Patent Grant
7055598
This invention relates, in general, to controlling the inflow of formation fluids from a well that traverses a hydrocarbon bearing subterranean formation and, in particular, to a fluid flow control device for controlling the inflow of formation fluids and a method for use of the same.
Without limiting the scope of the present invention, its background will be described with reference to producing fluid from a subterranean formation, as an example.
After drilling each of the sections of a subterranean wellbore, individual lengths of relatively large diameter metal tubulars are typically secured together to form a casing string that is positioned within each section of the wellbore. This casing string is used to increase the integrity of the wellbore by preventing the wall of the hole from caving in. In addition, the casing string prevents movement of fluids from one formation to another formation. Conventionally, each section of the casing string is cemented within the wellbore before the next section of the wellbore is drilled.
Once this well construction process is finished, the completion process may begin. The completion process comprises numerous steps including creating hydraulic openings or perforations through the production casing string, the cement and a short distance into the desired formation or formations so that production fluids may enter the interior of the wellbore. The completion process may also include installing a production tubing string within the well casing which is used to produce the well by providing the conduit for formation fluids to travel from the formation depth to the surface.
To selectively permit and prevent fluid flow into the production tubing string, it is common practice to install one or more sliding sleeve type flow control devices within the tubing string. Typical sliding sleeve type flow control devices comprise a generally tubular body portion having side wall inlet openings formed therein and a tubular flow control sleeve coaxially and slidably disposed within the body portion. The sleeve is operable for axial movement relative to the body portion between a closed position, in which the sleeve blocks the body inlet ports, and an open position, in which the sleeve uncovers the ports to permit fluid to flow inwardly therethrough into the interior of the body and thus into the interior of the production tubing string. The sliding sleeves thus function as movable valve elements operable to selectively permit and prevent fluid inflow. Generally, cylindrical shifter tools, coaxially lowered into the interior of the tubing string, are utilized to shift selected ones of the sliding sleeves from their closed positions to their open positions, or vice versa, to provide subsurface flow control in the well.
It has been found, however, that typical sliding sleeve type flow control devices are not suitable in completions requiring sand control as they are not compatible with typical sand control screens. Recently, a device has been proposed that combines sand control and fluid flow control, which was disclosed in U.S. Pat. No. 5,896,928. Specifically, the device includes a generally tubular body for placement into the wellbore. The tubular body has a sand control screen at an outer surface for preventing sand from entering into tubular body. After the fluid flows through the sand control screen it must pass through a labyrinth. A slidable sleeve on the labyrinth controls the fluid velocity therethrough. The slidable sleeve is moved by a remotely and electrically-operated device placed in the tubular body. The fluid leaving the labyrinth passes to the tubing string for carrying the fluid to the surface.
It has been found, however, the labyrinth type flow control devices are difficult and expensive to manufacture and can be unreliable under certain inflow conditions. Accordingly, need has arisen for a fluid flow control device for controlling the inflow of formation fluids in a completion requiring sand control. A need has also arisen for such a fluid flow control device that is not difficult or expensive to manufacture. Further, a need has arisen for such a fluid flow control device that is reliable in a variety of flow conditions.
The present invention disclosed herein comprises a fluid flow control device for controlling the inflow of formation fluids in completions requiring sand control and a method for use of the same. The fluid flow control device of the present invention is not difficult or expensive to manufacture. In addition, the fluid flow control device of the present invention is reliable in a variety of flow conditions.
The fluid flow control device of the present invention comprises a sand control screen having a base pipe with a set of openings that allows the production fluids to flow therethrough. The fluid flow control device also includes a sleeve coaxially disposed adjacent to the base pipe. The sleeve also has a set of openings that allows the production fluids to flow therethrough. The sleeve is selectively positionable relatively to the base pipe and may form an annulus therebetween such that the pressure drop in the production fluids flowing therethrough is selectively controllable by adjusting the alignment of the set of openings of the sleeve relative to the set of openings of the base pipe.
In one embodiment of the fluid flow control device of the present invention, the sleeve is axially selectively positionable relative to the base pipe. In another embodiment, the sleeve is rotatably selectively positionable relative to the base pipe. In yet another embodiment, the sleeve is axially and rotatably selectively positionable relative to the base pipe. In one embodiment of the fluid flow control device of the present invention, the sleeve is coaxially positioned interiorly relative to the base pipe. In another embodiment of the fluid flow control device of the present invention, the sleeve is coaxially positioned exteriorly relative to the base pipe.
In one embodiment of the fluid flow control device of the present invention, the set of openings of the sleeve has substantially the same geometry as the set of openings of the base pipe. In another embodiment, the set of openings of the sleeve has a different geometry than the set of openings of the base pipe. In one embodiment of the fluid flow control device of the present invention, the openings of the sleeve have substantially the same shape as the openings of the base pipe. In another embodiment, the openings of the sleeve have a different shape than the openings of the base pipe.
The fluid flow control device of the present invention has a fully open position wherein the pressure drop in the production fluids traveling through the set of openings of the sleeve, the annulus between the sleeve and the base pipe and the set of openings of the base pipe is at a minimum. In addition, most embodiments of the fluid flow control device of the present invention have partially open or choking positions wherein the pressure drop in the production fluids is increased. Further, some embodiments of the fluid flow control device of the present invention have a fully closed position wherein the production fluids are prevented from traveling therethrough.
The fluid flow control device of the present invention may be operated between its fully open position, its choking positions and its fully closed position using a variety of techniques such as using a mechanical shifting tool, using hydraulic pressure, using an electrically operated device or the like. In addition, downhole pressure sensors positioned exteriorly and interiorly of the fluid flow control device may be used to determine the pressure drop in the production fluids. Such pressure readings may be used by a downhole control circuit to automatically adjust the position of the sleeve relative to the base pipe to control the pressure drop in the production fluids. Other types of sensors may also be used in conjunction with the fluid flow control device of the present invention such as temperature sensors and fluid composition sensors that may be used to determine the constituents of the production fluids including, for example, the oil, gas, water, solids and fines content of the fluid as well as, for example, the API gravity of the fluid.
In another aspect of the present invention a method for controlling the inflow of production fluids comprises providing a production conduit including a sand control screen having a base pipe with a first set of openings and a sleeve coaxially disposed adjacent to the base pipe having a second set of openings, installing the production conduit within the wellbore, producing the production fluids into the production conduit through the first set of openings of the base pipe and the second set of openings of the sleeve and selectively adjusting the sleeve relative to the base pipe such that the pressure drop in the production fluids is controlled by adjusting the alignment of the first set of openings relative to the second set of openings.
The present invention also comprises a fluid flow control device that includes a tubular member having at least one fluid passageway in a sidewall section thereof. A sand control screen assembly is positioned exteriorly around the tubular member. The sand control screen assembly has a filter medium section that defines a first annular region with the tubular member and a housing section that defines a second annular region with the tubular member. A sleeve is slidably positioned within the second annular region. The sleeve has an open position wherein fluid communication is permitted between the second annular region and the fluid passageway and a closed position wherein fluid communication is prevented between the second annular region and the fluid passageway.
The fluid flow control device also includes a hydraulic control line that extends from a surface location to the sand control screen assembly. The hydraulic control line has a first section with a terminus that is selectively in fluid communication with the sleeve to operate the sleeve from the open position to the closed position. A eutectic valve is positioned within the housing section to selectively prevent and permit fluid communication between the first section of the hydraulic control line and the sleeve. The hydraulic control line also has a second section that passes through the first annular region and extends downhole of the sand control screen assembly.
The fluid flow control device has a sensor that may be positioned on the housing section of the sand control screen assembly to sense at least one downhole parameter such as temperature, pressure, fluid composition or the like. An energy conductor that extends from the surface and passes through the sand control screen assembly is in communication with the eutectic valve and the sensor. In operation, energy is supplied to the eutectic valve in response to one of the sensed downhole parameters, which melts the eutectic valve and establishes fluid communication between the first section of the hydraulic control line and the sleeve, thereby operating the sleeve from the open position to the closed position.
For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the present invention.
Referring initially to
Positioned within casing string 28 and extending from wellhead installation 22 is a tubing string 36. Tubing string 36 provides a conduit for formation fluids to travel from formations 14, 16 to the surface. A pair of packers 38, 40 provide a fluid seal between tubing string 36 and casing string 28 and define a production interval adjacent to formation 14. Likewise, packers 42, 44 provide a fluid seal between tubing string 36 and casing string 28 and define a production interval adjacent to formation 16.
Positioned within tubing string 36 in the production interval adjacent to formation 14 are fluid flow control devices 46, 48 and 50. Likewise, positioned within tubing string 36 within the production interval adjacent to formation 16 are fluid flow control devices 52, 54 and 56. As explained in greater detail below, each of the fluid flow control devices 46–56 provides not only fluid flow control capability but also sand control capability.
In the illustrated embodiment, there are three fluid flow control devices 46, 48, 50 associated with formation 14 and three fluid control devices 52, 54, 56 associated with formation 16. Accordingly, the inflow of fluid from formation 14 and formation 16 may be controlled. For example, if the reservoir pressure of formation 14 is significantly higher than the reservoir pressure of formation 16, fluid flow control devices 46, 48, 50 may be used to choke the fluid flow from formation 14 to a greater extent than fluid flow control devices 52, 54, 56 will choke the fluid flow from formation 16. In addition, the fluid flow control devices of the present invention are independently controllable within each production interval. For example, certain ones of fluid flow control devices 46, 48, 50 may be used to choke or even close off certain sections of the production interval adjacent to formation 14 to prevent the production of water or other undesirable fluids. Similarly, one or all of the fluid flow control devices associated with a particular production interval may be adjusted over time as the adjacent formation becomes depleted or as downhole equipment experiences wear.
It should be understood by those skilled in the art that even though
It should be understood by those skilled in the art that even though
Referring next to
Positioned around base pipe 64 is a filter medium 68. In the illustrated embodiment, filter medium 68 is a fluid-porous, particulate restricting material such as a plurality of layers of a wire mesh that are diffusion bonded or sintered together to form a porous wire mesh screen designed to allow fluid flow therethrough but prevent the flow of particulate materials of a predetermined size from passing therethrough. Disposed around filter medium 68 is an outer shroud 70. Outer shroud 70 has a plurality of openings 72 which allow the flow of production fluids therethrough. The exact number, size and shape of openings 72 are not critical to the present invention, so long as sufficient area is provided for fluid production and the integrity of outer shroud 70 is maintained. Outer shroud 70 is designed to protect filter medium 68 during installation of fluid flow control device 60 into the wellbore as well as during production therethrough.
Positioned coaxially within base pipe 64 is a sleeve 74. Sleeve 74 is slidable coupled within base pipe 64 using detents such as collets or pins (not pictured) or other suitable devices that are well known to those skilled in the art. Sleeve 74 has a plurality of openings 76. As with openings 66 of base pipe 64, openings 76 of sleeve 74 may have any geometric configuration that is suitable for allowing the flow of production fluids therethrough. While the illustrated embodiment depicts openings 76 of sleeve 74 as having the same shape and size as openings 66 of base pipe 64, this relationship is not required by the present invention. For example, a fluid flow control device of the present invention could have slotted openings in sleeve 74 while having round openings in base pipe 64. In the illustrated embodiment, the hole pattern of openings 66 of base pipe 64 and openings 76 of sleeve 74 have substantially the same geometry. In addition, openings 66 of base pipe 64 and openings 76 of sleeve 74 are substantially aligned with one another. Accordingly, when fluid flow control device 60 is in the depicted configuration, the pressure drop in the production fluids traveling therethrough is at a minimum and fluid flow control device 60 is considered to be in its fully opened position. Specifically, to enter in the interior of fluid flow control device 60, the fluid must travel through an entry opening, one of the openings 66 of base pipe 64, an annulus 78 between base pipe 64 and sleeve 74 and an exit opening, one of the openings 76 of sleeve 74. As openings 66 of base pipe 64 and openings 76 of sleeve 74 are substantially aligned with one another, the distance the fluid is required to flow in annulus 78 is at a minimum.
Referring now to
In the illustrated embodiment, sleeve 74 has been axially repositioned to increase the pressure drop experienced by production fluids traveling through annulus 78. Specifically, as the set of openings 66 of base pipe 64 and the set of openings 76 of sleeve 74 have substantially the same hole pattern, when openings 66 and openings 76 are axially misaligned, the distance the formation fluids must travel within annulus 78 is increased, thereby increasing the pressure drop in the formation fluids. The amount of this pressure drop or choking is determined based upon a number of factors including the extent of the misalignment of openings 66 relative to openings 76, the thickness of annulus 78, the viscosity of the formation fluids and the like. In addition, the surface characteristics of either the exterior of sleeve 74 or the interior of base pipe 64 or both may be configured to further control the pressure drop. For example, grooves, channels, knurling, other turbulizing surfaces or the like may be added to one or both of the surfaces to increase the turbulence in the fluid flow thereby increasing the pressure drop across a given distance. Accordingly, once fluid flow control device 80 is installed downhole, the desired amount of pressure drop may be obtained by selectively misaligning openings 66 relative to openings 76 by axially shifting sleeve 74 relative to base pipe 64. Also, it should be noted that sensors, such as position sensors, pressure sensors, temperature sensors, fluid composition sensors and the like may be used in conjunction with mechanical shifter 82 to determined the desired extent of the misaligning of openings 66 relative to openings 76, as explained in greater detail below.
Referring next to
In the illustrated embodiment, sleeve 74 has been rotated ninety degrees relative to base pipe 64. This rotation increases the distance between openings 76 of sleeve 74 and openings 66 of base pipe 64. Accordingly, the formation fluid being produced into fluid flow control device 90 must travel an increased distance in annulus 78 relative to the position shown in
Referring next to
The pressure information may be carried to the surface via energy conductors 104 where it may be processed then command signals may be returned to the control circuit of downhole electrical motor 102 via energy conductors 104 to initiate the operation of downhole electrical motor 102. Alternatively, the pressure information may be sent directly to the control circuit of downhole electrical motor 102 from pressure sensors 106, 108 to initiate operation of downhole electrical motor 102. Additionally, sleeve 74 may include a position sensor that identifies the relative position of sleeve 74 and base pipe 64 to further refine the operation of shifting sleeve 74. The position sensor may be powered by energy conductors 104 and may send signals to the surface or directly to the control circuit of downhole electric motor 102.
In the illustrated embodiment, downhole electrical motor 102 is operable to axially adjust the position of sleeve 74 relative to base pipe 64 and rotatably adjust the position of sleeve 74 relative to base pipe 64. By comparing
Referring now to
Referring next to
Referring now to
Screen connectors 138, 140 attach sand control screen 142 to base pipe 134 such that an annulus 144 is formed between sand control screen 142 and base pipe 134. It should be noted that centralizers or other support members may be disposed within annulus 144 to support sand control screen 142 and maintain the standoff between sand control screen 142 and base pipe 134. Coupled to the upper end of screen connector 140 is a housing member 146. Housing member 146 forms an annulus 148 with base pipe 134 adjacent to openings 136. Disposed within annulus 148 is a sliding sleeve 150 having a pair of seals 151 disposed on the interior side thereof to provide a seal against base pipe 134 and a pair of seals 153 disposed on the exterior side thereof to provide a seal against housing member 146.
Disposed exteriorly of base pipe 134 and extending from the surface is a hydraulic fluid conduit 152. One portion of hydraulic fluid conduit 152 extends into a fluid passageway 154 within housing member 146. Disposed within fluid passageway 154 is a valve 156, such as a eutectic valve. Another portion of hydraulic fluid conduit 152 extends into and through housing member 146 and screen connector 140 into annulus 144. This portion of hydraulic fluid conduit 152 extends through annulus 144 to exit sand control screen assembly 132 through screen connector 138.
Importantly, this portion of hydraulic fluid conduit 152 runs within a recess or channel in housing member 146 and on the inside of sand control screen 142, instead of the outside of sand control screen 142, which removes the need to band hydraulic fluid conduit 152 to the exterior of sand control screen 142 which would block the inflow of formation fluids through those portions of sand control screen 142 covered by the banding material. Also, this portion of hydraulic fluid conduit 152 is protected by having sand control screen 142 positioned exteriorly thereof. Alternatively, the channel on the exterior of housing member 146 could be extended along the exterior of sand control screen 142 such that hydraulic fluid conduit 152 could be positioned within the channel for protection. As can be seen in
A sensor 158 is positioned on the exterior of housing member 146. Sensor 158 may provide information relating to a variety of downhole parameters such as pressure, temperature, fluid composition or the like. Sensor 158 is in communication with the surface via energy conductors 160. Energy conductors 160 may provide power and communication capabilities to sensor 158 as well as to valve 156. In the case in which valve 156 is a eutectic valve and it is desirable to operate fluid flow control device 130 to the closed position, energy is conducted to valve 156 via energy conductors 160 to melt the eutectic material such that operating fluid from hydraulic fluid conduit 152 may be communicated to sliding sleeve 150. Energy conductors 160 also extend through fluid flow control device 130 in a manner similar to hydraulic fluid conduit 152 by passing through housing member 146, screen connector 140, annulus 144 and screen connector 138. Alternatively, instead of using sensor 158 to obtain information relating to downhole parameters, energy conductors 160 may include a fiber optic cable which may be used to obtain certain downhole parameters such as temperature and pressure at particular locations.
In operation and referring both to
If it is determined that production through fluid flow control device 130 should no longer continue, fluid flow control device 130 may be operated to its closed position as depicted in
As described above, hydraulic fluid conduit 152 and energy conductors 160 pass through sand control screen assembly 132 such that similar operations may be conducted on fluid flow control devices or other devices that are positioned downhole of fluid flow control device 130.
Referring now to
Unlike the previously disclosed fluid flow control devices, fluid flow control device 170 is constructed with a sleeve 184 coaxially positioned exteriorly of base pipe 174. Sleeve 184 has a plurality of openings 186 that have substantially the same geometry as openings 176 of base pipe 174. In the illustrated embodiment, sleeve 184 is closely received around base pipe 174 such that there is a friction fit therebetween. This friction fit can operate substantially as a seal to provide significant resistance to flow between sleeve 184 and base pipe 174 when openings 186 are not aligned with openings 176. Alternatively, an annulus may be formed between sleeve 184 and base pipe 174 operating substantially as annulus 78 discussed above. The operation of fluid flow control device 170 is hydraulically controlled in a conventional manner by increasing and decreasing the pressure within hydraulic control lines 188, 190 which allows sleeve 184 to axially shift relative base pipe 174.
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1975162 | Layne | Oct 1934 | A |
| 2342913 | Williams et al. | Feb 1944 | A |
| 2344909 | Williams et al. | Mar 1944 | A |
| 3005507 | Clark, Jr. et al. | Oct 1961 | A |
| 3486558 | Maxwell | Dec 1969 | A |
| 3627046 | Miller et al. | Dec 1971 | A |
| 3865188 | Doggett et al. | Feb 1975 | A |
| 4103741 | Daigle | Aug 1978 | A |
| 4418754 | Stepp | Dec 1983 | A |
| 4428428 | Smyrl et al. | Jan 1984 | A |
| 4494608 | Williams et al. | Jan 1985 | A |
| 4553595 | Huang et al. | Nov 1985 | A |
| 4558742 | Huang et al. | Dec 1985 | A |
| 4627488 | Szarka | Dec 1986 | A |
| 4646839 | Rickey | Mar 1987 | A |
| 4858690 | Rebardi et al. | Aug 1989 | A |
| 4886432 | Kimberlin | Dec 1989 | A |
| 4932474 | Schroeder, Jr. et al. | Jun 1990 | A |
| 4945991 | Jones | Aug 1990 | A |
| 5082052 | Jones et al. | Jan 1992 | A |
| 5111883 | Savery | May 1992 | A |
| 5113935 | Jones et al. | May 1992 | A |
| 5161613 | Jones | Nov 1992 | A |
| 5161618 | Jones et al. | Nov 1992 | A |
| 5228526 | Vshivkov et al. | Jul 1993 | A |
| 5332039 | Primeaux et al. | Jul 1994 | A |
| 5333688 | Jones et al. | Aug 1994 | A |
| 5343949 | Ross et al. | Sep 1994 | A |
| 5355953 | Shy et al. | Oct 1994 | A |
| 5355956 | Restarick | Oct 1994 | A |
| 5386874 | Laramay et al. | Feb 1995 | A |
| 5390966 | Cox et al. | Feb 1995 | A |
| 5419394 | Jones | May 1995 | A |
| 5435393 | Brekke et al. | Jul 1995 | A |
| 5443117 | Ross | Aug 1995 | A |
| 5476143 | Sparlin et al. | Dec 1995 | A |
| 5515915 | Jones et al. | May 1996 | A |
| 5588487 | Bryant | Dec 1996 | A |
| 5636691 | Hendrickson et al. | Jun 1997 | A |
| 5676208 | Finley | Oct 1997 | A |
| 5699860 | Grundmann | Dec 1997 | A |
| 5722490 | Ebinger | Mar 1998 | A |
| 5730223 | Restarick | Mar 1998 | A |
| 5755286 | Ebinger | May 1998 | A |
| 5842516 | Jones | Dec 1998 | A |
| 5848645 | Jones | Dec 1998 | A |
| 5865251 | Rebardi et al. | Feb 1999 | A |
| 5868200 | Bryant et al. | Feb 1999 | A |
| 5890533 | Jones | Apr 1999 | A |
| 5896928 | Coon | Apr 1999 | A |
| 5906238 | Carmody et al. | May 1999 | A |
| 5921318 | Ross | Jul 1999 | A |
| 5934376 | Nguyen et al. | Aug 1999 | A |
| 5988285 | Tucker et al. | Nov 1999 | A |
| 6003600 | Nguyen et al. | Dec 1999 | A |
| 6047773 | Zeltmann et al. | Apr 2000 | A |
| 6059032 | Jones | May 2000 | A |
| 6112815 | Bøe | Sep 2000 | A |
| 6112817 | Voll et al. | Sep 2000 | A |
| 6116343 | Van Petegem et al. | Sep 2000 | A |
| 6125933 | Ross | Oct 2000 | A |
| 6220345 | Jones et al. | Apr 2001 | B1 |
| 6227303 | Jones | May 2001 | B1 |
| 6230803 | Morton et al. | May 2001 | B1 |
| 6276458 | Malone et al. | Aug 2001 | B1 |
| 6286594 | French | Sep 2001 | B1 |
| 6302208 | Walker et al. | Oct 2001 | B1 |
| 6325150 | Rayssiguier | Dec 2001 | B1 |
| 6343651 | Bixenman | Feb 2002 | B1 |
| 6371208 | Norman et al. | Apr 2002 | B1 |
| 6371210 | Bode et al. | Apr 2002 | B1 |
| 6397950 | Streich et al. | Jun 2002 | B1 |
| 6405800 | Walker et al. | Jun 2002 | B1 |
| 6446729 | Bixenman et al. | Sep 2002 | B1 |
| 6450263 | Schwendemann | Sep 2002 | B1 |
| 6457518 | Castano-Mears et al. | Oct 2002 | B1 |
| 6464007 | Jones | Oct 2002 | B1 |
| 6478091 | Gano | Nov 2002 | B1 |
| 6488082 | Echols et al. | Dec 2002 | B1 |
| 6494261 | Pahmiyer | Dec 2002 | B1 |
| 6494265 | Wilson et al. | Dec 2002 | B1 |
| 6540022 | Dusterhoft et al. | Apr 2003 | B1 |
| 6543538 | Tolman et al. | Apr 2003 | B1 |
| 6547011 | Kilgore | Apr 2003 | B1 |
| 6557634 | Hailey, Jr. et al. | May 2003 | B1 |
| 6622794 | Zisk, Jr. | Sep 2003 | B1 |
| 6644412 | Bode et al. | Nov 2003 | B1 |
| 6681854 | Danos | Jan 2004 | B1 |
| 6695054 | Johnson et al. | Feb 2004 | B1 |
| 6719051 | Hailey, Jr. et al. | Apr 2004 | B1 |
| 6745843 | Johnson et al. | Jun 2004 | B1 |
| 6786285 | Johnson et al. | Sep 2004 | B1 |
| 6805202 | Gillespie et al. | Oct 2004 | B1 |
| 6857476 | Richards | Feb 2005 | B1 |
| 6886634 | Richards | May 2005 | B1 |
| 6899176 | Hailey, Jr. et al. | May 2005 | B1 |
| 20020074119 | Bixenmann et al. | Jun 2002 | A1 |
| 20020092649 | Bixenman et al. | Jul 2002 | A1 |
| 20020096329 | Coon et al. | Jul 2002 | A1 |
| 20020125006 | Hailey, Jr. et al. | Sep 2002 | A1 |
| 20020125008 | Wetzel et al. | Sep 2002 | A1 |
| 20020157837 | Bode et al. | Oct 2002 | A1 |
| 20020174981 | Den Boer et al. | Nov 2002 | A1 |
| 20020189815 | Johnson et al. | Dec 2002 | A1 |
| 20030000701 | Dusterhoft et al. | Jan 2003 | A1 |
| 20030000875 | Echols et al. | Jan 2003 | A1 |
| 20030056947 | Cameron | Mar 2003 | A1 |
| 20030056948 | Cameron | Mar 2003 | A1 |
| 20030075324 | Dusterhoft et al. | Apr 2003 | A1 |
| 20030089496 | Price-Smith et al. | May 2003 | A1 |
| 20030141061 | Hailey, Jr. et al. | Jul 2003 | A1 |
| 20030141062 | Cowan et al. | Jul 2003 | A1 |
| 20030188871 | Dusterhoft et al. | Oct 2003 | A1 |
| 20040020832 | Richards et al. | Feb 2004 | A1 |
| 20040035578 | Ross et al. | Feb 2004 | A1 |
| 20040035591 | Echols | Feb 2004 | A1 |
| 20040173350 | Wetzel et al. | Sep 2004 | A1 |
| Number | Date | Country |
|---|---|---|
| 0 431 162 | Jun 1991 | EP |
| 0 617 195 | Sep 1994 | EP |
| 1 132 571 | Sep 2001 | EP |
| 0 955 447 | Mar 2004 | EP |
| 2371319 | Jan 2002 | GB |
| 2 371 578 | Jul 2002 | GB |
| 2 381 021 | Apr 2003 | GB |
| 2 381 811 | May 2003 | GB |
| WO 9912630 | Mar 1999 | WO |
| WO 0061913 | Oct 2000 | WO |
| WO 0114691 | Mar 2001 | WO |
| WO 0142620 | Jun 2001 | WO |
| WO 0144619 | Jun 2001 | WO |
| WO 0149970 | Jul 2001 | WO |
| WO 0210554 | Feb 2002 | WO |
| WO 02055842 | Jul 2002 | WO |
| WO 02057594 | Jul 2002 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20040035578 A1 | Feb 2004 | US |
