US3172425A - Well control system - Google Patents

Description

March 9, 1965 J. B. cox

WELL CONTROL SYSTEM Filed March 22, 1962 m/ 3 w H w I 9 I a m m 0% C 2 m 7 7 M 4 G 5 I I v 5 7 w 5 m m F 1 v8 3 IO 5 I 3 .v 6 8 \O 2 O I O 2 w! c w m I 9 m I I I I l I llI m 5 6 l MW 3 MW 6 4 3 w 4% 1 M I9 W IG V I 2 O 4 H 3 s II NIL 6 0 7 fi 8 1| V Q I] m 4 b 3 fi E TEST FACILITY FIG. I.

JOHN B. COX

INV EN TOR.

TO PIPELINE ATTORNEY.

United States Patent 01 3,172,425 Patented Mar. 9, 1965 ice 3,172,425 WELL CONTROL SYSTEM John B. Cox, Midland, Tex., assignor to Socony Mobil Oil Company, Inc., a corporation of New York Filed Mar. 22, 1962, Ser. No. 181,704 7 Claims. (Cl. 137-610) This invention relates to a system for controlling wells productive of hydrocarbons as by placing them selectively on test or production or shutting them in and has for an object a reliable system applicable for use in automated systems where wells are programed for placement in any one of the three foregoing conditions.

At the present time, control systems are widely used for the automatic production of hydrocarbons from pro ducing fields. In a typical arrangement, a program is established sequentially to test oil wells, to place them on production, and for one reason or another to shut them in. Since the program and associated equipments are electrically powered, provision must be made to take into account possible power failures and thus avoid the necessity manually to reset controls such that there may be reestablished the program existing at the time power was interrupted.

Accordingly, it is a further object of the present invention to provide a well control system with a memory such that upon the occurrence of abnormal conditions in the power supply, such as surges and power failures, there will be provided means automatically for returning each and every well to the condition established for it at the time the power was disrupted and to be effective the moment normal power is restored to the over-all system.

As a safety precaution md further in accordance with the present invention, provision is made to shut in all of the wells upon the occurrence of a power failure.

With these objects in mind, there is provided in accordance with the present invention, a system for selectively applying power to condition-control elements comprising a circuit including two switches. Energizing circuits are provided for operating the switches. A control signal is momentarily applied to operate one of the switches to close a power circuit for applying power to one of the elements. With the operation of the one switch, there is an interruption in the energizing circuit of the other switch. A holding means holds the selected switch in the condition-energized state upon withdrawal of the control signal. The holding means in response to a signal of unique character to release the energized switch for return to its deenergized condition prior to the further selected energization of either of the switches.

In a specific embodiment of the present invention, the holding means is a mechanical latch means responsive to a signal of unique character which can be a signal of predetermined time duration and/or of polarity different from the signals employed to initiate the energization of the switches.

For other objects and attendant advantages of the present invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings wherein:

' FIG. 1 illustrates a well control system embodying the present invention; and

FIG. 2 schematically illustrates one circuit for carrying out the control functions of the present invention.

Referring now to FIG. 1, there is illustrated a typical field installation 10 wherein the outputs from each of the wells 11-14 are selectively directed either to a test facility 15 or to a production gathering line 16. In accordance with the present invention, the selection, or selected operations, of the wells 11-14 is under control of a master station 17 which generates command signals for application to selected ones of the controllers 18-21 by way of a suitable communication channel, here illustrated as a cable 22. The command or master station 17 may be located in the vicinity of the equipment 10' or may be remotely located therefrom.

Each of the controllers 18-21 is coupled respectively to three-way valves 23-26 which are operable selectively to place the wells on test, production, or to shut them in. The coupling is represented by the dashed lines 27-30.

Now, upon proper command signals issuing from the master control station 17, well 11 may be placed on test and wells 12-14 connected so that their outputsflow into a pipe line by way of a production manifold 31, gathering line 16, automatic custody transfer system 32, and a conduit 33. The output from well 11 flows to the test facility 15 by way of valve 23, test manifold 34, and gathering line 35. The output from the test facility is connected by way of line 36 to the input of the automatic custody transfer system 32.

In accordance with the present invention, each of the controllers 18-21 is provided with a memory such that in the event of a power failure and subsequent re-establishment of power the wells will all be returned to the condition established prior to the power failure. Thus, for example, well 11 would be placed on test; and wells 12-14 would again be placed on production. Provision is also made such that upon the failure of power the wells automatically will be shut in and returned to their previous condition of operation, such as, test or production, only when power has been reestablished. All of this is performed automatically without attention required from an operator and in the manner now to be described.

Referring now to FIG. 2, there is illustrated the controller 18 which is effective to control the flow from well 11 by operation of pneumatically operable three-way valve 23. The controller 18 is typical of circuits repre senting one embodiment of the present invention. Controllers 19-21, FIG. 1, may be exact duplicates of the circuit of FIG. 2 except where noted hereinafter. With the various elements in their positions shown in FIG. 2, the well 11 is shut in. The valve 23 is in position to terminate flow from well 11 at the housing of valve 23.

When the well 11 is to be put on test, a conditioncontrol "element 40, illustrated as a solenoid, is energized to operate a valve 41 to direct the flow of compressed air from a source (not shown) for operation of flow control valve 23. The flow of compressed air is by way of conduit 42, a passage 43 within the piston of valve 41, and thence by way of a line 44 to one side or chamber of an actuator 45. A valve stem (not shown) is now adjusted within the housing of valve 23 to direct the'flow of fluids from the well 11 by way of conduit 11a and thence by way of conduit 11b into the manifold 34 of FIG. 1.

On the other hand, should the well be placed on production, then solenoid 40 will be de-energized to complete a flow path to exhaust the air from one side of the chamber 45. Solenoid 50 now will be energized to cause the piston 51 within valve 52 to be raised in order to align the passage 53 within piston 51 with the conduit 54 coupled with the above-mentioned supply of compressed air. Compressed air will now flow to the underside of the chamber 45 by way of conduit 55. A flow of fluids from the well 11 will now be diverted over line 11c and thence into the production manifold 31 for eventual delivery to the pipe line.

Any number of systems can be employed selectively to initiate the controllers 18-21. For example, a direct cable connection may be had between each controller and the central station 17, over which cable can be transmitted any desirable coded intelligence.

' to. carry out the. desiredfiuid control at the well.

. .Such .a system is schematically represented in FIG. 2 wherein a switch 61, enclosed by dashed lines, represents elements of astepping switch responsive to appropriate signals from station 17. In order to place well 11 on test, the operator may operate a code generator or call selector 63 as by manipulating dial 630 to cause armature 60. of stepping switchf61 to engage switch contact a. Signal key 62 is now pressed to apply a positive-going pulse to energize relay 66. The positive-going pulse will be applied by way of the armature 60 of switch 61, rectifier 64, the operating coil 65 of relay 66, and thence to the other side of the generator 63. The generator "63 is energized from a source of A.C. represented by the terminals 67 and 68. The energization of the relay 66 will cause its armature to move up and complete a circuit to energize relay 73. This circuit may be traced from one terminal 67a of a power supply, thence by way of relay contacts 70a, conductor 71, contacts 66a of relay 66, the operating coil 73c of relay 73, and byway of conductor 74 toground. It will be observed that the ground connection is common to the other side of the power supply as represented by terminal 680. The energization of relay 73 will now complete a circuit to operate solenoid or condition-control element 40. This circuit may be traced from the grounded conductor 80, thence by way of the operating coil of the solenoid 40, conductor 3 closed contacts 73b of relay 73, conductor 82,'conductor 83, and thence to the source of power as represented by terminal 67a. a

As thus far described, the well 11 is now on test and will continue in this condition until deliberately caused to change condition by actionat the master station 17 or in'the event of a power failure. In the latter case, provision is made automatically to return the well, upon resumption of power, to the flow condition existing at the time power was interrupted. This function is performed by a memory device; in this instance, a latching means. More particularly, there is associated with the relay 73 a; mechanical latch comprising a latching member 84 which is spring pressed by way of spring 85 to engage the underside of catch 86. The latching means will maintain the relay 73 in its energized condition to be released solely. upon application to the latch of a unique signal generated at the station 17 The circuit arrangement of the present invention provides, in addition tothe memory function, the feature of shutting in allwells upon an interruption of power. For example, should power fail in the system, the condition-control element 40 will immediately be de-energized, causing the piston of valve 41 to drop to its illustrated position, cutting oil the supply of compressed air from vthe source or conduit 42, and venting the upper chamber of element 45 to the atmosphere by way of venting .tubeAIa. The valve 23 is actuated by internal spring biasing to return to its neutral position to shut in the well 11.

Upon re-establishment of power, the well 11 immediately will be placed on test by reason of the circuit memory that is, by reason of relay 73 being latched in an operative condition maintaining closed the energizing circuit for element 40.

It will be observed that with the relay 73 energized there is interrupted as byopening of the relay contacts .73afthe energizing circuit for the relay 70. This avoids "the accidental energization of relay 70 which would, with relay 73 energized, cause the well to be shut in, since compressed air would be placed on both sides of the diaphragm within element 45. The interruption of 4 the energizing circuit of relay 70 when relay 73 energized and Vice versa, as later will be seen, provides for positive action in the control system.

In order to change the flow condition of the well from test to product-ion, it is necessary .to release the mechanical latch to permit the armature of relay 73 to fall and interrupt the energizing circuit for control element t0. This is accomplished in one embodiment oi the present 111- vention by energizing relay 91 to close a circuit to actuate solenoid 87 to retract the arm 84 from latclifii. The energization of relay 91 closes a circuit which may be traced from terminal 67a, then by way of conductor 90, relay contacts 91a, conductor 92, the operating solenoid 87, conductor 93, and thence to the other side of the power supply as represented by the groundconnection; The relay 91 may be energized any number of ways} The particularmanner illustrated employs a circuitresponsive to a signal of unique character different from the signal to which relay 66 responds. More panticularly, a negative pulse is generated at the master control station 17 by depressing the control button 94 which generates a negative-going control signal. The signal is applied to the operating coil of the relay 91 by way of acircuit that may be traced from generator 63, thence by way of armature 60 of stepping switch 61, contact 60c, rectifier 95, relay 91, and conductors96 and 97 to the 'otherside of the generator. While the energizing circuit for relay 91 has beenillustrated having one endconnected to contact 60c, this end can be connected directly to the armature 60 to take advantage of the pulses of dilierent polarity available at the generator 63 and the blocking character istics of rectifiers 64 and which are connected one instance to pass only positive-going pulses in the other instance to passjonly negative going pulses. Other ways possibleltocontroljtherelay 91witl1out ueces= sarily affecting the operation 1 of any of the other relays include the substitution for relay 91 of a relay of the slow-acting type which would respond only to p sitive going pulses-of long duration. On the other. hand, there could be included in series-circuit relation with'the enter"- gizing circuit for the relay 91. a resistance-capacitance network whose time constant is related to the length of the positive signal being generated for operation of the relay 91. 7

Upon energization of the relay 91 and the closure of contacts 91a, the latch will be released and the "armature of relay 73 will now drop 'to open the energizing circuit for element 40. The well control valve 23 will be oper ated to shut in the Well, and at the same time the energiz ing circuitlfor the relay 7tl-is conditioned for energization of relay 70 should it be desired now to place the well on production. This is usually ==the case; and,'in such event, the armature 60 or" switch 61'will be movedto the fixed contact 6% andbutton 62 depressed to apply to theoperating coil of relay 100 by way of rectifier 64a a positivegoing pulse. Relay 160. is now energized to' close its contacts 100a. The relay-70 is now in turn energized by way of a circuit that may be traced from the power supply terminal 67a, conductor 83, relay contacts 73a, conductor 101, closed contacts 100a, theoperating coil 700 of relay 70, conductor 102,"and thence to ground.

The operation of relay 70 will now close an energizing circuit for the condition-control element 50 which will operate its associated valve to cause, compressed air to flow to the underside chamber of'the actuator 45 and thus move the valve 23 to a position to cause the flow of fluids from the well to the production manifold 31, FIG. 1. The energizing circuit for the condition control element 50 may be traced from the power'supply terminal 67a, thence by way of relay contacts 70b, conductor 103, and the operating coil of the condition-control element 50 to ground. The relay 70 is latched by a latching mechanism which includes the latching bar urged against the stem of relay 7% by spring '106 and'eiiga'ging the underside of the catch member 107.

Once again there is a condition wherein a memory is included in the control circuit such that in the event of a power failure all the wells under control will be shut in and the wells later returned to their former condition automatically upon return of power to the system.

It will also be observed that when the relay 70 is energized it interrupts the energizing circuit for the relay 73 as by opening the contacts 70a.

Another feature of the present circuit in adition to its memory is that three functions normally provided by separate control relays are now performed by but two relays. It will be remembered that the relay 73 when energized places a well on test and that the relay 70 when energized places a well on production. Now should it be desired at any time to shut in the well, then a control pulse is applied to energize the relay 91 thereby to release the latch for relay 73 as by energization of the solenoid 87 or to release the latch for the relay 70 as by energization of the solenoid 108. With both relays deenergized, the well automatically goes to a shut-in condition.

Although only one circuit has been illustrated and indeed but one manifold assembly, it will be understood that this particular circuit is well suited for use in, and has been used in, large field installations where all controls may be transmitted from a remote control station by way of a two-wire line.

While the invention has been described in connection with a specific embodiment, it will be understood that modifications will become apparent to those skilled in the art and it is intended to cover all such modifications as fall within the scope of the appended claims.

What is claimed is:

1. A well control system comprising condition-control elements for controlling the flow of fluid from a well, means for selectively applying power to said conditioncontrol elements comprising a circuit including two relays each having a control winding, energizing circuits for said control windings, means for momentarily applying a control signal for selectively energizing the control windings of one of said relays to close a power circuit for applying power to one of the elements, means for opening the enregizing circuit for One relay upon the energization of the selected relay, means for holding the selected relay in the condition-energized state upon withdrawal of said control signal, and means for applying a signal to said holding means to release the selected relay for return to its de-energized state prior to selected energization of either of said relays.

2. The system of claim 1 in which said holding means is responsive to a signal of unique character and different from said control signal for release of said selected relay to its de-energized state.

3. Control system for applying power to a fluid-control valve for directing the flow from a well to test or production or shut in, said system comprising a circuit including two relays each having a control winding, means for selectively energizing the control windings for closing a power circuit to apply power to the control valve, means for holding the power circuit in the closed condition, said holding circuit means being responsive to a signal of unique character for disabling said power circuit, and means for applying said signal of unique character to said means preparatory to selected energization of the other of said relays.

4. An automated oil field comprising a plurality of oil wells each connected by way of a three-way valve to! a well test manifold and to a production manifold, controllers for each of said valves for moving said valves to a first position to connect the wells to said test manifold, to a second position to connect the wells to said production manifold, or to a third position to shut in said wells, each of said controllers including two conditioncontrol elements operatively associated with one valve for moving said valve to any of said three positions, energizing circuits for said elements, a switch in each of said energizing circuits, operating circuits for said switches, means for momentarily applying a control signal for selectively energizing said operating circuits to close one of said switches to apply power to an associated one of said elements, means for maintaining said switch closed, and means for applying a signal to said maintaining means to open said switch prior to the selected later closure of either of said switches.

5. Control means for a norm-ally closed valve actuated to a test position upon energization of a first operator and to a production position upon energization of a second operator which comprises:

(a) a power source,

(b) a first latching relay having a normally open path in circuit between said source and said first operator and a normally closed path,

(c) a second latching relay having a normally open path in circuit between said source and said second operator and a normally closed path,

(d) a first circuit leading from said source including said normally closed path in said first relay and a first normally open control switch for energizing said second relay upon closure of said first control switch,

(e) a second circuit leading from said source including said normally closed path in said second relay and a second normally open control switch for energizing said first relay upon closure of said second control switch,

(f) means for selectively momentarily closing one said control switch to latch one relay, and

(g) a common unlatching circuit leading to both relays.

6. Control means for a normally closed valve actuated to a test position upon energization of a first operator and to a production position upon energization of a second operator which comprises:

(a) a power source,

(b) a first latching relay having a first actuating means,

a latch release, and a normally open path connected in circuit between said source and said first operator,

(0) a second latching relay having a second actuating means, a latch release, and a normally open path connected in circuit between said source and said second operator,

(d) a first circuit leading from said source including a normally closed circuit in said first relay, a normally open control switch, and the actuating means of said second relay,

(2) a second circuit leading from said source including a normally closed circuit in said second relay, a normally open control switch, and the actuating means of said first relay,

(1) means for selectively momentarily closing either said normally open control switch to energize and latch one relay while disabling the other relay, and

(g) a normally open supply circuit including both of the latch releases which, upon closure, unlatches either latched relay.

7. A well control system comprising:

(a) valve means for receiving flow from a well and directing such flow to a production header in response to a first condition or to a test header in response to a second condition,

(12) means for selectively establishing said first condition or said second condition including a pair of control elements and a pair of latching relays each having a coil and at least two circuits therethrough,

(c) a power source,

(d) a first energizing circuit leading to the coil of the first of said relays and including one of said two circuits of the second of said relays in series with a normally open switch,

(e) a second energizing circuit leading from said source to the coil of' the second of said relays andincluding one of said-two circuits of the first of said relays in series with a second normally open switch,

(f) a control circuit lea'ding from said source by way of the second circuit of the first of said'relaysfor said valve to establish said first condition when said first relay coil is energized,

(g) a fourth circuit leading from said source to said valve extending to said valve by way of the second circuit of said second relay for establishing said second conditionwh'en-said second relay coil is en ergized,

(/1) a common circuit leading from saidsource to the latch release means for both of said relays, and

(i) means for selectively closing the first normally open switch, the second normally open switch, or said last-named circuit.

References Cited in the file of this patent UNITED STATES PATENTS 2,225,055 Hoye Dec. 17, 1940 2,716,206 Salati Aug. 23, 1955 2,858,483 Pickels et" a1 Oct. 28, 1958 2,931,954 Diesel Apr. 5, 1960 3,036,229 Kemp et a1. May 22, 1962 3,051,433 7 Dale etal Aug. 28, 1962 Patent No. 3,172,425 March 9, 1965 John B. Cox

It is hereby certified that err ent requiring correction and that th corrected below.

or appears in the above numbered pate said Letters Patent should read as Column 1, line 47, for "in response" read is responsive line 49, for "deenergized" read de-energized column 5, line 9, for "adition" read addition same column 5, line 43, for "enregizing" read energizing Signed and sealed this 27th day of July 1965.

(SEAL) Attest:

ERNEST W. SWIDER' I EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims (1)

1. A WELL CONTROL SYSTEM COMPRISING CONDITION-CONTROL ELEMENTS FOR CONTROLLING THE FLOW OF FLUID FROM A WELL, MEANS FOR SELECTIVELY APPLYING POWER TO SAID CONDITIONCONTROL ELEMENTS COMPRISING A CIRCUIT INCLUDING TWO RELAYS EACH HAVING A CONTROL WINDING, ENERGIZING CIRCUITS FOR SAID CONTROL WINDINGS, MEANS FOR MOMENTARILY APPLYING A CONTROL SIGNAL FOR SELECTIVELY ENERGIZING THE CONTROL WINDINGS OF ONE OF SAID RELAYS TO CLOSE A POWER CIRCUIT FOR APPLYING POWER TO ONE OF THE ELEMENTS, MEANS FOR OPENING THE ENERGIZING CIRCUIT FOR ONE RELAY UPON THE ENERGIZATION OF THE SELECTED RELAY, MEANS FOR HOLDING THE SELECTED RELAY IN THE CONDITION-ENERGIZED STATE UPON WITHDRAWAL OF SAID CONTROL SIGNAL, AND MEANS FOR APPLYING A SIGNAL TO SAID HOLDING MEANS TO RELEASE THE SELECTED RELAY FOR RETURN TO ITS DE-ENERGIZED STATE PRIOR TO SELECTED ENERGIZATION OF EITHER OF SAID RELAYS.

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