Patent Publication Number: US-11047208-B2

Title: Chemical injection system

Description:
BACKGROUND 
     Well systems are deployed downhole to enable a variety of operations related to production of desirable well fluids, e.g. hydrocarbon-based fluids such as oil. Some well systems comprised tubular well strings with chemical injection systems for injecting various chemicals into the wellbore and/or surrounding formation to facilitate production of well fluids. Additionally, well systems may comprise hydraulic actuators used to enable selective actuation of a corresponding device. In well applications, for example, hydraulic actuators may be coupled with a variety of well tools employed in production operations, injection operations, and/or other types of well related operations. Hydraulic fluid is supplied to the downhole actuator under pressure and used to actuate the hydraulic actuator and thus the corresponding well tool. The hydraulic fluid may be supplied via independent hydraulic control lines or other suitable fluid flow passages routed along the well string. 
     SUMMARY 
     In general, a system and methodology are provided for facilitating both actuation of a well tool and chemical injection at a corresponding well zone or well zones. In a multi-zone operation, the well system comprises a plurality of operating modules coupled with corresponding actuators and chemical injection devices, e.g. mandrels. The well system is deployed downhole to a desired location in a borehole, e.g. a wellbore. The operating modules may be selectively shifted via electrical input to enable a desired chemical injection and/or actuation of the actuator (and thus the well tool) at desired well zones. In some embodiments, the operating modules may comprise contingency circuits to enable the chemical injection without electrical input. 
     However, many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and: 
         FIG. 1  is a schematic illustration of an example of a system employing a plurality of operating modules, actuators, and chemical injection devices, according to an embodiment of the disclosure; 
         FIG. 2  is a schematic illustration of an example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; 
         FIG. 3  is a schematic illustration similar to that of  FIG. 2  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 4  is a schematic illustration of another example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; 
         FIG. 5  is a schematic illustration similar to that of  FIG. 4  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 6  is a schematic illustration of another example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; 
         FIG. 7  is a schematic illustration similar to that of  FIG. 6  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 8  is a schematic illustration of another example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; 
         FIG. 9  is a schematic illustration of another example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; 
         FIG. 10  is a schematic illustration similar to that of  FIG. 9  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 11  is a schematic illustration of another example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; 
         FIG. 12  is a schematic illustration similar to that of  FIG. 11  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 13  is a schematic illustration similar to that of  FIG. 11  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 14  is a schematic illustration of another example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; 
         FIG. 15  is a schematic illustration similar to that of  FIG. 14  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 16  is a schematic illustration similar to that of  FIG. 14  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 17  is a schematic illustration of another example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; 
         FIG. 18  is a schematic illustration similar to that of  FIG. 17  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 19  is a schematic illustration of another example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; 
         FIG. 20  is a schematic illustration similar to that of  FIG. 19  but showing the operating module in a different operational position, according to an embodiment of the disclosure; 
         FIG. 21  is a schematic illustration of another example of an operating module coupled with an actuator and chemical injection device, according to an embodiment of the disclosure; and 
         FIG. 22  is a schematic illustration similar to that of  FIG. 21  but showing the operating module in a different operational position, according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
     The disclosure herein generally involves a system and methodology which may be used to facilitate actuation of devices in a variety of well and non-well applications. The technique may be employed to enable both actuation of a well tool and chemical injection at a corresponding well zone or well zones. In a multi-zone operation, the well system comprises a plurality of operating modules comprising or coupled with corresponding actuators and chemical injection devices. The actuators may be part of or coupled with flow control valves or other types of tools. 
     According to an embodiment, the well system is deployed downhole to a desired location in a borehole, e.g. a wellbore. The operating modules may be selectively actuated via electrical input to enable a desired chemical injection and/or actuation of the actuator (and thus the well tool) at desired well zones. In some embodiments, the operating modules may comprise contingency circuits to enable the chemical injection without electrical input. 
     For some downhole applications, an electrically operated module may include a manifold and may be used at each desired well zone to control a chemical injection line so that one chemical injection line may be used for multiple injection points. This electrically operated system may contain electrically operated valves, e.g. solenoid operated valves or proportional valves, to regulate the flow of chemicals. Consequently, a reduction in overall cost may be achieved by reducing the number of control lines running inside the well while enabling an increase in the number of well zones with chemical injection points without facing limits with respect to running out of penetrations at the wellhead or through packers. The system and methodology enable injection of the same chemical in several well zones simultaneously. In some embodiments, the rate of chemical injection may be adjusted on a zone by zone basis to, for example, match a production rate. 
     Referring generally to  FIG. 1 , an example of a system  30  is illustrated as having a plurality of operating module  32  hydraulically coupled with a plurality of corresponding actuator systems  34  and chemical injection systems  36 . As described in greater detail below, each actuator system  34  may comprise a hydraulically shiftable actuator coupled with a corresponding tool and each chemical injection system  36  may comprise a chemical injection mandrel through which chemicals are injected into a corresponding well zone. 
     As illustrated, the actuator systems  34  may be connected with a variety of corresponding devices  38 , e.g. well tools, which are actuated according to signals provide from a control system  40 , e.g. a surface control system. Similarly, the chemical injection systems  36  also may be actuated according to signals provided from control system  40 . By way of example, control system  40  may be a computer-based control system or other processor-based control system programmed to provide the appropriate electrical and hydraulic signals. In the example illustrated, system  30  is a well system and the operating modules  32 , actuator systems  34 , chemical injection systems  36  and tools  38 , e.g. flow control valves, are located in a borehole  42 , e.g. wellbore, extending down into a subterranean geologic formation  44 . However, system  30  may be used in a variety of non-well applications for controlling other types of devices/tools  38 . 
     In the embodiment illustrated, the control system  40  is operatively coupled with the operating modules  32  via an electrical line  46  and hydraulic lines  48  which may include appropriate hydraulic control lines and chemical injection lines for a given well related operation. The control system  40  may be used to operate the plurality of operating modules  32  simultaneously. However, the control system  40  and the operating modules  32  may be constructed for individual actuation of selected operating modules  32  by utilizing control signals that are unique to each operating module  32 . For example, unique electrical signals and/or hydraulic signals may be used to actuate individual operating modules  32  and thus individual devices  38  at specific well zones  45  of a plurality of well zones  45 . 
     Referring generally to  FIG. 2 , an example of one of the operating modules  32  is illustrated. In this embodiment, the operating module  32  is connected with an electric line  46  and hydraulic lines  48  in the form of a close line  50 , an open line  52 , and a chemical injection line  54 . Additionally, the operating module  32  comprises actuator system  34  hydraulically coupled with an actuator  56  of a corresponding tool  38  which in this example may be a flow control valve  58 . The operating module  32  further comprises chemical injection system  36  which may be selectively operated via control system  40  to inject a chemical, e.g. a chemical carrying fluid, through a chemical injection mandrel  60 . 
     By way of example, the actuation system  34  may comprise an electrically operated valve  62  coupled with close line  50 , open line  52 , and electric line  46 . The electrically operated valve  62  also is hydraulically coupled with actuator  56  via hydraulic lines  64 ,  66 . In the illustrated example, the electrically operated valve  62  is in the form of a normally open three way, two position solenoid operated valve  63 . However, other types of electrically actuated valves may be used to control flow of the hydraulic fluid to actuator  56 . 
     When control system  40  actuates valve  62  to an open flow position, hydraulic actuating fluid flows through open line  52 , through valves  62 , and through hydraulic line  66  to shift the actuator  56  in an open direction illustrated by arrow  68 . To move actuator  56  in a close direction, control system  40  directs actuating fluid through close line  50  and hydraulic line  64  to shift the actuator  56  in a close direction opposite to the open direction. 
     The operating module  32  also comprises chemical injection system  36  which includes an electrically operated valve  70  coupled with hydraulic open line  52  and electric line  46 . By way of example, the electrically operated valve  70  may be in the form of a normally closed two-way, two position solenoid operated valve  71 . The electrically operated valve  70  also is coupled with a normally closed pilot operated check valve  72  via a hydraulic connector line  74  which engages a B port of the pilot operated check valve  72  as illustrated. 
     The pilot operated check valve  72  also comprises an A port which is coupled with chemical injection line  54  via a flow control device  76 . By way of example, the flow control device  76  may be a Flosert™ device available from LEE Company of Connecticut, USA. Additionally, the pilot operated check valve  72  is connected to mandrel  60  via a hydraulic connector line  78  coupled with a C port of the pilot operated check valve  72  as illustrated. The chemical injection mandrel  60  may comprise a check valve  80  or a plurality of check valves  80  through which the chemical injection fluid flows before exiting into the surrounding borehole  42  via nozzle  82 . 
     According to an operational example, a chemical injection operation is initiated by pressuring up chemical injection line  54  and open line  52 . An electrical input is then provided to the solenoid operated valve  71  so as to actuate the valve  71 , as illustrated in  FIG. 3 . In other words, the solenoid operated valve  71  is shifted from the position illustrated in  FIG. 2  to the different operational position (actuated position) illustrated in  FIG. 3 . 
     As a result, pressurized hydraulic fluid is able to flow through valve  71 , through hydraulic connector line  74 , and to the normally closed pilot operated check valve  72 . The pressurized hydraulic fluid opens check valve  72  to enable injection of the desired chemical into borehole  42  through mandrel  60  as indicated by arrow  84 . The solenoid operated valve  71  may then be de-energized and the pressure in open line  52  may be decreased to bleed down the open line  52 . 
     To subsequently stop the injection of chemicals, the solenoid operated valve  71  is again actuated to the position illustrated in  FIG. 3 . Because the pressure in open line  52  has been reduced, the trapped volume of fluid in hydraulic connector line  74  is able to bleed out. As the pressure in hydraulic line  74  decreases, the pilot operated check valve  72  closes and the injection of chemicals stops. At this stage, the solenoid operated valve  71  may again be de-energized. It should be noted the electrical and hydraulic inputs may be controlled via control system  40 . The control system  40  also may be operated to energize or de-energize solenoid operated valve  63  to enable desired shifting of actuator  56  and tool  38 . 
     Referring generally to  FIGS. 4 and 5 , another embodiment of operating module  32  is illustrated. In this example, the normally closed pilot operated check valve  72  illustrated in  FIGS. 2, 3  has been replaced by a normally open pilot operated check valve  86 . To initiate a chemical injection operation, chemical injection line  54  is simply pressured up and the pressurized chemical injection fluid flows through the flow control device  76 , through the normally open pilot operated check valve  86 , through check valves  80  of mandrel  60 , and into the surrounding well zone  45  via nozzle  82 . 
     To stop the injection of chemicals, the hydraulic open line  52  is pressured up and the solenoid operated valve  71  is actuated to the position illustrated in  FIG. 5 . The pressurized actuating fluid in open line  52  is then able to flow through solenoid operated valve  71 , through hydraulic connector line  74 , and into the pilot operated check valve  86  to close the pilot operated check valve  86 . Once the pilot operated check valve  86  is closed, the solenoid operated valve  71  may be de-energized to trap the pressurized fluid in hydraulic connector line  74  and to thus maintain the pilot operated check valve  86  in the closed position. Subsequently, the pressurized fluid in hydraulic open line  52  may be bled off. The actuator system  34  may be controlled as described above. 
     Referring generally to  FIGS. 6 and 7 , another embodiment of operating module  32  is illustrated. In this example, the normally closed pilot operated check valve  72  is again employed in the chemical injection circuit. In this embodiment, however, the electrically operated valve  70 , e.g. solenoid operated valve  71 , is coupled directly with the chemical injection line  54 . 
     According to an operational example, an injection operation may be initiated by pressuring up chemical injection line  54  to a suitable actuation pressure. The solenoid operated valve  71  is then actuated to the position illustrated in  FIG. 7 . This allows the pressurized chemical injection fluid to flow through solenoid operated valve  71 , through connector hydraulic line  74 , and to the normally closed pilot operated check valve  72 , thus opening check valve  72 . Once check valve  72  is in an open flow position, chemical injection fluid is able to flow through mandrel  60  and into the corresponding well zone  45  as indicated by flow arrow  84 . The solenoid operated valve  71  may then be de-energized and the pressure of the chemical injection fluid in chemical injection line  54  may be adjusted to a desired pressure level to provide a desired flow through mandrel  60 . 
     To stop the injection procedure, the pressure in chemical injection line  54  is reduced to bleed the chemical injection line  54  and to thus stop the injection of fluid. The solenoid operated valve  71  may then be actuated to bleed out fluid trapped in hydraulic connector line  74 . This will effectively close the normally closed pilot operated check valve  72  and prevent any further flow of injection fluid therethrough. The solenoid operated valve  71  may then be de-energized and thus transitioned to the position illustrated in  FIG. 6 . 
     Referring generally to  FIG. 8 , another embodiment of operating module  32  is illustrated. In this example, the circuit configuration of operating module  32  is similar to that illustrated in  FIGS. 6 and 7 . However, the normally closed pilot operated check valve  72  illustrated in  FIGS. 6, 7  has been replaced by the normally open pilot operated check valve  86 . To initiate a chemical injection operation, chemical injection line  54  is simply pressured up and the pressurized chemical injection fluid flows through the flow control device  76 , through the normally open pilot operated check valve  86 , through check valves  80  of mandrel  60 , and into the surrounding well zone  45  via nozzle  82 . 
     To stop the injection of chemicals, the solenoid operated valve  71  is actuated to a flow-through position. The pressurized chemical injection fluid is then able to flow through solenoid operated valve  71 , through hydraulic connector line  74 , and into the pilot operated check valve  86  to close the pilot operated check valve  86 . Once the pilot operated check valve  86  is closed, the solenoid operated valve  71  may be de-energized to trap the pressurized fluid in hydraulic connector line  74  and to thus maintain the pilot operated check valve  86  in the closed position. Again, the actuator system  34  may be controlled as described above. 
     Referring generally to  FIGS. 9 and 10 , another example of operating module  32  is illustrated. In this embodiment, the chemical injection system  36  comprises a contingency circuit  88  to enable injection of the desired chemical or chemicals without electrical power. For example, the contingency circuit  88  enables chemical injection in the event electrical power is interrupted or no longer available. 
     In this example, the contingency circuit  88  is combined with a chemical injection circuit similar to that illustrated in  FIGS. 2 and 3 . The contingency circuit  88  comprises hydraulic connector lines  90 ,  92  coupled with close line  50  and open line  52 , respectively. The hydraulic connector lines  90 ,  92  also are coupled with corresponding ports B, C of a normally open pilot operated check valve  94 . Additionally, a port A of the pilot operated check valve  94  is coupled with a hydraulic connector line  96  which is in fluid communication with hydraulic connector line  74 . 
     According to an operational example in which contingency circuit  88  is utilized, the chemical injection may be stopped without electrical input by pressuring up close line  50 . The increased pressure in close line  50  causes the pilot operated check valve  94  to stay in an open position thus allowing bleeding of trapped pressure through open hydraulic line  52 . Consequently, the pilot operated check valve  72  closes and the injection of fluid is stopped. The close line  50  may then be bled to cause closure of the pilot operated check valve  94 . 
     Contingency injection (without electrical power) may then be initiated when open line  52  is pressured up and the flow of pressurized actuating fluid moves through pilot operated check valve  94 , hydraulic connector line  96 , hydraulic connector line  74 , and to pilot operated check valve  72 , thus opening check valve  72 . Once the check valve  72  is in an open flow position, the chemical injection line  54  may be pressured up to initiate injection of the desired chemical or chemicals through nozzle  82  (see arrow  84  in  FIG. 10 ). Closure of check valve  94  by bleeding off pressure effectively traps pressurized fluid in hydraulic connector lines  96 ,  74  and maintains pilot operated check valve  72  in an open position for injection of chemicals. 
     Referring generally to  FIGS. 11, 12 and 13 , another example of operating module  32  is illustrated. In this embodiment, the operating module comprises an electrically controlled flow circuit similar to that illustrated and described above with reference to  FIGS. 4 and 5 . However, the contingency circuit  88  has been added. The contingency circuit  88  may be used to stop and start chemical injection flow when electricity is not available. 
     According to an operational example, chemical injection in the contingency mode may be stopped by pressuring up open line  52  and flowing the pressurized actuating fluid through check valve  94 . This ensures the pressure in hydraulic connector lines  96 ,  74  increases to close the pilot operated check valve  86  and to stop further chemical injection, as illustrated in  FIG. 12 . The pilot operated check valve  94  may then be allowed to close so as to maintain a trapped, increased pressure in hydraulic connector lines  96 ,  74 . The trapped, increased pressure maintains the pilot operated check valve  86  in a closed position which prevents injection of chemicals. 
     To initiate injection of chemicals via mandrel  60  in the contingency mode, the close line  50  is pressured up sufficiently to open pilot operated check valve  94 . The fluid trapped under increased pressure in hydraulic connector lines  96 ,  74  is then allowed to bleed off through de-pressurized open line  52 . This allows the pilot operated check valve  86  to open under the pressure of injection fluid supplied via chemical injection line  54 . Once the injection of chemicals through nozzle  82  is underway, as indicated by arrow  84  in  FIG. 13 , the pressure in close line  50  may be bled off. As with other embodiments including contingency circuit  88 , chemical injection may be initiated and stopped even if electric line  46  is damaged or electrical power is otherwise unavailable to operate valve  70 . In normal operations, the operating module  32  may be electrically operated to provide the desired chemical injection and/or shifting of actuator  56 . However, the contingency circuit  88  enables control over injection even if electrical power becomes unavailable. 
     Referring generally to  FIGS. 14, 15 and 16 , another example of operating module  32  is illustrated. In this embodiment, the chemical injection system  36  comprises a pair of normally closed pilot operated check valves  72  in fluid communication with flow control device  76  and manifold  60 . One of the check valves  72  also is in fluid communication with close line  50  and the other check valve  72  may be placed in fluid communication with open line  52  across electronically actuated valve  70  and across a check valve  96 . Check valve  96  is coupled across the electronically actuated valve  70 , e.g. across the normally closed two-way, two position solenoid operated valve  71 . 
     According to an operational example, chemical injection may be initiated by pressuring up chemical injection line  54  and then open line  52 . An appropriate electrical signal is then provided to actuate solenoid operated valve  71 , as illustrated in  FIG. 15 . The higher pressure fluid flowing through valve  71  opens the lower illustrated pilot operated check valve  72  so that chemicals may flow through mandrel  60  for injection into the corresponding well zone. The solenoid operated valve  71  may then be de-energized while pressure is maintained in open line  52 . 
     To stop the chemical injection, the pressure in open line  52  is bled off. As a result, the pressure acting to open the lower illustrated pilot operated check valve  72  is released through check valve  96 . This allows the lower illustrated pilot operated check valve  72  to close and prevent further injection of the chemical injection fluid. 
     In this embodiment, the contingency circuit  88  is effectively provided by the upper illustrated pilot operated check valve  72 . To begin injection without electrical power, the close line  50  is pressured up and the resulting higher pressure fluid is supplied to the upper illustrated pilot operated check valve  72  via hydraulic line  98 , as illustrated in  FIG. 16 . While pressure in close line  50  maintains the upper illustrated pilot operated check valve  72  in the open position, the desired chemical or chemicals may be delivered therethrough for injection to the desired well zone. The chemical injection may be stopped simply by bleeding off the pressure in close line  50 , thus allowing the upper illustrated pilot operated check valve  72  to transition to the closed position blocking further flow of chemical injection fluid. 
     Referring generally to  FIGS. 17 and 18 , another example of operating module  32  is illustrated. In this embodiment, the operating module comprises an electrically controlled flow circuit similar to that illustrated and described above with reference to  FIGS. 2 and 3 . However, the contingency circuit  88  employs a sequence valve  100  having four ports A, B, C, D. When electrical power is available via electric line  46 , the operating module  32  functions similar to that described above with respect to the embodiment illustrated in  FIGS. 2 and 3  enabling independent operation of chemical injection and movement of actuator  56 /flow control valve  58 . 
     When electrical power is interrupted, however, the contingency mode may be employed to enable control over chemical injection by pressuring up the close line  50  while bleeding the open line  52 . The differing pressures in close line  50  and open line  52  act on ports B, C, D to shift the sequence valve  100  to an open position. In the open position, the trapped fluid in hydraulic connector lines  96 ,  74  may be bled through the low pressure open line  52  so as to stop the chemical injection. 
     To resume chemical injection, a higher pressure is applied to the fluid in open line  52  and this higher pressure fluid is able to move through sequence valve  100  and out of port A so as to once again pressure up hydraulic connector lines  96 ,  74 . The higher pressure in connector lines  96 ,  74  opens the pilot operated check valve  72  so that the injection of chemicals through check valve  72  and manifold  60  may be resumed as illustrated in  FIG. 18 . Once the desired chemical injection is established, the close line  50  and open line  52  may be bled while sequence valve  100  maintains pressure in connector lines  96 ,  74 . At this stage, independent operation of the actuator  56 /flow control valve  58  may be resumed. 
     Referring generally to  FIGS. 19 and 20 , another example of operating module  32  is illustrated. In this embodiment, the operating module comprises an electrically controlled flow circuit similar to that illustrated and described above with reference to  FIGS. 6 and 7 . However, the contingency circuit  88  employs sequence valve  100 . When electrical power is available via electric line  46 , the operating module  32  functions similar to that described above with respect to the embodiment illustrated in  FIGS. 6 and 7  enabling independent operation with respect to chemical injection and movement of actuator  56 /flow control valve  58 . As with certain other embodiments described herein, the sequence valve  100  may be closed to enable independent actuation of actuator  56 . 
     When electrical power is interrupted, however, the contingency mode may be employed to enable control over chemical injection. To stop the chemical injection, the chemical injection line  54  may be bled. Subsequently, close line  50  is pressured up to an appropriate pressure level while the open line  52  is bled. The action of pressuring close line  50  and bleeding open line  52  causes sequence valve  100  to open so the trapped volume of fluid in hydraulic connector lines  96 ,  74  may be bled through sequence valve  100  and chemical injection line  54 . The consequent reduction of pressure in hydraulic connector lines  96 ,  74  closes the pilot operated check valve  72  so as to prevent any further injection of chemicals. 
     To resume injection of chemicals through mandrel  60 , the chemical injection line  54  and close line  50  are pressured up which, in turn, opens the sequence valve  100  to enable application of the higher pressure in hydraulic connector lines  96 ,  74 . As a result, the pilot operated check valve  72  opens once again to enable flow of chemical injection fluid therethrough and ultimately out through nozzle  82  as indicated by arrow  84  in  FIG. 20 . Subsequently, the pressure in close line  50  may be bled to enable closure of sequence valve  100  so as to trap the higher pressure fluid in hydraulic connector lines  96 ,  74 . This higher pressure maintains pilot operated check valve  72  in an open flow configuration for continued flow of the injection chemical(s). 
     Referring generally to  FIGS. 21 and 22 , another example of operating module  32  is illustrated. In this embodiment, the operating module comprises an electrically controlled flow circuit similar to that illustrated and described above with reference to  FIGS. 6 and 7 . However, the contingency circuit  88  employs sequence valve  100  in combination with a dedicated contingency hydraulic line  102 . When electrical power is available via electric line  46 , the operating module  32  functions similar to that described above with respect to the embodiment illustrated in  FIGS. 6 and 7  enabling independent operation of chemical injection and movement of actuator  56 /flow control valve  58 . As with certain other embodiments described herein, the sequence valve  100  may be closed to enable independent actuation of actuator  56 . 
     When electrical power is interrupted, however, the contingency mode may be employed to enable control over chemical injection. To stop the chemical injection, the contingency hydraulic line  102  is pressured up to open sequence valve  100  so the trapped volume of fluid in hydraulic connector lines  96 ,  74  may be bled through sequence valve  100  and close line  50 . The consequent reduction of pressure in hydraulic connector lines  96 ,  74  closes the pilot operated check valve  72  so as to prevent any further injection of chemicals. 
     To resume injection of chemicals through mandrel  60 , the chemical injection line  54  and contingency line  102  are pressured up which, in turn, opens the sequence valve  100  to enable application of the higher pressure in hydraulic connector lines  96 ,  74 . As a result, the pilot operated check valve  72  opens once again to enable flow of chemical injection fluid therethrough and ultimately out through nozzle  82  as indicated by arrow  84  in  FIG. 22 . Subsequently, the pressure in contingency line  102  may be bled to enable closure of sequence valve  100  so as to trap the higher pressure fluid in hydraulic connector lines  96 ,  74 . This higher pressure maintains pilot operated check valve  72  in an open flow configuration for continued flow of the injection chemical(s) and independent operation of actuator  56 . 
     The overall system  30  may have a variety of components and configurations. For example, system  30  may be constructed as a well system comprising numerous types of well components, e.g. completion components, for use in a variety of well environments. Additionally, various numbers of operating modules  32 , hydraulic actuation systems  34 , chemical injection systems  36 , and actuatable devices  38 , e.g. flow control valves, may be used along various types of tubing strings in well applications and non-well applications. 
     Similarly, various hydraulic circuit layouts may be used in actuation systems  34  and chemical injection systems  36 . The actuation system  34  and chemical injection system  36  may be arranged in separate modules or combined in single modules for use in controlled chemical injection applications and/or actuator positioning applications. Similarly, various types of valves  62 ,  70 , pilot operated check valves, check valves, flow passageways, and other flow components may be used in the actuation system  34  and chemical injection system  36  of each operating module  32 . The electric line  46  and the hydraulic lines, e.g. hydraulic lines  50 ,  52 ,  54 ,  102 , may be routed along tubing strings or other equipment in various patterns and forms able to deliver the appropriate electric signals, hydraulic signals, and chemical injection fluids. In some applications, the electric line and/or hydraulic lines may be incorporated into well equipment to provide a signal path along the interior or within the walls of the well equipment. In other applications, the electric line and/or hydraulic lines may be combined in a cable routed downhole and coupled with the one or more operating modules  32 . 
     Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.