Note: Descriptions are shown in the official language in which they were submitted.
CA 02410574 2006-10-27
PIPE HANDLING APPARATUS AND METHOD OF
LANDING ITEMS AT A WELL LOCATION
BACKGROUND OF THE INVENTION
1. Field of the invention
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The present invention relates to a drill pipe and drill pipe holder used in
the oil and gas
well drilling industry. More particularly, the present invention relates to a
drill pipe holder that
holds a j oint of drill pipe in a landing string during the addition or
removal of a j oint of drill pipe
to or from the landing string, wherein the holder and the joint of drill pipe
held by the holder are
configured to support the load of the landing string with correspondingly
shaped shoulders that
engage when the holder holds the joint of drill pipe.
2. General Background of the Invention
Oil and gas well drilling and production operations involve the use of
generally
cylindrical tubes commonly known in the industry as "casing" which line the
generally cylindrical
wall of the borehole which has been drilled in the earth. Casing is typically
comprised of steel
pipe in lengths of approximately 40 feet, each such length being commonly
referred to as a
"joint" of casing. In use, joints of casing are attached end-to-end to create
a continuous conduit.
In a completed well, the casing generally extends the entire length of the
borehole and conducts
oil and gas from the producing formation to the top of the borehole, where one
or more blowout
preventors may be located on the sea floor.
Casing is generally installed or "run" into the borehole in phases as the
borehole is being
drilled. The casing in the uppermost portion of the borehole, commonly
referred to as "surface
casing," may be several hundred to several thousand feet in length, depending
upon numerous
factors including the nature of the earthen formation being drilled and the
desired final depth of
the borehole.
After the surface casing is cemented into position in the borehole, further
drilling
operations are conducted through the interior of surface casing as the
borehole is drilled deeper
and deeper. When the borehole reaches a certain depth below the level of the
surface casing,
depending again on a number of factors such as the nature of the formation and
the desired final
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depth of the borehole, drilling operations are temporarily halted so that the
next phase of casing
installation, commonly known as intermediate casing, may take place.
Intermediate casing, which may be thousands of feet in total length, is
typically made of
"joints" of steel pipe, each joint typically being in the range of about 38 to
42 feet in length (11.58
to 12.80 meters). The j oints of intermediate casing are attached end-to-end,
typically through the
use of threaded male and female connectors located at the respective ends of
eachjoint of casing.
In the process of installing the intermediate casing, joints of intermediate
casing are
lowered longitudinally through the floor of the drilling rig. The length of
the column of
intermediate casing grows as successive joints of casing are added, generally
one at a time, by
drill hands and/or automated handling equipment located on the floor of the
drilling rig.
When the last intermediate casing joint has been added, the entire column of
intermediate
casing, commonly referred to as the intermediate "casing string", must be
lowered further into
its proper place in the borehole. The task of lowering the casing string into
its final position in
the borehole is accomplished by adding joints of drill pipe to the top of the
casing string. The
additional joints of drill pipe are added, end-to-end, by personnel and/or
automated handling
equipment located on the drilling rig, thereby creating a column of drill pipe
known as the
"landing string." With the addition of each successive j oint of drill pipe to
the landing string, the
casing string is lowered further and further.
During this process as practiced in the prior art, when an additional joint of
drill pipe is
being added to the landing string, the landing string and casing string hang
from the floor of the
drilling rig, suspended there by a holder or gripping device commonly referred
to in the prior art
as "slips." When in use, the slips generally surround an opening in the rig
floor through which
the upper end of the uppermost joint of drill pipe protrudes, holding it there
a few feet above the
surface of the rig floor so that rig personnel and/or automated handling
equipment can attach the
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next joint(s) of drill pipe.
The inner surface of the prior art slips has teeth-like grippers and is curved
such that it
corresponds with the outer surface of the drill pipe. The outer surface of
prior art slips is tapered
such that it corresponds with the tapered inner or "bowl" face of the master
bushing in which the
slips sit.
When in use, the inside surface of the prior art slips is pressed against and
"grips" the
outer surface of the drill pipe which is surrounded by the slips. The tapered
outer surface of the
slips, in combination with the corresponding tapered inner face of the master
bushing in which
the slips sit, cause the slips to tighten around the gripped drill pipe such
that the greater the load
being carried by that gripped drill pipe, the greater the gripping force of
the slips being applied
around that gripped drill pipe. Accordingly, the weight of the casing string,
and the weight of
the landing string being used to "run" or "land" the casing string into the
borehole, affects the
gripping force being applied by the slips, i.e., the greater the weight the
greater the gripping force
and crushing effect.
As the world's supply of easy-to-reach oil and gas formations is being
depleted, a
significant amount of oil and gas exploration has shifted to more challenging
and difficult-to-
reach locations such as deep-water drilling sites located in thousands of feet
of water. In some
of the deepest undersea wells drilled to date, wells may be drilled from a rig
situated on the ocean
surface some 5,000 to 10,000 feet (1.524 to 3.048 kilometers) above the sea
floor, and such
wells may be drilled some 15,000 to 20,000 feet (4.572 to 6.096 kilometers)
below the sea floor.
It is envisioned that as time goes on, oil and gas exploration will involve
the drilling of even
deeper holes in even deeper water.
For many reasons, including the nature of the geological formations in which
unusually
deep drilling takes place and is expected to take place in the future, the
casing strings required
for such wells must be unusually long and must have unusually thick walls,
which means that
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such casing strings are unusually heavy and can be expected in the future to
be even heavier.
Moreover, the landing string needed to land the casing strings in such
extremely deep wells must
be unusually long and strong,.hence unusually heavy in comparison to landing
strings required
in more typical wells.
For example, a typical well drilled in an offshore location today may be
located in about
300 to 2000 feet (91.44 to 609.6 meters) of water, and may be drilled 15,000
to 20,000 feet
(4.572 to 6.096 kilometers) into the sea floor. Typical casing for such a
typical well may involve
landing a casing string between 15,000 to 20,000 feet (4.572 to 6.096
kilometers) in length,
weighing 40 to 60 pounds per linear foot (59.52 to 89.28 kilograms per meter),
resulting in a
typical casing string having a total weight of between 600,000 to 1,200,000
pounds (272,160 to
544,320 kilograms). The landing string required to land such a typical casing
string may be 300
to 2000 feet (91.44 to 609.6 meters) long which, at about 35 pounds per linear
foot (52.08
kilograms per meter) of landing string, results in a total landing string
weight of 10,500 to 70,000
pounds (4,762.8 to 31,752 kilograms). Hence, prior art slips in typical wells
have typically
supported combined landing string and casing string weight in the range of
between about
610,500 to 1,270,000 pounds (276,922.8 to 576, 072 kilograms).
By way of contrast, extremely deep undersea wells located in 5,000 to 10,000
(1.524 to
3.048 kilometers) feet of water, uncommon today but expected to be more common
in the future,
may involve landing a casing string 15,000 to 20,000 feet (4.572 to 6.096
kilometers) in length,
weighing 40 to 80 pounds per linear foot (59.52 to 119.04 kilograms per
meter), resulting in a
total casing string weight of 600,000 to 1,600,000 pounds (272,160 to 725,760
kilograms). The
landing string required to land such casing strings in such extremely deep
wells may be 5,000 to
10,000 feet (1,524 to 3,048 meters) long which, at 70 pounds per linear foot
(104.16 kilograms
per meter), results in a total landing string weight of about 350,000 to
700,000 pounds (158,760
to 317,520 kilograms). Hence, the combined landing string and casing string
weight for
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extremely deep undersea wells may be in the range of 950,000 to 2,300,000
pounds (430,920 to
1,043,280 kilograms), instead ofthe 610,500 to 1,270,000 pound (276,696 to
576,072 kilograms)
range generally applicable to more typical wells. In the future, as deeper
wells are drilled in
deeper water, the combined landing string and casing string weight can be
expected to increase,
perhaps up to as much as 4,000,000 pounds (1,814,400 kilograms) or more.
Under certain circumstances, prior art slips have been able to support the
combined
landing string and casing string weight of 610,500 to 1,270,000 pounds
(276,696 to 576,072
kilograms) associated with typical wells, depending upon the size, weight and
grade of the pipe
being held by the slips. In contrast, prior art slips cannot effectively and
consistently support the
combined landing string and casing string weight of 950,000 to 2,300,000
pounds (430,920 to
1,043,280 kilograms) associated with extremely deep wells, because of numerous
problems
which occur at such extremely heavy weights.
For example, prior art slips used to 'support combined landing string and
casing string
weight above the range of about 610,500 to 1,270,000 pounds (276,696 to
576,072 kilograms)
have been known to apply such tremendous gripping force that (a) the gripped
pipe has been
crushed or otherwise deformed and thereby rendered defective, (b) the gripped
pipe has been
excessively scored and thereby damaged due to the teeth-like grippers on the
inside surface of
the prior art slips being pressed too deeply into the gripped drill pipe
and/or (c) the prior art slips
have experienced damage rendering them inoperable.
A related problem involves the uneven distribution of force applied by the
prior art slips
to the gripped pipe j oint. If the tapered outer wall of the slips is not
substantially parallel to and
aligned with the tapered inner wall of the master bushing, that can create a
situation where the
gripping force of the slips in concentrated in a relatively small portion of
the inside wall of the
slips rather than being evenly distributed throughout the entire inside wall
of the slips. Such
concentration of gripping force in such a relatively small portion of the
inner wall of the slips can
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(a) crush or otherwise deform the gripped drill pipe, (b) result in excessive
and hamiful strain or
elongation of the drill pipe below the point where it is gripped and (c) cause
damage to the slips
rendering them inoperable.
This uneven distribution of gripping force is not an uncommon problem, as the
rough and
tumble nature of oil and gas well drilling operations cause the slips and/or
master bushing to be
knocked about, resulting in misalignment and/or irregularities in the tapered
interface between
the slips and the master bushing. This problem is exacerbated as the weight
supported by the
slips is increased, which is the case for extremely deep wells as discussed
above.
BRIEF SUMMARY OF INVENTION
The present invention does away with prior art slips and provides for a drill
pipe holder
which supports the drill pipe without crushing, defonning, scoring or causing
elongation of the
drill pipe being held. The holder of the present invention includes wedge
members which can be
raised out of and lowered into the holder.
The holder is used in combination with an enlarged diameter section of the
drill pipe
which is spaced apart from the ends of the drill pipe. The enlarged diameter
section has a
tapered shoulder which corresponds to a tapered shoulder on the movable wedge
members of the
holder, and the engagement of such shoulders provides support for the drill
pipe being held
without any of the problems associated with the prior art slips, regardless of
the weight of the
landing string and casing string.
Certain exemplary embodiment may provide a drilling rig, pipe, and pipe
support
apparatus, comprising: a) a drilling rig having a floor; b) a landing string
comprised of a
number of joints of drill pipe connected end to end extending from the rig; c)
a drill pipe
holder, located at the rig floor, that holds a joint of drill pipe in the
landing string and
supports the landing string during the addition or removal of a joint of drill
pipe to or from
the landing string; d) wherein the holder and the joint of drill pipe that is
held by the holder
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are configured to support the load of the landing string with correspondingly
shaped annular
shoulders that engage when the holder holds the joint of drill pipe; e) the
holder including a
main body and a plurality of wedge members, the wedge members forming an
interface
between the body and the joint of drill pipe being held by the holder.
Certain other exemplary embodiment may provide a drill pipe support apparatus
comprising: a) a landing string comprised of a number of joints of drill pipe
connected end to
end, each joint of pipe having pin and box end portions and an enlarged
diameter section
spaced in between the pin and box end, but closer to the box end portion; b) a
drill pipe
holder that holds a joint of drill pipe in the landing string and supports the
landing string at
the enlarged diameter section during the addition or removal of a joint of
drill pipe to or from
the landing string; c) wherein the holder and the joint of drill pipe that is
held by the holder
are configured to support the load of the landing string with correspondingly
shaped annular
shoulders that engage when the holder holds the joint of drill pipe; and d)
the holder
including a main body and a plurality of wedge members, the wedge members
forming an
interface between the body and the joint of drill pipe being held by the
holder.
Certain exemplary embodiment may provide a drilling rig, pipe, and pipe
support
apparatus, comprising: a) a drill platform having a floor with a work area; b)
a landing string
comprised of a number of joints of drill pipe connected end to end, each joint
having
enlarged, pin and box end portions, an enlarged diameter section that is
positioned between
the pin and box end portions, the majority of each joint of drill pipe being
of a smaller,
generally uniform diameter; c) the floor having a drill pipe holder that
supports the landing
string during the addition or removal of a joint of drill pipe to or from the
landing string; d)
wherein the holder and an uppermost joint of drill pipe that is supported by
the holder are
configured to support the load of the landing string at the enlarged diameter
section with
correspondingly shaped tapered annular shoulders that engage when the holder
supports the
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uppermost joint of drill pipe at the enlarged diameter section; e) the holder
including a main
body and a plurality of wedge members that form an interface between the body
and the
uppermost joint of drill pipe at the engaged annular shoulder.
Certain exemplary embodiment may provide a drill pipe support apparatus
comprising: a) a landing string comprised of a number of joints of drill pipe
connected end to
end, each joint of pipe having enlarged diameter pin and box end portions and
an enlarged
diameter section spaced in between the pin and box end portions, but closer to
the box end
portion; b) a drill pipe holder that supports the landing string at the
enlarged diameter section
during the addition or removal of a joint of drill pipe to or from the landing
string; c) wherein
the holder and an uppermost joint of drill pipe that is supported by the
holder are configured
to support the load of the landing string with correspondingly shaped tapered
annular
shoulders that engage when the holder supports the uppermost joint of drill
pipe; and d) the
holder including a main body, and a plurality of wedge members that form an
interface
between the body and the uppermost joint of drill pipe.
Certain exemplary embodiment may provide a drill pipe support apparatus
comprising: a) a landing string comprised of a member of joints of drill pipe
connected end
to end, wherein a number of joints of the drill pipe in the landing string
have an enlarged
diameter section and wherein the enlarged diameter section is spaced apart
from the ends of
the drill pipe, but closer to one end than the other; b) a drill pipe holder
that supports the
enlarged diameter section of drill pipe in the landing string during the
addition or removal of
a joint of drill pipe to or from the landing string; c) wherein the holder and
the joint of drill
pipe that is held by the holder are configured to support the load of the
landing string with
correspondingly shaped shoulders that engage when the holder holds the joint
of pipe,
wherein the shoulders are rotatable with respect to eachother regardless of
the distance
between said shoulders; d) the holder including a main body and a plurality of
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wedge members, the wedge member forming an interface between the body and the
joint of
drill pipe being held by the holder.
Certain exemplary embodiment may provide a drill pipe handling apparatus,
comprising: a) a drilling rig with a floor; b) a landing string comprised of a
number of joints
of drill pipe connected end to end, at least a plurality of the joints of pipe
having an enlarged
diameter section with a shoulder that is spaced apart from either end of the
pipe; c) first and
second holders that provide support for the landing string; d) wherein the
first holder is a
lower holder positioned near the rig floor that holds a joint of drill pipe in
the landing string
and supports the landing string during the addition or removal of a joint of
drill pipe to or
from the landing string, and a second holder that is an upper holder that
holds a joint of drill
pipe in the landing string and supports the landing string after a joint of
drill pipe has been
added to or removed from the landing string; e) each of the holders including
a main body
and a plurality of wedge members, the wedge members forming an interface
between the
body and the joint of drill pipe being held by the holder, each wedge member
having a
shoulder that corresponds in shape to the shoulder at the enlarged diameter
section, wherein
the shoulders are rotatable with respect to each other regardless of the
distance between said
shoulders.
Certain exemplary embodiment may provide a pipe handling apparatus comprising:
a) a landing string comprised of a number of joints of drill pipe connected
end to end, each
joint of pipe having generally cylindrically shaped pin and box end portions,
a generally
cylindrically shaped smaller diameter portion that extends over a majority of
the length of
each joint, and an enlarged diameter generally cylindrically shaped section
spaced in between
the pin and box end portions; b) a pair of vertically spaced apart drill pipe
holders that each
enable the landing string to be supported; c) wherein each holder and a joint
of drill pipe in
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the landing string that is held by a holder are configured to support the load
of the landing
string with correspondingly shaped shoulders that engage when the holder holds
the joint of
drill pipe, wherein the shoulders are rotatable with respect to each other
regardless of the
distance between said shoulders; and d) each holder including a main body and
a plurality of
wedge members, the wedge members forming an interface between the body and the
joint of
drill pipe being held by the holder.
Certain exemplary embodiment may provide a pipe handling apparatus comprising:
a) a landing string comprised of a number of joints of drill pipe connected
end to end, each
joint of pipe having generally cylindrically shaped pin and box end portions,
a generally
cylindrically shaped smaller diameter portion that extends over a majority of
the length of
each joint, and a generally cylindrically shaped enlarged diameter section
spaced in between
the pin and box end portions; b) a pair of vertically spaced apart drill pipe
holders that each
enable the landing string to be supported; c) wherein each holder and a joint
of drill pipe in
the landing string that is held by the holder are configured to support the
load of the landing
string with correspondingly shaped annular shoulders that engage when the
holder holds the
joint of drill pipe; and d) each holder including a main body, a plurality of
wedges that are
movable between engaged and disengaged positions, said wedges defining an
interface
between the body and the joint of pipe being held by the holder, and wherein
one of the
holders has a body that is movable in a vertical direction during use.
Certain exemplary embodiment may provide a method of landing items at a well
location, comprising the steps of: a) positioning a drilling rig above a well
location, the
drilling rig having a landing string that is comprised of a number of joints
of drill pipe, and a
holder that holds a joint of drill pipe in the landing string for supporting
the landing string; b)
attaching an item to the lower end of the landing string and lowering the
landing string such
that it spans the distance between the drilling rig and the well location; c)
wherein the holder,
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and the joint of drill pipe that is held by the holder, are configured to
support the load of the
landing string with correspondingly shaped shoulders that engage when the
holder holds the
joint of drill pipe, wherein the shoulders are rotatable with respect to each
other regardless of
the distance between said shoulders.
Certain exemplary embodiment may provide a method of well casing placement
comprising the steps of: a) positioning a drilling rig above a well location,
the drilling rig
having a landing string that is comprised of a number of joints of drill pipe,
and a holder that
holds a joint of drill pipe in the landing string for supporting the landing
string; b) lowering a
plurality of connected joints of casing to the well, said plurality of
connected joints of casing
defining a casing string, the casing string being supported by the landing
string; c)
configuring the combination of landing string and casing string so that the
overall combined
length of the landing string and casing string spans the distance between the
drilling rig and
the well location, and wherein the combined weight of landing string and
casing string is
between about 430,000 and 1,050,000 kilograms; d) wherein the holder, and the
joint of drill
pipe that is held by the holder, are configured to support the load of step
"c" with
correspondingly shaped shoulders that engage when the holder holds the joint
of drill pipe,
wherein the shoulders are rotatable with respect to each other regardless of
the distance
between said shoulders.
Certain exemplary embodiment may provide a method of landing casing string for
use
in water depths of at least about 90 meters, comprising the steps of: a)
positioning a drilling
rig above an undersea well location, the drilling rig having a landing string
that is comprised
of a number of joints of drill pipe, and a holder for supporting the landing
string when one or
more pipe joints is to be added to or removed from the landing string; b)
lowering a plurality
of connected joints of casing to the undersea well, said plurality of
connected joints of casing
defining a casing string, wherein the landing string in step "a" has upper and
lower end
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portions, the casing string being supported by the lower end portion of the
landing string; c)
configuring the combination of landing string and casing string so that the
overall, combined
length of the landing string and casing string spans at least a majority of
the distance between
the drilling rig and the undersea well location at the seabed, and wherein the
combined
weight of landing string and casing string is between about 430,000 and
1,050,000 kilograms;
d) wherein the holder, and an uppermost joint of drill pipe that is supported
by the holder, are
configured to support the load of step "c", wherein the uppermost joint of
drill pipe is
rotatable with respect to the holder regardless of the distance between the
uppermost joint of
drill pipe and the holder.
Certain exemplary embodiment may provide a method of deep sea well casing
placement for use in water depths of at least about 90 meters, comprising the
steps of: a)
positioning a drilling rig above an undersea well location, the drilling rig
having a landing
string that is comprised of a number of joints of drill pipe, and a holder for
supporting the
landing string when one or more pipe joints is to be added to or removed from
the landing
string; b) lowering a plurality of connected joints of casing to the undersea
well, said plurality
of connected joints of casing defining a casing string, wherein the landing
string in step "a"
has upper and lower end portions, the casing string being supported by the
lower end portion
of the landing string; c) configuring the combination of landing string and
casing string so
that the overall, combined length of the landing string and casing string
spans the distance
between the drilling rig and the undersea well location at the seabed, and
wherein the
combined weight of landing string and casing string is between about 430,000
and 1,050,000
kilograms; d) wherein the holder, and an uppermost joint of drill pipe that is
supported by the
holder, are configured to support the load of step "c" with correspondingly
shaped tapered
annular shoulders that engage when the holder supports the uppermost joint of
drill pipe.
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Certain exemplary embodiment may .provide a method of well casing placement
comprising the steps of: a) positioning a drilling rig above an undersea well
location, the
drilling rig having a lifting device, a landing string that is comprised of a
number of joints of
drill pipe, and a holder for supporting the landing string when one or more
pipe joints is to be
added to or removed from the landing string; b) supporting the landing string
with the lifting
device; c) lowering a plurality of connected joints of casing to the undersea
well, said
plurality of connected joints of casing defining a casing string, wherein the
landing string in
step "a" has upper and lower end portions, the casing string being supported
by the lower end
portion of the landing string; d) configuring the combination of landing
string and casing
string so that the overall, combined length of the landing string and casing
string spans at
least a majority of the distance between the drilling rig and the undersea
well location at the
seabed, and wherein the combined weight of landing string and casing string is
between
about 430,000 and 1,050,000 kilograms; e) wherein the holder, and an uppermost
joint of
drill pipe that is supported by the holder, are configured to support the load
of step "d",
wherein the uppermost joint of drill pipe is rotatable with respect to the
holder regardless of
the distance between the uppermost joint of drill pipe and the holder.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an overall elevational view of a drilling rig situated on a
floating drill ship,
said drilling rig supporting a landing string and casing string extending
therefrom in accordance
with the present invention toward the borehole that has been drilled into the
sea floor.
Figure 2 is an elevational view of drill pipe in accordance with the present
invention.
Figures 3 and 4 are fragmentary, sectional, elevational views of drill pipe in
accordance
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with the present invention.
Figure 5 is a perspective view of the wedge members of the lower and upper
holders of
the present invention, hinged together and closed.
Figure 6 is a cross sectional view taken along lines 6 - 6 in figure 5.
Figure 7 is a perspective view of the individual, unconnected wedge members of
the
lower and upper holders of the present invention.
Figure 8 is a perspective view of the wedge members of the lower and upper
holders of
the present invention hinged together in an open position.
Figure 9 is a fragmentary, sectional, elevational view of an alternative
embodiment of
drill pipe in accordance with the present invention, along with a side view of
a wedge member
used with the alternative embodiment in both the upper and lower holders of
the present
invention.
Figure 10 is an elevational view of the drill pipe and upper and lower holders
in
accordance with the present invention, in which the lower holder is supporting
the landing string
extending from the drilling rig, and the auxiliary upper holder is supporting
the weight of the
joints of drill pipe being added to or removed from the landing string.
Figure 11 is an elevational view of the drill pipe and holders in accordance
with the
present invention, wherein the landing string is being supported by the lower
holder, and wherein
additional joints of drill pipe have either been just added to or are about to
be removed from the
landing string being held by the lower holder.
Figure 12 in an elevational view of the drill pipe and holders in accordance
with the
present invention, wherein the landing string is supported by the upper
holder, and wherein the
upper holder and the wedges of the lower holder are being raised slightly so
as to clear the wedge
members of the lower holder from around the drill pipe prior to lowering the
joints of drill pipe
which have been added, or, alternatively, where the upper holder has just been
used to pull
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several joints of landing string up as in "tripping out" of the hole.
Figure 13 is a perspective view showing the upper holder without its wedge
members and
without the auxiliary upper holder.
Figure 14 is a cross sectional view taken along lines 14 - 14 of figure 13.
Figure 15 is an elevational view of the drill pipe and upper and lower holders
of the
present invention wherein the upper holder has just lowered the drill pipes
that were added and
wherein the weight of the landing string is about to be transferred from the
upper holder to the
lower holder.
Figure 16 is an elevational view of the drill pipe and upper and lower holders
of the
present invention wherein the lower holder is supporting the weight of the
landing string and
wherein the upper holder is about to be hoisted up so that additional joints
of drill pipe may be
added to the landing string or, alternatively, wherein the upper holder is
about to engage and
support the landing string in preparation for "tripping out" of the hole.
Figure 17 is an elevational view of an alternative embodiment of the drill
pipe in
accordance with the present invention.
Figure 18 is a cross sectional view taken along lines 18 - 18 of figure 17.
Figure 19 is an elevational view of an alternative embodiment of drill pipe in
accordance
with the present invention.
Figure 19A is a cross sectional view taken along lines 19A-19A of figure 19.
Figure 20 is an elevational view of an alternative embodiment of the present
invention
in which the joints are run with the female end down and the male end up.
Figure 21 is an elevational view of another alternative embodiment of drill
pipe in
accordance with the present invention.
Figure 21A is a cross sectional view taken along lines 21A-21A of figure 21.
Figure 22 is an elevational view of yet another alternative embodiment of the
present
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invention.
Figure 23 is an elevational side view of a further alternative embodiment of
wedge
members in accordance with the present invention.
For a furtlier understanding of the nature, obj ects and advantages of the
present invention,
reference should be had to the following detailed description, read in
conjunction with the
following drawings, wherein like reference numerals denote like elements and
wherein:
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 depicts generally the present invention 5 in overview. As shown in
figure 1,
drilling rig 8 is situated above ocean surface 12 over the location of
undersea well 14 that is
drilled below sea floor 16. Numerous lengths or "joints" of drill pipe 18 in
accordance with the
present invention, attached end-to-end and collectively known as "landing
string" 19, extend
from rig 8. Numerous lengths or "joints" of casing 34, attached end-to-end and
collectively
known as "casing string" 35, extend below landing string 19 and are attached
to landing string
19 via crossover connection 36. The landing string 19, crossover connection 36
and casing string
35 are situated longitudinally within riser 17 which extends from the rig 8 to
undersea well 14.
Figure 2 shows a drill pipe 18 in accordance with the present invention. In
addition to
a female or "box" end 20 and a male or "pin" end 22, drill pipe 18 of the
present invention also
has an enlarge diameter section 21 which is spaced apart from box end 20 and
pin end 22.
Enlarged diameter section 21 has a shoulder 21 a which is preferably tapered
as shown in figures
2 and 3. Shoulder 21 a surrounds at least a part and preferably all of the
circumferential perimeter
of drill pipe 18.
Also in accordance with the present invention, figure 10 shows drill pipe
lower holder
100 for supporting the landing string 19 during the addition or removal of one
or more joints of
drill pipe 18 to or from landing string 19. Lower holder 100 is preferably
located at the drilling
rig floor 9, where it may be situated in or adjacent to the floor.
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As also shown in figure 10, lower holder 100 includes main body 104 which
generally
surrounds an opening 11 in rig floor 9 through which landing string 19
protrudes. Main body 104
has an opening 103 and a tapered inner face 105 which defines a tapered bowl
generally
surrounding landing string 19 which protrudes therethrough.
Lower holder 100 also includes one or more wedge members 106, as depicted in
figures
10, 11 and 12. As shown in figure 7, the wedge members 106 of the present
invention are
preferably three in number and are preferably connected by hinges 108 as shown
in figures 5 and
8. Wedge members 106 have a tapered outer face 107, as shown in figures 5 and
7, which
corresponds with the tapered inner face 105 of main body 104, as shown in
figures 11 and 12.
The tapered bowl in main body 104 which is defined by its tapered inner face
105 receives wedge
members 106 as best depicted in figures 10 and 11.
As shown in figures 6 and 7, the inner side of wedge member 106 has a tapered
shoulder
109. Tapered shoulder 109 corresponds with tapered shoulder 21 a of enlarged
diameter section
21 of drill pipe 18, as best shown in figures 12 and 11. Tapered shoulder 109
of wedge member
106 is curved, as shown in figures 7 and 8, to correspond with the curved,
circumferential shape
of shoulder 21 a of enlarged diameter section 21. The inner side of wedge
member 106 also has
a curved surface 106a, as best shown in figures 7 and 8, which corresponds
with and
accommodates the curved outer surface 18a of drill pipe 18. The inner side of
wedge member 106
also has curved surface 106b, as best shown in figures 7 and 8, which
corresponds with and
accommodates the curved outer surface 21b of enlarged diameter section 21 of
drill pipe 18.
When wedge members 106 are in place in main body 104, as shown in figures 10
and 11,
the wedge members form an interface between body 104 and the joint of drill
pipe 18 being held
by holder 100, the engagement between shoulder 109 of wedge member 106 and
shoulder 21 a
of enlarged diameter section 21 providing support for the drill pipe 18 being
held by the holder
100.
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It should be understood that lower holder 100 of the present invention
provides support
for landing string 19 by the engagement of shoulder 109 of wedge member 106
with shoulder 21 a
of enlarged diameter section 21 of drill pipe 18. Accordingly, unlike prior
art slips, it is not
necessary for the curved inner surface 106a of wedge member 106 to have teeth-
like grippers or
bear against the drill pipe 18 being supported by the holder. Hence, the
present invention
overcomes the problems associated with crushing, deformation, scoring and
uneven distribution
of gripping force associated with prior art slips.
It should be understood that drill pipe 18 depicted in figure 10 as being
supported by
lower holder 100 is the uppermost length or "joint" of drill pipe in landing
string 19 depicted in
figure 1. It should also be understood that lower holder 100 of the present
invention supports not
only drill pipe 18 which appears in figure 10, but also the entire attached
landing string 19 and
casing string 35 extending from rig 8, as best shown in figure 1. In extremely
deep wells drilled
in extremely deep water for which the present invention is particularly
suited, the combined
weight of landing string 19 and casing string 35 may range from 950,000 to
2,300,000 pounds.
In the future, as deeper wells are drilled in deeper water, it is expected
that the present invention
may be supporting combined landing string and casing string weight of
4,000,000 pounds or
more.
Figure 1 depicts the installation or "running" of intermediate casing string
35, which will
be lowered longitudinally, through blowout preventors 15 and surface casing
32, into position
in borehole 24. Although figure 1 shows surface casing 32 already cemented
into position in
borehole 24, it should be understood that the present invention may not only
be used to run
intermediate casing, but surface and production casing as well. It should also
be understood that
the present invention, in addition to being used to land casing strings, may
also be used to land
any other items on or below the sea floor such as blow out preventors, subsea
production
facilities, subsea wellheads, production strings, drill pipe and drill bits.
It should be specifically
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understood that drill pipe 18 of the present invention may be used in the
drilling operation, with
drilling fluid being circulated through the lumen 23 of drill pipe 18.
In order to lower casing string 35 from the position shown in figure 1 into
borehole 24,
additional joints of drill pipe 18 are added, usually 1 to 4 at a time, above
the joint of drill pipe
18 being held by holder 100, as shown in figure 10. Figure 10 shows three
additional joints of
drill pipe 18 about to be added, although it should be understood that the
number of j oints of drill
pipe added at a time may vary.
After the additional joint or joints of drill pipe 18 have been attached, as
shown in figure
11, landing string 19 and attached casing string 35 may be lowered by a
distance roughly
equivalent to the length of the newly added joints of drill pipe. This is
accomplished via upper
holder 200 of the present invention, as depicted in figure 11. Upper holder
200 is supported by
elevator bails or "links" 210 which in turn are attached to the rig lifting
system (not shown).
Upper holder 200 includes a main body 204 having an opening 203 which may
accommodate the
passage of drill pipe 18 therethrough. The opening 203 of main body 204 has a
tapered inner
face 205 which defines a tapered bowl, as best shown in figure 13.
Upper holder 200 also includes one or more wedge members 206 having a tapered
outer
face 207 which corresponds with the tapered inner face 205 of main body 204.
The tapered bowl
in main body 204 defined by its tapered inner face 205 receives wedge members
206 as shown
in figures 11 and 12. Wedge members 206 of the present invention are
preferably three in
number and are preferably connected by hinges, similar to wedge members 106 as
depicted in
figures 5 and 7.
Wedge members 206 of upper holder 200 are preferably shaped and configured
similar
to wedge members 106 of lower holder 100, although there may be slight
variations in size and/or
dimensions between wedge members 106 and 206. Similar to tapered shoulder 109
of wedge
member 106 as depicted in figures 6 through 8, the inner side of wedge member
206 has a
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tapered shoulder 209. As shown in fig. 11, tapered shoulder 209 of wedge
member 206
corresponds with tapered shoulder 20a of box end 20 of drill pipe 18. Similar
to tapered shoulder
109 of wedge member 106, tapered shoulder 209 of wedge member 206 is curved to
correspond
with and accommodate the curved, circumferential shape of shoulder 20a of box
end 20.
When wedge members 206 are in place in main body 204, as shown in figure 12,
the
engagement between shoulder 209 of wedge member 206 and shoulder 20a of box
end 20 of drill
pipe 18 being held by holder 200 provides support for said drill pipe 18 being
held by holder 200.
Similar to curved surface 106a on the inner side of wedge member 106 as shown
in
figures 7 and 8, the inner side of wedge member 206 also has a curved surface
206a which
corresponds with and accommodates the curved outer surface 18a of drill pipe
18. Similar to
curved surface 106b on the inner side of wedge member 106 as best shown in
figures 7 and 8,
the inner side of wedge member 206 also has a curved surface 206b which
corresponds with and
accommodates the curved outer surface 20b of box end 20 of drill pipe 18.
When wedge members 206 are in place in main body 204 of upper holder 200, as
shown
in figure 12, said wedge members form an interface between body 204 and the
joint of drill pipe
18 being held by holder 200. In that position, as depicted in figure 12, the
rig lifting system (not
shown) can be used to slightly lift upper holder 200. When that happens, upper
holder 200 is
supporting the entire load including the landing string 19 and casing string 3
5, thereby taking the
load off wedge members 106 of lower holder 100. Wedge members 106 can then be
disengaged,
i.e., wholly or partially moved up and away from drill pipe 18, providing
sufficient clearance for
the landing string 19 to pass unimpeded through the opening 103 in main body
104 of lower
holder 100.
The rig lifting system may then be used to lower upper holder 200, along with
the landing
string and casing string it is supporting, by a distance roughly equivalent to
the length of the
newly added joints of drill pipe. More specifically, upper holder 200 is
lowered until the
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uppermost enlarged diameter section 21 of newly added drill pipe 18 is located
a distance above
main body 104 of holder 100 sufficient to provide the vertical clearance
needed for reinsertion
of wedge members 106 in main body 104, as shown in fig. 15. At that point,
wedge members
106 of lower holder 100 may be placed back into position in main body 104 of
holder 100.
Upper holder 200 may then be slightly lowered further so as to bring into
supporting engagement
shoulder 109 of wedge members 106 with shoulder 21 a of the uppermost enlarged
diameter
section 21 of newly added drill pipe 19, as shown in fig. 16. In this fashion,
the entire load
including the landing string and the casing string is transferred from upper
holder 200 to lower
holder 100.
Upper holder 200 can then be cleared away from the uppermost end of the
landing string.
This is accomplished by lowering holder 200 slightly such that wedge members
206 can be
disengaged, i.e., moved up and away from box end 20 that was previously being
held by holder
200, as shown in fig. 16. Holder 200 can then be hoisted up by the rig lifting
system, permitting
clearance for yet additional joints of drill pipe to be added to the upper end
of the landing string.
As this process is repeated over and over again, casing string 35 is lowered
further and
further. This process continues until such time as casing string 35 reaches
its proper location in
borehole 24, at which point the overall length of landing string 19 spans the
distance between rig
8 and undersea well 14.
It should be understood that the rig lifting system referenced herein may be a
conventional
system available in the industry, such as a National Oilwell 2040-UDBE
draworks, a Dreco
model "872TB-1250" traveling block and a Varco-BJ "DYNAPLEXTM" hook, model
51000, said
system being capable of handling in excess of 2,000,000 pounds (907,200
kilograms).
Some rigs have specialized equipment to hold aloft additional joints of drill
pipe as they
are being added to the landing string. However, for those rigs that do not
have such specialized
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equipment, the present invention provides for auxiliary upper holder 300, as
shown in figures 10
and 11. Auxiliary holder 300 is suspended below upper holder 200 by connectors
301.
Connectors 301 may be cables, links, bails, slings or other mechanical devices
which serve to
connect auxiliary holder 300 to upper holder 200.
Auxiliary holder 300 has a main body 304 which can be moved from an opened to
a
closed position, allowing it to capture and hold aloft the j oints of drill
pipe 18 to be added to the
pipe string, as shown in fig. 10. The inner surface of main body 304 includes
a tapered shoulder
which corresponds with tapered shoulder 21a. The inner surface of main body
304 is sized to
accommodate drill pipe 18 such that when main body 304 is in its closed
position and supporting
the joints of drill pipe to be added, as shown in figure 10, the tapered
shoulder of main body 304
engages tapered shoulder 21a, providing support for the joints of drill pipe
being added. When
upper holder 200 is to be used to lower the entire load to the position shown
in figure 15,
auxiliary holder 300 can be swung back, up and out of the way, so that it does
not interfere with
lower holder 100. Because the combined weight of the relatively few joints of
drill pipe being
added at any one time is significantly less than the combined weight of the
landing string and the
casing string extending below the rig, the size and strength of auxiliary
upper holder 300 may be
substantially less than that of upper holder 200. Auxiliary holder 300 may be
a conventional
elevator available in the industry, such as the 25-ton model "MG" manufactured
by Access Oil
Tools.
It should be understood that while the present invention is particularly
useful for landing
casing strings and other items, the invention may also be used to retrieve
items. For example, the
invention may be employed to retrieve the landing string and any items
attached thereto, such as
a drill bit, in an operation commonly referred to as "tripping out of the
hole," wherein the
operations described hereinabove are essentially reversed. While the landing
string is being
supported by lower holder 100, as shown in figure 16, upper holder 200 is
lowered to the position
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shown in figure 16. Wedge members 206 may then be lowered into main body 204
of upper
holder 200 so that shoulder 209 of wedge member 206 is brought into supporting
engagement
with shoulder 20a of box end 20.
At that point, the rig lifting system may be used to lift holder 200, thereby
transferring the
landing string load from lower holder 100 to upper holder 200. This allows
wedge members 106
of lower holder 100 to be wholly or partially moved up and away from drill
pipe 18, providing
sufficient clearance for pipe string 19 to pass unimpeded through the opening
103 in main body
104.
When tripping out of the hole, it is common practice to pull up two or more
joints at a
time, as would be the case shown in figure 12. The landing string would be
pulled up by upper
holder 200 such that the enlarged diameter section 21 of the drill pipe to be
held by lower holder
100 is slightly above wedge members 106, as is shown in figure 12. At that
point, wedge
members 106 would be lowered into position in main body 104. Upper holder 200
may then be
slightly lowered further so as to bring into supporting engagement shoulder
109 of wedge
member 106 with shoulder 21 a of enlarged diameter section 21 of the drill
pipe being held in
holder 100. In this fashion, the entire load is transferred to lower holder
100, permitting the drill
pipe that has been pulled up above holder 100 to be detached from the landing
string, as would
appear in figure 10. The removed joints of drill pipe would then be cleared
from the upper holder
and placed on the drilling rig, permitting upper holder 200 to be lowered
again so that more j oints
of drill pipe could be pulled up, as this process is repeated over and over
again until all of the
landing string and the items attached thereto have been retrieved.
As shown in figures 2 - 4, drill pipe 18 of the present invention has the
following
exemplary dimensions:
The end outside diameter (E.O.D.) of pin end 22 and box end 20 is preferably
in the range
between about 61/2 to 9 7/8 inches (16.51 to 25.0825 centimeters), and most
preferably between
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7'/2 and 8 inches (19.05 to 20.32 centimeters).
The end wall thickness (E.W.T.) of pin end 22 and box end 20 is preferably in
the range
between about 1 1/2 to 3 inches (3.81 to 7.62 centimeters), and most
preferably between 2 1/4
and 2 3/8 inches (5.715 to 6.0325 centimters).
The pipe inside diameter (P.I.D.), i.e., the diameter of the uniform bore or
lumen 23
extending throughout the length of drill pipe 18, is preferably in the range
between about 2 to
6 inches (5.08 to 15.24 centimeters), and most preferably between 2 1/3 and 3
1/2 inches (5.9267
to 8.89 centimeters).
The pipe wall thickness (P.W.T.), i.e., the thickness of the pipe wall
throughout the length
of drill pipe 18, except at the ends and at the enlarged diameter section, is
preferably in the range
between about 5/8 to 2 inches (1.5875 to 5.08 centimeters), and most
preferably between land
1 1/2 inches (2.54 to 3.81 centimeters).
The pipe outside diameter (P.O.D.), i.e., the outside diameter of drill pipe
18 throughout
its length, except at the ends and at enlarged diameter section 21, is
preferably in the range
between about 4 1/2 to 7 5/8 inches (11.43 to 19.3675 centimeters), and most
preferably between
5 and 6 5/8 inches (12.7 to 16.8275 centimeters).
The enlarged diameter wall thickness (E.D.W.T.), i.e., the thickness of the
pipe wall at
enlarged diameter section 21, is preferably in the range between about 1 1/2
to 3 inches (3.81 to
7.62 centimeters), and most preferably between 2 1/4 and 2 3/8 inches (5.715
to 6.0325
centimeters).
The length "L" of drill pipe 18 is preferably in the range between about 28 to
45 feet
(8.5344 to 13.716 meters), and most preferably between 28 and 32 feet (8.5344
to 9.7536
meters). It should be understood that length "L" may be any length that can be
accommodated
by the vertical distance between the rig floor and the highest point of the
rig.
The length of the enlarged diameter section (L. E.) is preferably in the range
between
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about 1 to 60 inches (2.54 to 152.4 centimeters), and most preferably between
6 and 12 inches
(15.24 to 30.48 centimeters).
The distance "D" between shoulder 21a and shoulder 20a is preferably in the
range
between about 2 to 11 feet (0.6096 to 3.3528 meters) , most preferably between
3 to 5 feet
(0.9144 to 1.524 meters). The design criteria for distance "D" include the
following: (a) the
distance "D" should be sufficient to provide adequate clearance, and thereby
avoid entanglement,
between the bottom of holder 200 and the top of holder 100 when said holders
are in the position
depicted in fig. 16; (b) the distance "D" should also be sufficient to permit
insertion and removal
of wedge members 206 into and out of the tapered bowl of upper holder 200; and
(c) the distance
"D" should preferably be such that the upperinost end of the drill pipe being
supported by lower
holder 100 is a reasonable working height (R.W.H.) above rig floor 9, as shown
in fig. 10, so as
to permit rig personnel and/or automated handling equipment to assist in
attaching or removing
joints of drill pipe to or from said uppermost end.
The angle of taper "A" of shoulders 21 a, 20a and 22a, which appear in figures
3 and 4,
can be any angle greater than 0 and less than 180 , preferably between 10
degrees and 45
degrees, and most preferably 18 degrees. The same angle "A" applies to the
angle of taper of
shoulder 109 of wedge member 106 and shoulder 209 of wedge member 206, as
shown in fig.
6.
As shown in figures 6 and 7, wedge members 106 and 206 of the present
invention have
the following exemplary dimensions:
The height ("H-1 ") of the wedge members is preferably in the range of about 5
to 20
inches (12.7 to 50.8 centimeters), and most preferably between 8 and 16 inches
(20.32 to 40.64
centimeters).
The distance ("H-2") between the top of the wedge members and shoulders 109,
209 is
preferably in the range of about 2 to 10 inches (5.08 to 25.4 centimeters),
and most preferably
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between 3 and 8 inches (7.62 to 20.32 centimeters).
The distance ("H-3 ") between the bottom of the wedge members and shoulders
109, 209
is preferably in the range of about 3 to 10 inches (7.62 to 25.4 centimeters),
and most preferably
between 5 and 8 inches (12.7 to 20.32 centimeters).
The top thickness ("T-1 ") of the wedge members is preferably in the range of
about 1 to
8 inches (2.54 to 20.32 centimeters), and most preferably between 2 and 6
inches (5.08 to 15.24
centimeters).
The thickness ("T-2") of the wedge members at shoulders 109, 209 is preferably
in the
range of about 1 1/2 to 8 1/2 inches (3.81 to 21.59 centimeters), and most
preferably between 2
1/2 and 6 1/2 inches (6.35 to 16.51 centimeters).
The bottom thickness ("T-3 ") of the wedge members is preferably in the range
of about
1/2 to 6 inches (1.27 to 15.24 centimeters), and most preferably between 1 and
4 inches (2.54 to
10.16 centimeters).
The angle of taper ("A.T.") of outer face 107,207 of the wedge members can be
any angle
greater than 0 and less than 180 , preferably between 10 degrees and 45
degrees.
As shown in figure 14, upper holder 200 of the present invention has the
following
exemplary dimensions:
The height of holder 200 ("H.H.") is preferably in the range of about 18 to 72
inches
45.72 to 182.88 centimeters), and most preferably between 24 and 48 inches
(60.96 to 121.92
centimeters).
The width of holder 200 ("W-1 ") is preferably in the range of about 24 to 72
inches (60.96
to 182.88 centimeters), and most preferably between 36 and 60 inches (91.44 to
152.4
centimeters).
The width of the top of opening 203 ("W-2") of holder 200 is preferably in the
range of
about 12 to 24 inches (30.48 to 60.96 centimeters), and most preferably
between 16 and 21
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inches (40.64 to 53.34 centimeters).
The width of the bottom of opening 203 ("W-3") of holder 200 is preferably in
the range
of about 6 to 18 inches (15.24 to 45.72 centimeters), and most preferably
between 9 and 15
inches (22.86 to 38.1 centimeters).
Figure 9 depicts an alternative embodiment of the present invention wherein
the
shoulders, for example shoulders 21 a and 20a, are square, i.e., wherein angle
"A" measures 90
degrees. In that alternative embodiment as depicted in figure 9, the shoulders
109 and 209,
respectively, of wedge members 106 and 206, respectively, are also square.
In the preferred embodiment of the invention as depicted in figure 12, wedge
members
106 are lifted out of position by a lifting apparatus which includes lifting
arms 112. Lifting arms
112 may be raised and lowered by way of an actuator 114, preferably a
pneumatic or hydraulic
piston-cylinder arrangement. Lifting arms 112 may be attached directly to
wedge members 106
or via connectors 111 as shown in figure 12. Connectors 111 may be cables,
links, bails, slings
or other mechanical devices which serve to connect lifting arms 112 to wedge
members 106.
Wedge members 106 preferably include lifting eye 115 to facilitate the
connection to lifting arms
112. It should be understood that the raising and lowering wedges 106 out of
and into position
in body 104 can be accomplished in a variety of ways, including manual
handling by rig
personnel. It should also be understood that the lifting apparatus for raising
and lowering wedge
members 106 must be sized and configured so as to permit sufficient clearance
for upper holder
200 when it is in the position shown in figures 15 and 16.
As depicted in figures 11 and 12, upper holder 200 preferably includes a
lifting apparatus
for raising and lowering wedge members 206 out of and into position in main
body 204. In the
preferred embodiment of the invention as depicted in figure 12, the lifting
apparatus includes
lifting arms 212. Lifting arms 212 may be moved up and down by actuator 214,
preferably a
hydraulic or pneumatic piston-cylinder arrangement. Lifting arms 212 may be
attached directly
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to wedge members 206 or via connectors 211. Connector 211 may be cables,
links, bails, slings
or other mechanical devices which serve to connect lifting arms 212 to wedge
members 206.
Wedge members 206 preferably include lifting eyes 215 to facilitate the
connection to lifting
arms 212.
In the preferred embodiment of the invention as shown in figure 13, upper
holder 200 is
removably attached to elevator links 210. Main body 204 of upper holder 200 is
preferably
comprised of steel having recessed areas 220 to accommodate therein placement
of elevator link
eyes 221. Elevator link eyes 221 are retained in the position shown in figures
13 and 14 by link
retainers 222. Link retainers 222 may be moved from the closed position shown
in figure 14 to
an open position by lifting release pins 224, thereby permitting retainer
links 222 to pivot about
hinge pin 225 to an open position, thus permitting removal of upper holder 200
from elevator
links 210. As best depicted in figure 12, upper holder 200 is also provided
with lifting eyes 230
to which connectors 301 may be attached.
Figures 17 and 18 depict an alternative embodiment of the present invention in
which
enlarged diameter section 21 is not enlarged completely around the
circumference of drill pipe
18. In this alternative embodiment of enlarged diameter section 21, shown in
cross section in
figure 18, there may be one or more cross sectional gaps in section 21 where
the diameter is not
enlarged.
In the preferred embodiment of the invention, drill pipe 18, including box end
20,
enlarged diameter section 21 and pin end 22, is made from a single piece of
pipe of uniform wall
thickness having the dimension E.W.T. in figure 4, said thickness being
reduced at intervals
along the pipe by milling between box end 20 and enlarged diameter section 21,
and by milling
between pin end 22 and enlarged diameter section 21. It should be understood
that in such
preferred embodiment of the invention, box and pin ends 20 and 22 and enlarged
diameter
section 21 are integral with the pipe, i.e., box end 20 and pin end 22 are not
created by welding
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or otherwise attaching said ends to drill pipe 18, nor is enlarged diameter
section 21 created
through welding or other means of attachment. In the preferred embodiment of
the invention,
each joint of drill pipe 18 is made of steel and weighs between 800 to 5,000
pounds (362.88 to
2,268 kilograms), most preferably between 1,000 to 2,000 pounds (453.6 to
907.2 kilograms),
or approximately 29 to 110 pounds per linear foot (43.152 to 163.68 kilogram
per meter), most
preferably 32 to 75 pounds per linear foot (47.616 to 111.6 kilograms per
meter).
Alternatively, drill pipe 18 of the present invention may be made of a piece
of pipe of
uniform thickness, referenced as P.W.T. in fig. 4, with attached box and pin
ends, and with an
attached enlarged diameter section 21. In this alternative embodiment, the box
end, pin end and
enlarged diameter section may be attached to the pipe by welding, bolting or
other means.
In a further alternative embodiment of the present invention, drill pipe 18
may be made
from titanium or from a carbon graphite composite.
Figures 19 and 21 show further alternative embodiments of the present
invention in which
drill pipe 18, having a length "L", is comprised of two separate drill pipes,
18S and 18L, the
former being shorter than the latter, each one having a female end 20 and a
male end 22. As
shown in figures 19 and 21,18S is attached end-to-end with 18L. In the
alternative embodiment
depicted in fig. 19, the mated male end 22 and female end 20 combine to form
enlarged diameter
section 21, having a tapered shoulder 21a defined by the tapered shoulder of
mated female end
20. In the alternative embodiment depicted in figure 21, the mated female end
20 serves as
enlarged diameter section 21, with the shoulder of said mated female end
serving as shoulder
21 a.
In yet a further alternative embodiment of the present invention shown in
figure 22, an
extra tapered shoulder 25 is provided on drill pipe 18 between enlarged
diameter section 21 and
the end of the drill pipe. In this embodiment of the invention, extra tapered
shoulder 25 has an
angle of taper "A" that corresponds with and is engaged by shoulder 209 of
wedge members 206,
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thereby providing support for the drill pipe being held by upper holder 200.
In this embodiment,
"D" is the distance between shoulder 21 a and shoulder 25.
The distance "D", the angle "A" and the length "L" in the alternative
embodiment shown
in figures 17, 19, 21 and 22 are comparable to those of the preferred
embodiment as shown in
figure 3.
Figure 23 depicts a further alternative embodiment of wedge members 106, 206
in
accordance with the present invention. The dimensions H-1, H-2, H-3, T-1, T-2
and T-3, and the
angles A and A.T. in the alternative embodiment shown in figure 23 are
comparable to those of
the embodiment as shown in figure 6.
It should be understood that in an alternative embodiment of the present
invention, the
drill pipe may be run with the male or pin end 22 up and the female or box end
20 down, as
depicted in fig. 20. In this alternative embodiment of the invention, tapered
shoulder 209 of
wedge member 206 corresponds with tapered shoulder 22a of pin end 22 of drill
pipe 18;
shoulder 209 is curved to correspond with and accommodate the curved,
circumferential shape
of shoulder 22a; and curved surface 206b of wedge member 206 corresponds with
and
acconunodates the curved outer surface 22b of drill pipe 18.
Crossover connection 36 depicted in figure 1 may include an "SB" Casing Hanger
Running Tool in conjunction with an "SB" Casing Hanger, all manufactured by
Kvaerner
National Oilfield Products.
It can be clearly observed in the figures that owing to the corresponding
shapes of the
shoulder 21 a,b of the enlarged diameter section 21 and the shoulder 109, 209
of the wedge
members 106, 206, the shoulders 21 a,b and 109, 209 are rotatable with respect
to each other
regardless of the distance between the shoulders 21a,b and 109, 209. That is,
given that the
holders 100, 200 containing the wedge members 106, 206 are configured to allow
the landing
string 18 containing the enlarged diameter section 21 to be inserted thereinto
so that the
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shoulders 21a,b and 109, 209 engage only when the landing string 18 is
positioned in the
holders 100, 200, it is clear that the shoulders 21 a,b and 109, 209 are
rotatable with respect to
each other when the shoulders 21 a,b and 109, 209 have a large distance
between them.
However, as a result of the corresponding configuration of the shoulders 21
a,b and 109, 209
as shown in the figures, the shoulders 21a,b and 109, 209 are also rotatable
with respect to
each other when the distance between them is small.
It should be understood that drilling rig 8 includes a drill platform having
floor 9
with a work area for the rig personnel who assist in the various operations
described
herein. Although figure 1 shows drilling rig 8 situated on a drill ship 10, it
should
be understood that the present invention may be used on drilling rigs situated
on
platforms that are permanently affixed to the sea floor, or on semi-
submersible
and other types of deep water rigs. Moreover, although the invention is
particularly
useful for rigs drilling in deep water, the invention may also be used with
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shallow-water rigs and with rigs drilling on land.
The following table lists the part numbers and part descriptions as used
herein and in the
drawings attached hereto:
PARTS LIST
PART NUMBER DESCRIPTION
5 invention in general overview
8 drilling rig
9 drilling rig floor
drill ship
10 11 opening in drilling rig floor
12 surface of ocean
14 undersea well
blowout preventors
16 sea floor
15 17 riser
18 drill pipe
18a curved outer surface of drill pipe
18S shorter joint of drill pipe of alternative embodiment
18L longer joirit of drill pipe of alternative embodiment
19 landing string
20 box (female) end of drill pipe
20a tapered shoulder of box end
20b curved outer surface of box end
21 enlarged diameter section of drill pipe
21a supporting shoulder of enlarged diameter section
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21b curved outer surface of enlarged diameter section
22 pin (male) end of drill pipe
22a tapered shoulder of pin end
22b curved outer surface of pin end
23 lumen of drill pipe 18
24 borehole
25 extra tapered shoulder
26 earthen formation
28 wall of borehole
32 surface casing
34 intermediate casing
35 casing string
36 crossover connection
100 lower holder
103 opening in main body 104
104 main body of lower holder
105 tapered inner face of main body 104
106 wedge members of lower holder
106a curved inner surface of wedge member 106 accommodating drill pipe
106b curved inner surface of wedge member 106 accommodating enlarged
diameter section 21
107 tapered outer face of wedge members 106
108 hinges connecting wedge members
109 tapered shoulder of wedge members 106
111 connectors between wedge members 106 and lifting arms 112
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112 lifting arms for lifting wedge members 106
114 actuator for moving lifting arm 112
115 lifting eye on wedge member 106
200 upper holder
203 opening in main body of upper holder
204 main body of upper holder
205 tapered inner face of main body 204
206 wedge members of upper holder
206a curved inner surface of wedge member 206 accommodating drill pipe
206b curved inner surface of wedge member 206 accommodating end of drill
pipe
207 tapered outer face of wedge member 206
209 tapered shoulder of wedge member 206
210 elevator links
211 connectors between wedge member 206 and lifting arms 212
212 lifting arm for lifting wedge member 206
214 actuator for moving lifting arm 212
215 lifting eye on wedge member 206
220 recessed area of upper holder
221 eye of elevator link
222 elevator link retainer
224 release pin
225 hinge
230 lifting eyes to support auxiliary upper holder
300 auxiliary upper holder
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301 connectors for auxiliary holder 300
304 main body of holder 300
The following table lists and describes the dimensions used herein and in the
drawings
attached hereto:
DIMENSION LIST
DIMENSION DESCRIPTION
E.O.D. end outside diameter of pin end and box end of drill pipe
E.W.T. end wall thickness of pin end and box end of drill pipe
P.I.D. pipe inside diameter
P.W.T. pipe wall thickness
P.O.D. pipe outside diameter
E.D.W.T. enlarged diameter wall thickness
R.W.H. reasonable working height of box end above rig floor
L length of drill pipe
D distance between supporting shoulders
A angle of shoulder taper
LE length of enlarged diameter section
T-1 top thickness of the wedge member
T-2 thickness of the wedge member at the shoulder
T-3 bottom thickness of the wedge member
H-1 height of the wedge member
H-2 distance between the top of the wedge member and the shoulder
H-3 distance between the bottom of the wedge member and the shoulder
A.T. Angle of taper of the outer face of the wedge member
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H.H. Height of upper holder
W-1 width of upper holder
W-2 width of top of opening of upper holder
W-3 width of bottom of opening of upper holder
The foregoing embodiments are presented by way of example only; the scope of
the
present invention is to be limited only by the following claims:
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