Patent Publication Number: US-10323488-B2

Title: Gravel pack service tool with enhanced pressure maintenance

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a U.S. National Stage Application of International Application No. PCT/US2014/072992 filed Dec. 31, 2014, which is incorporated herein by reference in its entirety for all purposes. 
     TECHNICAL FIELD 
     The present disclosure relates generally to well completion operations and, more particularly, to a gravel pack service tool with a compression closed valve for enhanced pressure maintenance. 
     BACKGROUND 
     Hydrocarbons, such as oil and gas, are commonly obtained from subterranean formations that may be located onshore or offshore. The development of subterranean operations and the processes involved in removing hydrocarbons from a subterranean formation typically involve a number of different steps such as, for example, drilling a wellbore at a desired well site, treating the wellbore to optimize production of hydrocarbons, and performing the necessary steps to produce and process the hydrocarbons from the subterranean formation. 
     After drilling a wellbore that intersects a subterranean hydrocarbon-bearing formation, a variety of wellbore tools may be positioned in the wellbore during completion, production, or remedial activities. It is common practice in completing oil and gas wells to set a string of pipe, known as casing, in the well to isolate the various formations penetrated by the well from the wellbore. The casing is typically perforated opposite the formation to provide flowpaths for the valuable fluids from the formation to the wellbore. If production tubing is simply lowered into the wellbore and fluids are allowed to flow directly from the formation, into the wellbore, and through the production tubing to the earth&#39;s surface, fine sand from the formation could be swept along with the fluids and carried to the surface by the fluids. 
     Gravel pack operations are typically performed in subterranean wells to prevent fine particles of sand or other debris from being produced along with valuable fluids extracted from the formation. If produced (i.e., brought to the earth&#39;s surface), the fine sand tends to erode production equipment, clog filters, and present disposal problems. Conventional gravel pack operations prevent the fine sand from being swept into the production tubing by installing a sand screen on the end of the production tubing. The wellbore in an annular area between the screen and the casing is then filled with a relatively large grain sand or ceramic proppant (i.e., “gravel”). The gravel prevents the fine sand from packing off around the production tubing and screen, and the screen prevents the large grain sand from entering the production tubing. 
     Gravel pack systems generally include a packer that is set to seal and anchor the gravel pack system, and the production tubing, in place within the perforated wellbore. Currently, workstring tubing is plugged below the packer and pressure applied to the tubing to set the packer. The tubing is raised afterward to position the tubing for gravel pack pumping operations. Unfortunately, this raising of the gravel pack system while the tubing is plugged can lead to a pressure differential between components above and below the packer. This pressure differential can pull parts of the formation inward toward the wellbore, leading to bridging off or collapse of the formation around the screen of the gravel pack system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a schematic partial cross-sectional view of a gravel pack system in a wellbore environment, in accordance with an embodiment of the present disclosure; 
         FIG. 2  is a schematic view of certain components of the gravel pack system of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 3  is a schematic cross-sectional view of the gravel pack system of  FIG. 1  with an open pressure maintenance valve, in accordance with an embodiment of the present disclosure; 
         FIG. 4  is a close up schematic view of the gravel pack system of  FIG. 3 , in accordance with an embodiment of the present disclosure; 
         FIG. 5  is a schematic cross-sectional view of the gravel pack system of  FIG. 1  with a closed pressure maintenance valve, in accordance with an embodiment of the present disclosure; 
         FIG. 6  is a close up schematic view of the gravel pack system of  FIG. 5 , in accordance with an embodiment of the present disclosure; 
         FIG. 7  is a schematic cross-sectional view of components of the gravel pack system of  FIG. 1 , in accordance with an embodiment of the present disclosure; and 
         FIG. 8  is a schematic cross-sectional view of components of the gravel pack system of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Illustrative embodiments of the present disclosure are described in detail herein. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation specific decisions must be made to achieve developers&#39; specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure. Furthermore, in no way should the following examples be read to limit, or define, the scope of the disclosure. 
     Certain embodiments according to the present disclosure may be directed to a gravel pack system that features a closeable valve to provide pressure maintenance to a subterranean formation prior to and while setting a packer of the gravel pack system within a wellbore. More specifically, the gravel pack system may include a service tool that provides pressure maintenance to the formation by maintaining fluid communication between the workstring tubing that the gravel pack system is coupled to and the annulus of the wellbore below the packer prior to and during setting of the packer. Thus, the pressure maintenance may be provided via fluid flowing through the workstring tubing. The service tool could also be configured for other tasks, such as providing wash down applications. The pressure maintenance through the formation available using the disclosed service tool may prevent the gravel pack system from swabbing the formation after setting the packer. That is, the service tool may maintain the pressure in the formation below the packer at the same pressure as the fluid in the workstring tubing so that raising the service tool does not create a vacuum in the lower portion of the wellbore. Creation of this vacuum or suction force in the wellbore below the packer, also known as “swabbing the formation”, could lead to collapse of a perforated portion of the formation. 
     Referring now to  FIG. 1 , an example of a wellbore operating environment  10  is shown. As depicted, the operating environment  10  includes a gravel pack system  12  that has been positioned in the wellbore  14  which intersects a subterranean formation or zone  16 . All or part of the gravel pack system  12  may be positioned in a cased or uncased portion of the wellbore  14 . In the illustrated embodiment, the system  12  includes a gravel pack packer  18 , a setting tool  20 , a service tool  22 , an outer completion string such as a gravel pack circulating sleeve  24 , and one or more screens  26 . 
     The gravel pack packer  18  is set in the wellbore  14  to isolate a zone of the wellbore  14  beneath the packer  18  for gravel packing. After the packer  18  is set in the wellbore  14 , an annulus  28  between the well screens  26  and the wellbore  14  may be packed with gravel  30 , as described in detail below. The setting tool  20  may be part of or coupled to the service tool  22 , and the setting tool  20  is designed to set the packer  18 . The packer  18  may be a mechanically or hydraulically set packer. In such instances, the setting tool  20  may set the packer  18  by directing pressurized hydraulic fluid to apply a compressive force to the packer  18 , thereby sealing the gravel pack portion of the wellbore  14 . After setting the packer  18 , the setting tool  20  may release from the packer  18 , enabling the service tool  22  and setting tool  20  to be moved axially (in a direction along the axis  31 ) through the gravel pack system  12  to open and close the circulating sleeve  24 . 
     As illustrated, the gravel pack system  12  may be attached to a tubular string  32  (e.g., workstring tubing string) that is conveyed into the wellbore  14 . The system  12  may be lowered into the wellbore  14  via the tubular string  32 . The tubular string  32  may be moved up and down at different points while positioning the system  12  in the wellbore  14  and after the setting tool  20  sets the packer  18  for gravel pack operations. 
     Existing gravel pack systems typically close off the portion of the tubular string above the packer from the portion of the service tool and wellbore below the packer while setting the packer. For example, some existing gravel pack systems utilize a dropped ball to block the flow of fluid from the tubular string through the gravel pack system, in order to divert high pressure fluid to set the packer. However, such techniques do not allow for pressure maintenance through the wellbore. That is, these techniques may allow the tubular string above the packer to reach pressures much higher than the pressure of the wellbore below the packer. At this point, if the tubular string is raised, the pressure differential could lead to undesirable swabbing of the formation. To prevent swabbing the formation  16  prior to and while setting the packer  18 , the disclosed system  12  includes a service tool  22  that enables pressure maintenance throughout the wellbore  14  prior to and during the packer setting process. As discussed in detail below, the service tool  22  may include an inner tube (e.g., circulating port) that defines a valve conduit for directing a flow of fluid from the tubular string  32  to a washpipe  34  (lower portion of the service tool  22 ) and into the wellbore  14  below the packer  18 . Thus, the system  12  may be capable of setting the packer  18  without blocking the flow of fluid from the workstring tubing through the service tool  22 . After setting the packer  18 , the system  12  may close a valve in the service tool  22 , thereby closing off the flow of fluid through the service tool  22  so that gravel pack operations can be performed. 
     It should be noted that, although  FIG. 1  depicts a vertical well, the principles of the present disclosure may be equally well-suited for use in deviated wells, inclined wells, horizontal wells, or multi-lateral wellbore completions. Also, the wellbore operating environment  10  depicted in  FIG. 1  may be provided through the use of an offshore platform, a land-based drilling and production rig, service rigs, or other oil and gas rigs located at any desired geographical location. 
     Having now discussed the general operational context in which the service tool  22  may be used, a more detailed description of various embodiments of the service tool  22  will be provided.  FIG. 2  schematically represents the components of the service tool  22  and the setting tool  20  that may be used to set the packer  18  while providing pressure maintenance in the wellbore  14 . It should be noted that other types of setting tools  20  may be used in other embodiments of the disclosed gravel pack system  12 . In the illustrated embodiment, the service tool  22  may utilize a battery powered setting tool  20  to set the gravel pack packer  18 . For example, the illustrated service tool  22  may include an electric pump  50  connected to the hydraulic setting tool  20 . The electric pump  50  may utilize filtered well fluids or utilize a reservoir of hydraulic fluid (or some other fluid)  52  directed toward a hydraulic piston  53  to provide the compression force to set the hydraulic packer. The electric pump  50  may be powered by a battery pack  54 , and controlled in response to a sensor  56  that measures, for example, hydraulic fluid pressure going to the piston  53 , temperature, or stresses and strains on components of the service tool  22 . 
     The illustrated service tool  22  may utilize the battery powered setting tool  20  to set the packer  18 , so that the gravel pack system  12  does not have to utilize a dropped ball to pressurize the setting tool  20 . By not using a dropped ball, the system  12  may not plug a flow of fluid through the internal flow tube of the service tool  22 . This may enable the service tool  22  to maintain the pressure through the wellbore  14  without having to use a more complicated flow diverting setup. In addition, the absence of a dropped ball may simplify the service tool  22 , since no ball seat and corresponding sleeves are needed to actuate the setting tool  20 . Further, the method of setting the disclosed service tool may reduce the number of balls that do not seal properly in the tubular string or gravel pack system  12 , thereby increasing the reliability of the system operation. Still further, the service tool  22  that does not utilize a dropped ball to actuate the setting tool  20  may also eliminate the rig time normally spent waiting for a dropped ball to land in the service tool  22 . Again, it should be noted that other types of service tools  22  and overall gravel pack systems  12  may be used in other embodiments to facilitate pressure maintenance along the wellbore  14  prior to and during setting the packer  18 , regardless of how the service tool  22  actuates the setting tool  20 . 
       FIGS. 3-6  illustrate an embodiment of certain components of the gravel pack system  12  that may be used to provide pressure maintenance through the wellbore  14 . Specifically, the illustrated embodiments show the service tool  22 , which is at least partially disposed in the circulating sleeve  24 .  FIGS. 3 and 4  illustrate the service tool  22  in operation when the gravel pack system  12  is being lowered into the wellbore  14  via workstring tubing  32  and while setting the packer  18  (as shown in  FIG. 1 ). At this time, the system  12  is providing pressure maintenance to the wellbore  14  by allowing fluid to flow from the workstring tubing  32  coupled to the upper portion of the service tool  22 , through the service tool  22 , down into the washpipe  34  (described above with reference to  FIG. 1 ), and through the screens  26  into the wellbore  14  at a position below the packer  18 . As discussed above, this may maintain approximately the same pressure both above and below the packer  18  prior to and during setting of the packer  18 . That way, if the service tool  22  is raised after setting the packer, it does not create a suction force through the lower part of the wellbore  14 . 
     As illustrated in  FIGS. 3 and 4 , the service tool  22  of the gravel pack system  12  includes a crossover port  70  and a valve  72  used to direct fluid flowing through the service tool  22 . In the illustrated embodiment, the valve  72  is disposed below the crossover port  70  (when the service tool  22  is oriented vertically within the wellbore  14 ), and the valve  72  may be open as the gravel pack system  12  is run into the wellbore  14  and while setting the packer. The valve  72 , when open, facilitates a flow of fluid from the workstring tubing  32 , through the service tool  22  and toward the washpipe described above. When the valve  72  is closed, the service tool  22  routes the fluid flowing from the workstring tubing coupled to an upper portion of the service tool  22  into the annulus  28  between the circulating sleeve  24  and the wellbore  14 . 
     In the illustrated embodiment, the service tool  22  includes two internal sleeves  74  and  76  disposed within the circulating sleeve  24 . The first sleeve  74  may be referred to as a mandrel sleeve  74  in some embodiments. The second sleeve  76  may be referred to as a housing sleeve  76 . The terms “mandrel sleeve”  74  and “housing sleeve”  76  refer to the placement of the sleeves relative to each other, since the mandrel sleeve  74  may be at least partially received into the housing sleeve  76 . The opening and closing action of the valve  72  may be actuated via the sliding of these sleeves  74  and  76  relative to each other, as described in detail below. As illustrated, the crossover port  70  may be formed in the mandrel sleeve  74  while the valve  72  may be formed in the housing sleeve  76 . However, it should be noted that in other embodiments the crossover port  70  and the valve  72  may be oppositely arranged in the sleeves  74  and  76 . In further embodiments, the crossover port  70  and the valve  72  may both be formed in the same sleeve (e.g.,  74  or  76 ). In still further embodiments, the valve  72  may include ports formed through both sleeves  74  and  76 . 
     As noted above, the illustrated valve  72  is in an open position. Specifically, the valve  72  may include a housing port  78  formed through the housing sleeve  76  that allows fluid to flow from a space  80  (between the circulating sleeve  24  and the housing sleeve  76 ) and an internal portion or flow path  82  through the service tool  22  (below the crossover port  70 ). While the valve  72  is open, a return port  84  of the service tool  22  may be sealed off at the packer bore so that fluid flowing into the flow path  82  is routed downward through the service tool washpipe and into the wellbore  14 . 
     When the valve  72  is in this open position, the system  12  may be used for pressure maintenance or as a washdown system. The service tool  22  may form a continuous flowline between the workstring tubing  32  coupled thereto and the washpipe at the lower portion of the service tool  22 . Treatment fluids may be pumped down the workstring tubing, through the open valve  72  of the service tool  22 , and into the fractured zone of the wellbore  14 . Thus, the service tool  22  may facilitate both pressure maintenance through the wellbore  14  and any desired washdown treatments while the valve  72  is open. 
     To keep the valve  72  open during run in and packer setting operations, the valve  72  may be pinned into the open position. For example, as illustrated in  FIG. 4 , one or more shear pins  86  may be coupled between the mandrel sleeve  74  and the housing sleeve  76  to maintain the valve  72  in the open position. In other embodiments, the service tool  22  may include a spring or other biasing component used to maintain the valve  72  in the open position. 
     As noted above, the valve  72  may be open as the setting tool  20  sets the packer  18  (as described with reference to  FIG. 1 ). This allows the inner diameter of the workstring tubing  32  to remain open to the formation while setting the packer. 
     The packer may be set, as described above, and pressure tested using fluid pumped down an annulus  27  (above the packer), shown in  FIG. 1 . All the while, the fluid from the workstring tubing  32  may flow through the valve  72  of the service tool  22  and into the formation below the packer. Thus, when the service tool  22  is raised after setting the packer to the first pump position, the formation is not swabbed due to a pressure differential between the workstring tubing  32  above the packer and the wellbore  14  below the packer. 
     Unlike existing gravel pack systems, the disclosed system  12  utilizes fluid from the workstring tubing  32 , not annulus fluid, to facilitate pressure maintenance down the wellbore  14 . Thus, the pressure can be maintained even while the packer is being set to form a pressure seal that isolates one portion of the annulus from another. In addition, by providing the pressure maintenance through the workstring tubing  32  instead of the annulus  27 , the service tool  22  may be shortened compared to tools that utilize the annulus fluid above the packer to provide pressure maintenance. 
     In some embodiments, the use of fluid flowing from the workstring tubing  32  may enable the service tool  22  to perform operations other than just pressure maintenance. For example, acid treatment fluid may be pumped from the workstring tubing  32  through the open valve  72 , the washpipe, and the screens to further stimulate the formation. To provide this stimulation position, the service tool  22  may have the valve  72  open and the return port  84  sealed to direct the high pressure acid treatment fluid into the perforated formation. 
     The service tool  22  may include certain features that aid in switching the valve  72  from an open position to a closed position after the packer is set. In the illustrated embodiment, the service tool  22  may include the valve  72 , a multi-acting ball check  88 , and a weight down collet  110 . The valve  72  may be used with a single acting collet or with a multi-acting collet. In some embodiments, the valve  72  may be used with a multi-acting ball check, a reverse acting ball check (RABC) valve, or a multi-acting reverse valve (MARV). The multi-acting ball check  88  may be pinned open in the run-in position, as illustrated. This allows fluid flowing through the valve  72  to continue down the flow path  82  toward the washpipe at the bottom of the service tool  22 . 
       FIG. 4  illustrates the flow of fluid through the service tool  22  when the valve  72  is open. First, fluid may flow from the workstring tubing  32  out through the crossover port  70  (e.g., arrows  90 ) into the space  80  between the service tool  22  and the circulating sleeve  24 . From here, the fluid may only flow into the valve  72  (e.g., arrow  92 ) since all other exits from the space  80  are sealed. For example, the system  12  may include a seal  94  formed between the service tool  22  and a projection of the circulating sleeve  24 , as well as a blocking component  96  positioned over a circulating port  98  (i.e., the inner tube) in the circulating sleeve  24 . The fluid may flow through the open valve  72  into the flow path  82  inside the service tool  22 , through the multi-acting ball check  88 , and down toward the washpipe, as illustrated by arrows  100 . Thus, the open valve  72  maintains an open flowline between the workstring tubing  32  coupled to the gravel pack system  12  above the packer and the washpipe portion of the service tool  22  below the packer prior to and while setting the packer. 
     After the packer is set, it may be desirable to close the valve  72  in order to route gravel through the service tool  22  into the annulus  28  for gravel packing. When it is time to perform the gravel pack operation, an operator may close the valve  72 . In some embodiments, the mechanism for closing the valve  72  includes the weight down collet  110 . The valve  72  may be closed when weight applied from the surface (e.g., via the workstring tubing  32 ) forces the mandrel sleeve  74  into the weight down position, as shown in  FIGS. 5 and 6 . 
     In some embodiments, the closing operation may rely on an operator controlling the workstring tubing by first picking up and then setting down weight on the mandrel sleeve  74 . As illustrated in  FIGS. 3 and 5 , the service tool  22  may include the weight down collet  110  on the housing sleeve  76 , while the circulating sleeve  24  may include a corresponding indicator collar portion  112  designed to engage with the weight down collet  110  under certain conditions. To close the valve  72 , an operator may control the workstring tubing to lift the service tool  22  relative to the stationary circulating sleeve  24  until the indexing feature  110  on the housing sleeve  76  locates in the indicator collar portion  112 , as illustrated in  FIG. 5 . From this position, the operator may control the workstring tubing to lower (e.g. put weight down on) the service tool  22 . The indicator collar portion  112  may keep the housing sleeve  76  from moving downward in response to the applied weight, and the compression of the mandrel sleeve  74  relative to the housing sleeve  76  may shear the shear pins  86  or snap out a collet to close the valve  72 . In the illustrated embodiment of  FIGS. 3-6 , the mandrel sleeve  74  may include an extension  114  designed to cover and substantially block the port  78  through the housing sleeve  76 , thereby closing and sealing the valve  72 . 
     The above described method for closing the valve  72  may be performed with relatively low, or no, wait time compared to systems that utilize dropped balls to close a valve. In addition, the service tool  22  may utilize a robust design built from components with a high reliability, so that the valve  72  can be easily controlled by an operator at the surface. It should be noted that other configurations of the service tool  22  may feature a valve  72  that can be closed using a similar method of putting weight down on a collet feature of the service tool  22 . 
     Certain embodiments of the service tool  22  may include a locking mechanism to maintain the valve  72  in the closed position after it is closed. For example, as described in detail below, the service tool  22  may include a lock ring or snap ring that locks the valve  72  closed by locking the mandrel sleeve  74  and the housing sleeve  76  in a fixed position relative to each other. In other embodiments, the service tool  22  may be designed to allow the valve  72  to be selectively closed and opened again multiple times without locking in the closed position. This option may be particularly useful if the service tool  22  is being used to perform the gravel pack operation and to perform fracturing or other jobs while downhole. 
     After the valve  72  is closed, the service tool  22  may be used to perform the gravel pack operation, as illustrated in  FIG. 6 . First, fluid may flow from the workstring tubing  32  out through the crossover port  70  (e.g., arrows  130 ) into the space  80  between the service tool  22  and the circulating sleeve  24 . From here, the fluid may only flow into the circulating port  98  since all other exits from the space  80  are sealed. The valve  72  is closed via the extension  114  disposed over the port  78 . In addition, the system  12  may include the seal  94  formed between the service tool  22  and the circulating sleeve  24 , and the blocking component  96  may be pushed away from the circulating port  98  to allow the fluid to exit the circulating sleeve  24  via the port  98 . 
     The fluid may flow through the annulus  28  outside the gravel pack system  12  and toward the screens of the system  12 , as shown by arrows  132 . Fluid returns from the gravel pack operation may come through the screens of the gravel pack system  12  and up the washpipe into the inside flow path  82  of the service tool  22 , as shown by arrows  134 . From here, the fluid returns may flow past the closed valve  72  and into the return path  84  (e.g., arrow  136 ) through the crossover section of the service tool  22 . Thus, the closed valve  72  allows fluid to transport proppant or particulates from the workstring tubing  32  to the annulus  28  around the screens in order to establish a gravel pack to control sand production from the formation. Once the gravel pack is performed as described above, the gravel packed into the annulus  28  of the wellbore  14  may prevent any undesirable effects (e.g., swabbing the formation) caused by raising the service tool  22  with the closed valve  72  through the wellbore  14 . 
     Although the valve opening/closing mechanisms, fluid flowpaths, and gravel operations available through the disclosed service tool  22  have been described above in reference to  FIGS. 3-6 , it should be noted that other specific tool configurations may be used to provide the same effects. For example,  FIGS. 7 and 8  provide two different embodiments of components of the service tool  22  that may be utilized to provide the desired pressure maintenance through the wellbore  14  prior to and during the packer setting operation. 
     For example,  FIG. 7  illustrates an embodiment of the service tool  22  that includes the crossover port  70  formed in the mandrel sleeve  74  and the closeable valve  72  formed via overlapping sections of the mandrel sleeve  74  and the housing sleeve  76 . As before, the valve  72  may be open in the run-in position to provide a flow path from the workstring tubing to the washpipe of the service tool  22 . When the valve  72  is in this open position, as illustrated, a fluid flow may exit the crossover port  70  and enter the service tool  22  again through the housing port  78  and a corresponding mandrel port  150  formed through the mandrel sleeve  74 . Thus, the housing port  78  and the mandrel port  150  may together form the valve  72 . The valve  72  is open when the housing port  78  and the mandrel port  150  are aligned, and the valve  72  is closed when the housing port  78  and the mandrel port  150  are no longer aligned. The valve  72  may be closed with sit down weight or compression applied to the mandrel sleeve  74  of the service tool  22 . Such compression may move seals  152  formed on a surface of the housing sleeve  76  (around the housing port  78 ) up onto a seal surface  154  of the mandrel sleeve  74 . In addition, a lock ring  156  disposed on the housing sleeve  76  may engage a corresponding catch profile  158  formed on the mandrel sleeve  74  to lock the mandrel sleeve  74  and the housing sleeve  76  into the compressed position. This may effectively lock the valve  72  in the closed position, so that fluid is then directed into the annulus to perform the gravel pack operation, as described above. 
     Other embodiments of the service tool  22  with the locking valve  72  may be utilized as well. For example, as shown in  FIG. 8 , the crossover port  70  may be disposed in the housing sleeve  76  and the components of the valve  72  may be located closer to the crossover port  70 . In this illustrated embodiment, the valve  72  may be open in the run-in position to provide a flow path from the workstring tubing to the washpipe of the service tool  22 . Specifically, the open valve  72  may allow a fluid flow to exit the crossover port  70  and enter an inner portion of the service tool  22  through the housing port  78  and the corresponding mandrel port  150 . The housing port  78  and the mandrel port  150  may together form the valve  72 . The valve  72  is open when the housing port  78  and the mandrel port  150  are aligned, and the valve  72  is closed when the housing port  78  and the mandrel port  150  are no longer aligned. 
     The valve  72  may be closed with sit down weight or compression applied to the housing sleeve  76  of the service tool  22 . Such compression may move the seals  152  of the housing sleeve  76  along the seal surface  154  of the mandrel sleeve  74 . In addition, the lock ring  156  disposed on the housing sleeve  76  may engage the corresponding catch profile  158  formed on the mandrel sleeve  74  to lock the mandrel sleeve  74  and the housing sleeve  76  into the compressed position. This may effectively lock the valve  72  in the closed position, so that fluid is then directed into the annulus to perform the gravel pack operation, as described above. 
     It should be noted that other variations of the components that make up the disclosed service tool  22  may be utilized in other embodiments. For example, the lock ring  156  and corresponding catch profile  158  may be arranged on the mandrel sleeve  74  and the housing sleeve  76 , respectively. In addition, the valve  72  may include any desirable combination of ports, extensions, seal surfaces, and so forth that facilitate a closeable flow path from the space  80  to the inner flow path  82  of the service tool  22  via sliding of two or more sleeves relative to each other. 
     Embodiments disclosed herein include: 
     A. A completion system including an outer completion string having at least one packer disposed thereon, a service tool arranged within the outer completion string and releasably attached to the packer, and a valve disposed in the service tool, wherein the valve is movable between a first position and a second position. The service tool includes an inner tube that defines a valve conduit. The first position of the valve allows fluid to flow from tubing coupled to the service tool above the packer into an annulus outside the service tool below the packer, and the second position of the valve prevents fluid from the tubing from entering the annulus. 
     B. A method includes directing a fluid flow from workstring tubing coupled to a completion system into a space between the service tool and an outer completion string disposed around the service tool. The method also includes directing the fluid flow from the space between the service tool and the outer completion string into an internal portion of the service tool and toward a washpipe disposed at a bottom portion of a service tool, when a valve of the service tool is in a first position. The method further includes blocking the fluid flow from entering the internal portion of the service tool when the valve is in a second position. 
     C. A gravel pack system including a service tool. The service tool includes a washpipe disposed at an end of the service tool. The service tool also includes a crossover port disposed in a wall of the service tool that enables fluid to flow between workstring tubing coupled to an upper portion of the service tool and a space between the service tool and an outer completion string. Further, the service tool includes a valve disposed in the wall of the service tool that directs fluid from the space between the service tool and the outer completion string into the service tool and toward the washpipe when the valve is open. 
     Each of the embodiments A, B, and C may have one or more of the following additional elements in combination: Element 1: wherein the valve in the first position maintains fluid communication between the tubing and the annulus below the packer prior to and during setting of the packer. Element 2: further including a setting tool comprising a battery, a pump, a controller, and a hydraulic piston for applying a compression force to actuate the packer by pressuring fluid via the pump to produce pressure behind the piston in order to seal and anchor the packer to a wellbore. Element 3: further including a setting tool for setting the packer in a wellbore while maintaining a pressure within the tubing at approximately the same pressure as in the wellbore below the packer. Element 4: wherein the service tool is releasable from the packer to move upward through the outer completion string with the valve in the first position. Element 5: wherein the service tool is movable from the first position to the second position via a compression force. 
     Element 6: further including locking the valve in the second position. Element 7: wherein locking the valve in the second position includes engaging a lock ring of a first sleeve of the service tool with a catch profile on a second sleeve of the service tool. Element 8: further including maintaining the valve in the first position prior to and while a setting tool coupled to the service tool sets a packer in a wellbore. Element 9: further including setting the packer via a setting tool while maintaining fluid communication between the workstring tubing and the wellbore below the packer. Element 10: further including closing the valve by applying a compression force to the service tool via the workstring tubing. Element 11: further including directing the fluid flow from the washpipe, through one or more screens disposed at a lower portion of the outer completion string, and into an annulus when the valve is in the first position. 
     Element 12: further including the outer completion string; a packer for isolating a portion of a wellbore formed in a subterranean formation, wherein at least a portion of the outer completion string is disposed at a position below the packer and at least partially surrounding the service tool; one or more screens disposed at a lower end of the outer completion string; and a setting tool disposed within and removably coupled to the packer, wherein the setting tool is coupled to the service tool. Element 13: wherein the outer completion string includes a gravel pack circulating sleeve comprising a circulating port through a wall of the gravel pack circulating sleeve that enables fluid to flow from the space between the service tool and the outer completion string to a position outside the outer completion string. Element 14: wherein the service tool includes a shearable connection that maintains the valve open and shears in response to compression of the service tool. Element 15: wherein the service tool further includes a locking mechanism for locking the valve in a closed position when the valve is closed in response to compression of the service tool. Element 16: 
     wherein the service tool further includes a first sleeve having the crossover port disposed therein and a second sleeve, wherein the first and second sleeves of the service tool are in a sliding engagement for closing or opening the valve, and wherein one of the first sleeve or the second sleeve includes an extension that closes over the valve when the first sleeve and the second sleeve are compressed relative to each other. Element 17: wherein the service tool further includes a first sleeve having the crossover port disposed therein and a second sleeve, wherein the first and second sleeves of the service tool are in a sliding engagement for closing or opening the valve, and wherein the first sleeve includes a first port formed therein and wherein the second sleeve includes a second port formed therein such that the valve is open when the first and second ports are aligned with each other, and the valve is closed when the first and second ports are no longer aligned. 
     Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the following claims.