passage means alternatively to each of the conduit strings; and

means on said body means for delivering pressurized gas to said passage means.

2. The gas lift injection valve assembly of claim 1 wherein said body means further comprises dual lowcr chambers separated by a centrally located wall portion and dual upper chambers communicating with said lower chambers and with said passage means.

3. The gas lift injection valve assembly of claim 2 wherein said passage means further comprises a generally centrally located upper passage extending from said pressurized gas delivery means into said body means; two branch passages extending from said upper passage each to one of said dual upper chambers; secondary passages extending from said dual upper chambers to said dual lower chambers; and, port means between said lower chambers and the conduit strings.

4. The gas lift injection valve assembly of claim 1 wherein said pressure responsive valve means further comprises a dual-element valve member sealingly and slidably mounted in said body means and having pressure responsive areas thereon; and, dual valve seats in said passage means arranged to receive in sealing engagement said valve member, each said valve seat circumscribing said passage means between said body means and the conduit strings.

5. The gas lift injection valve assembly of claim 1 wherein said means for delivering pressurized gas comprises a bellows-type, differential pressure operated valve assembly having ports therein communicating with the annulus of the wellbore and further having a valved flow passage between said ports and said passage means.

6. The gas lift injection valve assembly of claim 1 further comprising two tubular elongated conduit adapters attached one to each side of said valve assembly and arranged to align co-axially with the dual string production tubing in a dual-zone well; each of said conduit adapters having connection means at each end for connection to standard sections of oil well production tubing.

7. A dual string gas lift valve assembly for use in a wellbore, said assembly comprising:

a body member adapted to be engaged with a dual conduit string;

gas passage means through said body member communicating from the annulus of the wellbore to the dual conduit string; and

valve means in said body member for alternately opening said passage means to one conduit string while simultaneously closing said passage means to the other conduit string;

said valve means having pressure responsive areas thereon exposed to pressures in each of the conduit strings; said valve means being slidably and sealingly mounted in said body member and arranged to be moved slidably therein by pressures in the conduit strings.

8. The gas lift valve assembly of claim 7 further comprising checkvalve means in said passage means arranged to allow flow into the conduit strings, but prevent flow from the conduit strings.

9. The gas valve assembly of claim 8 further comprising elongated tubular conduit adapters attached to said valve assembly and arranged to be coaxially aligned with the conduit strings and further having connection means at each end for connection to standard tubing sections.

10. The gas lift valve assembly of claim 9 further comprising pressure responsive injection gas regulating means connected to said gas lift valve assembly and having fluid communication passages from the annulus of the well to said valve assembly, with pressure responsive valve means in said fluid communication passages in valving relationship therewith.

11. The gas lift valve assembly of claim 10 wherein said body member further comprises a generally solid body having dual upper chambers containing said checkvalve means and dual lower chambers divided by a generally centrally located wall section; with said valve means in said body member comprising an elongated valve body slidably and sealingly mounted in said wall section; with said gas passage means communicating from said regulating means through said dual upper chambers and said dual lower chambers to dual ports in the wall of said body at said lower chambers, with one said port in each lower chamber, said each port being coaxially aligned with said elongated valve body and arranged to be alternatively closed and opened by said valve body.

12. A dual string gas injection assembly for use in gas-lift oil wells having dual production strings, said assembly comprising:

a body member adapted to be connected between two well conduits and inserted in the wellbore; dual gas flow channels in said body member arranged to communicate one with each of the well conduits;

a pressure responsive valve member movable in both of said gas flow channels and arranged to open and close said channels alternatively, said valve member being movable in response to fluid pressure from the well conduits; and

pressurized gas supply means communicating with said flow channels and arranged to provide pressurized gas to said flow channels.

13. A pressurized gas injection assembly for use in gas-lift operation in a dual string well; said assembly comprising: a

a generally solid body member adapted to be placed between two well conduits and having port means therein communicating with the well conduits;

dual flow channels in said body member communicating with said port means, each of said channels having an upper chamber and a lower chamber. with said two lower chambersbeing laterally adjacent and separated by a wall section;

checkvalve means in each of said upper chambers arranged to allow flow through said channels to said port means, but prevent flow from said port means through said flow channels;

a slidable valve member sealably located in said wall section and arranged to alternately open one of said flow channels to said port means while simultaneously closing said other flow channel to said port means;

pressure responsive areas on said valve member arranged to receive fluid pressure from the well conduits;

means for connecting said body member to the well conduits; and,

a gas injection valve communicating between the well annulus and said flow channels and adapted to respond to pressurized gas in the annulus to open said injection valve to allow gas from the annulus to flow therethrough.

14. The gas injection assembly of claim 13 wherein said connecting means further comprises elongated tubular sections securedly attached to said body member and coaxially aligned with the production strings in the wellbore; said tubular sections having connection means at each end for connection with standard tubing sections.

15. The gas injection assembly of claim 14 wherein said gas injection valve comprises a tubular cylindrical housing having a central bore passage, port means through the wall thereof, an expandable bellows element securedly attached therein to define an expansion-contraction chamber, and a valve member on said bellows element arranged to open and close said cen-

Claims

1. A dual string, gas lift injection valve assembly comprising: body means adapted to engage two strings of conduit; passage means in said body arranged to communicate with the strings of conduit; checkvalve means in said passage means adapted to allow fluid flow through said passage means in one direction only; pressure responsive valve means in said passage means communicating with the conduit strings, said pressure responsive means arranged in said passage means to receive fluid pressure from the conduit strings and to move responsively thereto to open and close said passage means alternatively to each of the conduit strings; and means on said body means for delivering pressurized gas to said passage means.

2. The gas lift injection valve assembly of claim 1 wherein said body means further comprises dual lower chambers separated by a centrally located wall portion and dual upper chambers communicating with said lower chambers and with said passage means.

7. A dual string gas lift valve assembly for use in a wellbore, said assembly comprising: a body member adapted to be engaged with a dual conduit string; gas passage means through said body member communicating from the annulus of the wellbore to the dual conduit string; and valve means in said body member for alternately opening said passage means to one conduit string while simultaneously closing said passage means to the other conduit string; said valve means having pressure responsive areas thereon exposed to pressures in each of the conduit strings; said valve means being slidably and sealingly mounted in said body member and arranged to be moved slidably therein by pressures in the conduit strings.

12. A dual string gas injection assembly for use in gas-lift oil wells having dual production strings, said assembly comprising: a body member adapted to be connected between two well conduits and inserted in the wellbore; dual gas flow channels in said body member arranged to communicate one with each of the well conduits; a pressure responsive valve member movable in both of said gas flow channels and arranged to open and close said channels alternatively, said valve member being movable in response to fluid pressurE from the well conduits; and pressurized gas supply means communicating with said flow channels and arranged to provide pressurized gas to said flow channels.

13. A pressurized gas injection assembly for use in gas-lift operation in a dual string well; said assembly comprising: a generally solid body member adapted to be placed between two well conduits and having port means therein communicating with the well conduits; dual flow channels in said body member communicating with said port means, each of said channels having an upper chamber and a lower chamber, with said two lower chambers being laterally adjacent and separated by a wall section; checkvalve means in each of said upper chambers arranged to allow flow through said channels to said port means, but prevent flow from said port means through said flow channels; a slidable valve member sealably located in said wall section and arranged to alternately open one of said flow channels to said port means while simultaneously closing said other flow channel to said port means; pressure responsive areas on said valve member arranged to receive fluid pressure from the well conduits; means for connecting said body member to the well conduits; and, a gas injection valve communicating between the well annulus and said flow channels and adapted to respond to pressurized gas in the annulus to open said injection valve to allow gas from the annulus to flow therethrough.

15. The gas injection assembly of claim 14 wherein said gas injection valve comprises a tubular cylindrical housing having a central bore passage, port means through the wall thereof, an expandable bellows element securedly attached therein to define an expansion-contraction chamber, and a valve member on said bellows element arranged to open and close said central bore passage.