US3002526A

US3002526A - Well production controller

Info

Publication number: US3002526A
Authority: US
Inventors: Ben D Terral
Original assignee: Camco Inc
Current assignee: Camco Inc
Priority date: 1959-08-10
Filing date: 1959-08-10
Publication date: 1961-10-03
Anticipated expiration: 1978-10-03

Description

Oct. 3, 1961 B. D. TERRAL WELL PRODUCTION CONTROLLER 2 sheets sheet 1 Filed Aug. 10, 1959 A TTORNEY Oct. 3, 1961 B. D. TERRAL 3,002,526

WELL PRODUCTION CONTROLLER Filed Aug. 10, 1959 2 Sheets-Sheet 2 5. .D. 7 e r r a INVENTOR.

BY @c mew;

3,002,526 WELL PRODUCTION CONTROLLER Ben D. Terra], Houston, Tern, assignor to Qamco, Incorporated, Houston, Tex., a corporation of Texas Filed Aug. 10, 1959, Ser. No. 832,519 '10 Claims. (Cl. 137-4925) This invention relates to surface controllers for timing periodic production of well fluids by a gas lift system and more particularly to improved mechanism operated automatically in response to certain pressure conditions in a selected part of the system for overriding the set operational cycle of a timer to thereby modify the period or duration of pressure gas injection. v

A conventional gas lift system'for intermittent produc tion of liquid oil from a well includes a pair of well conduits, one for the production of well fluids and the other for delivery of pressure gas to be injected into the production conduit below the liquid leveltherein, together with a pressure gas feed valve connected at the well head with the gas delivery conduit and arranged to be cycled between opening and closing periods of predetermined durations. Intermittent valve operation is usually indexed by a timing wheel or continuously driven and constant speed rotor carrying a number of circumferentially spaced pins or cams to engage successively with and to actuate a controller for signaling valve operation.

Under variable well operating conditions, pressures downstream of the feed valve and within either or both the delivery and production conduits may build up rapidly in the valve opening phase of the cycle and exceed a desired pressure level before the valve normally closes. To

provide improved mechanism which senses pressure excess and responds by causing a driven controller member to overrun the timing driver thereof during the valve opening interval to shorten the same and correspondingly increase the valve closing interval whereby to reduce the likelihood of excessive pressure build-up and enable dissipation of pressures between successive valve opening phases, is one of the primary objects of the present invention.

A further object of the invention is to provide a feed valve indexing member to be driven normally from a constant speed driving member and through a lost motion connection accommodating overrun of the driven member to valve closing relation under accelerated motion transmitted thereto through a short stroke in response to pressures above a given level downstream of the valve in any opening period thereof.

Another object of the invention is to provide a con troller having its several dependently interconnected components compactly assembled in cooperative locations on opposite faces of a small mounting plate protectively housed within a weatherproof container whose front and rear walls both constitute access doors which can be separately opened for inspection and adjustment of the components on one side or the other of the mounting plate.

In the accompanying drawings, FIG. 1 is a transverse vertical section of a double door housing with the controller mechanism mounted therein and with one of the housing doors in open position; FIG. 2 is an elevation looking into the housing from one side; FIG. 3 is an elevation looking into the housing from the side opposite that of FIG. 2; and FIG. 4 is a diagrammatic illustration with parts in section of the various component-s in operative relation to one another.

A common installation of a gas lift system involves a source of pressure gas and a time controlled motor valve connecting the pressure source to casing annulus space around a production tubing string set Within the casing and carrying a number of vertically spaced apart valves through which the pressure gas is injected into the pro- 3,002,526 Patented Got. 3, 1961 fire duction string for lifting liquid to the surface. In the diagrammatic illustration in FIG. 4 of the drawing, the motor valve assembly 1 controls'communication from its inlet 2 or the pressure gas supply to the outlet 3 leading to the well annulus space. In the usual direct acting motor valve assembly, the valve is normally held closed by its connection with a movable wall or flexible diaphragm and the action on the diaphragm of pressure gas opposing a valve opening spring. The pressure chamber of the diaphragm is either vented or supplied with pressure gas through a conduit 4 and a pilot valve assembly including a housing 5 having an internal chamber with which the pipe 4 communicates for connection alternately with an exhaust port 6 and with a pressure gas inlet pipe 7.

A spring seated valve 8 normally closes the exhaust port 6 and a normally open pressure responsive pilot piston and downwardly seating valve controls pressure gas flow from the inlet 7 to the motor valve pipe line 4. The relatively small area on the underside of the piston 9 is exposed to pressure within the line 7 for raising the same from a passage closing seat therefor. A larger area presented by a flexible diaphragm engaging the upper side of the pilot piston 9 can be alternately vented or subjected to line pressure through the pipe line lit) for depressing the piston 9 and closing oh the pressure supply through the line 7 and concurrently engaging an upwardly projecting stem of the valve S to open the latter for exhaust purposes. Periodic operation of the pilot piston valve 9 for venting the line 4 will open the motor valve for a short interval followed by restoration of the pilot valve to the position in which the exhaust is closed and pressure is directed to the conduit 4 for closing the motor valve.

Gas lift installations are often made with a motor valve unit 1 embodying a reverse acting valve which is spring pressed in the direction of flow from the inlet 2 to the outlet 3 when the chamber above the flexible diaphragm is vented and which valve is opened by pressure fluid acting to depress the diaphragm. The only change necessary in the pilot valve assembly 5 for adapting it to a reverse acting motor valve is to shift the connection of the pressure line 7 to the lower port indicated at 6 and thereby open to atmosphere the upper lateral port leading from the interior of the body 5 above the valve seat for the piston valve 9. In such conversion, the interior chamber of the valve body 5 will be supplied with pressure fluid under control of the lOWer valve 8 and will be exhausted under control of the upper piston valve 9 and valve action will be responsive to line pressures on differential areas above the valve 9 and below the valve 8.

The pipe r10 is connected to the interior of a housing 11 of a multiple way valve assembly containing a shiftable valve element 12 which at opposite limits of its travel engages and closes seats in opposite end walls of the housing 11. One of the end wall seats surrounds a vent through which the line 10 is open to atmosphere when the valve closes the opposite wall opening. When the vent is closed by the shiftable valve 12, the line 10 will receive pressure fluid through the housing 11 via a branch 13 leading from a T-connection having another branch joined to the pressure line 7 and a third branch joined by a pressure line 14 to a T-

connection joining conduits

15 and 16, the latter being connected with the outlet of a pressure reducing regulator 17 whose inlet is connected to the pressure gas supply source. The reduced pressure delivered from the regulator =17 will pass through either of the branches 7 or 13, depending on the position of the control valve 12 for action on the opposite differential areas of the pilot piston valve 9 for either raising or lowering the same and thereby control the alternate closing and opening of the motor valve 1.

Control of the shiftable valve 12 is timed for intermittent response to the operation of a suitable motor such as a clock mechanism. According to the present invention, the clock mechanism is geared for rotating a pair of coaxial driving and driven wheels or

rotor discs

18 and 19 having suitable motion transmitting connection therebetween. The motion transmitting connection is illustrated as including a lateral pin 20 carried by the driving disc 18 in radially spaced relation to the axis of rotation and extended through an elongated arcuate slot 21 in the driven wheel 19. With the direction of rotation of the driving rotor 18 being counterclockwise, as viewed in FIG. 4, the motion transmitting pin 20 when advanced to the forward limit of the arcuate slot 21 carries the disc 1? forward with the disc 18 and at the same rate. The slot 21 will, however, allow a lost motion or an overrun of the disc 19 relative to the constant speed of the driving rotor 18. Separate motor means is provided for effecting such overrun, as, for example, when system pressure downstream of the motor valve 1 exceeds a predetermined level and eliminates the need for additional pressure gas through the motor valve 1.

The driven wheel 19 usually carries a large number of circumferentially and uniformly spaced screw threaded perforations near its rim for receiving any desired number of transverse pins, only one of which is shown at 22 in MG. 4. Such pins 22 come into engagement successively with a follower 23 adjustably mounted by a 4 relationship but as the pressures rise, the Bourdon tube will expand and, at some position as determined by the adjustable setting of the screw 38, the rock lever 36 threaded screw 24 on a rock lever 25 for lifting the lever about its end fulcrum mounting 26 and at its opponite end away from a projecting stem on the control valve 12. Normally, the weight of the lever 25 plus the elastic force of a spring, if desired, depresses the valve 12 against line pressure to seat the valve against inflow of the pressure gas into the housing 11 and to vent the housing. Engagement of a lift pin 22 with the follower 23 occurs for a short time interval of wheel rotation, during which the motor valve will be open. As soon as the pin 22 is carried beyond the follower 23, the valve will again be closed through another time interval. Such successive intervals will be of durations controlled by the number of pins 22 carried by the driven wheel, all according to conventional practice.

Preferably, the periphery of the driven wheel 19 is ribbed or notched for better co-operation with a toothed or beveled end of a motion transmitting projector or pawl which advances the driven wheel and pin 22 in response to actuation of a secondary motor. This secondary motor is illustrated as including a cylinder 27 containing a pressure actuated reciprocatory piston 28 having a projecting stem 29 to engage a pivoted lever arm 30 whose free end carries the previously mentioned projector or pawl 31. Suitable spring means 32 exerts force on the lever arm 30 for retracting the same in the absence of pressure gas acting thereon through the power driven piston 28. Such power is supplied behind the piston to the housing 27 through a pressure line 33 leading from the interior of a valve housing 34. The housing 34 contains a shiftable valve 35 which has alternate positions in one of which the housing 34 is vented through one end and in the other of which the vent is closed and the pressure line 15 is opened for supplying pressure gas through the housing and the line 33 to the secondary motor.

Position of the valve 35 is controlled by engagement of a stem thereof with a rock lever 36 which has suitable spring means 37 acting thereon for shifting the valve to the position in which the housing 34 is vented. One arm of the lever 36 carries an adjustable set screw 38 for engagement with the free end of a Bourdon tube 39 whose opposite end is fixed in an anchor block 40 and communicates through a pipe connection 41 with some part of the system downstream of the motor valve 1 for telegraphing pressure levels to the valve control rock arm 36. Whenever such pressures are below a selected level, the Bourdon tube will be in a relatively contracted will move with the free end of the Bourdon tube 39 to thereby close the vent from the housing 34 and supply line pressure to the secondary motor. Bourdon tube contraction can be utilized to shift the valve 35 to its operating pressure fiuid flow position for those installations calling for a motor power stroke in response to a pressure drop below a desired level at a given point in the system.

Motor response projects the motion transmitting pawl 31 into engagement with the periphery of the disc 19 and advances the disc within the lost motion limit of the elongated slot 21. The length of the slot 21 exceeds the diameter of the pin 20 by an amount which will enable forward rotation of the driven disc 19 for carrying the timing pin 22 from a position which has lifted the rock lever 25 to a position beyond the follower 23 for return of the rock lever 25 and closing of the motor valve.

FIGS. 1, 2 and 3 illustrate a commercial embodiment of the invention, having the parts previously referred to indicated by the same reference characters. These parts are compactly arranged in co-operative relation to one another by being secured on one or the other of the opposite faces of a mounting plate 42 secured as by screw studs 43 to a series of laterally inwardly projecting attachment ears within a rectangular band 44 on which are hinged the front and

rear closure doors

45 and 46, both of relatively deep and cupped castings or stampings and which co-operate with the band 44 in constituting a weatherproof housing protectively enclosing the several parts.

As seen in FIGS. 1 and 2, there are mounted on one face of the plate 42 the main drive motor or clockworks within a housing 47 and whose output shaft 48 carries or has keyed thereon the driving rotor 18 and has loosely mounted thereon the driven wheel 19 which convenientiy is made in the form of a pair of light weight spaced apart and hub secured discs for peripherally providing firm and detachable securement of actuator or camming pins 22. The lever 25 is mounted on the plate 42 on the same side as the clock motor 47. Also mounted on the same side of the plate 42 is the control valve 11 and the projector pawl 31 and one arm of the lever 30 whose rock shaft is pivoted to project through the mounting plate.

Fixed to the rock shaft on the opposite side of the plate is a lever arm 30a for engagement with the piston stem within the motor housing 27 fixed on said opposite side of the mounting plate 42. Also mounted on this same side of the mounting plate are the pilot valve housing 5, the Bourdon tube 39 and the control valve housing 34, together with the piping for connecting the various parts as previously described.

The mounting arrangement enables the several components to be compactly assembled in relation to one another and in two groups but access to all can be easily had by swinging open the closure doors. These doors are openable each independently of the other for effecting adjustments or replacements of components on opposite sides of the central mounting plate. Each closure door at its free edge carries a pivoted latching arm 49 on the inside thereof on a rock shaft which projects to the outside and has an operating handle 50 for swinging the latch into and out of co-operative engagement with the housing band 44.

While a single embodiment is herein described, it is to be understood that the invention is inclusive of various modifications such as come within the scope of the appended claims.

What is claimed is:

l. in a controller for use with a gas lift well system having a production conduit and a lift gas conduit connected with the production conduit for the transfer of pressure lift gas thereto, the improvement which consists of intermittently operable means controlling admission of pressure gas to the lift gas conduit and comprising a motor valve, a timer therefor having a driven rotor connected with the motor valve and operated to open and close the same at spaced intervals, a driving rotor, a drive transmitting connection joining said rotors and incorporating lost motion means to free the driven rotor for forward rotation relative to the driving rotor and means effecting such forward rotation and responsive to a given pressure level within a selected part of the system.

2. The controller as in claim 1 wherein the last mentioned means includes a power actuated motor, a drive transferring connection between the motor and said driven rotor and means responsive to system pressure and controlling the application of actuating power to said motor.

3. The controller as in claim 1 wherein said drive transmitting connection includes a drive lug fixedly carried by one of said rotors and a lug receiving formation on the other rotor which provides a bearing seat engageable by the lug for transferring driving rotor movement to the driven rotor and also provides lug receiving clearance exceeding the size of the lug in the direction of rotor movement and accommodating driven rotor movement independently of the driving rotor.

4-. A surface controller for a gas lift system having a valve governing delivery of pressure fluid to the system, said surface controller including valve opening and closing control means, a driven member having intermittently effective operating connection with said control means and timing periodic operation thereof in response to movement of said driven member and a pair of separate driving instrumentalities operable to effect movement of said driven member, one of said driving inst-rumentalities being in constant operation as the normal driving means for the driven member and having motion transmitting and driven member overrunning connection with said driven member and the other of said driving instrumentalities being normally inactive but responding to abnormal operating conditions and having drive connection with the driven member to compel the same to override the normal drive means.

5. A surface controller for a gas lift system having a valve governing delivery of pressure fluid to the system, said surface controller including valve opening and closing control means, a driven member having intermittently eifective operating connection with said control means and timing periodic operation thereof in response to driven member movement, continuously operating drive means having drive transmitting connection with the driven member for moving the same at a substantially constant rate and other drive means having drive transmitting connection with the driven member and operable to impart a speed increasing impulse thereto of relatively short duration.

6. A surface controller including a rotary indexing wheel, a pressure fluid feed control valve for a pressure fluid system, intermittently operated valve actuation means connected with said wheel and shiftable between alternate valve opening relation and valve closing relation in response to wheel rotation, a continuously rotating drive wheel having a pin and elongated slot connection with the indexing wheel for driving the same when the pin is at one end of its slot, a motor engageable upon energization thereof with said indexing wheel to advance the same ahead of said drive wheel the limit of said pin and elongated slot connection and means com trolling energization of said motor in response to a given fluid pressure level in the system fed by said control valve.

7. In a controller of the character described, a pres sure fluid system having a pressure fluid feed control valve, a rotatable timer disc having circumferentially spaced valve actuating devices for the intermittent operation of the valve in response to disc rotation, a drive disc, means mounting the discs coaxially, a pin carried by one of the discs and projected into an elongated slot in the other disc as a drive and lost motion connection between the discs, a projectable plunger engageable upon projection with the timer disc to advance the same relative to the drive disc as accommodated by the =lost motion pin and slot connection and actuating means projecting said plunger in response to system pressure in excess of a given value for modifying the valve opening interval.

8. In a controller of the character described, a housing having access doors on opposite sides thereof, a mounting plate positioned centrally of the housing between the side doors, an intermittently operated fluid pressure feed control device mounted on one side of the plate for operation in controllnig fluid pressure in a system to be controlled, coaxial timer and drive discs rotatably mounted on the plate on the same side thereof with the control device, means on the timer disc for operating said control de vice, a pin and slot lost motion drive connection between the discs, a projectable plunger assembly mounted on the other side of said plate and provided with a part extended through the plate for motion transmitting relation with the timer disc and system pressure responsive means governing actuation of the plunger assembly and mounted by the plate on the same side thereof as and adjacent to said plunger assembly.

9. In a controller of the character described, valve means to feed pressure fluid to a system to be controlled, timer mechanism operable to open the valve intermittently for given time intervals, system pressure responsive means having motion transmitting means connected with and operable to advance the timing mechanism for shortening a valve opening interval when system pressure is in excess of a given level, a mounting plate having said valve means and the timer mechanism secured on one face thereof and said pressure responsive means secured on the opposite face thereof and a housing having fixed walls enclosing said plate and a pair of access doors cooperating with the fixed walls and overlying both faces of said mounting plate.

10. A pressure fluid system controller including a pressure fluid feed valve mechanism, timing mechanism connect-ed with the valve mechanism for cycling the operation thereof, a system pressure responsive mechanism active to override and modify the cycling operation of said valve mechanism by the timing mechanism, a mounting wall having certain of said mechanisms secured on one face thereof and other of said mechanisms secured on the opposite face of the mounting wall, a housing band encirling the wall around its margin and housing doors covering both faces of the wall and being secured independently of one another to said housing band and individually openable for selective access to the mechanisms secured on either face of the wall.

References Cited in the file of this patent UNITED STATES PATENTS 2,251,306 Thompson Aug. 5, 1941 2,550,410 Garrett Apr. 24, 1951 2,638,110 Parks May 12, 1953