Dual diverter and orientation device for multilateral completions and method

Information

  • Patent Grant
  • 6311776
  • Patent Number
    6,311,776
  • Date Filed
    Wednesday, April 19, 2000
    24 years ago
  • Date Issued
    Tuesday, November 6, 2001
    23 years ago
Abstract
In a broad aspect, the invention is a downhole well tool for use within a well casing having a locking slot, an orienting profile, an alignment slot, and a lateral well bore window. The tool may broadly include a body member having a first and a second longitudinal bore extending therethrough, a diverter member extending therefrom and having a diverter surface. The second longitudinal bore extends through the diverter member. The tool may also include an outwardly-biased orienting key movably secured to the body member and engageable with the orienting profile and the alignment slot, and an outwardly-biased locking key movably secured to the body member and engageable with the locking slot. The diverter surface is aligned with the lateral well bore window when the orienting key is engaged with the alignment slot and the locking key is engaged with the locking slot. The tool also includes a first production tubing extending through the first longitudinal bore and aligned with the diverter surface, and a second production tubing extending through the second longitudinal bore. One of the first and second production tubings is releasably secured to the body member.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to subsurface well equipment and, more particularly, to an apparatus and method for simultaneously setting two production tubings in a well having at least one lateral well bore.




2. Description of the Related Art




To make production of hydrocarbons more economical, it has become commonplace for oil and gas companies to drill and complete one or more lateral, or branch, well bores, each extending from a main wellbore running to the earth's surface. After the main and lateral well bores have been drilled, the standard prevailing practice is to complete the lateral and main wells separately. This requires separate trips into the well to set the necessary tools and production tubing, each trip resulting in significant costs in time and money. The present invention has been developed to reduce these costs. As will be explained below, in broad terms, the present invention achieves this objective by doing in one trip what heretofore has been done in two.




SUMMARY OF THE INVENTION




In a broad aspect, the invention is a downhole well tool for use within a well casing having a locking slot, an orienting profile, an alignment slot, and a lateral well bore window, the tool comprising: a body member having a first and a second longitudinal bore extending therethrough, a diverter member extending therefrom and having a diverter surface, the second longitudinal bore extending through the diverter member; an outwardly-biased orienting key movably secured to the body member and engageable with the orienting profile and the alignment slot; an outwardly-biased locking key movably secured to the body member and engageable with the locking slot, the diverter surface being aligned with the lateral well bore window when the orienting key is engaged with the alignment slot and the locking key is engaged with the locking slot; a first production tubing extending through the first longitudinal bore and aligned with the diverter surface; and a second production tubing extending through the second longitudinal bore, one of the first and second production tubings being releasably secured to the body member. Another feature of this aspect of the invention is that the second production tubing is releasably secured to the diverter member. Another feature of this aspect of the invention is that a lower end of the diverter member is cone-shaped. Another feature of this aspect of the invention is that the orienting and locking keys are outwardly biased by at least one spring. Another feature of this aspect of the invention is that the orienting key is disposed for radial movement within a first recess in the body member. Another feature of this aspect of the invention is that the locking key is disposed for movement within a second recess in the body member. Another feature of this aspect of the invention is that the locking key is hingedly attached to the body member. Another feature of this aspect of the invention is that the locking key is shearably disconnectable from the body member. Another feature of this aspect of the invention is that the body member includes a locking profile remotely engageable with a well tool for disengaging the well tool from the casing. Another feature of this aspect of the invention is that the diverter member extends upwardly from the body member, and the locking slot, orienting profile and alignment slot are disposed in the well casing below the lateral well bore window. Another feature of this aspect of the invention is that the diverter member extends downwardly from the body member, and the locking slot, orienting profile and alignment slot are disposed in the well casing above the lateral well bore window.




In another aspect, the invention may be a downhole well tool for use within a well casing having a lateral well bore window, the tool comprising: a discriminator connected within the well casing and having a locking slot, an orienting profile, and an alignment slot; a body member having a first and a second longitudinal bore extending therethrough, a diverter member extending therefrom and having a diverter surface, the second longitudinal bore extending through the diverter member; an outwardly-biased orienting key movably secured to the body member and engageable with the orienting profile and the alignment slot; an outwardly-biased locking key movably secured to the body member and engageable with the locking slot, the diverter surface being aligned with the lateral well bore window when the orienting key is engaged with the alignment slot and the locking key is engaged with the locking slot; a first production tubing extending through the first longitudinal bore and aligned with the diverter surface; and a second production tubing extending through the second longitudinal bore, one of the first and second production tubings being releasably secured to the body member. Another feature of this aspect of the invention is that the second production tubing is releasably secured to the diverter member. Another feature of this aspect of the invention is that a lower end of the diverter member is cone-shaped. Another feature of this aspect of the invention is that the orienting and locking keys are outwardly biased by at least one spring. Another feature of this aspect of the invention is that the orienting key is disposed for radial movement within a first recess in the body member. Another feature of this aspect of the invention is that the locking key is disposed for movement within a second recess in the body member. Another feature of this aspect of the invention is that the locking key is hingedly attached to the body member. Another feature of this aspect of the invention is that the locking key is shearably disconnectable from the body member. Another feature of this aspect of the invention is that the body member includes a locking profile remotely engageable with a well tool for disengaging the well tool from the casing. Another feature of this aspect of the invention is that the diverter member extends upwardly from the body member, and the discriminator is connected to the well casing below the lateral well bore window. Another feature of this aspect of the invention is that the diverter member extends downwardly from the body member, and the discriminator is connected to the well casing above the lateral well bore window.




In another aspect, the present invention may be a downhole well tool for use within a well casing having a lateral well bore window, the tool comprising: a body member having a first and a second longitudinal bore extending therethrough; a first production tubing extending through the first longitudinal bore; a second production tubing extending through the second longitudinal bore, the first and second production tubings being coupled together so as to restrict relative longitudinal movement therebetween, one of the first and second production tubings being releasably secured to the body member; means for diverting the first production tubing through the lateral well bore window; and means for aligning the diverting means with the lateral well bore window.




In still another aspect, the present invention may be a method of completing a well having a main well bore and at least one lateral well bore, the method comprising: positioning a completion assembly in the main well bore, the completion assembly comprising at least a first and a second production tubing and a tubing diverter; simultaneously lowering the first and second production tubings, guided by the tubing diverter, the first production tubing being lowered into the at least one lateral well bore, and the second production tubing being lowered into one of the main well bore and another lateral well bore.




In another aspect, the present invention may be a method of completing a well having a main well bore and at least one lateral well bore, the method comprising: setting a first packer in the at least one lateral well bore, the first packer having a polished bore receptacle extending therefrom and being adapted to receive a first production tubing; setting a second packer in one of the main well bore and another lateral well bore, the second packer having a polished bore receptacle extending therefrom and being adapted to receive a second production tubing; simultaneously lowering the first and second production tubings into the main well bore, aligning a diverter and the first production tubing adjacent the at least one lateral well bore; and simultaneously lowering the first and second production tubings until they each engage the polished bore receptacles on the first and second packers, respectively. Another feature of this aspect of the invention is that the first and second production tubings are connected to a dual packer, one of the first and second production tubings is connected to the diverter, and the method further includes simultaneously lowering the dual packer into the well casing with the first and second production tubings and the diverter. Another feature of this aspect of the invention is that the method may further include: connecting a work string to the dual packer; using the work string to lower the dual packer, first and second production tubings, and diverter into the main well bore; using the work string to simultaneously push the first and second production tubings into engagement with the polished bore receptacles on the first and second packers, respectively; disconnecting the work string from the dual packer; and retrieving the work string. Another feature of this aspect of the invention is that the method may further include connecting the first production tubing to a third production tubing extending to the earth's surface, and connecting the second production tubing to a fourth production tubing extending to the earth's surface. Another feature of this aspect of the invention is that the method may further include connecting the first and second production tubings to a central production tubing extending to the earth's surface.











BRIEF DESCRIPTION OF THE DRAWINGS





FIGS. 1A-1D

illustrate a longitudinal cross-sectional view of the downhole tool of the present invention.





FIG. 2

is a cross-sectional view taken along line


2





2


of FIG.


1


.





FIG. 3

is a cross-sectional view taken along line


3





3


of FIG.


2


.





FIG. 4

is a longitudinal cross-sectional view illustrating a section of well casing in which the tool shown in

FIGS. 1-3

is engageable.





FIGS. 5A-5E

illustrate a longitudinal cross-sectional view of the downhole tool shown in

FIGS. 1A-1D

located within the well casing.





FIG. 6

is basically a combination of

FIGS. 2 and 4

, and illustrates the tool engaged with the well casing.





FIG. 7

is a cross-sectional view taken along line


7





7


of FIG.


6


.





FIG. 8

is an elevational view showing the tool of the present invention oriented and locked within the main casing with the first and second production tubings ready to be pushed into the their respective well bores for well completion.





FIG. 9

is an elevational view of an alternative embodiment of the present invention.





FIG. 10

an elevational view of another embodiment of the present invention.




While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.











DETAILED DESCRIPTION OF THE INVENTION




Referring to the drawings in detail, wherein like numerals denote identical elements throughout the several views, it can be seen with reference to

FIGS. 1-3

that, in a broad aspect, the downhole tool


10


of the present invention may broadly include a body member


12


, an orienting key


14


(see, e.g., FIGS.


2


and


3


), a locking key


16


(see, e.g., FIGS.


2


and


3


), a first production tubing


18


(see, e.g.,

FIGS. 1C and 5A

) and a second production tubing


20


(see, e.g., FIGS.


1


D and


5


A). As best shown in

FIGS. 1C and 1D

, the body member


12


further includes a diverter member


22


extending therefrom and having a diverter surface


24


. The body member


12


further includes a first longitudinal bore


26


and a second longitudinal bore


28


extending therethrough. The second longitudinal bore


28


also extends through the diverter member


22


. The lower end of the diverter member


22


may be cone-shaped. With reference to

FIGS. 2 and 3

, the orienting key


14


is movably secured to the body member


12


, and engageable with an orienting profile


30


and an alignment slot


32


, both of which are disposed in a well casing


34


(see FIG.


4


). Referring to

FIGS. 2-4

, the orienting key


14


is biased outwardly (e.g., by one or more springs


36


) and may be disposed for radial movement within a first recess


38


in the body member


12


. The locking key


16


is movably secured to the body member


12


, and engageable with a locking slot


40


in the well casing


34


(FIG.


4


). As shown in

FIGS. 2 and 3

, the locking key


16


is biased outwardly (e.g., by a spring


42


, which may be secured to the locking key


16


) and may be hingedly disposed in a second recess


44


in the body member


12


. With reference to

FIG. 4

, it is noted that the profile


30


, the orienting slot


32


, and the locking slot


40


may be formed as part of the well casing


34


, or as a separate component (sometimes referred to as a “muleshoe” or a “discriminator”


46


), which is attached to the well casing


34


.




With reference now to

FIG. 6

, which is basically a combination of

FIGS. 2 and 4

, the tool


10


of the present invention is shown engaged with the well casing


34


. The manner in which the tool


10


is moved into this position will now be explained.




As the tool


10


(see

FIG. 2

) is being lowered into the well casing


34


(see the top of FIG.


4


), a lower edge


15


of the orienting key


14


(

FIG. 2

) will come into contact with the profile


30


(FIG.


4


). Further downward movement of the tool


10


will cause the key


14


to move along the profile


30


and into engagement with the alignment slot


32


, thereby rotating the tool


10


and the attached diverter surface


24


—recall FIGS.


1


C and


1


D—into proper alignment with a lateral well bore window


48


, as shown in

FIGS. 5B-5E

; the lateral well bore window


48


has an upper edge


50


(see

FIG. 5B

) and a lower edge


52


(see FIG.


5


E). Referring back to

FIGS. 2 and 4

, as the orienting key


14


travels along the profile


30


, the locking key


16


will move inside the discriminator


46


, which will depress the locking key


16


into the recess


44


. When the orienting key


14


moves into the alignment slot


32


, the locking key


16


will be longitudinally aligned with the locking slot


40


. And when the lower edge


15


of the orienting key


14


bottoms out on a lower edge


33


of the alignment slot


32


(FIG.


4


), the locking key


16


will be shifted into the locking slot


40


under force of the spring


42


. Upward movement of the tool


10


will then be restrained by contact of an upper edge


17


of the locking key


16


with an upper edge


41


of the locking slot


40


, as shown in FIG.


6


. If it is desired to remove the tool


10


from the well casing


34


, the tool


10


may be disengaged by imparting an upward force to the tool


10


of sufficient magnitude to shear whatever mechanism by which the locking key


16


is movably secured to the body member


12


(e.g., a hinge pin


54


). A customary well tool (not shown) may be engaged with a locking profile


56


in the tool


10


(see, e.g., the top of

FIG. 2

) and used to impart the upward shearing force to the tool


10


.




Referring now to

FIGS. 5A-5E

, which illustrate the tool


10


after it has been oriented and locked in place, it can be seen that the diverter member


22


has been rotated such that the diverter surface


24


is properly aligned with the lateral well bore window


48


, and is properly positioned to guide the first production tubing


18


into a lateral well casing


58


extending from the main casing


34


. This can also be seen with reference to FIG.


8


. Up to this point, one of the first and second production tubings


18


and


20


have been releasably secured to the body member


12


. For example, as shown in

FIG. 1D and 5E

, the second production tubing


20


is releasably secured to the body member


12


, as at the lower end of the diverter member


22


(e.g., by any type of fastener


60


, including but not limited to screw, shear pin, bolt, etc.). The first and second production tubings


18


and


20


are connected so as to prevent relative longitudinal movement therebetween, such as by being directly connected together, or by both of them being connected to another well device, such as a packer. As such, by directly securing one of the production tubings


18


and


20


to the body member


12


, the other one is indirectly secured to the body member


12


.




The next step is to push or lower the first and second production strings


18


and


20


into their respective completed positions. This is done by imparting a downward force to the first and second production tubings


18


and


20


of sufficient magnitude to shear the fastener


60


so that the production tubings


18


and


20


may be pushed into place. With reference to

FIG. 8

, the first production tubing


18


will be guided along the diverter surface


24


into the lateral well casing


58


and into engagement with a polished bore receptacle extending from a first packer


62


that has previously been set in place and positioned to receive the first production tubing


18


. The second production tubing


20


will be pushed downwardly and into engagement with another polished bore receptacle extending from a second packer


64


, which may be positioned within the main well bore or in another lateral well bore


66


. It is further noted that the first and second production tubings


18


and


20


may extend to the earth's surface (not shown), or they may terminate in a relatively larger, or central, production tubing


68


, as shown in

FIG. 8

, which extends to the earth's surface (not shown).




Alternative embodiments and additional features of the present invention will now be described in connection with

FIGS. 9 and 10

.




With reference to

FIG. 9

, an alternative embodiment


10


′ of the tool of the present invention is shown locked within a main well casing


34


′ adjacent a lateral well casing


58


′. It is noted that the tool


10


′ shown here is configured basically upside-down relative to the tool


10


discussed above and illustrated in

FIGS. 1-3

. Instead of the diverter member


22


′ extending downwardly, it extends upwardly from the body member


12


′. Also, the discriminator


46


′ is attached to the casing


34


′ at a position below the lateral well casing


58


′ instead of above it. The tools


10


and


10


′ are similar, however, in all other basic respects (e.g., two longitudinal bores therethrough, two production tubings


18


′ and


20


′ disposed through those bores, diverter surface


24


′ aligned with lateral well bore window


48


′, etc.). The manner in which the various components of the completion shown in

FIG. 9

are installed will now be discussed.




After the casings


34


′ and


58


′ have been cemented in place, first and second packers


62


′ and


64


′, each having polished bore receptacles, are set in place in the lateral well casing


58


′ and main well casing


34


′, respectively. An assembly consisting of a dual packer


70


, the tool


10


′ and the production tubings


18


′ and


20


′ is connected to a work string (not shown) and lowered into the well. Both production tubings


18


′ and


20


′ are connected to the dual packer


70


, and one of the production tubings


18


′ or


20


′ is connected to the tool


10


′, so that the tool


10


′ is “hanging” below the dual packer


70


from one of the production tubings


18


′ or


20


′. This assembly is lowered into the well casing


34


′ and set in place therein in the manner as explained above with regard to the tool


10


and

FIGS. 1-4

(i.e., the locking and orienting keys cooperate with the discriminator


46


′ to orient and align the diverter surface


24


′ with the lateral well bore window


48


′ and lock the tool


10


′ to the casing


34


′). Once the assembly is set in place, a weight may be placed down on the work string (not shown) to simultaneously push the production tubings


18


′ and


20


′ into engagement with their respective polished bore receptacles. The work string (not shown) is then remotely disconnected from the dual packer


70


and removed to the earth's surface (not shown). Next, dual production tubings


72


and


74


may be lowered into engagement with the dual packer


70


so as to establish fluid communication with the production tubings


18


′ and


20


′, respectively. Alternatively, instead of running the dual production tubings


72


and


74


all the way from the earth's surface (not shown), a single production tubing


76


, shown in

FIG. 10

, may be used to establish fluid communication to the earth's surface. In this alternative embodiment, a swivel


78


is connected between the tubing


76


and a wireline reentry tool


80


, which has two relatively short sections of production tubing


82


and


84


extending therefrom for engagement with the dual packer


70


and the production tubings


18


′ and


20


′.




From the above, it should now be apparent that the present invention results in an improved and more efficient approach to completing dual string wells where at least one of the production strings is completed in a lateral well bore. By employing the present invention, significant cost savings may be realized by simultaneously running dual production strings into the well, in one trip, instead of making two trips into the well, one for each production string.




It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials or embodiments shown and described, as obvious modifications and equivalents will be apparent to one skilled in the art. Accordingly, the invention is therefore to be limited only by the scope of the appended claims.



Claims
  • 1. A downhole well tool for use within a well casing having a locking slot, an orienting profile, an alignment slot, and a lateral well bore window, the tool comprising:a body member having a first and a second longitudinal bore extending therethrough, a diverter member extending therefrom and having a diverter surface, the second longitudinal bore extending through the diverter member; an outwardly-biased orienting key movably secured to the body member and engageable with the orienting profile and the alignment slot; at least one orienting spring disposed to outwardly bias the orienting key; an outwardly-biased locking key movably secured to the body member and engageable with the locking slot, the diverter surface being aligned with the lateral well bore window when the orienting key is engaged with the alignment slot and the locking key is engaged with the locking slot; at least one locking spring disposed to outwardly bias the locking key; a first production tubing extending through the first longitudinal bore and aligned with the diverter surface; and a second production tubing extending through the second longitudinal bore, one of the first and second production tubings being releasably secured to the body member.
  • 2. The downhole well tool of claim 1, wherein the second production tubing is releasably secured to the diverter member.
  • 3. The downhole well tool of claim 1, wherein a lower end of the diverter member is cone-shaped.
  • 4. The downhole well tool of claim 1, wherein the orienting and locking keys are outwardly biased by at least one spring.
  • 5. The downhole well tool of claim 1, wherein the orienting key is disposed for radial movement within a first recess in the body member.
  • 6. The downhole well tool of claim 1, wherein the locking key is disposed for movement within a second recess in the body member.
  • 7. The downhole well tool of claim 6, wherein the locking key is hingedly attached to the body member.
  • 8. The downhole well tool of claim 1, wherein the locking key is shearably disconnectable from the body member.
  • 9. The downhole well tool of claim 1, wherein the body member includes a locking profile remotely engageable with a well tool for disengaging the well tool from the casing.
  • 10. The downhole well tool of claim 1, wherein the diverter member extends downwardly from the body member, and the locking slot, orienting profile and alignment slot are disposed in the well casing above the lateral well bore window.
  • 11. A downhole well tool for use within a well casing having a lateral well bore window, the tool comprising:discriminator connected within the well casing and having a locking slot, an orienting profile, and an alignment slot; a body member having a first and a second longitudinal bore extending therethrough, a diverter member extending therefrom and having a diverter surface, the second longitudinal bore extending through the diverter member; an outwardly-biased orienting key movably secured to the body member and engageable with the orienting profile and the alignment slot; at least one orienting spring disposed to outwardly bias the orienting key; an outwardly-biased locking key movably secured to the body member and engageable with the locking slot, the diverter surface being aligned with the lateral well bore window when the orienting key is engaged with the alignment slot and the locking key is engaged with the locking slot; at least one locking spring disposed to outwardly bias the locking key; a first production tubing extending through the first longitudinal bore and aligned with the diverter surface; and a second production tubing extending through the second longitudinal bore, one of the first and second production tubings being releasably secured to the body member.
  • 12. The downhole well tool of claim 11, wherein the second production tubing is releasably secured to the diverter member.
  • 13. The downhole well tool of claim 11, wherein a lower end of the diverter member is cone-shaped.
  • 14. The downhole well tool of claim 11, wherein the orienting and locking keys are outwardly biased by at least one spring.
  • 15. The downhole well tool of claim 11, wherein the orienting key is disposed for radial movement within a first recess in the body member.
  • 16. The downhole well tool of claim 11, wherein the locking key is disposed for movement within a second recess in the body member.
  • 17. The downhole well tool of claim 16, wherein the locking key is hingedly attached to the body member.
  • 18. The downhole well tool of claim 11, wherein the locking key is shearably disconnectable from the body member.
  • 19. The downhole well tool of claim 11, wherein the body member includes a locking profile remotely engageable with a well tool for disengaging the well tool from the casing.
  • 20. The downhole well tool of claim 11, wherein the diverter member extends downwardly from the body member, and the discriminator is connected to the well casing above the lateral well bore window.
  • 21. A method of completing a well having a main well bore and at least one lateral well bore, the method comprising:positioning a completion assembly in the main well bore, the completion assembly comprising a body member having a first and a second longitudinal bore extending therethrough, at least a first and a second production tubing, a tubing diverter integrally connected to the body member, an orienting key engageable with an orienting profile in a casing disposed in the main well bore and outwardly biased by at least one orienting spring, and a locking key engageable with a locking slot in the casing and outwardly biased by at least one locking spring; and simultaneously lowering the first and second production tubings, guided by the tubing diverter, the first production tubing being lowered into the at least one lateral well bore, and the second production tubing being lowered into one of the main well bore and another lateral well bore.
  • 22. A method of completing a well having a main well bore and at least one lateral well bore, the method comprising:setting a first packer in the at least one lateral well bore, the first packer having a polished bore receptacle extending therefrom and being adapted to receive a first production tubing; setting a second packer in one of the main well bore and another lateral well bore, the second packer having a polished bore receptacle extending therefrom and being adapted to receive a second production tubing; simultaneously lowering the first and second production tubings into the main well bore, aligning a diverter and the first production tubing adjacent the at least one lateral well bore; and simultaneously lowering the first and second production tubings until they each engage the polished bore receptacles on the first and second packers, respectively.
  • 23. The method of claim 22, wherein the first and second production tubings are connected to a dual packer, one of the first and second production tubings is connected to the diverter, and the method further includes simultaneously lowering the dual packer into the well casing with the first and second production tubings and the diverter.
  • 24. The method of claim 23, further including:connecting a work string to the dual packer; using the work string to lower the dual packer, first and second production tubings, and diverter into the main well bore; using the work string to simultaneously push the first and second production tubings into engagement with the polished bore receptacles on the first and second packers, respectively; disconnecting the work string from the dual packer; and retrieving the work string.
  • 25. The method of claim 22, further including connecting the first production tubing to a third production tubing extending to the earth's surface, and connecting the second production tubing to a fourth production tubing extending to the earth's surface.
  • 26. The method of claim 22, further including connecting the first and second production tubings to a central production tubing extending to the earth's surface.
RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/129,950, filed Apr. 19, 1999.

US Referenced Citations (34)
Number Name Date Kind
1900163 Dana Mar 1933
2492079 Wiley Dec 1949
2804926 Zublin Sep 1957
3330349 Owsley et al. Jul 1967
4396075 Wood et al. Aug 1983
4415205 Rehm et al. Nov 1983
4444276 Peterson, Jr. Apr 1984
4807704 Hsu et al. Feb 1989
5311936 McNair et al. May 1994
5318121 Brockman et al. Jun 1994
5325924 Bangert et al. Jul 1994
5330007 Collins et al. Jul 1994
5411082 Kennedy May 1995
5427177 Jordan, Jr. et al. Jun 1995
5454430 Kennedy et al. Oct 1995
5462120 Gondouin Oct 1995
5474131 Jordan, Jr. et al. Dec 1995
5526880 Jordan, Jr. et al. Jun 1996
5533573 Jordan, Jr. et al. Jul 1996
5564503 Longbottom et al. Oct 1996
5685373 Collins et al. Nov 1997
5762149 Donovan et al. Jun 1998
5785133 Murray et al. Jul 1998
5845707 Longbottom Dec 1998
5871046 Robison Feb 1999
5878815 Collins Mar 1999
5884704 Longbottom et al. Mar 1999
5918669 Morris et al. Jul 1999
5944109 Longbottom Aug 1999
5960874 Morris et al. Oct 1999
6009942 Williamson Jan 2000
6089320 LaGrange Jul 2000
6125937 Longbottom et al. Oct 2000
6158513 Nistor et al. Dec 2000
Provisional Applications (1)
Number Date Country
60/129950 Apr 1999 US