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CROSS-REFERENCE TO RELATED APPLICATION 
     The present document is based on and claims priority to U.S. Provisional Application Ser. No. 61/478,257 filed Apr. 22, 2011, incorporated herein by reference. 
    
    
     BACKGROUND 
     Hydrocarbon fluids, e.g. oil and natural gas, are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore is drilled, various forms of well completion components may be installed to control and enhance the efficiency of producing fluids from the reservoir. In some applications, for example, a formation isolation valve (FIV) may be used to isolate the formation or portions of the formation. Such a valve may be run in a sand face completion. 
     Formation isolation valves generally are actuated to a closed position with a shifting tool after run-in of a sand face completion and then opened through a subsequent operation, e.g. an intervention operation. In some applications the subsequent operation may be an interventionless operation, but existing interventionless operations are relatively time-consuming and expensive. For example, certain existing systems enable opening of the formation isolation valve via tubing pressure cycles with liquid in the tubing. Generally, the density of the fluid above the closed valve is such that the hydrostatic pressure of the fluid column above the closed valve is lower than the formation pressure below the valve. This is done to allow the information to flow naturally after the valve is opened to put the well on production. However, in a well drilled and completed in a depleted formation the formation pressure below the valve may be lower than the hydrostatic pressure from the fluid column above the valve. To allow the well to start production in this type of situation, the fluid column above the closed valve is displaced partially or fully with nitrogen gas. After the valve is opened, the gas pressure is bled off to reduce the pressure to a level below the formation pressure so the well can start flowing. However, the nitrogen in the tubing can inhibit the effectiveness of the cycles and also can require substantial amounts of time to open the formation isolation valve. 
     SUMMARY 
     In general, the present disclosure provides a technique for actuating a downhole tool, such as a valve, in a simple, rapid, and cost-effective manner. The technique comprises installing the downhole tool with a trip saver. The trip saver can be actuated by increasing a pressure, e.g. a tubing pressure, beyond a threshold level. Once the trip saver is actuated, a fluid under suitable pressure is provided to a downhole tool through a passageway opened via the trip saver. This enables actuation of the downhole tool, e.g. valve, to a desired state. 
    
    
     
       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 only the various implementations described herein and are not meant to limit the scope of various technologies described herein, and: 
         FIG. 1  is a partial cross-sectional illustration of a completion system including a valve with a trip saver module, according to an embodiment of the disclosure; 
         FIG. 2  is a partial cross-sectional illustration of a valve with trip saver module, according to an embodiment of the disclosure; 
         FIG. 3  is a schematic illustration of the operation of a valve and trip saver module configured to open upon pressuring up the tubing, according to an embodiment of the disclosure; 
         FIG. 4  is a schematic illustration similar to that of  FIG. 3  but in a different operational position, according to an embodiment of the disclosure; 
         FIG. 5  is a schematic illustration of the operation of a valve and trip saver module configured to open upon pressure bleed off of the tubing, according to an embodiment of the disclosure; 
         FIG. 6  is a schematic illustration similar to that of  FIG. 5  but in a different operational position, according to an embodiment of the disclosure; 
         FIG. 7  is a schematic illustration of the operation of a valve and trip saver module configured to open upon pressure bleed off of the tubing and showing the actuation of the valve, according to an embodiment of the disclosure; 
         FIG. 8  is a schematic illustration of the operation of a valve and trip saver module configured to use an indexing trigger device set to actuate upon a predetermined number of tubing pressure cycles, according to an embodiment of the disclosure; 
         FIG. 9  is a schematic illustration similar to that of  FIG. 8  but in a different operational position, according to an embodiment of the disclosure; 
         FIG. 10  is a schematic illustration of the operation of a valve and trip saver module configured to use an indexing trigger device set to actuate upon a predetermined number of tubing pressure cycles and showing the actuation of the valve, according to an embodiment of the disclosure; 
         FIG. 11  is a schematic illustration of the operation of a valve and trip saver module configured to use either an indexing trigger device set to actuate upon a predetermined number of tubing pressure cycles or an electronic trigger device set to actuate upon a tubing pressure signal, according to an embodiment of the disclosure; and 
         FIG. 12  is a schematic illustration of the operation of a valve and trip saver module configured to use either an indexing trigger device set to actuate upon a predetermined number of tubing pressure cycles or an electronic trigger device set to actuate upon a tubing pressure signal and showing the actuation of the valve due to the indexing trigger device, according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, numerous details are set forth to provide an understanding of some illustrative embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the present disclosure may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
     The disclosure herein generally relates to well completion installation systems, and more particularly to a completion system comprising a downhole tool, e.g. a formation isolation valve, having an actuator that is operable via a rupture member, e.g. a rupture disc. Various embodiments of the concepts presented herein may be applied to a wide range of applications and fields, including many types of downhole applications. 
     Referring generally to  FIG. 1 , an embodiment of a well system  20  is illustrated as comprising a completion  22  deployed in a wellbore  24  via tubing  26 , e.g. production tubing or coiled tubing. Completion  22  may include a wide variety of components, depending in part on the specific application, geological characteristics, and well type. In the example illustrated, the wellbore  24  is substantially vertical and lined with a casing  28 . However, various embodiments of completion  22  may be used in a well system having many types of wellbores, including deviated, e.g. horizontal, single bore, multilateral, single zone, multi-zone, cased, uncased (open bore), or other types of wellbores. 
     The illustrated completion  22  is designed to facilitate production of a desired fluid, e.g. a hydrocarbon-based fluid, from a formation  30  surrounding the wellbore  24  to a surface  32 . The completion  22  comprises a downhole tool  34  which may be actuated without intervention via the aid of a trip saver module  36  which is a remote operation module. In the specific example illustrated, downhole tool  34  comprises a valve  38 , e.g. a formation isolation valve, constructed with trip saver module  36 . However, completion  22  may comprise many other types of components, including additional formation isolation valves  38 . 
     By way of example, the completion  22  may comprise an upper completion  40  and a lower completion  42  although some applications utilize a combined, single trip completion. The upper completion  40  may comprise a packer  44  and tubing  26  as well as a variety of other components, including sensors and valves, e.g. flow control valves and safety valves. The specific selection of components depends on the application of overall well system  20 . Similarly, the lower completion  42  may comprise many types of components, such as a screen hangar packer  46  and valve  38  with trip saver module  36 . The lower completion  42  also may include a variety of other components, including screens, inflow control devices, additional formation isolation valves, additional packers, sensors, and other components, depending on the specific application of overall well system  20 . In this example, the lower completion  42  is initially run in hole prior to running of the upper completion  40  downhole into engagement with the lower completion  42 . 
     Referring generally to  FIG. 2 , a partial cross-sectional sectional enlargement of the valve  38 , along with its trip saver module  36 , is illustrated. In this example, the valve  38  comprises a valve member  48  operated by an actuator  50  coupled to the trip saver module  36 . The valve member  48  is illustrated as a ball valve type of valve element, but other types of valve elements, e.g. sliding sleeves, can be used in valve  38 . The trip saver module  36  is configured to remotely open the valve  38  in response to signals sent from the surface  32  of the well system  20 . 
     One form of signals may comprise changes in pressure delivered downhole through, for example, tubing  26 . The changes in pressure may be increases in pressure or decreases in pressure, i.e. bleeding off pressure. In some applications, the pressure signals may comprise various cycles of increased and decreased tubing pressure. In other applications, the signals may comprise changes in tubing pressure corresponding to timing, e.g. set patterns of signals, specific frequency signals, or patterns of spacing between pressure pulses. The signals also may comprise changes in tubing pressure corresponding to magnitude, e.g. set patterns of signal pressure magnitudes or specific levels of pressure changes. Upon receiving a single pressure pulse of sufficient magnitude, for example, the trip saver module  36  may be actuated to open the valve  38 , e.g. a formation isolation valve, via actuator  50 . However, other types of signals, e.g. electric signals, also may be used and delivered downhole to, for example, an electronic trigger device. 
     Referring generally to  FIGS. 3 and 4 , a schematic illustration is provided of an example of a valve  38  comprising an embodiment of trip saver module  36 . In this example, the valve member  48  of valve  38  is operated by actuator  50  which comprises a piston  52  slidably received in a chamber or cylinder  54 . The chambers of cylinder  54  on both sides of the piston  52  are at atmospheric pressure. Those atmospheric chambers acting on opposite sides of piston  52  are in communication with each other via hydraulic lines  56 ,  58  and a chamber  80 . A pressure increase in the atmospheric chambers, e.g. due to seal damage, is the same on both sides of the piston  52  to prevent accidental opening or actuating of the valve  38 . The piston  52  may be driven back and forth by a hydraulic pressure applied through hydraulic lines  56 ,  58 , respectively. The hydraulic lines  56 ,  58  are coupled with the trip saver module  36  of valve  38 . 
     In the embodiment illustrated, trip saver module  36  comprises an actuation component  60  coupled to formation pressure via, for example, a passageway  62 . The actuation component  60  may comprise a compensating piston  64  and a liquid chamber  66 , e.g. an oil chamber, filled with a suitable liquid  68 , e.g. oil. The trip saver module  36  further comprises a trip saver component  70  coupled to tubing pressure via, for example, a passageway  72 . The tubing pressure is directed down through tubing  26 . It should be noted that the different pressures, e.g. first and second pressures, acting on actuation component  60  and on trip saver component  70  may be created at different pressure regions along wellbore  24 . The pressure also may be directed downhole along various combinations of regions internal and external to tubing  26 . The trip saver component  70  may comprise at least one rupture member  74  and a pressure isolation piston  76  slidably retained within, for example, a valve block  78 . In some embodiments, a plug having seals can be held in position with a shear member, e.g. shear pins, and can be used in place of the rupture disc. Initially, the pressure isolation piston  76  may be retained at a predetermined position within the chamber or cylinder  80  of valve block  78  by a shear member  82 , such as a shear pin. In the specific example illustrated, the trip saver component  70  utilizes a pair of rupture members  74  in the form of rupture discs. 
       FIG. 3  illustrates valve  38  and its trip saver module  36  in an initial state prior to rupturing of rupture members  74 . In this state, actuating component  60  is coupled to formation pressure through passageway  62  via compensating piston  64  and oil chamber  66 . The compensating piston  64  and oil chamber  66  help prevent contamination of the operating fluid  68 , e.g. hydraulic fluid, used to actuate valve  38 . 
     When sufficient pressure is applied through the tubing  26  or through another suitable passage, the pressure threshold of rupture discs  74  is exceeded and the rupture discs are burst. This allows the tubing pressure to operatively interact with pressure isolation piston  76 , as illustrated in  FIG. 4 . The pressure shifts pressure isolation piston  76  to the right, as illustrated in  FIG. 4 , and shears the shear member  82 . After shearing the shear member  82 , pressure isolation piston  76  continues to shift within the valve block  78  until fluid communication is established between oil chamber  66  and one side of piston  52  of actuator  50 , as represented by arrows  84 . The formation pressure moves compensating piston  64  and forces fluid  68  through valve block  78  and along hydraulic line  58  to shift piston  52  and actuator  50 , as represented by arrows  86 . 
     As a result of the fluid communication into chamber  54  under formation pressure, the formation isolation valve  38  is actuated via actuator  50  to, for example, an open position. Opening the valve member  48  of valve  38  establishes fluid communication between formation  30  and production tubing  26 . Although the compensating piston  64  is illustrated as reacting to formation pressure to actuate the valve  38 , other forces may be employed to actuate the valve  38  once the threshold pressure of the tubing  26 /rupture discs  74  is passed. In some cases, for example, resilient force devices such as mechanical or gas springs may be used to move the compensating piston  64  once the pressure isolation piston  76  is translated from its initial position. The actuation component  60  and the pressure isolation piston  76  provide a primary and secondary redundancy to ensure proper actuation of tool  34 . However, various types of similar or dissimilar devices can be used to provide the desired actuation and/or redundancy. It should be noted that two or more similar devices, e.g. two pressure isolation piston  76 , may be used in a variety of ways to provide primary and secondary actuation mechanisms for redundancy. For example, a pair of pressure isolation pistons  76  may be used in which one of the pressure isolation pistons is coupled to a rupture disc and the other pressure isolation piston is coupled to an electronic trigger device. The electronic trigger device is designed to move the other pressure isolation piston  76  upon receipt of a predetermined signal transmitted downhole. 
     Referring generally to  FIGS. 5-7 , another embodiment of the valve  38  and its trip saver module  36  is illustrated. In this embodiment, the trip saver module  36  is designed to actuate the valve  38  to, for example, an open flow position when pressure is bled off within tubing  26 . It should be noted that many of the components described below are similar to or the same as components described in the embodiment illustrated in  FIGS. 3-4 , and those components have been labeled throughout this description with the same reference numerals. 
     As illustrated in  FIG. 5 , one or more rupture discs  74  again initially block tubing pressure from reaching pressure isolation piston  76 , and pressure isolation piston  76  is held in place by shear member  82 . Upon reaching and/or passing the threshold tubing pressure, the one or more rupture discs  74  in the valve block  78  are burst, thus allowing the tubing pressure to exert a force against the pressure isolation piston  76 . The tubing pressure is at a sufficient level to break shear member  82 , thus allowing an initial movement of pressure isolation piston  76  to the right, as illustrated in  FIG. 6 . However, this initial movement of the pressure isolation piston does not establish a communicative fluid pathway between the oil chamber  66  and one side of piston  52  of actuator  50 . 
     The pressure isolation piston  76  remains at this position until a bleed off of tubing pressure occurs. As the tubing pressure is bled off, a resilient member  88 , e.g. a spring or other form of resilient device, biases the pressure isolation piston  76  in an opposite, e.g. leftward, direction, as illustrated in  FIG. 7 . The pressure isolation piston  76  continues to translate in this opposite direction within the valve block  78  until a fluid pathway is established between the oil chamber  66  and one side of piston  52 , as represented by arrows  90 . Consequently, the actuator  50  is moved to open (or otherwise actuate) the valve  38  under the pressure of liquid  68 . Liquid  68  is again acted on by compensating piston  64  which moves as a result of the formation pressure or other suitable pressure. One advantage of such a system is that tubing pressure is removed from one side of the valve  38  prior to opening the valve. This provides the ability to prevent or inhibit a fluid shock from being delivered to the formation upon the opening of the valve  38 . 
     Referring generally to  FIGS. 8-10 , another embodiment of the valve  38  and its trip saver module  36  is illustrated. In this embodiment, the trip saver module  36  is designed to utilize an indexing trigger device  92  which is set to actuate upon a predetermined number of tubing pressure cycles. In the illustrated example, the indexing trigger device  92  is part of trip saver component  70  and is exposed to tubing pressure via passageway  72 . The indexing trigger device  92  may be used to initially hold pressure isolation piston  76  instead of using shear member  82 , as illustrated in  FIG. 8 . 
       FIG. 8  illustrates valve  38  and its trip saver module  36  in an initial state prior to rupturing of rupture members  74 . In this state, actuating component  60  is coupled to formation pressure through passageway  62  via compensating piston  64  and oil chamber  66 . When sufficient pressure is applied through the tubing  26  or through another suitable passage, the pressure threshold of rupture discs  74  is exceeded and the rupture discs are burst. This allows the tubing pressure to operatively interact with indexing trigger device  92 . Consequently, translation of the pressure isolation piston  76  to move the actuator  50  occurs after first increasing pressure to a certain threshold level followed by a series of low pressure cycles directed through tubing coupled to the well completion. 
     The indexing trigger device  92  may be constructed in a variety of forms and may comprise, for example, J-slots through which the device transitions upon successive increases and decreases of pressure in tubing  26 . In some applications, the indexing trigger device  92  may be similar to a device described and published in US Patent Publication US2009/02421999A1 entitled “Systems and Techniques to Actuate Isolation Valves”. However, the indexing trigger device may comprise a variety of components  94 ,  96 ,  98  to achieve desired functions. By way of example, component  96  may comprise an indexing piston mechanism acting against a spring member  98 . In the embodiment illustrated, the right side of indexing piston mechanism  96  is in communication with the oil chamber  66  and thus with formation pressure. 
     After the initial bursting of the rupture discs  74 , the tubing pressure may be cycled relative to the formation pressure to cause back and forth translation of the indexing piston mechanism  96  of indexing trigger device  92 , as represented by arrow  100  in  FIG. 9 . As the indexing piston mechanism  96  is translated, pins (not shown) may travel along a pathway, e.g. a J-slot pathway, counting the number of relative pressure cycles. When the predetermined number of pressure cycles is reached, a longer slot or pathway, e.g. a longer J-slot, is accessed to permit the rightward movement of the indexing piston mechanism  96 . The rightward movement causes a corresponding movement of pressure isolation piston  76 , as illustrated in  FIG. 10 . After shifting pressure isolation piston  76 , fluid communication is established between oil chamber  66  and one side of piston  52  of actuator  50 , as represented by arrows  102 . The formation pressure moves compensating piston  64  and forces fluid  68  through valve block  78  and along hydraulic line  58  to shift piston  52  and actuator  50 , as represented by arrows  86 . 
     As a result of the fluid communication into chamber  54  under formation pressure, the valve  38  is actuated via actuator  50  to, for example, an open position. Opening the valve member  48  of valve  38  again establishes fluid communication between formation  30  and production tubing  26 . When using the indexing trigger device  92 , the cycle count of the indexing system may be isolated from random fluctuations of tubing pressure during completion operations and other well related operations. Only after application of the threshold pressure to break rupture discs  74  is the indexing trigger device  92  able to react to tubing pressure cycles. 
     Referring generally to  FIGS. 11 and 12 , another embodiment of the valve  38  is illustrated. In this example, the trip saver module  36  comprises an embodiment of the trip saver component  70  having both the indexing trigger device  92  and an electronic trigger device  104 . The indexing trigger device  92  and the electronic trigger device  104  provide redundancy and each system cooperates with its own pressure isolation piston  76 . For example, the system may be designed to actuate the valve  38  based on either the indexing trigger device  92 , set to actuate upon a predetermined number of tubing pressure cycles, or the electronic trigger device  104 , set to actuate upon a tubing pressure signal. 
     The indexing trigger device  92  may be designed to operate in a manner similar to that described above with reference to  FIGS. 8-10 . Upon actuation of the indexing trigger device  92  from its initial position (illustrated in  FIG. 11 ) to its rightmost position (illustrated in  FIG. 12 ), liquid from liquid chamber  66  moves a shuttle piston  106  to a position which isolates the lower portion of the valve block  78  containing electronic trigger device  104  and its corresponding pressure isolation piston  76 . This allows the portion of trip saver component  70  containing indexing trigger device  92  to control movement of actuator  50  and actuation of valve  38 . 
     However, in the event of failure of the indexing trigger device  92  or if the tubing pressure cannot reach the necessary threshold level, the electronic trigger device  104  may be used to actuate the valve  38 . It should be noted that electronic trigger device  104  also can be used on its own or as the primary trip saver device in trip saver component  70  instead of serving as a redundant system. Regardless, the electronic trigger device  104  may be designed to use a pressure sensor  108  which detects the sending of a predetermined signal via tubing pressure within tubing  26 . The signal may comprise time-based, magnitude-based, or other suitable signals detectable by the electronic trigger device  104 . 
     The design of electronic trigger device  104  may vary depending on the parameters of a given application. According to one example, the electronic trigger device  104  comprises a power source  110  which may be in the form of a battery or other storage device. The power source  110  also may be in the form of supplied power or generated power. The electronic trigger device  104  may further comprise electronics  112 , coupled to power source  110 , and an actuator  114  designed to translate a piston  116  or another suitable component against pressure isolation piston  76 . By way of example, the actuator  114  may comprise a motor, a hydroelectric pump, a screw system, a solenoid, or another suitable type of actuator. 
     Upon receipt of the predetermined signal by sensor  108 , the electronics  112  control operation of actuator  114  to move piston  116  against pressure isolation piston  76 . As a result, the pressure isolation piston  76  is shifted in the rightward direction via electronic trigger device  104 . Consequently, shuttle piston  106  is shifted in an opposite direction and fluid communication is established between oil chamber  66  and one side of piston  52 . The formation pressure moves compensating piston  64  and forces fluid  68  through valve block  78  and along the appropriate hydraulic line to shift piston  52  and actuator  50 . As with the indexing trigger device  92 , this movement of actuator  50  transitions the valve  38  to a desired flow position, such as an open flow position enabling flow from formation  30  into tubing  26 . 
     The various embodiments of the valve  38  and its trip saver module  36  may be used in many types of applications and environments. In one example, the lower completion  42  is initially run downhole with sand screens. To provide access to formation  30 , the casing  28  proximate the desired portion of formation  30  is perforated. As the wash pipe is pulled-out-of-hole, a shifting tool at the end of the wash pipe is used to close the one or more valves  38 , thus isolating the formation  30  from the surface of the well. 
     This enables installation of the upper completion  40  without having to deal with fluids flowing from the formation  30 . After the upper completion  40  is installed, an operator is able to easily and selectively open the one or more valves  38  to begin production of the well without having to go through the time, trouble and expense of an intervention. The trip saver module(s)  36  provides the ability to open the formation isolation valve(s) remotely through the use of tubing pressure via one or more of the methodologies and systems described herein. 
     The components of valve  38  and of overall well system  20  can be adjusted to accommodate a variety of structural, operational, and/or environmental parameters. For example, various combinations of completion components may be employed in constructing lower completions, upper completions, or combined, single completions. Additionally, the specific components and arrangements of components within the trip saver module and in the overall formation isolation valve may be modified to accommodate a wide variety of applications and environments. Furthermore, the components described above provide for may be combined to provide two types of actuating mechanisms arranged as a primary and a secondary actuator for providing redundancy. The two actuating mechanisms may be the same type of device or two different types of devices. Other combinations of components also may be employed. In some applications, for example, a rupture disc is coupled to one of the pressure isolation pistons of the pair of pressure isolation pistons and an electronic trigger device is coupled to the other pressure isolation piston of the pair of pressure isolation pistons. The electronic trigger device moves the other pressure isolation piston upon receipt of a predetermined signal transmitted downhole. 
     Although only a few embodiments of the present invention 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 invention. Accordingly, such modifications are intended to be included within the scope of this invention as defined in the claims.

Summary:
A technique facilitates actuation of a downhole tool, such as a valve, in a simple, rapid, and cost-effective manner. The technique comprises installing the downhole tool with a trip saver. The trip saver can be actuated by increasing a tubing pressure or other suitable pressure source beyond a threshold level. Once the trip saver is actuated, a fluid under suitable pressure is provided to a downhole tool through a passageway opened via the trip saver. This enables actuation of the downhole tool to a desired state.