US3324803A

US3324803A - Liquid control for gas wells

Info

Publication number: US3324803A
Authority: US
Inventors: Kelley Kork; Robert K Kelley
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-04-27
Filing date: 1965-04-27
Publication date: 1967-06-13
Anticipated expiration: 1984-06-13

Description

June 13, 1967 K. KELLEY ETAL LIQUID CONTROL FOR GAS WELLS Filed April 27, 1965 United States Patent() 3,324,803 LIQUID CONTRGL FOR GAS WELLS Kork Kelley, 518 W. 7th, and Robert K. Kelley, Box 892, both of Liberal, Kans. 67901 Filed Apr. 27, 1965, Ser. No. 451,187 9 Claims. (Cl. 10S- 232) This invention relates to improvements in a liquid control for gas wells and more particularly to devices for limiting and removing accumulations of liquids which would otherwise interfere with gas production.

Liquids such as water and/or oil, etc. tend to accumulate in many producing gas wells. It is necessary to remove these liquids, particularly the water, because the lillling up of the bore hole restricts the flow of the gas. If ynot removed, the water level will rise or build up in the bore hole and in time will kill the well or 'stop the iiow of gas completely.

Various methods are presently Ibeing utilized to remove accumulations of water from gas wells. ln some instances, it is pumped out by the conventional rod-type pump driven by a pumping unit at this surface. In other wells, a small tubing string is installed from the surface down into the well bore, and the gas pressure in the well is used to ow the water -out through the tubing string. The flow provided in this manner can 'be either constant or intermitten. However, constant flow is extremely wasteful because, once the water is exhausted from the well, the gas under pressure contained therein is vented `directly to the atmosphere.

Known systems for providing intermittent ow through the tubing string are controlled either manually or by cycle timer devices. Manual control is costly because it requires almost constant attendance at each well in order to open the valve in the tubing string when a certain quantity of water accumulates and to close the valve as soon as the accumulation of water is exhausted from the well. Cycle timers are ineicient, costly, and require fairly constant attendance. If the valve in the tubing string is left open for too short a period, not all of the Water will be exhausted from the well during each cycle and a water -buildup will occur. lf the valve is left open for too long a period, all of the waterwill be exhausted and very considerable quantities of gas will be allowed to escape.

In quite deep or comparatively low pressure wells, the stored energy contained in-the compressed gas is not Sullicient to lift the column of liquid contained in the tubing "string 'and the described modes of operation are impossible. ln such cases, devices known las gas lifts have been employed to inject gas from 'the well bore into the tubing -string in such manner as to lift relatively short columns or slugs of liquid through the tubing string to the surface. However, the foregoing comments relating to manual and cycle timer intermittent liow control apply equally to these gas lift devices.

The present invention contemplates an apparatus for automatically controlling the removing of the accumulation of liquids from gas well by lifting slugs of liquid through the tubing string only so long as liquid is available at the entrance thereto. This is accomplished by mounting an automatic, bucket-type liquid-gas separator at the lower end of the tubing string in such manner as to coact with a gas lift device or devices to produce the desired results. The tubing string is open to the well bore ICC only when liquid is available, and the gas lift device is responsive to the static head of the liquid rising in the tubing string to inject the compressed gas from the well bore into the tubing 'string beneath a column or slug of liquid of the desired height, the gas lift device being formed to shut off the flow of gas from the well bore to the tubing string in response to a pressure drop therein which occurs as soon as the liquid slug is'discharged at the surface.

Accordingly, it is a principal object of the present invention to provide an apparatus for automatically controlling the removing of the accumulation of liquids from wells providing a substantial gas pressure in the well bore.

Another object of the present invention is to provide an apparatus of the character described which will automatically slug out a portion of the liquid as it accumulates to a certain level within the well bore.

A further object of the invention is to provide an apparatus of the character described which will function automatically and in an el'ricient manner to avoid wastage and loss of gas and pressure from the Well.

A still further `object of the present invention is to provide apparatus for intermittently ejecting accumulations of liquid lfrom -a well fbore through a tubing string and which functions automatically in response to a predetermined static head within the tubing string.

Yet another object of the present invention is to provide an apparatus of the character described which incorporates a positive action liquid-gas sepa-rator functioning automatically to Ipermit entry of liquid from the well bore into the tubing string and to close off communication between the tubing string and the well -bore when the liquid supply is exhausted.

Another object of the present invention is to provide an apparatus of the character described which is compact, sturdy, foolproof, and maintenance-free so as to provide a long yoperating life at the bottom o-f a well.

Further objects and advantages of the invention will be apparent as the speciiication progresses, and the new and useful features of the liquid control for gas wells will fbe fully defined in the claims attached hereto.

The preferred for-m of the invention is shown in the accompanying drawing forming a part of this description, in which:

FIGURE 1 is a vertical cross-sectional View of an apparatus constructed in accordance with the pre'sent invention and mounted within a gas well, portions being broken away and shown in section for clarity of illustration;

FIGURE 2, `an enlarged vertical cross-sectional view taken substantially on the plane of line 2 2 of FIGURE l; and FIGURE 3, an enlarged vertical cross-sectional view of .a gas lift device comprising part of the apparatus of the present invention and shown in operative position with respect to associated portions of a well bore and tubing string.

While only the preferred form of the invention is shown, it should be understood that various changes or modifications may be made within the scope of the claims attached hereto without departing from the spirit of the invention.

Referring to the drawings in detail, it will be seen that the apparatus for automatically controlling liquid depth in gas wells and oil wells of the present invention consists essentially of a liquid-gas separator 11 operatively positioned within a well bore 12, a tubing string 13 within the well bore 12 connected to the liquid-gas separator 11 to receive liquid accumulations 14 therefrom, and communicating with the surface 16, together with a -gas lift device 17 connected to the tubing string 13 `and responsive to a predetermined pressure therein for supplying gas under pressure from the well bore to the tubing string so as to lift a column of liquid 18 through the tubing string to the surface.

In accordance with the present invention, the liquidgas separator 11 is of the positive Iaction type which will supply liquid to the tubing string so long as liquid is present at the entrance thereof, and which will automatically closs olf the liquid entrance to the tubing string when the liquid supply thereat is exhausted. Liquid-gas separators of this type are disclosed in our Patent No. 2,291,902, issued Aug. 4, 1942, and entitled Gas Anchor, and in our copending application Ser. No. 433,909, led Feb. 19,

1966, and entitled Method and Apparatus for Eiecting Gas Control in Oil Wells.

The 'liquid-gas separator 11 includes a valve means 19 adapted for communicating the tubing string 13 with the lower portion of the interior of an open top cylindrical bucket 21 mounted for vertical reciprocaton within the well bore 12. The bucket 21 has a weight sutiicient to pull the valve means 19 open against the gas pressure in the well when the bucket is partially lled with liquid and also has an effect-ive displacement sulcient to float the bucket in the surrounding liquid when the bucket is substantially empty, for urging the valve means 19 closed.

As here shown, the :liquid-gas separator 11 has its valve means 19 and bucket 21 operatively carried within a capsule 22 secured to the lower end of the tubing string 13. Openings 23 are forced in the capsule 22 to permit entry of liquid and gas from the well bore 12, .and a bull plug 24 is provided at the lower end of the capsule 22 for cleaning out any debris which may accumulate.

The valve means 19 is here shown as being mounted on the lower end of a tube 26 secured in coaxial relation within the capsule 22 and connected to the tubing string 13 to form an operative extension thereof. Valve means 19 here includes a ball check 27 formed to permit liquid to enter the tubing str-ing but to prevent liquid from leaving the tubing string through the valve means. Also included in valve means 19 is a valve member 28 connected "by a rod 29 to the bottom of bucket 21 for vertical movement therewith toward and away from a valve seat 31.

A quantity of liquid is contained within the capsule 22 at all times, this quantity being suicient to cause the bucket, when empty, to oat upwardly and seat valve member 28. When the. liquid accumulation in the well bore 12 rises to the lowermost of the openings 23, it 'will pour into the capsule 22 and into the bucket 21. As the lbucket lls, the otation elect is destroyed and the Weight of the bucket is sufficient to pull the valve member 28 downwardly away from seat 31 against the pressure in the well bore. The liquid contained within bucket 21 is then free to enter the tubing string 13. As the supply of liquid in the bucket 21 is depleted, the flotation effect again overcomes the Weight of the bucket and urges the valve member 28 upwardly to closed position. Thus, it will be seen that the liquid gas separator functions automatically to supply liquid to the tubing string 13 as soon as the liquid accumulation in the well bore reaches a predetermined level as determined by the openings 23. The liquid gas separator also functions automatically to close ol communication between the tubing string 13 and the well bore 12 .as soon as the supply of liquid in the bucket 21 is exhausted to a predetermined level.

In accordance with the present invention, the gas lift device 17 is formed to respond to a predetermined static head of liquid in the tubing string 13 above the liquid gas separator 11 to supply gas under pressure from the well bore 12 to the tubing string a spaced distance below the liquid level therein so as to lift a column or slug 18 of 4 liquid through the tubing string 13 for discharge therefrom at the surface 16.

Preferably, the gas lift device 17 includes a Valve formed for communicating the well bore 12 with the iuterior of tubing string 13, means tending to hold the valve in closed position with a predetermined force, and pressure responsive means in the gas lift device formed for overcoming the last-named means and urging the valve to open position in response to va predetermined pressure in the tubing string.

As here shown the gas lift device 17 includes a housing 32 providing a reference chamber 33 filled with a predetermined qu-antity of gas to provide a predetermined pressure. A bellows 34 is connected to the reference chamber 33 and to a valve member 36 which is movable vertically toward and away from a valve seat 37 upon expansion and contraction of the bellows.

The bellows 34 hermetically separ-ates the chamber 33 from a valve chamber 38 provided by housing 32 and in which valve member 36 and valve seat 37 are contained. Chamber 38 is in communication with the interior of tubing string 13. Bellows 34 has an effective actuating area exposed to the pressure in chamber 38 which is larger than the effective actuating area of the valve member 36, as defined by the area of the valve seat 37 which communicates through ball check valve 39 with the interior of the well bore 12.

The reference pressure contained within -chamber 33 is related to the effective actuating area of bellows 34, the eifective actuating area of valve member 36, and the gas pressure in the well bore |12 in such manner that the valve 36 is urged downwardly to closed position until suiicient pressure exists in tubing string 18 to 'join with the upward force exerted on valve member 36 by the gas pressure in the well bore to overcome the downward force exerted by the reference pressure in cih-amber 33 and cause the valve 36 to move upwardly away from seat 37.

Thus, it may be seen that the static head of liquid entering the tubing string through the liquid-gas separator 11 will eventually exert sufficient pressure in chamber 38 to trigger the gas lift device and snap the valve open, admitting gas under pressure from the well bore into the tubing string. This gas under pres-sure will continue to flow into the tubing string lifting the slug of liquid ahead of it until the slug reaches the surface and is discharged. It should be noted that the pressure in chamber 38, when valve 36 is closed, is determined by the static head of the liquid contained in the tubing string. Accordingly, the reference pressure contained in chamber 33, taken in connection with the geometry of the bellows 34 and valve and seat 36 and 37 will determine the height the liquid will reach in the tubing string at which the described triggering open of the lgas lift device will occur.

In particularly deep wells, it may be necessary to install additional gas lift devices in yorder to life the slug of liquid through the tubing string to the surface. Each of these gas lift devices can be of a structure substantially the same as the gas lift device described and function in a similar manner. Accordingly, detailed description of the structure and function of the additional gas lift devices should not be necessary.

When the slug of liquid reaches the surface and is discharged into the yopen air, as from pipe 41, the back pressure caused by the weight of the liquid slug will be removed and the pressure in reference chamber 33 will act through bellows 34 to cause the valve 36 to snap downwardly against seat 37. The gas lift device 17 will remain in its closed operative position until such time as sufficient liquid accumulates in the well to pass through the gasliquid separator 11 and rise in the tubing string 13 to the desired height, whereupon the static head yof the liquid will again trigger the gas lift device 17.

From the foregoing it will be seen that the liquid control for gas Wells of the present invention operates in a highly ecient manner to eject unwanted accumulations of liquid from gas producing wells in an intermittent manner, utilizing the gas pressure within the well and being responsive 'to accumulati-ons of liquid within the well above a desired level.

We claim:

1. An apparatus for controlilng liquid depth in gas wells and oil wells, comprising a positive action liquidgas separator operatively positioned Within the well bore, a tubing string within the well bore connected to said liquid-gas separator to receive liquid therefrom and communicating with the surface, and a gas lift valve connected to -said tubing string and responsive to a predetermined pressure therein for supplying gas under pressure from the well bore to said tubing string so as to lift a column lof liquid through the tubing string to the surface.

2. An apparatus for automatically controlling liquid depth in gas wells and oil wells, comprising a liquid-gas separator supported in operative position within the Well bore and having valve means controlled by emptying and lling of a bucket for allowing passage therethrough of a liquid While preventing passage of a gas, a tubing string within the well bore connected to the valve means of said liquid gas separator to receive liquid therefrom and communicating with the surface, and a gas lift valve positioned Within the well bore and connected to said tubing string for supplying gas under pressure from the well bore, said gas lift valve being formed to respond to a predetermined static head of liquid in said tubing string above said liquid-gas separator whereby when the liquid level in said tubing string reaches a predetermined height said gas lift valve will open to supply gas under pressure from the well bore to the tubing string a spaced distance below said liquid level so as to lift a column of liquid through the tubing string for discharge therefrom at the surface, said gas lift valve being responsive to the pressure drop in the tubing string occurring upon discharge of said column of liquid therefrom to shut ot the supply of gas under pressure from the Well bore to said tubing string.

3. An apparatus for controlling liquid depth in gas wells and oil wells, comprising a positive action liquidgas separator operatively positioned within the Well bore, a tubing string within the well bore connected to said liquid-gas separator to receive liquid therefrom and communicating with the surface, and a gas lift valve positioned above said liquid-gas separator and connected to said tubing string thereat, said gas lift valve being formed for supplying gas under pressure from the well bore to said tubing string fin response to a predetermined static head in the tubing string for lifting a column of liquid through the tubing string for discharge therefrom outside of the well bore.

4. An apparatus for controlling liquid depth in gas Wells and oil wells, comprising a positive action liquid-gas separator operatively positioned within the well bore, a tubing string within the well bore connected to said liquid-gas separator to receive liquid therefrom and communicating with the surface, and a gas lift valve connected to said tubing string and responsive to a predetermined pressure therein for supplying gas under pressure from the Well bore to said tubing string so as to lift a column of liquid through the tubing string to the surface; said liquid gas separator Ibeing attached to the lower end of said tubing string at a desired location within the well and including an open topped bucket formed for vertical reciprocation within the well bore, and valve means communicating said tubing string with the lower portion of the interior of said bucket, said bucket being connected to said valve means and having a weight sutlicient to pull said valve means open against the gas pressure in the well when said bucket is partially filled with liquid and having an effective displacement suliicient to float said bucket in the surrounding liquid when said bucket is substantially empty for urging said valve means closed.

5. An apparatus as described in claim 4, land wherein said valve means is mounted in the lower portion of the interior of said bucket and includes a valve member movable vertically toward and away from a valve seat connected to the intake end of the tubing string, and a check valve providing one-Way flow into the tubing string.

6. An apparatus for controlling liquid depth in gas Wells and oil wells, comprising a positive action liquid-gas separator operatively positioned within the well bore, a tubing string within the well bore connected to said liquid-gas separator to receive liquid therefrom and communicating with the surface, and a gas lift device connected to said tubing string and responsive to a predetermined pressure therein for supplying gas under pressure from the well bore to said tubing string so as to lift a column of liquid through the tubing string to the surface; said gas lift device including a valve formed for communicating the interior of the well bore with the interior of said tubing string, means in said gas lift device tending to hold said valve in closed position with a predetermined force, and pressure responsive means in said gas lift device formed for overcoming said last-named means and urging the valve to open position in response to a predetermined pressure in said tubing string.

7. An apparatus as described in claim 6, and wherein said gas lift device provides a reference chamber lilled with a predetermined quantity of gas to provide a predetermined presure, a bellows connected to said reference chamber and said valve and formed to provide an eiective actuating area larger than the effective actuating area of said valve whereby the pressure in said reference chamber acting through said bellows will hold said valve in closed position against gas pressure in said Well bore until the pressure within said tubing string reaches a predetermined amount.

8. im apparatus for controlling liquid depth in gas wells and oil wells, comprising a positive action liquidgas separator operatively positioned within the Well bore, a tubing string within the well bore Connected to said liquid-gas separator to receive liquid therefrom and communicating with the surface, and a gas lift device connected to said tubing string and responsive to a predetermined pressure therein for supplying gas under pressure from the well bore to said tubing string so as to lift a column of liquid through the tubing string to the surface; said liquid gas separator being attached to the lower end of said tubing string at a desired location within the well and including an open topped bucket formed for vertical reciprocation within the well bore, and valve means communcating said tubing string with the lower portion of the interior of said bucket, said bucket having a weight sutiicient to pull said valve means open against the gas pressure in the Well when said bucket is partially filled with liquid and having an effective displacement suliicient to oat said bucket in the surrounding liquid when said bucket is substantially empty for urging said valve means closed; said gas lift device including a valve formed for communicating the interior of the well bore with the interior of said tubing string, means in said gas lift device tending to hold said valve in closed position with a predetermined force, and pressure responsive means in said gas lift device formed for overcoming said last-named means and urging the valve to open position in response to a predetermined pressure in said tubing string.

9. An apparatus as described in claim 8, and wherein said valve means is mounted in the lower portion of the interior of said bucket and includes a valve member movable vertically toward and away from a valve seat connected t-o the intake end of the tubing string, and a check valve providing one-way flow into the tubing string, and wherein said gas lift device provides a reference chamber filled with a predetermined quantity of gas to provide a predetermined pressure, a bellows connected to said reference chamber and said valve and formed to provide an effective actuating area larger than the effective actuating area of said valve whereby the pressure in said reference chamber acting through said bellows will hold said valve in closed position against gas pressure in said well bore until the pressure Within said tubing string reaches a predetermined amount.

V8 References Cited UNITED STATES PATENTS 2,128,475 8/1938 Rodger-s 1.03--40 ROBERT M. WALKER, Primm Examiner.

MARK NEWMAN, DONLEY I. STOCKIN G,

Examiners.

W. J. KRAUSS, Assistant Examiner,

Claims

1. AN APPARATUS FOR CONTROLLING LIQUID DEPTH IN GAS WELLS AND OIL WELLS, COMPRISING A POSITIVE ACTION LIQUIDGAS SEPARATOR OPERATIVELY POSITIONED WITHIN THE WELL BORE, A TUBING STRING WITHIN THE WELL BORE CONNECTED TO SAID LIQUID-GAS SEPARATOR TO RECEIVE LIQUID THEREFROM AND COMMUNICATING WITH THE SURFACE, AND A GAS LIFT VALVE CONNECTED TO SAID TUBING STRING AND RESPONSIVE TO A PREDETERMINED PRESSURE THEREIN FOR SUPPLYING GAS UNDER PRESSURE FROM THE WELL BORE TO SAID TUBING STRING SO AS TO LIFT A COLUMN OF LIQUID THROUGH THE TUBING STRING TO THE SURFACE.