U.S. patent application number 12/416804 was filed with the patent office on 2010-10-07 for methods for forming boring shoes for wellbore casing, and boring shoes and intermediate structures formed by such methods.
Invention is credited to Christopher C. Beuershausen, Angela D. High, Adam Richard Williams.
Application Number | 20100252331 12/416804 |
Document ID | / |
Family ID | 42825256 |
Filed Date | 2010-10-07 |
United States Patent
Application |
20100252331 |
Kind Code |
A1 |
High; Angela D. ; et
al. |
October 7, 2010 |
METHODS FOR FORMING BORING SHOES FOR WELLBORE CASING, AND BORING
SHOES AND INTERMEDIATE STRUCTURES FORMED BY SUCH METHODS
Abstract
Methods of attaching a crown of a boring shoe to a casing
section include attaching an adaptable shank to a crown, and
machining the adaptable shank to configure an end thereof for
attachment to a casing section after attaching the adaptable shank
to the crown. Additional methods include welding an end of an
adaptable shank to a crown to form a boring shoe, selecting the
adaptable shank to have an average wall thickness greater than
about five percent (5%) of a maximum diameter of the crown, and
configuring an opposite end of the adaptable shank for attachment
to a particular type of casing section after welding the shank to
the crown. Boring shoes have an adaptable shank attached to a
crown, wherein the shank comprises a generally cylindrical wall
having an average wall thickness greater than about five percent
(5%) of a maximum diameter of the crown.
Inventors: |
High; Angela D.; (Tyler,
TX) ; Beuershausen; Christopher C.; (Magnolia,
TX) ; Williams; Adam Richard; (Conroe, TX) |
Correspondence
Address: |
TRASKBRITT, P.C.
P.O. BOX 2550
SALT LAKE CITY
UT
84110
US
|
Family ID: |
42825256 |
Appl. No.: |
12/416804 |
Filed: |
April 1, 2009 |
Current U.S.
Class: |
175/320 ;
166/380; 175/402 |
Current CPC
Class: |
E21B 17/14 20130101;
E21B 17/042 20130101 |
Class at
Publication: |
175/320 ;
166/380; 175/402 |
International
Class: |
E21B 19/18 20060101
E21B019/18; E21B 7/20 20060101 E21B007/20; E21B 17/14 20060101
E21B017/14 |
Claims
1. A method of attaching a crown of a boring shoe to a section of
casing, comprising: attaching a first end of an adaptable shank to
the crown of the boring shoe; and machining an opposite second end
of the adaptable shank to configure the second end of the adaptable
shank for attachment to the section of casing after attaching the
first end of the adaptable shank to the crown.
2. The method of claim 1, further comprising forming the adaptable
shank to comprise a generally cylindrical structure.
3. The method of claim 2, further comprising forming the adaptable
shank to comprise a metal alloy.
4. The method of claim 3, further comprising forming the adaptable
shank to comprise a steel alloy.
5. The method of claim 2, further comprising selecting the metal
alloy to exhibit a tensile yield strength of at least about 60,000
pounds per square inch.
6. The method of claim 2, further comprising forming the adaptable
shank to have a length between about twenty-five (25) centimeters
(about ten (10) inches) and about two hundred (200) centimeters
(about seventy-nine (79) inches).
7. The method of claim 1, further comprising forming the adaptable
shank to have an average wall thickness greater than about five
percent (5%) of a maximum diameter of the crown.
8. The method of claim 7, further comprising forming the average
wall thickness of the adaptable shank to be about 10% or more of
the maximum diameter of the crown.
9. The method of claim 8, further comprising: forming the maximum
diameter of the crown to be about 12.25 inches; and forming the
average wall thickness of the adaptable shank to be about 1.22
inches or more.
10. The method of claim 8, further comprising forming the average
wall thickness of the adaptable shank to be about 12.5% or more of
the maximum diameter of the crown.
11. The method of claim 10, further comprising: forming the maximum
diameter of the crown to be about 6.00 inches; and forming the
average wall thickness of the adaptable shank to be about 0.750
inches or more.
12. The method of claim 10, further comprising forming the average
wall thickness of the adaptable shank to be about 15% or more of
the maximum diameter of the crown.
13. The method of claim 12, further comprising: forming the maximum
diameter of the crown to be about 8.50 inches; and forming the
average wall thickness of the adaptable shank to be about 1.313
inches or more.
14. The method of claim 7, further comprising: forming the maximum
diameter of the crown to be about 17.50 inches; and forming the
average wall thickness of the adaptable shank to be about 1.125
inches or more.
15. The method of claim 7, further comprising: forming the maximum
diameter of the crown to be about 24.00 inches; and forming the
average wall thickness of the adaptable shank to be about 1.263
inches or more.
16. The method of claim 7, wherein attaching a first end of an
adaptable shank to the crown of the boring shoe comprises: abutting
a surface of the first end of the adaptable shank to a surface of
the crown; and welding an interface between the surface of the
crown and the abutting surface of the first end of the adaptable
shank.
17. The method of claim 16, wherein welding the interface between
the surface of the crown and the abutting surface of the first end
of the adaptable shank comprises depositing a weld material in a
weld groove.
18. The method of claim 1, wherein machining the opposite second
end of the adaptable shank comprises machining threads on at least
one of an interior surface and an exterior surface of the adaptable
shank.
19. A method of attaching a boring shoe to a section of casing,
comprising: selecting an adaptable shank to have an average wall
thickness greater than about five percent (5%) of a maximum
diameter of a crown to be welded thereto; welding the first end of
the adaptable shank to the crown to form the boring shoe; and
configuring an opposite second end of the adaptable shank for
attachment to the section of casing after welding the first end of
the adaptable shank to the crown.
20. The method of claim 18, further comprising selecting the
adaptable shank to have a length between about twenty-five (25)
centimeters (about ten (10) inches) and about two hundred (200)
centimeters (about seventy-nine (79) inches).
21. The method of claim 20, further comprising selecting the
average wall thickness of the adaptable shank to be about 10.0% or
more of the maximum diameter of the crown.
22. The method of claim 21, further comprising selecting the
average wall thickness of the adaptable shank to be about 12% or
more of the maximum diameter of the crown.
23. The method of claim 22, further comprising selecting the
average wall thickness of the adaptable shank to be about 15% or
more of the maximum diameter of the crown.
24. The method of claim 19, further comprising: welding the first
end of the adaptable shank to the crown at a first geographic
location; transporting the boring shoe from the first geographic
location to a second geographic location using a vehicle; and
configuring the opposite second end of the adaptable shank for
attachment to the section of casing at the second geographic
location.
25. A boring shoe, comprising: a crown configured for at least one
of drilling and reaming a wellbore; and an adaptable shank attached
to the crown, the adaptable shank comprising a generally
cylindrical wall having an average wall thickness greater than
about five percent (5%) of a maximum diameter of the crown.
26. The boring shoe of claim 25, wherein the crown is welded to the
adaptable shank.
27. The boring shoe of claim 26, wherein the average wall thickness
of the generally cylindrical wall is greater than about 10% of the
maximum diameter of the crown.
28. The boring shoe of claim 27, wherein the average wall thickness
of the generally cylindrical wall is greater than about 12% of the
maximum diameter of the crown.
29. The boring shoe of claim 28, wherein the average wall thickness
of the generally cylindrical wall is greater than about 15% of the
maximum diameter of the crown.
30. The boring shoe of claim 29, wherein the adaptable shank
comprises a metal alloy material exhibiting a tensile yield
strength of at least about 60,000 pounds per square inch.
Description
TECHNICAL FIELD
[0001] The present invention relates to earth-boring shoes
configured for attachment to a section of wellbore casing, to
methods of manufacturing such earth-boring shoes, and to methods of
adapting such earth-boring shoes for attachment to a section of
wellbore casing.
BACKGROUND
[0002] The drilling of wells for oil and gas production
conventionally employs longitudinally extending sections or
so-called "strings" of drill pipe to which, at one end, is secured
a drill bit of a larger diameter. After a selected portion of the
borehole has been drilled, the borehole is usually lined or cased
with a string or section of casing. Such a casing or liner usually
exhibits a larger diameter than the drill pipe and a smaller
diameter than the drill bit. Therefore, drilling and casing
according to the conventional process typically requires
sequentially drilling the borehole using drill string with a drill
bit attached thereto, removing the drill string and drill bit from
the borehole, and disposing casing into the borehole. Further,
often after a section of the borehole is lined with casing, which
is usually cemented into place, additional drilling beyond the end
of the casing may be desired.
[0003] Unfortunately, sequential drilling and casing may be time
consuming because, as may be appreciated, at the considerable
depths reached during oil and gas production, the time required to
implement complex retrieval procedures to recover the drill string
may be considerable. Thus, such operations may be costly as well,
since, for example, the beginning of profitable production can be
greatly delayed. Moreover, control of the well may be difficult
during the period of time that the drill pipe is being removed and
the casing is being disposed into the borehole.
[0004] Some approaches have been developed to address the
difficulties associated with conventional drilling and casing
operations. Of initial interest is an apparatus which is known as a
reamer shoe that has been used in conventional drilling operations.
Reamer shoes have become available relatively recently and are
devices that are able to drill through modest obstructions within a
borehole that has been previously drilled. In addition, the reamer
shoe may include an inner section manufactured from a material
which is drillable by rotary drill bits. Accordingly, when cemented
into place, reamer shoes usually pose no difficulty to a subsequent
drill bit. For instance, U.S. Pat. No. 6,062,326 to Strong et al.
discloses a casing shoe or reamer shoe in which the central portion
thereof may be configured to be drilled through. In addition, U.S.
Pat. No. 6,062,326 to Strong et al. discloses a casing shoe that
may include diamond cutters over the entire face thereof, if it is
not desired to drill therethrough. Such reamers that are configured
for attachment to a casing string are referred to hereinafter as
"reamer shoes."
[0005] As a further extension of the reamer shoe concept, in order
to address the problems with sequential drilling and casing,
drilling with casing is gaining popularity as a method for
initially drilling a borehole, wherein the casing is used as the
drilling conduit and, after drilling, the casing is cemented into
and remains within the wellbore to act as the wellbore casing.
Drilling with casing employs a drill bit that is configured for
attachment to the casing string instead of a drill string, so that
the drill bit functions not only to drill the earth formation, but
also to guide the casing into the wellbore. This may be
advantageous as the casing is disposed into the borehole as it is
formed by the drill bit, and therefore eliminates the necessity of
retrieving the drill string and drill bit after reaching a target
depth where cementing is desired. Such drill bits that are
configured for attachment to a casing string are referred to
hereinafter as "drill shoes."
[0006] As used herein, the terms "earth-boring shoes" and "boring
shoes" mean and include any device that is configured for
attachment to an end of a section of casing and used for at least
one of drilling a wellbore, reaming a previously drilled wellbore,
and guiding casing through a previously drilled wellbore, as the
section of casing to which the device is attached is advanced into
a subterranean formation. Earth-boring shoes and boring shoes
include, for example, drill shoes, reamer shoes, casing shoes
configured to merely guide casing through a wellbore and ensure
that the wellbore diameter remains as drilled (i.e., has not
decreased as sometimes occurs in reactive or sloughing formations),
and shoes that both drill and ream as casing to which they are
attached is advanced into a subterranean formation.
[0007] Commercially available casing sections are sold in a variety
of different diameters and with a variety of different coupling
configurations. As a result, when an earth-boring shoe is
manufactured for a particular customer, a conventional boring shoe
must be manufactured for the particular diameter of casing to which
the boring shoe is to be attached. Furthermore, the boring shoe
must be provided with a connection portion that is configured
(e.g., with threads) to complimentarily engage the particular
connection portion of the casing string to which the boring shoe is
to be attached.
[0008] There is a need in the art for improved methods of coupling
boring shoes to casing strings, and for improved methods of
adapting boring shoes for attachment to casing strings having
different connection configurations.
BRIEF SUMMARY
[0009] In some embodiments, the present invention includes methods
of attaching a crown of a boring shoe to a section of casing. A
first end of an adaptable shank may be attached to the crown of a
boring shoe, and an opposite, second end of the adaptable shank may
be machined to configure the second end of the adaptable shank for
attachment to a section of casing after attaching the first end of
the adaptable shank to the crown.
[0010] In additional embodiments, the present invention includes
methods of attaching boring shoes to sections of casing. A first
end of an adaptable shank is welded to a crown to form a boring
shoe. The adaptable shank is selected to have an average wall
thickness greater than about five percent (5%) of a maximum
diameter of the crown. An opposite, second end of the adaptable
shank is configured for attachment to a particular type of casing
section after welding the first end of the adaptable shank to the
crown.
[0011] Yet further embodiments of the present invention include
boring shoes having an adaptable shank attached to a crown, wherein
the adaptable shank comprises a generally cylindrical wall having
an average wall thickness greater than about five percent (5%) of a
maximum diameter of the crown.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0012] While the specification concludes with claims particularly
pointing out and distinctly claiming that which is regarded as the
present invention, the advantages of embodiments of this invention
may be more readily ascertained from the following description of
certain embodiments of the invention when read in conjunction with
the accompanying drawings, in which:
[0013] FIG. 1 is a perspective view of an embodiment of a shoe tool
of the present invention that includes a crown attached to an
adaptable shank;
[0014] FIG. 2 is a schematic illustration showing the shoe tool of
FIG. 1 attached to a section of casing and disposed within a
subterranean formation;
[0015] FIG. 3 is a longitudinal cross-sectional view of an
embodiment of a shoe tool like that of FIG. 1 including a crown
attached to an adaptable shank;
[0016] FIG. 4 is an enlarged cross-sectional view of an interface
between the crown and the adaptable shank shown in FIG. 3;
[0017] FIG. 5 is a longitudinal cross-sectional view of the shoe
tool shown in FIGS. 3 and 4 after adapting the shank for connection
to casing in accordance with embodiments of methods of the present
invention; and
[0018] FIG. 6 is a longitudinal cross-sectional view of the shoe
tool shown in FIG. 5, further illustrating a section of casing
coupled to the shank of the shoe tool.
DETAILED DESCRIPTION
[0019] Illustrations presented herein are not meant to be actual
views of any particular device or system, but are merely idealized
representations which are employed to describe embodiments of the
present invention. Additionally, elements common between figures
may retain the same numerical designation.
[0020] An embodiment of a boring shoe 10 of the present invention
is shown in FIG. 1. The boring shoe 10 shown in FIG. 1 is an
intermediate structure that has not yet been adapted for attachment
to any particular section of casing. After formation of the
intermediate boring shoe 10 shown in FIG. 1, the boring shoe 10 may
be adapted for attachment to a particular section of casing, as
described in further detail herein below.
[0021] The boring shoe 10 shown in FIG. 1 may be a reamer shoe or a
drill shoe configured for attachment to a section of casing for use
in forming a wellbore in a subterranean formation. As shown in FIG.
1, the boring shoe 10 includes a crown 20 and an adaptable shank 30
that is attached to the crown 20.
[0022] In some embodiments, the crown 20 may be configured to drill
a wellbore in a subterranean formation. In other embodiments, the
crown 20 may be configured to ream (i.e., enlarge the diameter of)
a previously drilled wellbore. In yet other embodiments, the crown
20 may be configured to merely guide casing through a wellbore and
ensure that the wellbore diameter remains as previously drilled and
has not decreased as sometimes occurs in reactive or sloughing
formations. In other words, the crown 20 may only ream sections of
the wellbore that have an undersized diameter due, for example, to
encroachment of the formation material into the wellbore.
[0023] The crown 20 includes a body 21 that may be formed of and
comprise, for example, a metal or metal alloy (e.g., steel,
aluminum, brass, or bronze), or a composite material including
particles of a relatively harder material (e.g., tungsten carbide)
embedded within a relatively softer metal or metal alloy (e.g.,
steel, aluminum, brass, or bronze). The material of the body 21 may
be selected to exhibit physical properties that allow the body 21
to be drilled through by another drill bit after the boring shoe 10
has been used to advance a section of casing attached thereto into
a subterranean formation, as known in the art.
[0024] Drilling and/or reaming structures may be provided on
exterior surfaces of the body 21 of the crown 20. For example, the
crown 20 may comprise a plurality of blades 22 that define fluid
courses 24 therebetween. Apertures 25 may be formed through the
crown 20 for allowing fluid (e.g., drilling fluid and/or cement) to
be pumped through the interior of the boring shoe 10, out through
the apertures 25 in the crown 20, and into the annular space
between the walls of the formation in which the wellbore is formed
and the exterior surfaces of the boring shoe 10 and the casing
sections to which the boring shoe 10 may be attached. For example,
the apertures 25 may comprise fluid passageways extending through
the body 21 of the crown 20. Optionally, nozzles (not shown) may be
secured to the crown 20 within the fluid passageways to selectively
tailor the hydraulic characteristics of the boring shoe 10. Cutting
element pockets may be formed in the blades 22, and cutting
elements 26, such as, for example, polycrystalline diamond compact
(PDC) cutting elements, may be secured within the cutting element
pockets.
[0025] Also, each of blades 22 may include a gage region 23 that
together define the largest diameter of the crown 20 and, thus, the
diameter of any wellbore formed using the crown 20 and boring shoe
10. The gage regions 23 may be longitudinal extensions of the
blades 22. Wear-resistant structures or materials may be provided
on the gage regions 23. For example, tungsten carbide inserts,
cutting elements, diamonds (e.g., natural or synthetic diamonds),
or hardfacing material may be provided on the gage regions 23 of
the crown 20.
[0026] In additional embodiments, the crown 20 may not include
blades 22 and cutting elements 26, like those shown in FIG. 1. In
such embodiments, the crown 20 may comprise other cutting and/or
reaming structures such as, for example, deposits of hardfacing
material (not shown) on the exterior surfaces of the crown 20. Such
a hardfacing material may comprise, for example, hard and abrasive
particles (e.g., diamond, boron nitride, silicon carbide, carbides
or borides of titanium, tungsten, or tantalum, etc.) embedded
within a metal or metal alloy matrix material (e.g., an iron-based,
cobalt-based, or nickel-based metal alloy). Such deposits of
hardfacing material may be shaped into elongated, protruding
structures on the exterior surfaces of the crown 20.
[0027] FIG. 2 is a simplified schematic illustration showing the
boring shoe 10 attached to a section of casing 39 and disposed
within a wellbore that has been formed in a subterranean formation
using the boring shoe 10. As previously discussed, the casing 39,
with the boring shoe 10 attached thereto, may be rotated and
advanced into the subterranean formation as drilling fluid is
pumped down through the interior of the casing 39, out through the
apertures 25 in the crown 20, and up through the fluid courses 24
(FIG. 1) and up through the annular space between the walls of the
formation within the wellbore and the exterior surfaces of the
casing 39 to the surface of the formation.
[0028] Once the casing 39 has been advanced to a desirable location
within the formation, drilling with the boring shoe 10 may be
ceased, and the casing 39 may be cemented in place. To cement the
casing 39 in place, cement (not shown) or another curable material
may be forced through the interior of casing 39, through the
apertures 25 in the crown 20, up through the fluid courses 24 (FIG.
1), and into the annulus between the wall of wellbore and the outer
surface of the casing 39, where it may be allowed to harden. Of
course, conventional float equipment may be used for controlling
and delivering the cement through the boring shoe 10 and into the
annulus between the wall of the wellbore and the casing 39.
Cementing the casing 39 in place within the wellbore may stabilize
the wellbore and seal the subterranean formations penetrated by the
boring shoe 10 and the casing 39.
[0029] In some instances, the size and placement of the apertures
25 that are employed for drilling operations may not be
particularly desired for cementing operations. Furthermore, the
apertures 25 may become plugged or otherwise obstructed during a
drilling operation. As shown in FIGS. 1 and 2, at least one of the
crown 20 and the shank 30 of the boring shoe 10 may include one or
more frangible regions 28 that can be breached (e.g. a metal disc
that can be fractured, perforated, ruptured, removed, etc.) to form
one or more additional apertures that may be used to provide fluid
communication between the interior and the exterior of the boring
shoe 10. Drilling fluid and/or cement optionally may be caused to
flow through such frangible regions 28 after breaching the
same.
[0030] Referring again to FIG. 1, the boring shoe 10 includes an
adaptable shank 30 having a first end 31A attached to the crown 20
and a second end 31B that may be adapted and used to couple the
boring shoe 10 to a section of casing (not shown in FIG. 1). The
shank 30 may have a size and shape that allows it to be adapted,
after attachment to the crown 20, for coupling to a wide variety of
different casing configurations, as discussed in further detail
herein below.
[0031] FIG. 3 is a longitudinal, cross-sectional view of another
embodiment of an intermediate boring shoe 50 of the present
invention. The intermediate boring shoe 50 is similar to the boring
shoe 10 shown in FIG. 1, and includes a crown 40 having a body 41
that is attached to an adaptable shank 30, as previously described
in relation to FIG. 1.
[0032] The adaptable shank 30 is a cylindrical structure having a
length L. By way of example and not limitation, the length L of the
adaptable shank 30 may be between about twenty-five (25)
centimeters (about ten (10) inches) and about two hundred (200)
centimeters (about seventy-nine (79) inches).
[0033] The adaptable shank 30 has a wall thickness T.sub.W that is
one-half of the difference between the outer diameter OD of the
shank 30 and the inner diameter ID of the shank 30. The wall
thickness T.sub.W may vary, depending upon the size (e.g., the
diameter) of the crown 40 to which the shank 30 is attached. The
wall thickness T.sub.W of the shank 30, however, may be
sufficiently large to allow the shank 30 to be adapted for use with
a number of different casing sections having a variety of weights
and coupling configurations that might be used with the particular
size of crown 40 to which the shank 30 is attached. Although the
shank 30 of FIG. 3 is shown having an outer diameter that is less
than an outer diameter of the crown 40 to which the shank 30 is
attached, in additional embodiments, the shank 30 may have an outer
diameter that is larger than a diameter of the crown 40 to which
the shank 30 is attached.
[0034] Table 1 below lists a variety of different diameters of
crowns that are often used in the industry, together with the outer
diameter OD, the inner diameter ID, and the wall thickness T.sub.W
of examples of adaptable shanks 30 of the present invention that
may be attached to such crowns. All dimensions in Table 1 are given
in inches, and dimensions in centimeters are provided in
parenthesis.
TABLE-US-00001 TABLE 1 Shank T.sub.W as Crown Casing Percentage of
Diameter Diameter Shank OD Shank ID Shank T.sub.W Crown Diameter
6.00 in 4.50 in 5.125 in 3.625 in 0.750 in 12.5% (15.24 cm) (11.43
cm) (13.02 cm) (9.21 cm) (1.91 cm) 8.50 in 7.625 in 8.625 in 6.00
in 1.313 in 15.4% (21.59 cm) (19.37 cm) (21.91 cm) (15.24 cm) (3.34
cm) 12.25 in 9.625 in 10.750 in 8.310 in 1.220 in 10.0% (31.12 cm)
(24.45 cm) (27.31 cm) (21.11 cm) (3.10 cm) 17.50 in 13.375 in
14.500 in 12.250 in 1.125 in 6.4% (44.45 cm) (33.97 cm) (36.83 cm)
(31.12 cm) (2.86 cm) 24.00 in 20.00 in 21.125 in 18.60 in 1.263 in
5.3% (60.96 cm) (50.80 cm) (53.66 cm) (47.24 cm) (3.21 cm)
[0035] As shown in Table 1, in some embodiments of the present
invention, the crown 40 may have a diameter that is about 12.25
inches or less, and the adaptable shank 30 may have a wall
thickness that is about 10% or more of the diameter of the crown
40, about 12% or more of the diameter of the crown 40, or even
about 15% or more of the diameter of the crown 40. As one
particular non-limiting example, the crown 40 may have a diameter
of about 12.25 inches, the shank 30 may have an outer diameter OD
of about 10.750 inches, an inner diameter ID of about 8.310 inches
or less, and a wall thickness T.sub.W of about 1.220 inches or more
(i.e., about 10.0% or more of the diameter of the crown 40). As
another particular non-limiting example, the crown 40 may have a
diameter of about 8.50 inches, the shank 30 may have an outer
diameter OD of about 8.625 inches, an inner diameter ID of about
6.00 inches or less, and a wall thickness T.sub.W of about 1.313
inches or more (i.e., about 15.4% or more of the diameter of the
crown 40). As yet another particular non-limiting example, the
crown 40 may have a diameter of about 6.00 inches, the shank 30 may
have an outer diameter OD of about 5.125 inches, an inner diameter
ID of about 3.625 inches or less, and a wall thickness T.sub.W of
about 0.750 inches or more (i.e., about 12.5% or more of the
diameter of the crown 40). Other non-limiting examples of
embodiments of the invention are also set forth in Table 1
above.
[0036] As shown in Table 1, in additional embodiments of the
present invention, the crown 40 may have a diameter that is greater
than about 12.25 inches, and the adaptable shank 30 may have a wall
thickness that is about 5% or more of the diameter of the crown 40,
or even about 6% or more of the diameter of the crown 40. As one
particular non-limiting example, the crown 40 may have a diameter
of about 17.50 inches, the shank 30 may have an outer diameter OD
of about 14.500 inches, an inner diameter ID of about 12.250 inches
or less, and a wall thickness T.sub.W of about 1.125 inches or more
(i.e., about 6.4% or more of the diameter of the crown 40). As
another particular non-limiting example, the crown 40 may have a
diameter of about 24.00 inches, the shank 30 may have an outer
diameter OD of about 21.125 inches, an inner diameter ID of about
18.60 inches or less, and a wall thickness T.sub.W of about 1.263
inches or more (i.e., about 5.3% or more of the diameter of the
crown 40).
[0037] The adaptable shank 30 may be formed from and comprise a
metal material such as, for example, an iron-based metal alloy
(e.g., a steel alloy). In some embodiments, the adaptable shank 30
may be formed from and comprise a material that exhibits a tensile
yield strength of at least about 60,000 pounds per square inch
(PSI), at least about 90,000 pounds per square inch (PSI), or even
at least about 120,000 PSI pounds per square inch (PSI). As
previously mentioned, the adaptable shank 30 may be separately
formed from the crown 40 and subsequently attached thereto.
[0038] FIG. 4 is an enlarged cross-sectional view of an interface
between the crown 40 and the adaptable shank 30 shown in FIG. 3. As
shown in FIG. 4, the shank 30 may be attached to the crown 40 by
abutting an end surface 34 of the shank 30 against an end surface
48 of the crown 40 and welding an interface between the shank 30
and the crown 40. In other words, a weld material 60 (e.g., one or
more weld beads) may be provided around an exterior surface of the
intermediate boring shoe 50 along the interface between the crown
40 and the shank 30. In some embodiments, the shank 30 may have a
beveled, frustoconical surface 36 at the first longitudinal end 31A
thereof, and the crown 40 may have a complementary beveled,
frustoconical surface 49. The frustoconical surface 36 of the shank
30 and the frustoconical surface 49 of the crown 40 may define a
weld groove therebetween when the shank 30 is abutted against the
crown 40. A weld material 60 may be deposited in the form of one or
more weld beads within the weld groove to weld the shank 30 and the
crown 40 together. The shank 30 may be abutted against, and welded
to, the crown 40 prior to adapting the shank 30 for attachment to a
section of casing.
[0039] In additional embodiments, complementary threads (not shown)
may be provided on the crown 40 and the shank 30 to allow the crown
40 and the shank 30 to be threaded together to attach the crown 40
and the shank 30 together. In such embodiments, a weld material 60
also may be provided along the interface between the crown 40 and
the shank 30 to further secure the crown 40 and the shank 30
together.
[0040] Referring to FIG. 5, after attaching the shank 30 and the
crown 40 together, the shank 30 may be adapted for attachment to a
particular section of casing. The shank 30 may be adapted for
attachment to a particular section of casing by, for example, doing
one or more of the following: reducing the length L of the shank
30, reducing the wall thickness T.sub.W of the shank 30, and
providing one or more features on the shank 30, and/or shaping one
or more surfaces of the shank 30, for coupling to an end of a
section of casing. The wall thickness T.sub.W of the shank 30 may
be reduced by reducing the outer diameter of the shank 30, by
increasing the inner diameter of the shank 30, or by both reducing
the outer diameter and increasing the inner diameter of the shank
30.
[0041] The outer diameter of the shank 30 may be reduced, and the
inner diameter of the shank 30 may be increased, as desirable,
using, for example, conventional machining processes such as
turning processes, milling processes, and combinations of turning
and milling processes.
[0042] To configure the shank 30 for coupling to a section of
casing, one or more features may be provided on the shank 30,
and/or one or more surfaces of the shank 30 may be provided with a
certain shape, as previously mentioned. For example, an inner
surface 38A of the shank 30 may be formed to comprise what is
referred to in the art as a "threaded box."
[0043] To form a threaded box in the inner surface 38A of the shank
30, a section of the inner surface 38A of the shank 30 at the
second end 31B thereof may be formed to comprise a taper, such that
the section of the inner surface 38A has a frustoconical shape have
a diameter that is greatest at the opening of the shank 30 at the
second end 31B thereof, the diameter becoming progressively smaller
moving in the longitudinal direction toward the first end 31A of
the shank 30. The angle of the taper of the inner surface 38A of
the shank 30 at the second end 31B may be selected to correspond to
the angle of a taper on the exterior surface of a section of casing
to which the shank 30 is to be attached. Such a taper also may be
formed in the inner surface 38A using, for example, conventional
machining processes such as turning processes, milling processes,
and combinations of turning and milling processes.
[0044] Furthermore, threads 37 may be formed on a section of the
inner surface 38A of the shank 30 at the second end 31B (e.g., on a
tapered section of the inner surface 38A). The size (e.g.,
dimensions), shape, and spacing (e.g., pitch) of the threads 37
also may be selected to correspond to the size (e.g., dimensions),
shape, and spacing (e.g., pitch) of complementary threads on a
section of casing to which the shank 30 is to be attached. The
threads 37 also may be formed in the inner surface 38A using, for
example, conventional machining processes such as turning
processes, milling processes, and combinations of turning and
milling processes. Threads may also be formed by rolling the
surface to be threaded against a threading die, as known in the
art, and such roll threading processes also may be employed in
embodiments of the present invention.
[0045] In some embodiments, threads 37 may be formed on the inner
surface 38A of the shank 30 at the second end 31B thereof without
providing any taper on the inner surface 38A. In other words, the
inner surface 38A may remain at least substantially cylindrical,
and a section of the cylindrical inner surface may be threaded.
[0046] In additional embodiments of the present invention, an outer
surface 38B of the shank 30 may be formed to comprise what is
referred to in the art as a "threaded pin," which is a male pin
member having threads on an exterior surface thereof that is
configured to mate with, and engage, a female threaded box, as
previously described herein.
[0047] Referring to FIG. 6, after adapting the shank 30 for
attachment to a particular section of casing 61, the shank 30 and
the section of casing 61 may be coupled together in preparation for
drilling and/or reaming with the boring shoe 50 as the casing 61
and the boring shoe 50 are advanced into a subterranean
formation.
[0048] In the embodiment shown in FIG. 6, a threaded box is
provided on the inner surface 38A of the shank 30 at the second end
31B thereof, and the section of casing 61 has a threaded pin 62 at
an end 64 thereof that is complementary to, and configured to mate
with and engage, the threaded box at the second end 31B of the
shank 30.
[0049] In additional embodiments of the invention, however, the
shank 30 may be formed to comprise a threaded pin, and the casing
61 may comprise a complementary threaded box configured to engage
the threaded pin of the shank 30. In yet further embodiments, each
of the shank 30 and the casing 61 may comprise a threaded pin, and
a collar having a threaded box on both ends thereof may be used to
couple the threaded pin of the shank 30 to the threaded pin of the
casing 61. Such collars are commercially available and frequently
used in the art.
[0050] Thus, in accordance with some embodiments of methods of the
present invention, an adaptable shank may be attached to a crown of
a boring shoe prior to identifying the type of casing to which the
boring shoe will ultimately be attached. As a result, a
manufacturer need not fabricate a variety of different types of
shanks for each size of boring shoe, each type corresponding to the
different types of casing to which the boring shoe might be
attached. In contrast, a single, adaptable shank in accordance with
embodiments of the present invention may be fabricated for each
size of boring shoe, and the adaptable shank can be adapted, after
attachment to a crown, for attachment to a particular type of
casing.
[0051] Furthermore, in accordance with some embodiments of methods
of the present invention, an adaptable shank may be attached to a
crown of a boring shoe prior to identifying the type of casing to
which the boring shoe will ultimately be attached. The crown, with
the adaptable shank attached thereto, may be transported to another
location other than where the crown and shank were attached
together (e.g., the location of a distributor, the location of a
drilling site, etc.) by way of a vehicle (e.g., a truck, plane, or
boat). After transporting the crown, with the adaptable shank
attached thereto, to another location, a particular type of casing
to which the crown and adaptable shank are to be attached may be
identified, and the adaptable shank may be adapted, as previously
described herein, for attachment to that particular type of
casing.
[0052] While the present invention has been described herein with
respect to certain embodiments, those of ordinary skill in the art
will recognize and appreciate that it is not so limited. Rather,
many additions, deletions and modifications to the embodiments
described herein may be made without departing from the scope of
the invention as hereinafter claimed. In addition, features from
one embodiment may be combined with features of another embodiment
while still being encompassed within the scope of the invention as
contemplated by the inventors.
* * * * *