US3111906A

US3111906A - Gas lift operation of wells

Info

Publication number: US3111906A
Application number: US88192A
Authority: US
Inventors: Norman A Nelson
Original assignee: Jersey Production Research Co
Current assignee: Jersey Production Research Co
Priority date: 1961-02-09
Filing date: 1961-02-09
Publication date: 1963-11-26
Anticipated expiration: 1980-11-26

Description

Nov. 26,1963 N. A. NELSON 3,111,906

GAS LIFT OPERATION OF WELLS Filed Feb. 9. 1961 4 Sheets-Sheet 1 FLOWLINE 22 I I 21-- i1 VH ':-:r 5 5: H SNAP-ACTING swn'cn LL n I FIG. I.

1 ans nuecnou LINE ans um- VALVE (CLOSED) (oven)- (OPEN)- 1 ELECTRIC POWER souace INVENTOR. NORMAN A. NE LSON,

ANCHOR l3 Nov. 26, 1963 N. NELSON GAS LIFT OPERATION OF WELLS 4 Sheets-Shet 2 Filed Feb. 9, 19 61 J :9... A Hum Hum. m 0 z 2-. M r w 2 l c m H m m o mw W G 6 H E W I A E N RPS II N un hrunu J N F L N A w M 2 M L F F, 5 R 2 O 3 5 N w w w J 5 H1 8 e m m T TW P P A A N N s s w v hhllfi n M I I mm" 8 M v D F l D D uw u E u U L E s 0 T SAL P w L S M N w 0 O Nov; 26, 1963 r N. A. NELSON 3,111,906

GAS LIFT OPERATION OF WELLS Filed Feb. 9, 1961 4 Sheets-Sheet 3 INVENTOIC NORMAN A- NELSON.

BY A

A TOR. Y.

7 Nov. 26, 1963 Filed- Feb. 9. 1961 GAS-LIFT vans; I

(OPEN) (CLOSED) (CLOSEDL N. A. NELSON GAS LIFT OPERATION OF WELLS 4 Sheets-Sheet 4 FIIG.4.

24 1.0)! use 6A5 INJECTION LINE ANCHOR INVENTOR.

NORMAN A. NE LSON d -Jam United States Patent 3,111,906 GAS LIFT OPERATION OF WELLS Norman A. Nelson, Houston, Tex., assignor, by mesne assignments, to Jersey Production Research Company, Tulsa, Okla., a corporation of Delaware Filed Feb. 9, 1961, Ser. No. 88,192 11 Claims. (Cl. 103-231) The present invention is directed to the gas lift operation of wells. More specifically the invention is concerned with operating a system in which gas lift valves in a well tubing are operated from the wellhead. In its more specific aspects, the invention is concerned with method and apparatus for operating gas lift valves in a tubing string in a well wherein a signal is provided at the surface which controls the operation of gas lift valves.

The present invention may be briefly described as a method for employment in a well in which a pipe string is arranged therein which communicates with a subsurface earth interval. A tubing is provided in the pipe string which extends to the earths surface and the tubing has arranged therein a plurality of vertically spacedapart gas lift valves which are operable from the earths surface. The pipe string and the tubing contain a liquid under pressure sufficient to cause the liquid to extend normally to a height suflicient to cover one of the gas lift valves but insufilcient to cause the liquid to flow to the earths surface. In the particular method of the present invention, a gasiforrn fluid such as a hydrocarbon gas, for example, natural gas or components thereof, such as methane, ethane, propane and the like, is injected into the annulus between the tubing string and the pipe string under a selected pressure sutlicient to lift the liquid in the tubing above one of the valves to the earths surface. Thereafter, one of the valves, which may be the same or another one of the valves, is selectively operated responsive to a change in the well of the selected pressure after a predetermined period of time, whereby the gasiform fluid is injected into the tubing and the liquid in the tubing above said one of the valves is lifted to the earths surface.

The change in pressure to which the valves are responsive after the selected period of time may be a change in pressure either in the annulus or in the tubing string. When the change in pressure is in the annulus, the pressure will decrease from the selected pressure, while when the change in pressure is in the tubing string, the pressure will increase.

The selected pressure may be any pressure at which the gas in injected into the annulus suflicient to lift the liquid in the tubing above one of the valves to the earths surface. For example, this pressure may be a pressure such as a pressure in the range from about 500 to about 1000 psi. for wells from about 3000 to about 15,000 feet in depth.

The apparatus of the present invention includes means at the earths surface responsive to a signal which is a function of a change in pressure in the well after the lapse of a predetermined period of time for selectively opening and closing gas lift valves in the tubing string. This means may suitably include means for raising and lowering the tubing wherein the valves are opened and closed or may include wireline operating means engageable and/or 'disengageable with the valves to open and close the valves.

The present invention involves a method for automatically controlling gas lift operation by using a combination of time and pressure signals that result in the bottom or lower of several gas lift valves in a tubing string being employed in lifting liquid :to the earths surface in an automatic operation. The removal of liquid from the tubing string may involve in one mode and embodiment having all of the gas lift valves open initially. As gas is injected into the annulus, the well liquid is forced upwardly out of the tubing until the gas uncovers an upper of the valves. The fluid or liquid in the tubing thus becomes aerated with gas and the tubing pressure increases with an accompanying decrease in casing pressure due to gas passing through the valve. The time required for the gas to proceed from an upper valve to the next lower valve depends upon the dimension and depth of the installation and may be reasonably determined. A controlling means reacts to the increase in tubing pressure and/or to a decrease in casing pressure only after the predetermined time period sending a signal to a means for opening and closing the valves, such as by raising or lowering the tubing or by raising and lowering a wireline means which engages or disengages sequentially with the valves. The signal :thus causes the valves to be closed and after the first increment if the tubing pressure does not drop after a specified interval of time, say fifteen minutes, the valve next lower down is closed until a drop in tubing pressure is realized. This would involve that the upper valve is closed and the fluid is now being raised from above the next lower valve. After a period of time, the controller again reacts to the surface pressure and the valve next lower down is then closed in the same fashion as the upper valve and the sequence of operation is continued or repeated until a depth is reached below which the well fluid or liquids may not be raised to the surface. When the cycle reaches this point at the end of the time period, there is no pressure in the tubing which indicates that the installation had closed the lower operating valve and then it will proceed upwardly to the next upper valve which thus reopens the next upper valve and thus the well would continue to gas lift through this valve. Thus, this type of operation is applicable to constant flow installation.

When the well gas lifts continuously from the lower operating valve, the surface pressures are between 2 highvlow limits. However, if a well has a low productivity of well liquids, intermittent operations from the lowest valve may be required. This is indicated by low tubing pressure due to closing of all the valves. When this condition is known to exist, the signm locks out the previously mentioned timers and engages a third timer that opens the valve for the desired injection time and then closes the valve for the remainder of the cycle thereby providing automatic time cycling for intermittent operations of the well.

There are three time signals and two pressure signals controlling the operation in accordance with the present invention. These time signals and pressure signals are indicated in the fol-lowing table.

T1Unloading time.

TgTlllle for well to die with all valves closed.

T;-Intermitting time cycle.

P|-Pressure when well blows through.

P Pressure when well is dead.

Ps-PICSSUI'G wlen well ls constant flowing on intermediate pressure between P and P2.

are K The invention will be further illustrated by reference to the drawing in which:

FIG. 1 is a view in partial section of one preferred mode and embodiment;

FIG. 2 is a partial sectional view of another mode and embodiment employing wireline operated valves;

FIG. 3 is a partial sectional view of a mode and embodiment employing hydraulic or pneumatic energy; and

FIG. 4 is a similar view to FIG. 2 employing hydraulic or pneumatic energy.

Referring now to the drawing in which identical numerals will be employed to designate identical parts and particularly to FIG. 1, numeral 11 designates a well casing having a tubing 12 arranged therein. The tubing 12 is arranged and locked into place with a tubing anchor 13. Vertically spaced in the tubing 12 are a plurality of

gas lift valves

14, 15 and 16 having parts which are movable relative to each other such that in one position the gas lift valve is closed and in another position the gas lift valve is open. In other words, by raising or lowering the tubing 12, the

gas lift valves

14, 15 and 16 may be closed or opened.

The tubing 12 extends to the well head through a stuffing box 17 which provides a seal but allows the tubing 12 to be moved vertically. The tubing 12 has arranged thereon racks 18 which engage with pinions 19 powered by gears 20. The tubing 12 extends above the earths surface and is connected to a flexible section 21, which in turn connects to a flow line 22.

The casing-tubing annulus 23 is in fluid communication with a gas injection line 24, which connects to the casing 11 below the stuffing box 17. The gas injection line 24 connects by

conduits

25 and 26 to pressure responsive means P and P respectively.

Pressure responsive means P and P form part of a surface controller generally indicated by numeral 27 and including well-known, electrically operated timers T and T as well as

T Solenoids

28, 29, 30, 31 and 32 are provided in controller 27 for controlling respectively T P P T and T The solenoid '32 is connected to a switch 33 by means 34, while the solenoid 31 is connected to a switch 35 by means 36. The solenoid 30 is connected to

switches

37, 44 and 45 by means 38, and the sole noid 29 is connected to

switches

39, and 46 by means 41. The solenoid 28 is connected to

switches

42 and 47 by means 43. The electrical circuitry involves an elec trical connection 72 between T and switch 39 and electrical connection 73 between T and switch 45 while T connects into switch 46 which in turn connects with switch 44 by electrical connection 74. T also connects into a switch 47 which connects by an electrical lead 48 into a snap acting switch 49, and connects to lead 53. The switches 50 and 51 on P and P respectively, and timers T T and T connect by suitable electric leads 52a to an electric power source 52 and control solenoids 30 and 29, respectively, through

electrical leads

70 and 71, respectively and solenoid 28 through electrical lead 69.

The leads 48 and 53 connect the surface controller to the controls of motor 66. The

switches

49 and 54, which are similar, are operated by

solenoids

55 and 56, respectively, and the

switches

49 and 54 are operated by

switch openers

57 and 58, which are pivotally arranged on

pivots

59 and 60. The

switch openers

57 and 58 are operated by a spring urged means 61 which is provided with a cam follower 62 engageable with a cam 63 operated by a gear 64 engageable with a gear 65 connected to a motor 66. The motor 66 is operated through

leads

67 and 68 which connect respectively to

switches

49 and 54. The gear 65 connects to one of the gears 20.

The timers T T and T connect to solenoids 32, 31 and 28 by

electrical leads

67, 68, and 69 while the pressure responsive means P and P electrically connect to solenoids 30 and 29 by

electrical leads

70 and 71. As mentioned, the timer T is electrically connected to switch 39, and this is done by an electrical lead 72, while the timer T connects to switch 45 by electrical lead 73. The timer T connects into switch 46 by electrical lead 74, and, as has been indicated, T connects by electric lead 53 to switch 54.

The pressure responsive means P and P may be connected by

conduits

25 and 26 to flow line 22, and it is understood that these pressure responsive means P and P may form part of a surface controller 27 as has been described, the only dilference being that the

conduits

25 and 26 will be connected to the flow line 22 rather than to the gas injection line 24. When

conduits

25 and 26 are connected into the gas injection line 24, a decrease in pressure in the annulus 23 will cause the operation of the device after the lapse of time indicated, whereas if the

conduits

25 and 26 are connected to the flow line 22 an increase in pressure in the tubing 12 after a lapse of time will cause operation of the

valves

14, 15 and 16, as will be described further.

Referring now to FIG. 2, where identical numerals will be employed to designate identical parts, the tubing 12 is provided with a stufiing box which closes the upper end of the tubing and allows the use of a wireline 81 which is in the well and is connected to a sinker bar 810. The wireline 81 is spooled onto a drum 82 which is connected by a gear 83 to a gear 84 on a suitable electric motor 85. The gear 84 in turn connects with the gear 86 which is connected to a cam 87 which engages with the cam follower 62.

Arranged in the tubing 12 are a plurality of

valves

88, 89, 90, and 91 which are spring biased such that the valves 88 to 91 are normally in a closed position. As the sinker bar is lowered into a valve such as 90, the valve mechanism depresses a spring such as 92 and allows opening of the valve communicating with the annulus 23 to allow passage of gas into the tubing 12.

The other elements of the embodiment of FIG. 2 are identical to and designated by identical numerals to the parts in FIG. 1. Therefore, further description thereof is not required.

Referring now to FIG. 3 wherein identical parts are designated by identical numerals, in this mode and embodiment the mechanism is operated by a liquid from a hydraulic pump or by gas or pneumatic pressure. In this particular instance, the pressure responsive means P and P and the timers T T and T may be similar to those in FIG. 1 and FIG. 2, but here the timing devices such as T T and T and the pressure responsive means P and P connect by suitable conduits to valves which are either pneumatic or hydraulic and which are operated responsive to the pressure and time signals from the timing devices and pressure responsive means. The timers T T and T in the embodiment of FIG. 3 may be wellknown fluid operated timers receiving fluid energy from an external source (not shown) or may contain as an integral part thereof well-known energy supply means such as clockwork mechanisms In this particular instance, a supply of hydraulic fluid 01' gas under pressure is admitted by line 100 from a source, not shown, to a valve 101 which is connected by means 102 to timer T The valve 103 is operated by means 104 connected to timer T The timer T also connects by conduit 105 to a valve 106. The timer T connects by conduit 107 to valve 108 and valve 108 is interconnected by conduit 109 to a pressure responsive means 110. The pressure responsive means P is connected through an arm and linkage 111 to

valves

106, 115 and 122, while the pressure responsive means P connects by arm and linkage 112 to

valves

113, 124 and 126. Valve 101 interconnects by a conduit 101a to valve 103 and interconnects by conduit 114 to valve 115 and by branch conduit 128 to valve 106. Valve 115 connects in turn by conduit 116 to a conduit 117 which, in turn, connects to a valve 118 interconnected with conduit 109 and pressure responsive means 119 which, in turn, connects into valve 113 which is interconnected by conduit 120 with valve 115. Valve 103 is connected by conduit 121 with valve 122 which, in turn, connects by conduit 123 with valve 124 which connects into conduit 117 and thereby communicates with valve 118. Valve 122 connects by conduit 125 with valve 126 which interconnects by conduit 127 with T Valve 106 connects by conduit 105 with T The several timing devices T T and T and pressure responsive means P and P make up a separate controller enclosed by the dotted lines and indicated generally by the numeral 130.

Conduits

131 and 132 lead from the surface controller 130 into

snap acting valves

133 and 134 and connect, respectively, to valve openers !135 and 136 by suitable conduit and interconnection means as shown.

Valve closers

57 and 58 serve functions similar to those of

switch openers

57 and 58 of FIG. 1. The other mechanisms employed in FIG. 3 are identical with the mechanisms employed and described with respect to FIG. 1 and, accordingly, are designated by identical parts. However, the motor 66 in FIG. 1 is replaced by hydraulically or pneumatically operated motor 137 to which the gear 65 is attached which meshes with the gear 64 to which the cam 63 is operatively connected.

As has been described with respect to the other embodiment, the surface controller 130 may be connected into the flow line 22 rather than into the gas line 24 as shown. As indicated in the dotted lines, P and P may connect by

conduits

25 and 26 into the flow line 22.

Referring now to FIG. 4, identical parts are designated by identical numerals to those used in FIG. 2 and FIG. 3. In other words, the surface controller 130 of FIGS. 3 and 4 are identical and are designated by identical parts, and the hoisting mechanism of FIG. 2 and the attendant operations are similar to those of FIG. 2, while the

valves

133 and 134 and

openers

135 and 136 and

closers

57 and 58 are identical to those of FIG. 3. Therefore, in the interest of briefness, further description of FIG. 4 is not required.

The present invention will be further described with reference to FIG. 1. In this particular operation, all of the valves 14, .15, and 16 will be in the open position. Well liquids will be present in the casing-tubing annulus 23, to some level above valve 14, and gas will be forced under pressure through the gas injection line 24 into the annulus 23, causing part of the well liquids to move through the

valves

14, 15, and 16 into the tubing 12 and thence to flow line 22. Gas will continue to be forced into the gas injection line 24 in sufficient amounts and 6 under suflicient pressure to create and maintain a flow of the well liquids into and through the flow line 22. As lifting continues, liquids will be removed from the well above valve 14 and the gas will blow around, causing pressure in line 24 to be reduced. The timing device T is on and at the end of a predetermined period of time, say 45 minutes, and simultaneously with the end of this time, solenoid 32 is energized and shifts switch 33 to allow an electrical impulse to flow to switches 44 and 45. The pressure in line 24 is assumed to be low, causing pressure-responsive device P to close switch 50. This energizes solenoid 30, causing switches 37 and 44 to be shifted and switch 45 to be closed. The electrical impulse flows through switches 45 and 44, and simultaneously through lead 73 to timing device T and through switch 42 and lead 48 to switch 49. The impulse to T 2 causes T to start. The impulse to switch 49 causes motor 66 to be rotated one revolution and in an amount suflicient to raise tubing 12 and thereby close valve 14. Timing device T holds solenoid 32 on for a period of time, say 5 minutes, suflicient for valve 14 to close and timer T to start, then shuts itself and solenoid 32 off allowing switch 33 to return to normal. After timer T has run for a predetermined period of time, say 15 minutes, it causes solenoid 31 to be energized, causing switch 35 to close. The pressure in line 24 is assumed still to 'be low, and thus pressure-responsive device P still causes switches 37 and 44 to be shifted and switch 45 to be on. When switch 35 is closed, an electrical impulse is allowed to flow through switch 35 to switch 37 to switch 40 to switch 42 through lead 48 to switch 49, causing motor 66 to be actuated and raise the tubing 12 and thus close valve 15. Timer T causes switch 35 to remain closed for a period of about 5 minutes and then open again. After a second period of say 15 minutes, timer T again causes switch 35 to close. Assuming the pressure in line 24 is still low, a sequence similar to the one just described will cause valve 16 to be closed.

If, however, the pressure in line 24 is at an intermediate stage at the end of the second 15-minute period of T pressure-responsive device P would cause switch 50 to open, causing switches 37 and 44 to return to normal position and switch 45 to return to off position. Also, pressure-responsive device P would not have caused switches '39, 40, and 46 to operate and so no action would take place relative to positioning the several valves .14, 15, and 16.

If, on the other hand, the pressure in gas injection line 24- has become high at the end of any 15-minute period of T then pressure-responsive device P would have closed switch 51, causing solenoid 29 to be energized and causing

switches

39 and 46 to be closed and switch 40 to be open. Thus, when timer T causes switch 35 to be closed, the electrical impulse could pass through switch 35 to 37 to 39 through lead 72 and cause timer T to start again. Simultaneously with the starting of timer T timer T will receive an electrical impulse through lead 74, causing it to stop.

At the end of the predetermined period for timer T say 45 minutes, solenoid 32 will be energized, and assuming pressure in gas injection iine 24 is still high and switch 46 is thus still closed, an electrical impulse will pass through switch 33, through 44, through 46, and on through

leads

74 and 69 to timer T and solenoid 28. Solenoid 28 will turn switch 42 off and switch 47 on. These switches will remain in these positions until manually reset. The impulse to timer T starts T which at this time takes control of motor 66 and causes intermittent opening and closing of whichever of

valves

14, 15, and 16 was last closed. Energizing solenoid 28 results in any further signals due to timers T or T being blocked from reaching motor 66, as switch 42 is in the open position. After a brief period of time, say 5 minutes, timer T shuts itself and solenoid 32 off.

With respect to FIG. 2 wherein the surface controller 27 is identical to surface controller 27 of FIG. 1, the operation is identical to that described with respect to FIG. 1 excepting that a hoist motor and a drum carrying a wireline 81 is used instead of raising and lowering the tubing 12 to close and open the valves. In short, with respect to FIG. 2, the same particular operations are employed to open the

valves

88, 89, 90 and 91 by raising and lowering the sinker bar 82 on the wireline 81 by rotation of the hoist motor 85 and thus rotating the drum 82 carrying the wireline 81. It is believed unnecessary to burden this description with further descriptive matter of the surface controller 27 in view of the detail that has been given with respect to FIG. 1.

Referring now to FIG. 3, with all of the

valves

14, 15 and 116 in open position, well liquids will be present in annulus 23 to some level above valve 14 and gas will be forced under pressure through line 24 into annulus 23, causing part of the well liquids to move through

valves

14, 15, and 16 into tubing 12 and thence to flow line 22. Gas will continue to be forced into line 24 by means not shown in sufiicient amount and under suflicient pressure to create and maintain a flow of the well liquids into and through flow line 22. As lifting continues, liquid will be removed from the well above valve 14 and gas blows around, causing pressure in line 24 to be reduced. At the end of a selected period of time, say 45 minutes, timer device T is in operation and a force is applied through means 102 to valve 101 to shift the valve 101 from its normal position and allow fluid pressure from supply 100 to proceed into line 1 14 and line 128. If the pressure in gas injection line 24 is low, then pressure responsive means P causes the arm and linkage 111 to be rotated a sufficient amount to open valve 106 and to shift

valves

115 and 122. This movement of the

valves

115 and 122 allows pressure in line 128 to pass through valve 106 and line 105 and start a period of time of say 15 minutes for the timing device T and simultaneously to allow pressure in line 1 14 to pass through valve 115 to line 116 and through normally open valve 118 and thence through line 132 to valve opener 136. This opens valve 134 and allows pressure fluid to proceed to motor 137 operating it and causing valve 14 to be closed by lifting of the tubing 12. After a selected period of time, for example minutes, timing device T causes valve 101 to be shifted back to its normal position as shown in FIG. 3. Pressure flow is then to line 101a and to valve 103 which is opened by timing device T running for 15 minutes. This allows pressure to pass into line 121. If pressure in line 24 through which gas is being supplied to annulus 23 is low and remaining low, the valves operated by pressure responsive means P will be in the same position described previously, and pressure from line 121 passes through valve 122 to line 123 and through valve 124 and thence to line 117, valve 118, line 132 actuating the valve opener 136 and valve 134 and providing power fluid to motor 137 which closes valve 15 by raising tubing 12 another increment. Valve 103 is once again closed after a period of say 5 minutes.

At the end of a second 15-minute period, timing device T opens valve 103 and allows pressure to pass to line 121. If the same pressure exists in line 24, the same sequence is repeated and valve 16 would then be closed.

If, however, an intermediate pressure between P, and P exists in gas injection line 24 at the end of the second l5sminute period, no action would take place relative to positioning of the

several valves

14, 15 and 16.

If, on the other hand, the pressure in line 24 is high, then pressure responsive means P will actuate arm and linkage 111 causing

valves

106, 115, and 122 to return to normal positions, and pressure responsive means P will extend actuating arm and linkage 112 and cause

valves

113 and 126 to be opened, valve 124 being closed. Pressure then flows through line 121 and through valve 122 into line 125, thence the pressure flow is through valve 126 to line 127 to timing device T, causing it to be actuated at the end of a 45-minute period, simultaneously pressure flowing through line 127 stops timer T At the end of this 45-minute period the timing device T then shifts valve 101 allowing pressure to pass into lines 1 14 through valve into line 120. If the pressure is still high in line 24, P actuates arm and linkage 112 and causes

valves

113 and 126 to remain opened and valve 124 remains closed. Pressure from line passes through valve .113 into line 109 simultaneously closing valve 118 and opening valve 108 and thus setting into operation timing device T Timing device T now controls the motor to raise and lower the tubing 12 to open and close one of the

valves

14, 15 or 16, depending upon which valve is being employed. Valve 118 locks out signals from timing devices T and T and valve 108 allows timing device T to control the operation.

It will thus be seen that in conjunction with the operation described in FIG. 3, a hydraulic or pneumatic fluid may be used to control the controller 130.

The operation of the motor 137, the cam 63, the

valve openers

59 and 60 have been described in the previous embodiment, and in the interest of briefness, further reference thereto will not be had.

The operation with respect to FIG. 4 is similar to that described with respect to FIG. 3 relative to the surface controller 130 and with reference to FIG. 2 relative to the operation of the

valves

88, 89, 90 and 91, as well as the motor 85, the hoisting drum 82 and the attendant equipment.

The valves shown in FIGS. 3 and 4 have adjacent thereto in the drawing the symbols NC and NO. NC means normally closed and NO means normally open.

In the several figures of the drawing, the pressure responsive means P and P as well as the timing devices T T and T are shown schematically. The pressure responsive means may be any pressure responsive means such as a Bourdon tube as illustrated, or a bellows type device or any device which will convert a pressure pulse to a mechanical force, such as a piston biased by a spring, and the like.

Likewise, the valve openers and 136 and the

switch closers

55 and 56, as well as the

valves

54 and 49 are items well known to the art. Apparatus elements of this nature are manufactured by Instruments, Inc. of Tulsa, Oklahoma and by Micro Switch, a Division of Minneapolis-Honeywell Regulator Company of Freeport, Illi nois. Generally, limit or micro switches may be used in electrically powered embodiments of this invention, while well-known micro valves may be used otherwise.

The present invention is quite important and useful in that in the artificial lift of oil wells by gas lift, injection of gas is into the tubing from the tubing-casing annulus. This may be accomplished in wells where there is large clearance by installing the type of gas lift valves which are controlled at the valves by pressure. However, with the recent increase in tubingless completions with a resulting reduction in well tubing and casing dimensions, a problem has been created in that insufficient clearance is provided in the casing-tubing annulus for employment of the conventional type of valve which may require an increase in the tubing size to accommodate the valve. In accordance with the present invention, valves such as described herein are employed in an automatic sequence of operations such as that these valves may be used in areas and locations where ordinarily they are not useable. Therefore, the present invention is quite important and useful in that it provides apparatus and a mode for operating the apparatus and arrangement by way of which automatic operation of gas lift may be provided. Heretofore it was not practical in areas of confinement such as experienced in tubingless completions or in slim holes to achieve the desired objects of the present invention.

Vhile the invention has been described and illustrated by injection of gas into the casing-tubing annulus and lifting liquid in the tubing, it is within the spirit and scope of this invention to inject gas into the tubing and lift liquid in the annulus to the earths surface.

Also, other mechanisms may be used for lif and lowering the tubing strings or for opening and closing the valves through wirelines, such as hydraulically or pneumatically operated means embodying pistons and cylinders, and the like, or equivalent mechanisms.

In the description taken with the drawing and in the several examples, times and time cycles are given for illustration purposes only. Actually the times and/r cycles may vary widely depending on the particular installations. Thus, the times before a given signal is transmitted to operate a valve may vary from about minutes up to about 60 minutes, although this invention is not limited thereto. Likewise, the time cycles may be multiples of the time before a given valve is operated, depending on the number of signals transmitted to the several valves or depending on the number of valves employed.

Likewise, any number of gas lift valves may be used besides the specific number shown in the drawing.

The nature and objects of the present invention having been completely described and illustrated, what I wish to claim as new and useful and secure by Le'ters Patent is:

1. In a well having a pipe string therein communicating fluidly with a subsurface earth interval in which a tubing is arranged extending to the earths surface providing an annulus with the inner wall of the pipe string,

said tubing having arranged therein a plurality of vertically spaced-apart mechanically operated gas lift valves operable from the earths surface, wherein means are provided for injecting a gasiform fluid into the Well, apparatus for continuous and intermittant operation of said well which comprises:

means at the earths surface operatively connected to said gas lift valves and responsive to a signal which is a function of a change in pressure in said well after lapse of a predetermined period of time for selectively remotely opening and closing said valves,

means operatively connected to said opening and closing means for providing said signal,

said means for providing said signal comprising:

first and second pressure-responsive means fluidly communicating with said injection means,

first, second, and third timing means,

first control means operatively connected to said first timing means for controlling energy supplied to said signal producing means,

second control means operatively connected to said second timing means,

third control means operatively connected to said first pressure-responsive means, to said first and second control means, and to said second timing means for controlling energy thereto,

fourth control means operatively connected to said second pressure-responsive means, to said third control means, and to said first timing means for controlling energy thereto, and

means opcratively associated with said third timing means and with said fourth control means for locking out said first and second timing means,

said third timing means being separately connected to said opening and closing means for intermittent operation of said well,

whereby any liquid above one of said valves in said tubing is lifted to the earth's surface.

2. Apparatus in accordance with claim 1 in which the signal-providing means is electric.

3. Apparatus in accordance with claim 1 in which the signal-providing means is hydraulic.

4. Apparatus in accordance with claim 1 in which the signal-providing means is pneumatic.

,iireos 5. In a well having a pipe string therein communicating fluidly with a subsurface earth interval in which a tubing is arranged extending to the earths surface providing an annulus with the inner wall of the pipe string,

said tubing having arranged therein a plurality of vertically spaced-apart mechanically operated gas lift valves operable from the earths surface, wherein means are provided for injecting a gasiform fluid into the annulus, apparatus for continuous and intermittent operation of said well which comprises:

means at the earths surface operatively connected to said gas lift valves and responsive to a signal which is a function of a change in pressure in said annulus after lapse of a predetermined period of time for selectively remotely opening and closing said valves,

said means for providing said signal comprising:

first, second, and third timing means,

second control means operatively connected to said second timing means,

third control means cperatively connected to said first pressure-responsive means, to said first and second control means, and to said second timing means for controlling energy thereto,

means operatively associated with said third timing means and with said fourth control means for locking out said first and second timing means,

whereby any liquid above one of said valves in said tubing is lifted to the earths surface.

6. Apparatus in accordance with claim 5 in which the signal-providing means is electric.

7. Apparatus in accordance with claim 5 in which the signal-providing means is hydraulic.

8. Apparatus in accordance with claim 5 in which the signal-providing means is pneumatic.

9. Apparatus in accordance with claim 5 wherein said opening and closing means includes means for raising and lowering said tubing string.

10. Apparatus in accordance with claim 9 in which the raising and lowering means comprises a rack and pinion.

11. Apparatus in accordance with claim 5 wherein said opening and closing means includes wireline operated means engageable and disengageable with said valves.

References Cited in the file of this patent UNITED STATES PATENTS 2,268,036 Kyner July 16, 1940 2,255,648 Bryan Sept. 9, 1941 2,275,346 Bryan Mar. 3, 1942 2,278,532 Crickmer Apr. 7, 1942 2,658,460 Davis Nov. 10, 1953 2,746,395 Carpenter May 22, 1956 2,759,429 Bubb Aug. 21, 1956 2,777,398 Carpenter Jan. 15, 1957 2,803,197 Wiley Aug. 20, 1957 2,838,008 Nisle June 10, 1958 2,869,475 Bobo Jan. 20, 1959 2,876,434 Oberlin Mar. 3, 1959

Claims

1. IN A WELL HAVING A PIOPE STRING THEREIN COMMINICATING FLUIDLY WITH A SUBSURFACE EARTH INTERVAL IN WHICH A TUBING IS ARRANGED EXTENDING TO THE EARTH''S SURFACE PROVIDING AN ANNULUS WITHTHE INNER WALL OF THE PIPE STRING, SAID TUBING HAVING ARRANGED THEREIN A PLURALITY OF VERTICALLY SPACED-APART MECHANICALLY OPERATED GAS LIFT VALVES OPERABLE FROM THE EARTH''S SURFACE, WHEREIN MEANS ARE PROVIDED FOR INJECTING A GASIFORM FLUID INTO THE WELL, APPARATUS FOR CONTINUOUS AND INTERMITTANT OPERATION OF SAID WELL WHICH COMPRISES: MEANS AT THE EARTH''S SURFACE OPERATIVELY CONNECTED TO SAID GAS LIFT VALVES AND RESPONSIVE TO A SIGNAL WHICH IS A FUNCTION OF A CHANGE IN PRESSURE IN SAID WELL AFTER LAPSE OF A PREDETERMINED PERIOD OF TIME FOR SELECTIVELY REMOTELY OPENING AND CLOSING SAID VALVES, MEANS OPERATIVELY CONNECTED TO SAID OPENING AND CLOSING MEANS FOR PROVIDING SAID SIGNAL, SAID MEANS FOR PROVIDING SAID SIGNAL COMPRISING: FIRST AND SECOND PRESSURE-RESPONSIVE MEANS FLUIDLY COMMUNICATING WITHSAID INJECTION MEANS, FIRST, SECOND, AND THIRD TIMING MEANS, FIRST CONTROL MEANS OPERATIVELY CONNECTED TO SAID FRIST TIMING MEANS FOR CONTROLLING ENERGY SUPPLIED TO SAID SIGNAL PRODUCING MEANS, SECOND CONTROL MEANS OPERATIVELY CONNECTED TO SAID SECON TIMING MEANS, THIRD CONTROL MEANS OPERATIVELY CONNEECTED TO SAID FIRST PRESSURE-RESPONSIVE MEANS, TO SAID FIRST AND SECOND CONTROL MEANS, AND TO SAID SECOND TIMING MEAN SFOR CONTROLLING GENERGY THERETO, FOURTH CONTROL MEANS OPERATIVELY CONNECTED TO SAID SECOND PRESS-RESPONSIVE MEANS, TO SAID THIRD CONTROL MEANS, AND TO SAID FIRST TIMING MEANS FOR CONTROLLING ENERGY THERETO, AND MEANS OPERATIVELY ASSOCIATED WITH SAID THIRD TIMING MEANS AND WITH SAID FOURTH CONTROL MEANS FOR LOCKING OUT SAID FIRST AND SECOND TIMING MEANS, SAID THIRD TIMING MEANS BEING SEPARATELY CONNECTED TO SAID OPENING AND CLOSING MEANS FOR INTERMITTENT OPERATION OF SAID WELL, WHEREBY ANY LIQUID ABOVE ONE OF SAID VALVES IN SAID TUBING IS LIFTED TO THE EARTH''S SURFACE.