N/A
N/A
1. Field of the Invention
This invention relates to a novel method and system for transporting, assembling, storing, and disassembling oilfield tubulars in and around a single drilling deck, derrick, and rotary system while drilling operations are simultaneously and independently occurring.
2. Description of the Related Art
Drilling for oil and gas with a rotary drilling rig is being undertaken to increasingly greater depths both offshore and on land. The increase in depth translates into longer drilling time, and increased cost. The cost to operate such rigs is already substantial (rental rates for some offshore rigs can exceed U.S. $400,000 to $500,000 per day). Therefore, any productive operation that can be accomplished independently of drilling operations to save even small amounts of time in the drilling process is economically significant.
The term “tubular” as used herein means all forms of drill pipe (including heavy weight drill pipe, such as HEVI-WATE™ tubulars), casing, drill collars, liner, bottom hole assemblies, and other types of tubulars known in the art. HEVI-WATE™ is a registered trade mark of Smith International, Inc. of Houston, Tex. Drilling operations require frequent stops when a small part of the tubular string extends above the drilling deck. Additional tubulars must be moved from a storage rack and connected with the upper end of the tubular string, which may cause significant delay in drilling. The length of a typical single drill pipe section is 30 feet (about 10 m). A stand is created by connecting together two or more single sections of tubulars. In the past, stands have been assembled or made up with four or five single sections of tubulars. A top drive rotary system is often used in place of the rotary table to turn the drill string, and is now the prevalent method of rotary drilling. One of the benefits of the top drive is that it can drill with pre-assembled tubular stands.
Therefore, the creation and handling of tubular stands independently of the drilling process is a potentially important way to save time and money.
A method and system of handling tubulars simultaneously with drilling operations is described in U.S. Pat. No. 4,850,439 to Lund, the disclosure of which is incorporated herein by reference for all purposes. Lund proposes a preparation hole and an auxiliary hoist for offline stand building. While drilling operations are occurring, Lund proposes a first tubular being lifted in a vertical position when the auxiliary hoist is moved upward so that the tubular is swung from the cable over and then lowered into the preparation hole. Lund proposes that another tubular can then be swung over the first tubular for connection ('439 patent, col. 7, ln. 58 to col. 8, ln. 19). For a third tubular, if the free space below the top of the preparation hole is less than the length of two tubulars, Lund proposes another auxiliary hoist. In such circumstance, the preparation hole must be displaced or tilted from the vertical suspension line of the first auxiliary hoist ('439 patent, col. 9, ln. 58 to col. 10, ln. 46).
Another offline stand building method and system has been proposed by Smedvig Asia Ltd. of Singapore. Smedvig proposes a self erecting offshore tender rig to transfer and erect drilling equipment on a platform. After the drilling equipment is erected on the platform, Smedvig proposes a high line cable system to move tubulars from the tender rig to the platform, a racker crane at the top of the derrick that moves parallel to the drilling deck, and two preparation holes.
Smedvig proposes that while drilling operations are occurring on the platform, a single tubular on the rig can be manually connected at both ends while in horizontal position to the high line cable system. The high line cable system is used to lift and transport the tubular across the water from the rig to the pipe ramp on the platform, where the tubular is manually disconnected. A gripping device connected by cable to a hoist on the racker crane is then manually connected to the upper end of the tubular on the pipe ramp. The tubular is then hoisted in the vertical position, and swung from the cable over the first preparation hole. The tubular is then lowered into the hole, and the gripping device released. The process can be repeated with a second tubular, which can be swung into position in the second preparation hole. The process can be repeated with a third tubular for connection with the first tubular into a double stand. The double stand is then hoisted by the racker crane and lowered for connection with the second tubular for a triple. The completed stand is hoisted up and carried by the racker crane to a vertical tubular storage rack at the top of the derrick. Smedvig also proposes that the first preparation hole can have an adjustable bottom for acceptance of different size tubulars.
Another offline stand building method and system is proposed in U.S. Pat. No. 6,976,540 to Berry, the disclosure of which is incorporated herein by reference for all purposes. Berry proposes, among other things, a load and preparation pipe handling device (“preparation device”), a storage pipe handling device (“storage device”), and tubular storage areas at the top of the derrick. The preparation device includes a vertical truss rotatable about its longitudinal axis. The preparation device includes a gripping device attached at the end of a hoisting cable extending out from the vertical truss. The gripping device is manually attached to one end of a tubular that has been placed near the preparation device on the catwalk or the pipe ramp so that when the cable is retracted back toward the preparation device, the lifted tubular is swung from the cable, similar to the Lund and Smedvig systems.
Berry then proposes that the truss can then swing the vertical tubular in a circular path to a first preparation hole, which has been placed along the path. The preparation device can then lower the first tubular into the first preparation hole. Using two preparation holes, much like the Smedvig system, a stand is assembled. The assembled stand is then lifted vertically by the preparation device to the top of the derrick, and directly exchanged to the storage device, which can either store it or transport it for drilling operations ('540 patent, col. 7, lns. 26-40 and col. 8, his. 30-35).
The oil industry has proposed systems for the online transferring of tubulars from the horizontal position on a pipe rack to the vertical position over the well center. One such system is proposed in U.S. Pat. No. 4,834,604 to Brittian et al., the disclosure of which is incorporated herein by reference for all purposes. Brittian proposes a strongback connected to a boom that is pivotally fixed to a base located adjacent to the rig. The strongback transfers the tubular directly through the V-door from a horizontal position to a vertical position so that a connection between the tubular and the tubular string can be made. Another system is proposed in U.S. Pat. No. 6,220,807 to Sorokan, the disclosure of which is incorporated herein by reference for all purposes. An online pipe handling system is proposed for using a bicep arm assembly pivotally connected to a drilling rig, and a forearm assembly and a gripper head assembly both pivotally connected to the bicep arm assembly. The gripper head assembly grabs the horizontal positioned tubular on the pipe rack adjacent to the rig, and rotates the tubular to a vertical position over the well center.
A horizontal to vertical pipe handling system is proposed in Pub. No. US 2006/0151215 to Skogerbo. Skogerbo discloses an Eagle Light/HTV-Arm, which is distributed by Aker Kvaerner MH of Houston, Tex. The Eagle Light HTV (horizontal to vertical) device is proposed for online transfer of tubulars from a horizontal position at the catwalk to a vertical position in the derrick directly over the well center or into the mousehole. Aker Kvaerner MH also distributes bridge crane systems and storage fingerboards. National Oilwell Varco of Houston, Tex. also manufactures a similar HTV online pipe handling device.
Another online method and apparatus for transferring tubulars between the horizontal position on the pipe rack to the vertical position over the well center is proposed in U.S. Pat. No. 6,705,414 to Simpson et al. Simpson proposes a bucking machine to build tubular stands in the horizontal position on the catwalk. A completed stand is horizontal at a trolley pick-up location, and becomes vertical at the rig floor entry. The stand, clamped to a trolley, is pulled along and up a track with a cable winch. A vertical pipe racking device located in the upper derrick is proposed to transfer the stand directly from the trolley.
The disadvantages of the above tubular handling methods and systems include significant human physical contact with the tubulars and lifting equipment at numerous times and locations, which can result in costly delay or possible injury. The alignment and transfer operations are lengthy and complex. The paths of the tubulars in the offline stand building are not fully restricted, which creates delay and safety hazards. The offline stand building operation may be interrupted when equipment is being used in the online drilling operations. Therefore, a more efficient method and system for handling tubulars that minimizes or eliminates human physical contact with the tubulars and lifting equipment, restricts and controls the path of the tubulars throughout the entire offline operation, requires minimal inefficient movement of the tubulars, and eliminates any potential interruption of the tubular building and drilling process would be desirable.
A system and method for building and handling oilfield tubular stands is disclosed that utilizes a single derrick, drilling deck, and rotary system, and separates the drilling process from the offline stand building process. A guided path horizontal to vertical arm (“HTV”) lifts tubulars stored horizontally on the catwalk, and then moves the tubulars in a single vertical plane such that no interference occurs with the drilling process, and multiple articulated motions are reduced. The HTV moves the tubulars between the catwalk and the preparation hole for assembling or disassembling the tubular stands. A stand arm is positioned for lifting and lowering the tubulars into and out of the preparation hole, and transporting the tubulars vertically for storage into an auxiliary tubular racking station in the upper part of the derrick.
A bridge racker crane also mounted in the upper part of the derrick removes tubular stands from the auxiliary tubular racking station and transports them to either the top drive, or to another tubular racking station in the derrick. Using the auxiliary tubular racking station, the offline stand building operation is advantageously uninterrupted when the bridge racker crane is unavailable due to its need to participate in the simultaneously occurring drilling operations.
A better understanding of the present invention can be obtained with the following detailed descriptions of the various disclosed embodiments in the drawings:
The present invention involves a system and method for offline building of tubular stands, while drilling operations are simultaneously and independently occurring. As shown in the drawings, this offline stand building comprises moving tubulars from a horizontal position on the catwalk 22 adjacent to the V-door 26 of the derrick 10, lifting and guiding the tubulars in the same plane to a vertical position directly above a preparation hole 46 with a horizontal to vertical arm 48, lowering the vertically positioned tubulars into the preparation hole 46, using a stand arm 58 to move the tubulars in the vertical position for connection into a stand by an auxiliary tubular make up device 56, and transporting the stand vertically to an auxiliary tubular racking station 60 in the upper part of the derrick 10. A bridge racker crane 86 transports the tubular stands from the auxiliary tubular racking station 60 to either the top drive 12, or to first 128 or second 130 tubular racking stations.
An exemplary drilling rig, generally indicated as R, of the invention is shown in
Reviewing both
Catwalk
In
A primary tubular advancing station 13 comprises at least the well center 14. Also, a drilling hoist, the top drive 12, a tubular make up device 42, and other equipment necessary to advance tubulars into the well center 14 can be provided in the primary tubular advancing station 13. A mousehole 32 is located radially outward from the well center 14, and is positioned substantially on a line between well center 14 and the longitudinal centerline of the carriage 30. The carriage has wheels that run on two parallel rails 34 mounted on the top of the catwalk 22. The rails 34 extend across the drilling deck 16 to a location near the well center 14.
As shown in
HTV
As further shown in
An auxiliary tubular handling station, generally indicated as 54, is shown in
Preparation Hole
The preparation hole 46 is shown in detail in
Stand Arm
Returning to
Bridge Racker Crane
As shown in
Due to the difference in length between casing and drill pipe, casing stands typically consist of two tubulars, whereas drill pipe stands typically consist of three tubulars. As shown in
Tubular Racking Stations
As shown in
Method of Use
Offline
The present invention is also directed to a method of offline stand building while drilling operations are simultaneously and independently occurring. It should be understood that while the offline stand building operation occurs as described below, drilling operations may be simultaneously occurring. For example, while offline stand building is occurring, the bridge racker crane 86 can remove completed tubular stands from any of these three tubular racking stations 60, 128 or 130 and carry them to the top drive 12 for drilling or placement in the well center 14. Alternatively, single horizontal tubulars, such as tubular 36, can be advanced from the carriage 30 directly to a location near the well center 14. The top drive 12 can attach to the end of a single tubular 20 (
It should also be understood that while the method of building stands of three tubulars is described below, the same method can be used for the construction of stands with other numbers of tubulars. With that understanding, according to one exemplary embodiment of the method of the invention, an offline tubular stand may be assembled in the following manner:
As shown in
As shown in
As shown in
As shown in
As can now be seen from the above, as the bridge crane 86 is being used for online operations, then the offline stand building activities can still continue uninterrupted. The bridge crane 86 is not in the critical path of the offline stand building operation. There will be occasions when the bridge crane 86 will work with either the offline or online operations, and not hinder the speed and functionality of the other operation.
Online
While
Laydown
The online and offline operations can also be simultaneously and independently performed in reverse order from that described above for removal, disconnection, and laydown of tubulars. In the primary or online operation, the top drive 12 pulls the tubular string up through the well center 14 for the disconnection of either a single tubular or a tubular stand from the string using the tubular make up device 42. If a tubular stand is disconnected, it can then be lifted up the derrick 10 for transfer to the bridge crane 86, and transported to one of the tubular racking stations. The stands of tubulars can be simultaneously and independently disconnected and moved to the pipe rack 43 on the offline side of the catwalk 22 using the stand aim 58 and the HTV 48. If a single tubular, for example tubular 20 (
The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the details of the illustrated system and construction and the method of operation may be made without departing from the spirit of the invention.
This application is a continuation of U.S. application Ser. No. 11/710,638 filed on Feb. 23, 2007, now U.S. Pat. No. 7,802,636, which is hereby incorporated by reference for all purposes in its entirety.
Number | Name | Date | Kind |
---|---|---|---|
1776605 | Tibbetts | Sep 1930 | A |
1829879 | Stephens | Nov 1931 | A |
2354217 | Mullinix et al. | Jul 1944 | A |
2381166 | Hollerith | Aug 1945 | A |
2503516 | Shrewsbury | Apr 1950 | A |
2773605 | De Jarnett | Dec 1956 | A |
2808229 | Bauer et al. | Oct 1957 | A |
3001594 | Suderow | Sep 1961 | A |
3038432 | Goldman | Jun 1962 | A |
3191201 | Richardson et al. | Jun 1965 | A |
3279404 | Richardson et al. | Oct 1966 | A |
3404741 | Gheorghe et al. | Oct 1968 | A |
3412981 | Richardson et al. | Nov 1968 | A |
3461828 | Bielstein | Aug 1969 | A |
3477235 | Branham et al. | Nov 1969 | A |
3494484 | McFadden | Feb 1970 | A |
3501017 | Johnson et al. | Mar 1970 | A |
3552343 | Scott | Jan 1971 | A |
3561811 | Turner, Jr. | Feb 1971 | A |
3601075 | Deslierres | Aug 1971 | A |
3602302 | Kluth | Aug 1971 | A |
3615027 | Ham | Oct 1971 | A |
3628336 | Moore et al. | Dec 1971 | A |
3633771 | Woolslayer et al. | Jan 1972 | A |
3682242 | Brooks et al. | Aug 1972 | A |
3734210 | Wilderman | May 1973 | A |
3739736 | Carreau et al. | Jun 1973 | A |
3768663 | Turner et al. | Oct 1973 | A |
3774562 | Dean, III | Nov 1973 | A |
3780883 | Brown | Dec 1973 | A |
3799364 | Kelly et al. | Mar 1974 | A |
3802209 | Weaver | Apr 1974 | A |
3822663 | Boschen, Jr. | Jul 1974 | A |
3828561 | Moore et al. | Aug 1974 | A |
3880105 | Bryant | Apr 1975 | A |
3931782 | Childers et al. | Jan 1976 | A |
3937515 | Langowski | Feb 1976 | A |
3976207 | Schultz | Aug 1976 | A |
3986619 | Woolslayer | Oct 1976 | A |
3987910 | Brunato | Oct 1976 | A |
4013178 | Brown et al. | Mar 1977 | A |
RE29373 | Boschen, Jr. | Aug 1977 | E |
4042123 | Sheldon et al. | Aug 1977 | A |
4067453 | Moller | Jan 1978 | A |
4099630 | Beck | Jul 1978 | A |
4108255 | Smith | Aug 1978 | A |
4126348 | Palmer | Nov 1978 | A |
4139891 | Sheldon et al. | Feb 1979 | A |
4189255 | Macan et al. | Feb 1980 | A |
4195950 | Goldman | Apr 1980 | A |
4208158 | Davies et al. | Jun 1980 | A |
4227831 | Evans | Oct 1980 | A |
4235566 | Beeman et al. | Nov 1980 | A |
4269543 | Goldman et al. | May 1981 | A |
4269554 | Jackson | May 1981 | A |
4274778 | Putnam et al. | Jun 1981 | A |
4305686 | Magill | Dec 1981 | A |
4334584 | Magill | Jun 1982 | A |
4345864 | Smith, Jr. et al. | Aug 1982 | A |
4351258 | Ray et al. | Sep 1982 | A |
4397605 | Cowgill et al. | Aug 1983 | A |
4403897 | Willis | Sep 1983 | A |
4403898 | Thompson | Sep 1983 | A |
4426182 | Frias et al. | Jan 1984 | A |
4446807 | Johnson | May 1984 | A |
4457250 | Oshima et al. | Jul 1984 | A |
4458768 | Boyadjieff | Jul 1984 | A |
4462733 | Langowski et al. | Jul 1984 | A |
4470468 | Phares | Sep 1984 | A |
4470740 | Frias | Sep 1984 | A |
4483644 | Johnson | Nov 1984 | A |
4486137 | Buckner | Dec 1984 | A |
4509448 | Pease | Apr 1985 | A |
4519728 | Oshima et al. | May 1985 | A |
4533055 | Haney | Aug 1985 | A |
4571125 | Oshima et al. | Feb 1986 | A |
4601252 | Wuttudal | Jul 1986 | A |
4602894 | Lorenz | Jul 1986 | A |
4604961 | Ortloff et al. | Aug 1986 | A |
4605077 | Boyadjieff | Aug 1986 | A |
4610315 | Koga et al. | Sep 1986 | A |
4621974 | Krueger | Nov 1986 | A |
4629014 | Swisher et al. | Dec 1986 | A |
4658903 | Tateishi | Apr 1987 | A |
4692081 | Bennett et al. | Sep 1987 | A |
4709766 | Boyadjieff | Dec 1987 | A |
RE32589 | Goldman et al. | Feb 1988 | E |
4725179 | Woolslayer et al. | Feb 1988 | A |
4738321 | Olivier | Apr 1988 | A |
4744710 | Reed | May 1988 | A |
4762185 | Simpson | Aug 1988 | A |
4765401 | Boyadjieff | Aug 1988 | A |
4791997 | Krasnov | Dec 1988 | A |
4819730 | Williford et al. | Apr 1989 | A |
4822230 | Slettedal | Apr 1989 | A |
4834604 | Brittain et al. | May 1989 | A |
4850439 | Lund | Jul 1989 | A |
4862973 | Voigts et al. | Sep 1989 | A |
4901805 | Ali-Zade et al. | Feb 1990 | A |
5052860 | Ingle | Oct 1991 | A |
5092712 | Goldman et al. | Mar 1992 | A |
5107940 | Berry | Apr 1992 | A |
5181798 | Gilchrist, Jr. | Jan 1993 | A |
5183122 | Rowbotham et al. | Feb 1993 | A |
5248003 | Song et al. | Sep 1993 | A |
5381750 | Pollack | Jan 1995 | A |
5458454 | Sorokan | Oct 1995 | A |
5622452 | Goldman | Apr 1997 | A |
5647443 | Broeder | Jul 1997 | A |
5921714 | Goldman | Jul 1999 | A |
5934216 | Childers et al. | Aug 1999 | A |
6047781 | Scott et al. | Apr 2000 | A |
6048135 | Williford et al. | Apr 2000 | A |
6056071 | Scott et al. | May 2000 | A |
6068069 | Scott et al. | May 2000 | A |
6085851 | Scott et al. | Jul 2000 | A |
6089333 | Rise | Jul 2000 | A |
6171027 | Blankestijin | Jan 2001 | B1 |
6203248 | Childers et al. | Mar 2001 | B1 |
6220807 | Sorokan | Apr 2001 | B1 |
6231269 | Shear et al. | May 2001 | B1 |
6311788 | Weixler | Nov 2001 | B1 |
6343662 | Byrt et al. | Feb 2002 | B2 |
6378450 | Begnaud et al. | Apr 2002 | B1 |
6481931 | Welsh | Nov 2002 | B1 |
6484806 | Childers et al. | Nov 2002 | B2 |
6491174 | Day | Dec 2002 | B1 |
6513605 | Loedden | Feb 2003 | B1 |
6527493 | Kamphorst et al. | Mar 2003 | B1 |
6533519 | Tolmon et al. | Mar 2003 | B1 |
6550128 | Lorenz | Apr 2003 | B1 |
6591904 | Cicognani et al. | Jul 2003 | B2 |
6609573 | Day | Aug 2003 | B1 |
6634443 | Paech et al. | Oct 2003 | B1 |
6688398 | Pietras | Feb 2004 | B2 |
6695559 | Pietras | Feb 2004 | B1 |
6701861 | Key et al. | Mar 2004 | B2 |
6705414 | Simpson et al. | Mar 2004 | B2 |
6766860 | Archibald et al. | Jul 2004 | B2 |
6779614 | Oser | Aug 2004 | B2 |
6821071 | Woolslayer et al. | Nov 2004 | B2 |
6854520 | Robichaux | Feb 2005 | B1 |
6857483 | Dirks et al. | Feb 2005 | B1 |
6860694 | Slettedal | Mar 2005 | B2 |
6926488 | Bolding et al. | Aug 2005 | B1 |
6932553 | Roodenburg et al. | Aug 2005 | B1 |
6969223 | Tolmon et al. | Nov 2005 | B2 |
6976540 | Berry | Dec 2005 | B2 |
6994505 | Hawkins, III | Feb 2006 | B2 |
6997265 | Berry | Feb 2006 | B2 |
7004259 | Pietras | Feb 2006 | B2 |
7021374 | Pietras | Apr 2006 | B2 |
7055594 | Springett et al. | Jun 2006 | B1 |
7083007 | Herst | Aug 2006 | B2 |
7090035 | Lesko | Aug 2006 | B2 |
7096977 | Juhasz et al. | Aug 2006 | B2 |
7128161 | Pietras | Oct 2006 | B2 |
7137454 | Pietras | Nov 2006 | B2 |
7140443 | Beierbach et al. | Nov 2006 | B2 |
7228913 | Folk et al. | Jun 2007 | B2 |
7228919 | Fehres et al. | Jun 2007 | B2 |
7246983 | Zahn et al. | Jul 2007 | B2 |
7537424 | Innes et al. | May 2009 | B2 |
7540338 | Belik | Jun 2009 | B2 |
7802636 | Childers et al. | Sep 2010 | B2 |
20030049077 | Geiger, Jr. et al. | Mar 2003 | A1 |
20030159853 | Archibald et al. | Aug 2003 | A1 |
20030159854 | Simpson et al. | Aug 2003 | A1 |
20030196791 | Dunn et al. | Oct 2003 | A1 |
20040045703 | Hooper | Mar 2004 | A1 |
20040136813 | Pietras | Jul 2004 | A1 |
20050051343 | Pietras et al. | Mar 2005 | A1 |
20050126792 | Berry | Jun 2005 | A1 |
20050238463 | Smith | Oct 2005 | A1 |
20050269133 | Little | Dec 2005 | A1 |
20050274508 | Folk et al. | Dec 2005 | A1 |
20060081379 | Fehres et al. | Apr 2006 | A1 |
20060104746 | Thompson | May 2006 | A1 |
20060113073 | Wright et al. | Jun 2006 | A1 |
20060113075 | Springett et al. | Jun 2006 | A1 |
20060137910 | Hamner | Jun 2006 | A1 |
20060151215 | Skogerbo | Jul 2006 | A1 |
20070017704 | Belik | Jan 2007 | A1 |
20070031215 | Belik | Feb 2007 | A1 |
20070193750 | Wright et al. | Aug 2007 | A1 |
20080101891 | Belik | May 2008 | A1 |
20080128167 | Eriksen | Jun 2008 | A1 |
20080136203 | Krijnen et al. | Jun 2008 | A1 |
20080164064 | Belik et al. | Jul 2008 | A1 |
20080202812 | Childers et al. | Aug 2008 | A1 |
Number | Date | Country |
---|---|---|
1917451 | Nov 1969 | DE |
2345167 | Apr 1974 | DE |
0139237 | May 1985 | EP |
0234880 | Sep 1987 | EP |
0258705 | Mar 1988 | EP |
0406986 | Jan 1991 | EP |
1379830 | Oct 1963 | FR |
2381166 | Sep 1978 | FR |
2670742 | Jun 1992 | FR |
1214346 | Dec 1970 | GB |
1494720 | Dec 1977 | GB |
1540544 | Feb 1979 | GB |
2041836 | Sep 1980 | GB |
2066758 | Jul 1981 | GB |
2071734 | Sep 1981 | GB |
2094376 | Sep 1982 | GB |
2119427 | Nov 1983 | GB |
2125862 | Mar 1984 | GB |
2137261 | Oct 1984 | GB |
2158132 | Nov 1985 | GB |
2160166 | Dec 1985 | GB |
2160564 | Dec 1985 | GB |
2175629 | Dec 1986 | GB |
2264734 | Sep 1993 | GB |
2264736 | Sep 1993 | GB |
2291664 | Jan 1996 | GB |
2386853 | Oct 2003 | GB |
2386856 | Oct 2003 | GB |
60-146787 | Aug 1985 | JP |
62-80196 | Apr 1987 | JP |
63-134783 | Jun 1988 | JP |
10-169355 | Jun 1998 | JP |
8802980 | Dec 1988 | NL |
WO8201212 | Apr 1982 | WO |
WO8301810 | May 1983 | WO |
WO8303118 | Sep 1983 | WO |
WO8707674 | Dec 1987 | WO |
WO8801008 | Feb 1988 | WO |
WO8808806 | Nov 1988 | WO |
WO9309330 | May 1993 | WO |
WO9315303 | Aug 1993 | WO |
WO 2008012580 | Jan 2008 | WO |
Number | Date | Country | |
---|---|---|---|
20100326672 A1 | Dec 2010 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 11710638 | Feb 2007 | US |
Child | 12807356 | US |