Abstract:
An apparatus for controlling fluid flow that includes a chamber having a first valve and a second valve; a sensor that senses a pressure parameter associated with the chamber; and a controller programmed to operate the first valve and the second valve in response to the sensed pressure parameter may be used to control for flow and to obtain data relating to a formation and/or formation fluid. The apparatus may include a manifold for using a fluid mover to convey fluid between the first location and the second location and at least one module received by the manifold.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    This disclosure pertains generally to devices and methods for conveying fluids in a borehole formed in a subsurface formation. 
       BACKGROUND OF THE DISCLOSURE 
       [0002]    To obtain hydrocarbons such as oil and gas, well boreholes are drilled using a drill string having a bottomhole assembly (BHA). The BHA may include instruments and devices for forming the borehole, controlling borehole pressure, managing drilling fluid circulation, and measuring certain downhole operating parameters associated with the drill string. After the borehole has been formed, still further equipment may be used to test formation fluids or rock properties, isolate pay zones, etc. Some tools and instruments used during and after drilling incorporate flow control devices to control flow of a particular fluid. In some instances, the fluid may be a natural fluid (e.g., formation fluids), a functional fluid (e.g., drilling fluids), or a hydraulic fluid. 
         [0003]    In one aspect, the present disclosure addresses the need for flow control devices that have enhanced reliability while used in subsurface applications such as those described above. 
       SUMMARY OF THE DISCLOSURE 
       [0004]    In aspects, the present disclosure provides an apparatus for controlling fluid flow between a first location and a second location. The apparatus may include a body having a fluid conduit, the conduit having an inlet in fluid communication with the first location and an outlet in fluid communication with the second location, the body further having a chamber; a valve element disposed in the chamber, the valve element having a seal separating the chamber into a pressure section and a flow section, wherein the pressure section is in hydraulic communication with the outlet via an outlet fluid branch; a shear seal having at least one movable sealing element disposed on the valve element and at least one stationary sealing element disposed in the body; and a biasing member urging the valve element to a closed position wherein the at least stationary one sealing element is in sealing engagement with the at least one movable sealing element, wherein a pressure communicated by the outlet fluid branch also urges the valve element to the closed position. 
         [0005]    In aspects, the present disclosure also provides an apparatus for controlling fluid flow between a first location and a second location that includes a manifold for using a fluid mover to convey fluid between the first location and the second location and at least one module received by the manifold. The at least one module may include a first fluid conduit connecting a first and a second connector, a coupling in fluid communication with the fluid mover and the first fluid conduit, and a plurality of flow control devices in fluid communication with the first fluid conduit, wherein each flow control device includes: a body having a fluid conduit, the conduit having an inlet in fluid communication with the first location and an outlet in fluid communication with the second location, the body further having a chamber in hydraulic communication with the outlet via an outlet fluid branch; a valve element disposed in the chamber; a shear seal having at least one movable sealing element disposed on the valve element and at least one stationary sealing element disposed in the body; and a biasing member urging the valve element to a closed position wherein the at least stationary one sealing elements is in sealing engagement with the at least one movable sealing element, wherein a pressure communicated by the outlet fluid branch also urges the valve element to the closed position. The module has a first and a second orientation when received by the manifold, the module conveying fluid only from the first connector to the second connector when in the first orientation and only from the second connector to the first connector when in the second orientation. 
         [0006]    Examples of certain features of the disclosure have been summarized rather broadly in order that the detailed description thereof that follows may be better understood and in order that the contributions they represent to the art may be appreciated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    For a detailed understanding of the present disclosure, reference should be made to the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals, wherein: 
           [0008]      FIG. 1  shows a schematic of a flow control device that uses shear seals according to one embodiment of the present disclosure; 
           [0009]      FIGS. 2-4  each show a schematic of a flow control device that uses shear seals according to other embodiments of the present disclosure; 
           [0010]      FIG. 5  shows an isometric view of a movable shear seal member according to one embodiment of the present disclosure; 
           [0011]      FIGS. 6A-B  show a schematic of a flow control device that uses shear seals in a reversible manifold according to one embodiment of the present disclosure; 
           [0012]      FIG. 7  shows a schematic of a flow control device that uses shear seal in a reversible manifold according to another embodiment of the present disclosure; 
           [0013]      FIG. 8  shows a schematic of another flow control assembly that uses shear seal in a reversible manifold according to another embodiment of the present disclosure; 
           [0014]      FIG. 9A-B  shows a schematic of another flow control device that uses shear seal according to embodiment of the present disclosure; and 
           [0015]      FIG. 10  shows a schematic of a downhole tool deployed in a wellbore that may use one or more flow control devices according to the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    In aspects, the present disclosure relates to devices and method for enhancing the reliability of flow control devices. Certain embodiments of the present disclosure include a self-piloting check valve that is actuated by borehole or formation fluid. The valve may employ shear seals to increase reliability by reducing the likelihood of debris fouling. Certain other embodiments may use shear seals with a “dirty fluid pressure relief valve.” As used herein, the term “dirty” fluid is any fluid having a characteristic that may be harmful (e.g., cause erosion, corrosion, fouling, etc.) to the surfaces and materials making up a flow control device. For example, the fluid may be highly viscous and/or include entrained materials that are abrasive and can become lodged between contacting surfaces. Illustrative “dirty” fluids are naturally occurring fluids such as formation fluids and drilling fluids. The term “clean” fluid is a fluid that has one or more qualities that have been engineered or processed to a predetermined specification (e.g., viscosity, size of entrained particles, etc.). One illustrative “clean” fluid is hydraulic fluid. The teachings may be advantageously applied to a variety of systems both in the oil and gas industry and elsewhere. Merely for brevity, certain non-limiting embodiments will be discussed in the context of tools configured for wellbore uses. 
         [0017]    Referring initially to  FIG. 1 , there is schematically illustrated one embodiment of a flow control device  100  that may be used to control flow between a first location  102  (e.g., a subsurface formation) and a second location  104  (e.g., a fluid sampling tank or a wellbore annulus). In one configuration, the flow control device  100  allows unrestricted flow from the first location  102  to the second location  104 , but blocks fluid flow from the second location  104  to the first location  102 . 
         [0018]    The flow control device  100  may include a body  106  that has a chamber  108  in which a valve element  110  translates. The valve element  110  may be a shuttle or other body that is shaped and dimensioned to selectively block fluid flow. The valve element  110  may include a seal  112  and a biasing member  114 . The seal  112  forms a liquid tight fluid barrier between the valve element  110  and the body  106 , which forms a pressure section  107  and a flow section  109 . As discussed in greater detail below, varying pressure in the pressure section  107  and the flow section  109  can be used to displace the valve element  110 . The biasing member  114  may be any feature that generates an axial force for displacing the valve element  110  to a closed position. Suitable biasing members include, but are not limited to, coiled springs, spring washers, leaf springs, etc. 
         [0019]    The flow control device  100  also includes shear seal elements  116 ,  118 , and  120 . The shear seal elements  116  and  120  are each disposed in a bore formed in the body  106  and remain mostly stationary during operation. The shear seal elements  116  and  120  may be formed as disks, plates, or tubes. A tubular form may be suitable to accommodate fluid flow. The shear seal element  118  is fixed to and moves with the valve element  110 . The shear seal element  118  may be formed as a cylinder, block, or plate that seats within a recess of the valve element  110 . Alternatively, the shear seal element  118  may be integral with the valve element  110 ; e.g., a surface of the valve seal element  110  may be treated, shaped, or otherwise processes to present a shear seal surface. Thus, as opposed to elastomeric seals, these shear seal elements  116 ,  118   120  do not deform to form a seal. 
         [0020]    In some embodiments, biasing members  126  may be used to push shear seal elements  116  and  120  into contact with the shear seal element  118 . Although the biasing members  126  may cause some slight movement, the shear seal elements  116  and  120  are considered stationary for the purposes of the present disclosure. When the surfaces of the shear seal elements  116 ,  118  and  120  are in contact, a fluid tight barrier is formed that blocks fluid flow along a flow path  130  across the body  106 . An illustrative sealing contact is show with numeral  128 . Generally speaking, the shear seal surfaces in contact are relatively hard, flat, and smooth surfaces that have relatively low tolerances. 
         [0021]    In one embodiment, the flow path  130  has an inlet  132  and an outlet  134 . The outlet  134  includes two branches  136  and  138 , each of which receives fluid from the flow section  109  via a separate connection. As shown, the branch  136  is in fluid communication with the pressure section  107 . Therefore, fluid pressure at the outlet  134  can be transmitted to a pressure face  140  formed on the valve element  110 . 
         [0022]    The pressure applied to the pressure face  140  may be used to ensure that fluid flows in only one direction through the flow path  130 . Specifically, the applied pressure generates a closing force that assists the biasing member  114  to move the valve element  110  to the closed position. It should be noted that the closing force applied to the valve element  110  increases as fluid pressure increases at the outlet  134 , which assists in maintaining the valve element  110  in the closed position. The closing action may be in response to the occurrence of a predetermined pressure condition. The predetermined pressure condition may be a pressure at the outlet  134  exceeding a predetermined value, a pressure at the inlet  132  being less than a pressure at the outlet  134  by a predetermined amount, or a pressure differential between the inlet  132  and the outlet  134  exceeding a predetermined value or some other application-specific pressure condition. 
         [0023]    When the fluid pressure is greater at the first location  102  than at the second location  104 , the valve element  110  is piloted open. This is due to the pressure in the flow section  109  being greater than the pressure in the pressure section  107  by a preset value. Specifically, the pressure differential across the seal  112  is large enough to urge the valve element  110  and the seal  112  against the biasing member  114 . To open, this fluid pressure must be high enough to overcome the frictional forces generated by the biasing members  126  acting on the shear seal elements  116 - 120  and the axial biasing force generated by the biasing member  114 . The valve element  110  is axially displaced until a flow bore  142  formed in the valve element  110  aligns with the branches  136  and  138 . When so positioned, the fluid flows into the inlet  132 , through the flow bore  142 , along the branches  136  and  138 , and exits at outlet  134 . 
         [0024]    When the fluid pressure at the first location  102  drops below a preset value and/or does not exceed the pressure at the second location  104  by a preset value, the valve element  110  is piloted closed. This is due to the pressure in the flow section  109  being insufficient to counteract the pressure section  107  and the biasing force of the biasing element  114 . In this situation, the pressure in the pressure section  107  assists the biasing member  114  in urging the valve element  110  to a closed position. The valve element  110  is axially displaced until the shear seal elements  116  and  120  come into contact with the shear seal element  118 , and form sealing surfaces  128 . When so positioned, the fluid flow is blocked between the inlet  132  and the branches  136  and  138 . 
         [0025]    The flow control elements according to the present disclosure are susceptible to numerous variants. Some illustrative and non-limiting embodiments are shown in  FIGS. 2-5 . For brevity, certain common elements such as the biasing members  126  will not be discussed. 
         [0026]    Referring to  FIG. 2 , in one variant, the flow control device  100  includes a body  106 , a valve element  110 , a seal  112 , a biasing member  114 , shear seal elements, collectively  150 , and a flow path  130  across the body  106  as previously discussed. In this embodiment, the valve element  110  includes a flanged section  164  that includes a secondary seal  165  that separate a second pressure section  169  from the flow section  109 . As before, the flow path  130  has an inlet  152  and an outlet  158 . However, the inlet  152  has a first branch  154  that communicates pressure to the second pressure section  169  and a second branch  156  that conveys fluid to the flow section  109 . The second branch  156  has two separate fluid connections to the flow section  109 . The outlet  158  has a first branch  160  that receives fluid from the flow section  109  and a second branch  162  that communicates pressure to the pressure section  107 . Thus, the second branch  162  does not separately connect to the flow section  109 . 
         [0027]    Fluid flow across the body  106  occurs when the inlet second branch  156 , the flow bore  142  of the valve element  110 , and the outlet first branch  160  are in fluid communication with one another. This will be referred to as the open position. The valve element  110  moves to the open position when the inlet first branch  154  increases the pressure in the second pressure section  169 . When the pressure applied to the flanged section  164  is sufficient to overcome the biasing force of the biasing element  114  and frictional forces, the valve element  110  slides axially until the flow bore  142  aligns with the inlet second branch  156 . 
         [0028]    The valve element  110  moves to the closed position upon occurrence of a predetermined pressure condition; e.g., when the fluid pressure at the outlet  158  exceeds a predetermined value. The outlet second branch  162  applies fluid pressure to the pressure face  140  to urge the valve element  110  to the closed position, which occurs when the inlet first branch  154 , the flow bore  142  of the valve element  110 , and the outlet first branch  160  are not in fluid communication with one another. 
         [0029]    Referring to  FIG. 3 , in another variant, the flow control device  100  includes a body  106 , a valve element  110 , a seal  112 , a biasing member  114 , shear seal elements, collectively  150 , and a flow path  130  across the body  106  as previously discussed. In this embodiment, the flow path  130  has an inlet  170  having a first branch  174  and a second branch  176  and an outlet  180  having a first branch  182  and a second branch  184 . Additionally, the valve element  110  includes a flanged section  164  that includes an optional secondary seal  165  that separate a second pressure section  169  from the flow section  109 . Fluid flow across the body  106  occurs when the inlet first branch  174 , the flow bore  142  of the valve element  110 , and the outlet branch  182 ,  184  are in fluid communication with one another; i.e., the open position. The inlet second branch  174  conveys fluid into the second pressure section  169 , which applies fluid pressure to the flanged section  164  to urge the valve element  110  to the open position. 
         [0030]    In a manner previously discussed, the outlet second branch  184  applies fluid pressure to the pressure face  140  to urge the valve element  110  to the closed position; i.e., when the inlet first branch  176 , the flow bore  142  of the valve element  110 , and the outlet branches  182 ,  184  are not in fluid communication with one another. 
         [0031]    Referring to  FIG. 4 , in yet another variant, the flow control device  100  includes a body  106 , a valve element  110 , a seal  112 , a biasing member  114 , shear seal elements, collectively  150 , and a flow path  130  across the body  106  as previously discussed. In this embodiment, the flow path  130  has an inlet  190  and an outlet  200 . Additionally, the body  106  includes a pressure conduit  204  that is filled with a pressure transmitting media, such as a hydraulic fluid or grease (not shown). The pressure transmitting media may be a fluid that is different than the fluid flowing through the flow control device  100 . A pressure communicator  208  may be used to block fluid communication between the pressure conduit  204  and the outlet  200  while allowing the pressure in the outlet  200  to be communicated to the pressure transmitting media (not shown) in the pressure conduit  204 . Illustrative pressure communicators include, but are not limited to, pistons, diaphragms, and membranes. Thus, the pressure communicator  208  can increase and decrease the pressure in the pressure conduit  204  using the pressure of the fluid at the outlet  200 . As discussed previously, this applied pressure may be used to assist in closing the valve element  110  in a manner previously discussed. A plug or barrier  212  may be used to seal off and isolate the hydraulic fluid (not shown) in the pressure conduit  204  from the fluid flowing through the body  106 . 
         [0032]    Still another variant (not shown) may be based on the  FIG. 1  embodiment. The variant may be similar to the flow control device  100  of  FIG. 1  in that the variant generally may include a body  106  and a valve element  110 . However, the flow conduits and the shear seal assembly may be varied in certain aspects. 
         [0033]    First, the outlet  134  includes two branches  136  and  138 , but only one of which receives fluid from the flow section  109 . Thus, the branch  136  is only in fluid communication with the pressure section  107  and the branch  138  is only in fluid communication with the flow section  109 . Therefore, only one stationary shear seal element  120  is needed to block flow. In this variant, the shear seal element  116  may be replaced with a block, plug, cylinder or other support element that does not have a shear seal surface. Still, a biasing member  126  may be used to push the support element, such as a cylinder block (not shown), into contact with the shear seal element  118 , which then presses against the shear element  120 . When the surfaces of the shear seal elements  118  and  120  are in contact, a fluid tight barrier is formed that blocks fluid flow along a flow path  130  across the body  106 . 
         [0034]    Second, the shear seal element  118  may be formed as a platen member  80  that includes contact surfaces  82  and  84 . The platen member  80  also includes support arms  86  that extend from a landing portion  88 . A flow gap  89  separates the arms  86  such that the arms  86  are cantilevered; i.e., connected at only one end. One or both of the contact surfaces  82  and  84  may be polished and smooth surfaces that are relatively hard. During the closed position, the landing  88  is adjacent to the shear seal element  120 . The biasing member  126  pushes the support member (not shown, but in place of shear seal element  116 ) against the landing portion  88 . The landing portion  88  is pushed against the shear seal element  120 , which may or may not include a biasing member  126 . Thus, a shear seal element  118  is formed in the flow section  109  at the contacting shear seal surfaces. 
         [0035]    During the open position, only the support arms  86  are adjacent to the shear seal element  120  and the support element that is in place of the shear seal element  116 . The support arms  86  are formed to have sufficient length so that the support element (not shown) and the seal element  120  seal flatly and cannot rock or pivot. Additionally, in some embodiments, the flow gap  89  is sized to expose substantially all of the opening in the shear seal element  120  to fluid flow. Stated differently, the support arms  86  do not substantially block flow into the fluid branch  138 . By substantially, it is mean block flow no more than 40%. 
         [0036]    In still other variants, a separate control line may be used to flow fluid into the pressure section  107  to pilot the valve element  110  to the closed position. This fluid may be different from the fluid flowing through the flow control device. For instance, a clean hydraulic fluid may be used to pilot the valve element  110  closed and the flow control device may be used to control the flow of drilling mud. 
         [0037]    In certain embodiments, the flow control devices  100  may be used in a reversible manifold. For example, the above-described valves may be arranged to control flow in connection with a fluid mover. As used herein, a fluid mover is any device that adds energy to a fluid stream, e.g., centrifugal pumps, turbines, piston pumps, reciprocating pumps, etc. As discussed below, the flow control devices  100  may be arranged within the manifold to allow fluid to be selectively reversed. 
         [0038]    Referring to  FIG. 6A , in one embodiment, a “plug-in” manifold valve block  240  may include symmetrical fluid connections  242 ,  244 ,  246 , and  248 . Connections  244 ,  248  provide fluid communication between a reciprocating pump  250  and the manifold  240 . Connections  242 ,  246  provide fluid communication between a first location  102  (e.g., an uphole location) and a second location  104  (e.g., a downhole location). The manifold valve block  240  also includes flow control devices  260 ,  262 ,  264 , and  266 , which may be any of the flow control devices  100  previously described, that allow fluid flow in only one direction. In one arrangement, the pump  250  may be used to draw fluid from the downhole location  104 , via connection  246 , through flow control devices  262 ,  260 , and pump out the fluid via connection  246  to the uphole location  102 . The reciprocating action also allows the pump  250  to draw fluid from the downhole location  104 , via connection  248 , through flow control devices  266 ,  264 , and pump out the fluid via connection  246  to the uphole location  102 . 
         [0039]    Referring now to  FIG. 6B , the manifold may be decoupled from the pump  250  to switch the flow direction. The flow direction may be reversed by switching the positions of the connections  242  and  244 . In the reversed arrangement, the pump  250  may be used to draw fluid from the uphole location  102 , via connection  246 , through flow control devices  262 ,  260 , and pump out the fluid via connection  242 . The reciprocating action also allows the pump  250  to draw fluid from the uphole location  102 , via connection  246 , through flow control devices  266 ,  264 , and pump out the fluid via connection  242 . As should be appreciated, the pump  250  may be easily preconfigured to pump uphole or pump downhole. The flow lines shown in  FIGS. 5 and 6  may be wellbore fluid, and not hydraulic oil. Therefore, such reconfiguring has advantage because it would not require assembly or disassembly of a circuit containing hydraulic oil, but only to unplug the manifold  240 , rotate the connections, and reconnect the manifold  240  to the pump  350 . 
         [0040]    Referring to  FIG. 7 , there is shown another embodiment of flow control devices used in a reversible manifold  280  having a first module  290  and a second module  300 . In this embodiment, a “plug-in” reversible manifold  280  may include symmetrical fluid connections  302 ,  304 ,  306 ,  308 ,  310  and  312 . Connections  304 ,  310  provide fluid communication between a reciprocating pump  250  and the second module  300 . Connections  302 ,  308 ,  306 , and  312  provide fluid communication between a first location  102  (e.g., an uphole location) and a second location  104  (e.g., a downhole location). The first manifold module  290  includes connections  302 ,  304 , and  306  and flow control devices  260  and  262 . A second module  300  includes connections  308 ,  310 , and  312  and flow control devices  264  and  266 . The flow control devices  260 ,  262 ,  264 , and  266  may be any of the flow control devices  100  previously described that allow flow in only one direction. To reverse flow, the first module  290  is removed and flipped to reverse the positions of the connections  302  and  306 . Also, the second module  300  is removed and flipped to reverse the positions of the connections  308  and  312 . After the blocks  280  and  290  have been reconnected to the pump  250 , the flow is now in a reversed direction. 
         [0041]    Referring to  FIG. 8 , there is shown one embodiment of a “dirty valve” system that uses fluids other than clean hydraulic fluids (or “dirty” fluids) to pilot a valve to the open and closed positions. In one embodiment, the system  400  may include a reciprocating pump  250 . The pump may have first and second chambers  452  and  454 , respectively, and a piston  456  that varies the volume of each of the chambers  452  and  454 . Lines  458 ,  460  provide fluid communication between a first location  102  (e.g., an uphole location) and a second location  104  (e.g., a downhole location), respectively. The system  400  also includes a pair of flow control devices  470  and  480  that control flow between the pump  250  and the lines  458  and  460 . 
         [0042]    Referring now to  FIGS. 9A and 9B , there are shown further details for the first and second flow control devices  470  and  480 . Because of similarities in construction, certain features are discussed only in connection with the first flow control device  470  for brevity. The first flow control device  470  may include a body  106  that has a chamber  108  in which a valve element  110  translates. The valve element  110  may be a shuttle or other body that is shaped and dimensioned to selectively block fluid flow. The valve element  110  may include sealing flanges  490 ,  492 ,  496 , and a biasing member  114 . The flow control device  470  also includes shear seal assemblies  150 . The gaps between the sealing flanges  490 ,  492 ,  494  form fluid paths across the first flow control device  470 . The shear seal assemblies  150  selectively block flow across these gaps in a manner previously discussed. 
         [0043]    The various fluid paths associated the first flow control device  470  will be described with reference to  FIGS. 8 and 9A . In the arrangement shown, the flow control device  470  receives fluid from the line  458  through an inlet  510  and directs this fluid via an outlet  512  to a line  514  connected to the second chamber  454 . The flow control device  470  receives fluid from the first chamber  452  via line  516  through an inlet  518  and directs this fluid via an outlet  520  to the line  460 . The first control device  470  also includes a first port  522  and a second port  524 . The first port  522  receives a pressurized fluid via the line  472 , which is connected to line  514 , to assist the biasing element  114  in maintaining the valve element  110  in the closed position. The second port  524  receives a pressurized fluid via the line  474 , which is connected to line  516 , to urge the valve element  110  to the open position. 
         [0044]    The various fluid paths associated the second flow control device  480  will be described with reference to  FIGS. 8 and 9B . In the arrangement shown, the second flow control device  480  receives fluid from the line  458  through an inlet  530  and directs this fluid via an outlet  532  to the line  516  connected to the first chamber  452 . The flow control device  480  receives fluid from the second chamber  454  via line  514  through an inlet  534  and directs this fluid via an outlet  536  to the line  460 . The second control device  480  also includes a first port  538  and a second port  540 . The first port  538  receives a pressurized fluid via the line  482 , which is connected to line  516 , to assist the biasing element  114  in maintaining the valve element  110  in the closed position. The second port  540  receives a pressurized fluid via the line  484 , which is connected to line  514 , to urge the valve element  110  to the open position. 
         [0045]    In one mode of operation, the piston  456  initiates a first stroke by first reducing the volume of the first chamber  452  while increasing the volume of second chamber  454 . This action forces fluid from the chamber  452  via the line  516  into and through the valve  470 . It should be noted that the pressure in the line  516  is transmitted to the port  538  of the flow control device  480 , which keeps the flow control device  480  in the closed position. At the same time, the pressure in the line  516  is transmitted to the port  524  of the flow control device  470 , which maintains the flow control device  470  in the open position. Thus, the fluid flows through the flow control device  470  to the line  460 . Simultaneously, the increasing volume in the second chamber  454  creates a negative pressure that draws fluid from the line  458 , across the open flow control device  470 , and into the line  514 . Thus, the chamber  454  fills with fluid as fluid is ejected from the chamber  452 . 
         [0046]    After completing this first stroke, the piston  456  reduces the volume of the second chamber  454  while increasing the volume of first chamber  452 . This action forces fluid from the second chamber  454  via the line  514  into and through the valve  480 . It should be noted that the pressure in the line  514  is transmitted to the port  522  of the flow control device  470 , which keeps the flow control device  470  in the closed position. At the same time, the pressure in the line  514  is transmitted to the port  540  of the flow control device  480 , which maintains the flow control device  480  in the open position. Thus, the fluid flows through the flow control device  480  to the line  460 . Simultaneously, the increasing volume in the first chamber  452  creates a negative pressure that draws fluid from the line  458 , across the open flow control device  480 , and into the line  516 . Thus, the chamber  452  fills with fluid as fluid is ejected from the chamber  452 . 
         [0047]    As noted previously, the teachings of the present disclosure may be used in any number of industries. One non-limiting application is for tools used in a wellbore.  FIG. 10  schematically illustrates a wellbore system  10  deployed from a rig  12  into a borehole  14 . While a land-based rig  12  is shown, it should be understood that the present disclosure may be applicable to offshore rigs and subsea formations. In some embodiments, the wellbore system  10  may be a drilling system configured to form the borehole  14  using tools such as a drill bit (not shown). In such embodiments, the carrier  16  may be a coiled tube, casing, liners, drill pipe, etc. In other embodiments, the wellbore system  10  may be conveyed with a non-rigid carrier. In such arrangements, the carrier  16  may be wirelines, wireline sondes, slickline sondes, e-lines, etc. The term “carrier” as used herein means any device, device component, combination of devices, media and/or member that may be used to convey, house, support or otherwise facilitate the use of another device, device component, combination of devices, media and/or member. 
         [0048]    The wellbore system  10  may include a number of tools, instruments, and devices that utilize fluid flow to perform desired functions. Illustrative devices include pumps and valves. As is known, fluids in the borehole  14  can include entrained material that can clog these flow control devices. The shear seal arrangements of the present disclosure may be used in such devices to render flow control devices less susceptible to clogging and reduced operating efficiency. These shear seal arrangements may be particularly effective when the fluid being conveyed is a fluid other than a clean hydraulic fluid; e.g., drilling fluid, a formation fluid, etc. 
         [0049]    While the foregoing disclosure is directed to the one mode embodiments of the disclosure, various modifications will be apparent to those skilled in the art. It is intended that all variations be embraced by the foregoing disclosure.