Abstract:
A wet connection system including a first connector configured to connect to a first control line. The first connector including at least one first pathway arranged to fluidly communicate with the first control line, and a biased movable plug movable within the first connector; and, a second connector configured to connect to a second control line. The second connector including a second pathway in fluid communication with the second control line and a biased sleeve movable within the second connector; wherein the first and second connectors are each pressure balanced to prevent internal control line pressure. External borehole pressures from moving the plug and sleeve from their biased positions blocking the respective first and second pathways in the disconnected condition of the wet connection system. Mating of the first connector with the second connector moves the movable plug and the sleeve against their bias to fluidically couple the first and second pathways in a connected condition of the wet connection system. Also included is a method of pressure balancing a hydraulic wet connection system in a downhole environment.

Description:
BACKGROUND 
       [0001]    In the drilling and completion industry, the formation of boreholes for the purpose of production or injection of fluid is common. The boreholes are used for exploration or extraction of natural resources such as hydrocarbons, oil, gas, water, and alternatively for CO2 sequestration. 
         [0002]    It is sometimes necessary to connect, disconnect, and/or reconnect various components of tools within a borehole in the downhole environment. When control lines are provided in the separate components, they must be reconnected by connectors on each separate component so as to provide a common pathway. Some downhole hydraulic connectors rely on a spring reinforced poppet to resist the encroachment of wellbore fluids into the control line when the components are separated, however this method is limited in pressure differential by the force of the spring holding the poppet in place. Once the hydrostatic pressure overcomes the spring, borehole fluid will leak into the control line. Other downhole hydraulic connectors supply virtually no borehole fluid protection at all and simply allow the fluid access to the control line. This may not be desirable depending on the borehole fluid and the internal make up of the tools to which the control line is attached. As an alternative to allowing borehole fluid encroachment, another method involves running a lower string while mated to an upper tool string with control line all the way to surface in order to maintain a positive pressure balance on the control line. 
         [0003]    The art would be receptive to improved apparatus and methods for downhole wet connectors that address the hydraulic control lines attached to such connectors. 
       BRIEF DESCRIPTION 
       [0004]    A wet connection system includes a first connector configured to connect to a first control line, the first connector including at least one first pathway arranged to fluidly communicate with the first control line, and a biased movable plug movable within the first connector; and, a second connector configured to connect to a second control line, the second connector including a second pathway in fluid communication with the second control line and a biased sleeve movable within the second connector; wherein the first and second connectors are each pressure balanced to prevent internal control line pressure and external borehole pressures from moving the plug and sleeve from their biased positions blocking the respective first and second pathways in the disconnected condition of the wet connection system, and mating of the first connector with the second connector moves the movable plug and the sleeve against their bias to fluidically couple the first and second pathways in a connected condition of the wet connection system. 
         [0005]    A wet connection system including at least one of a first connector and a second connector, the first connector configured to connect to a first control line, the first connector includes a first connector housing having a first bore, at least one first pathway separate from the first bore, and a fluidic mating area, the at least one first pathway configured to fluidly communicate the fluidic mating area with the first control line, the fluidic mating area interposed between a biasing area of the first bore and a second connector receiving area of the first bore; a biased movable plug movable within the first bore, the movable plug having a first end facing the biasing area of the first bore and a second end facing the second connector receiving area of the first bore, the movable plug biased to block the fluidic mating area to prevent fluidic communication between the first bore and the at least one first pathway in a disconnected condition of the wet connection system, the movable plug movable outside of the fluidic mating area in a connected condition of the wet connection system; and a pressure balancing aperture balancing pressure between the biasing area and the second connector receiving area; and, the second connector configured to connect to a second control line, the second connector including: a probe housing a second pathway in fluid communication with the second control line, the probe including at least one radially directed connector port communicating with the second pathway; a biased movable sleeve configured to at least partially surround the probe and cover the at least one connector port in the disconnected condition and reveal the at least one connector port in the connected condition; first and second radial seals between the sleeve and probe, the first seal disposed on a first side of the at least one connector port and the second seal disposed on a second side of the at least one connector port in the disconnected condition of the wet connection system. 
         [0006]    A method of pressure balancing a hydraulic wet connection system in a downhole environment, the method includes providing a first connector with a pressure balancing aperture balancing pressure between opposing sides of a biased movable plug, the plug biased to block, in a disconnected condition, a first pathway in the first connector, the first connector configured to prevent internal control line pressure and external borehole pressures from moving the plug from its biased position in a disconnected condition of the wet connection system; providing a second connector with first and second seals between a probe and a biased movable sleeve, the sleeve biased to block, in a disconnected condition, ports in the probe that connect to a second pathway, the second connector configured to prevent internal control line pressure and external borehole pressures from moving the sleeve from its biased position in a disconnected condition of the wet connection system; selecting one of the first connector and the second connector as a downhole connector, and the other of the first connector and the second connector as an uphole connector; assembling the downhole connector to a first control line; installing the downhole connector to an uphole end of a downhole tool component; employing the downhole tool component in a borehole; assembling the uphole connector to a second control line; installing the uphole connector to a downhole end of an uphole tool component; running the uphole tool component into the borehole; and, connecting the uphole connector to the downhole connector; wherein connecting the uphole connector to the downhole connector moves the movable plug and the sleeve against their bias to fluidically couple the first and second pathways in a connected condition of the wet connection system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawing, like elements are numbered alike: 
           [0008]      FIG. 1  shows a cross-sectional view of an exemplary embodiment of a female connector for a downhole wet connection system; 
           [0009]      FIG. 2  shows a cross-sectional view of an exemplary embodiment of a male connector for a downhole wet connection system; 
           [0010]      FIG. 3  shows a cross-sectional view of the female connector of  FIG. 1  in contact with the male connector of  FIG. 2 ; 
           [0011]      FIG. 4  shows a cross-sectional view of the female connector of  FIG. 1  fully connected with the male connector of  FIG. 2 ; 
           [0012]      FIG. 5  shows a cross-sectional view of another exemplary embodiment of a female connector for a downhole wet connection system; 
           [0013]      FIG. 6  shows a cross-sectional view of the female connector of  FIG. 5  in contact with the male connector of  FIG. 2 ; and, 
           [0014]      FIG. 7  shows a cross-sectional view of the female connector of  FIG. 5  fully connected with the male connector of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
         [0016]    Exemplary embodiments of a hydrostatically pressure balanced downhole hydraulic wet connection system are described herein. In the exemplary embodiments, the connection system can be run downhole while disconnected without increased downhole hydrostatic pressure shifting any features therein that will subsequently be moved as the connectors within the connection system are mated. This prevents the introduction of wellbore fluids into the hydraulic control lines attached to the connectors despite a differential between the internal control line pressure and the wellbore hydrostatic pressure. As the male and female connectors of the connection system are mated, features are moved creating a continuous hydraulic path to a previously placed control line. 
         [0017]    With reference to  FIGS. 1-4 , an exemplary embodiment of a wet connection system  10  is shown to include a female connector  12  (shown in  FIGS. 1 ,  3 , and  4 ) and a male connector  14  (shown in  FIGS. 2 ,  3 , and  4 ). The female connector  12  is connectable to a first tool component  16 , such as a carrier tool, control string, or upper completion, while the male connector  14  is connectable to a second tool component  18 , such as a carrier tool, control string, or lower completion. Typically the female connector  12  will be positioned uphole of the male connector  14  within a borehole, because the male connector  14  is less likely to suffer from a collection of debris therein, however the connectors  12 ,  14  are functional in a reversed orientation. The female connector  12 , shown on its own in  FIG. 1 , will now be described. The female connector  12  includes a female connector housing  20  having a longitudinal bore  22  extending along a longitudinal axis  24  of the female connector  12 . At least one bleed port  26  penetrates the female connector housing  20  and fluidically connects the longitudinal bore  22  to an exterior of the housing  20 , such as the environment of the borehole during use of the wet connection system  10 . The bleed port  26  functions as a pressure balancing aperture by allowing equal pressure to be placed on both sides of a movable plug  28 , which will be described in more detail further below. 
         [0018]    A control line  30  is supported at a first end  32  of the female connector housing  20  by a control line supporting structure  34 , such as a male jamnut connector  36  that is inserted into a female connector nut  38 . The control line supporting structure  34 , in particular the female connector nut  38 , is sealed to a control line supporting structure receiving portion  40  of the housing  20 , adjacent the first end  32  thereof, with seal  42 . In the illustrated embodiment, the control line supporting structure receiving portion  40  of the housing  20  receives the female connector nut  38  partially therein, with a shoulder  44  of the female connector nut  38  abutting with the first end  32  of the housing  20 , and the female connector nut  38  partially receives the jamnut connector  36  therein. The control line  30  is supported within a longitudinal bore of the jamnut connector  36  and within a longitudinal bore of the female connector nut  38 . 
         [0019]    The control line  30  includes a longitudinal bore  46  which is in fluid communication with fluid path hub  48  in the housing  20  of the female connector  12 . The fluid path hub  48  includes one or more radially extending fluid paths  50  that connect, respectively, to first ends  52  of one or more longitudinally extending fluid paths  54  within the housing  20 . In the illustrated embodiment, the longitudinally extending fluid paths  54  are substantially parallel to the longitudinal axis  24  and do not include any moving parts therein, in contrast to poppet valves that typically obstruct fluid pathways. Second ends  56  of the longitudinally extending fluid paths  54  fluidically connect to a fluidic mating area  58 . Fluidic mating area  58  may include an outer diameter that is larger than an outer diameter of the longitudinal bore  22 , or may include separate radially extending paths that connect the longitudinal bore  22  to the longitudinally extending fluid paths  54 . 
         [0020]    A spring  60  is positioned within a spring area  62  of the longitudinal bore  22  of the housing  20 . A first end  64  of the spring  60  abuts against a block  66  that is sealed by seal  68  within the housing  20 . The seal  68 , such as an O-ring, is supported within a groove or indent in the block  66 . The block  66 , which may be seated within the longitudinal bore  22 , is axially interposed between the fluid path hub  48  and the spring area  62 , so as to seal the longitudinal bore  22  from the fluid path hub  48 . A second end  70  of the spring  60  abuts against a first end  72  of the movable plug  28 . The movable plug  28  is supported within the longitudinal bore  22  by seals  74 ,  76  that flank the fluidic mating area  58 . The seals  74 ,  76 , such as O-rings, are radial seals that have a substantially same diameter as each other and are supported within indents in the housing  20 , where the indents are radially expanded sections from the longitudinal bore  22 . Because the seals  74 ,  76  are supported within indents in the housing  20 , they do not move with the movable plug  28 , and are therefore substantially axially immovable. The first end  72  of the movable plug  28  may include a shoulder  78  that abuts a stop  80 , a reduced diameter section of the longitudinal bore  22 , to prevent the movable plug  28  from being pushed further out the housing  20  by the spring  60 . The movable plug  28  is biased by the spring  60  in direction A to block the fluidic mating area  58  with the movable plug  28 , thus preventing fluid communication between the paths  54  and an exterior of the female connector  12  in a disconnected condition of the female connector  12 , as depicted in  FIG. 1 . The longitudinal bore  22  of the housing  20  further includes a male connector receiving area  82 , that may additionally included a flared portion  84  to guide and receive operative portions of the male connector  14  therein, as will be further described below. 
         [0021]    The male connector  14 , shown on its own in  FIG. 2 , includes a male connector housing  86  that receives a movable sleeve  88  within a first end  90  and a control line supporting structure  92  within a second end  94  of housing  86 . A first end  96  of the male connector sleeve  88  is exterior of the housing  86  and a second end  98  of the male connector sleeve  88  is disposed internally within the housing  86 . A shoulder  100  of the male connector sleeve  88 , such as an enlarged outer diameter portion of the sleeve  88 , abuts with a stop  102 , such as a reduced diameter portion of longitudinal bore  104  adjacent the first end  90  of the male connector housing  86 , to prevent the male connector sleeve  88  from disengaging with the housing  86 . The control line supporting structure  92  may include a male connector nut  106  received within a control line supporting structure receiving portion  108  of the male connector housing  86  and a jamnut connector  110  received within the male connector nut  106 . A control line  112  is supported within a longitudinal bore of the jamnut connector  110  and within a longitudinal bore of the connector nut  106 . The control line supporting structure  92  may be substantially the same as the control line supporting structure  34  attached to the female connector housing  20 . 
         [0022]    The control line  112  includes a longitudinal bore  114  which is in fluid communication with a longitudinal bore  116  of a male connector probe  118  that extends along a longitudinal axis  120  of the male connector  14 . The male connector probe  118  extends beyond the first end  90  of the male connector housing  86 . The male connector probe  118  includes radially directed ports  122  adjacent a first end  124  of the male connector probe  118  that connects the longitudinal bore  116  of the male connector probe  118  to an exterior of the male connector probe  118 . The longitudinal bore  116 , which forms a pathway from the control line  112  to the ports  122  need not contain any moving parts therein. The ports  122  are located exteriorly of the housing  86 . The first end  124  of the probe  118  may be positioned exteriorly of the sleeve  88 . A second end  126  of the probe  118  fluidically connects the longitudinal bore  116  of the probe  118  with the longitudinal bore  114  of the control line  112 . A spring  128  surrounds the male connector probe  118  within the male connector housing  86 . A first end  130  of the spring  128  abuts the second end  98  of the movable sleeve  88  and a second end  132  of the spring  128  abuts the connector nut  106 . The spring  128  biases the movable sleeve  88  in the direction B. The movable sleeve  88  is sealed to the male connector probe  118  via radial seals  134 ,  136 , such as O-rings, which are axially secured relative to the sleeve  88  within indents of the sleeve  88 . The ports  122  are axially disposed between the seals  134 ,  136 , in the biased condition of the movable sleeve  88 , such that fluid communication between an exterior of the male connector probe  118  and the longitudinal bore  116  of the male connector probe  118  is prevented in the disconnected condition of the male connector  14 . 
         [0023]      FIG. 3  depicts initial contact of the male connector  14  with the female connector  12 . The first end  96  of the movable sleeve  88  abuts with the second end  33  of the housing  20  while the first end  124  of the male connector probe  118  is guided within the longitudinal bore  22  of the housing  20  by the flared portion  84  of the male connector receiving area  82  of the bore  22 . At the initial contact depicted in  FIG. 3 , the movable plug  28  still blocks the fluidic mating area  58  and the movable sleeve  88  still blocks the male connector ports  122 . Further engagement between the female and male connectors  12 ,  14  is shown in  FIG. 4 , such as via an upper completion pushing the female connector  12  onto the male connector  14  attached to a lower completion. The second end  33  of the female connector housing  20  pushes the movable sleeve  88  into the male connector housing  86  in direction A against the bias of the spring  128 , while the movable plug  28  is pushed by the male connector probe  118  in direction B against the bias of the spring  60 . In the fully connected condition shown in  FIG. 4 , the ports  122  of the male connector probe  118  are positioned in the fluidic mating area  58  of the female connector housing  20  of the female connector  12 . The probe  118  in the connected condition is sealed within the housing  20  by the seals  74 ,  76  that flank the fluidic mating area  58 . In the connected condition, the longitudinal axis  24  of the female connector  12  aligns with the longitudinal axis  120  of the male connector  14  to form a common longitudinal axis of the wet connection system  10 . Also in the connected condition, the control line  30  is in fluid communication with the control line  112 . The hydraulic path from the control line  30  to the control line  112  is via the fluid path hub  48 , radially extending paths  50 , longitudinally extending paths  54 , fluid mating area  58 , male connector ports  122 , and longitudinal bore  116  of the male connector probe  118 . 
         [0024]    In the embodiment shown in  FIGS. 1-4 , wellbore pressure is ported to the longitudinal bore  22  of the female connector  12  via the bleed port  26  allowing the connection system  10  to maintain pressure balance and eliminate a de-mating force created from applied control line pressure. De-mating forces are only generated by hydrostatic differential pressure vs. the internal control line hydrostatic pressure and sleeve/plug springs, which does not occur in the wet connection system  10 . 
         [0025]    With reference to  FIGS. 5-7 , another exemplary embodiment of a wet connection system  200  is shown to include a female connector  212  and a male connector  14 . The male connector  14  may be the same or substantially the same as the male connector  14  shown in  FIG. 2  of the wet connection system  10  and therefore reference may be made to  FIGS. 2-4  for a description of the male connector  14  of the wet connection system  200 . The female connector  212 , shown on its own in  FIG. 5 , will now be described. The female connector  212  includes a female connector housing  220  having a longitudinal bore  222  extending along a longitudinal axis  224  of the female connector  212 . A control line  30  is supported adjacent a first end  232  of the female connector  212  by a control line supporting structure  34 , as in the wet connection system  10 . That is, the male jamnut connector  36  is inserted into the female connector nut  38  and received in a control line supporting structure receiving portion  240 , as in the female connector  14  of the wet connection system  10 . 
         [0026]    The control line  30  includes longitudinal bore  46  which is in fluid communication with fluid path hub  248  and one or more radially extending fluid paths  250  that connect to first ends  252  of one or more longitudinally extending fluid paths  254  within the female connector housing  220 . Second ends  256  of the longitudinally extending fluid paths  254  fluidically connect to the fluidic mating area  258 . Fluidic mating area  258  may include an outer diameter that is larger than an outer diameter of the longitudinal bore  222 , or may include separate radially extending paths that connect the longitudinal bore  222  to the longitudinally extending paths  254 . A spring  260 , or other biasing device, is positioned within a biasing area or spring area  262  of the longitudinal bore  222  of the female connector housing  220 . A first end  264  of the spring  260  abuts against a block  266  that is sealed by seal  268  within the female connector housing  220 . The seal  268 , such as an O-ring, is supported within a groove in the block  266 . The block  266  is axially interposed between the fluid path hub  248  and the spring area  262  of the longitudinal bore  222 . A second end  270  of the spring  260  abuts against a first end  272  of a movable plug  228 . The movable plug  228  is supported within the longitudinal bore  222  by seals  274 ,  276  that flank the fluidic mating area  258 . The seals  274 ,  276 , such as O-rings, have a same diameter as each other and are supported within indents in the movable plug  228  to move with the movable plug  228  during connection. The first end  272  of the movable plug  228  may include a shoulder  278  that abuts a stop  280  within the longitudinal bore  222  to prevent the movable plug  228  from being pushed further out the female connector housing  220  by the spring  260 . The movable plug  228  is biased by the spring  260  in direction A to block the fluidic mating area  258  with the movable plug  228 , thus preventing fluid communication between the longitudinal paths  254  and an exterior of the female connector housing  220  in a disconnected condition of the female connector  212 . The longitudinal bore  222  of the housing  220  further includes a male connector receiving area  282  having a flared portion  284  to guide and receive the male connector  14  therein. 
         [0027]    Between a second end  273  of the movable plug  228  and the second end  233  of the female connector housing  220 , a seal  286 , such as an O-ring, is provided in an indent in the male connector receiving area  282  of the longitudinal bore  222 . Also different from the movable plug  28  of the female connector  12 , the movable plug  228  of the female connector  212  includes a longitudinal piston port  288  extending from the first end  272  to the second end  273  of the movable plug  228 , providing fluid communication between the spring area  262  of the longitudinal bore  222  and an exterior of the female connector  212  in the disconnected condition of the female connector  212 . Also unlike the female connector  12 , the female connector housing  220  does not include the bleed port  26 . 
         [0028]    The wet connection system  200  operates substantially as does the wet connection system  10 , however the male connector probe  118 , upon entry within the longitudinal bore  222  of the female connector housing  220 , is sealed to the female connector  212  by the seal  286  instead of the seals  74 ,  76 , as shown in  FIG. 7 . It should be noted that seal  286  and seals  134 ,  136  may have the same inner diameter to seal the male connector probe  118  therein with substantially constant radially directed sealing forces. By blocking the piston port  288  with the probe  118 , well bore pressure (pressure from the borehole in which the wet connection system  200  is employed) is eliminated within the system  200  after mating. Applied control line pressure will generate a de-mating force but hydrostatic forces are eliminated. That is, in the wet connection system  200 , the bleed port  26  of the wet connection system  10  is eliminated, the seals  274 ,  276  are placed on the movable plug  228 , and the piston port  288  in the movable plug  228  allows fluid bypass in a disconnected condition and while initially mating the male and female connectors  14 ,  212 . However, in the connection condition as shown in  FIG. 7 , hydrostatic pressure is eliminated from the connectors  14 ,  212 . De-mating forces are generated by the sleeve/plug springs  260 ,  128  and the applied control line force. Both connection systems  10 ,  200  will have benefits depending on the purpose of the control line connection required for a particular downhole operation. 
         [0029]    An exemplary operating procedure of the wet connection systems  10 ,  200  will involve assembling a first connector (either male  14  or female  12 ,  212 ), attaching it to control line  30 ,  112 , and installing it in a carrier tool that will subsequently be placed at the top of a lower completion or section of tool string, e.g. tool component  18 , that is intended to connect or disconnect at a future point. A second connector (female  12 ,  212  or male  14 ) is assembled, attached to a control line  112 ,  30 , and installed in a carrier tool that will subsequently be placed at the bottom of a completion or section of tool string, e.g. tool component  16 , that is intended to connect or disconnect at a future point. While each connector is disconnected, the sleeve  88  in the male connector  14  covers ports  122  and the movable plug  28 ,  228  in the female connector  12 ,  212  covers the fluidic mating area  58 ,  258  separating the exterior of each connector  14 ,  12 ,  212  from the internal control line volume, respectively. The sleeve/plug is sealed with an equal pressure area on both sides so that both control line pressure and ambient (hydrostatic) pressure impart equal forces in both axial directions, directions A, B. This prevents the internal or external pressure from moving the sleeve/plug. The sleeve/plug is biased with a spring  128 ,  60 ,  260  against a shoulder that prevents an unwanted shift from occurring. The tool component  16  and second connector with control line attached thereto is then run into the borehole to connect with the first connector. When male and female connectors  14 ,  12 ,  212  are mated the sleeve/plug is moved by the other connector exposing the internal control line pressure of one connector to the internal control line pressure of the other connector. Control line pressure can then be applied to downhole tools or other chemicals can then be injected to the formation. When de-mating is required, the biasing spring  128 ,  60 ,  260  returns the sleeve/plug to its starting position. 
         [0030]    The use of the pressure balanced sleeve and plug in the wet connection systems  10 ,  200  described herein is an improvement over downhole hydraulic connectors that rely on a spring reinforced poppet to resist the encroachment of wellbore fluids into the control line, as such connectors having spring reinforced poppets are limited in pressure differential by the force of the spring holding the poppet in place. Once the hydrostatic pressure overcomes the spring of the spring reinforced poppets, wellbore fluid will leak into the control line. The wet connect systems  10 ,  200  are further an improvement over downhole hydraulic connectors that supply virtually no wellbore fluid protection at all and simply allow the fluid access to the control line, which may not be desirable depending on the wellbore fluid and the internal make up of the tools the control line is attached to. The wet connection system  10  also advantageously does not create additional de-mating forces with applied control line pressure. This allows the operator to apply control line pressure without concern that the pressure is causing the male and female connectors  14 ,  12  to de-mate. 
         [0031]    The wet connection systems  10 ,  200  advantageously provide the ability to run the connectors  12 ,  212 ,  14  downhole without concern of wellbore fluid encroachment into the hydraulic control lines  30 ,  112 . Radial seals are used in the wet connection systems  10 ,  200  that are balanced in the axial direction no matter where a higher pressure is located. This is especially true in the case of running multiple stage completions. Prior hydraulic connectors require either allowing wellbore fluid encroachment or running the lower string while mated to an upper tool string with control line all the way to surface in order to maintain a positive pressure balance on the control line. Not having to run control line along an upper run-in string saves hours of rig time required to install control line protection that would subsequently have to be removed on the way back out of a borehole. 
         [0032]    While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.