Note: Descriptions are shown in the official language in which they were submitted.
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LIGHT-WEIGHT SINGLE JOINT MANIPULATOR ARM
BACKGROUND OF THE INVENTION
Field of the Invention
[001]The present invention provides a device and a method for manipulating
tubular segments
for make up and installation of a tubular string in a well.
Description of the Related Art
[002] Tubular strings installed in wells are made up by threadably coupling
individual tubular
segments at a well site. For example, a string of drill pipe is made from
threadably coupling
joints of drill pipe to rotate and advance a drill bit downhole. A casing
string is made up by
threadably coupling casing segments to line a drilled borehole to prevent
collapse and to
facilitate cementing. A production string is made up and run through casing
strings to provide a
conduit from the formation to the surface for producing oil or gas.
[003]Valuable rig time is consumed in retrieving, positioning and threadably
coupling segments
of pipe into a string. Since hundreds of segments may be made up and run into
a borehole,
saving just seconds per connection results in a substantial savings in rig
time.
[004]The amount of time required to engage and rotate the pipe segment and
make up the
threaded connection to the pipe string is only a portion of the rig time
consumed in making a
connection. The time consumed in obtaining and positioning each add-on segment
atop the
string for make up is determined in part by the efficiency of tools used to
retrieve and manipulate
the segment.
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[005]Tools are available for manipulating and positioning segments for make up
into a string.
Existing tools typically consist of a single joint elevator suspended by a
rope slung beneath a
main string elevator. Suspending the single joint elevator by a rope imposes
many limitations on
the efficiency of the process of adding pipe segments to the pipe string.
These existing systems
require rig personnel to swing or carry the single joint elevator to the
receiving door and place it
onto the pipe segment to be added onto the string. Also, once the pipe segment
is coupled to the
rope and hoisted above the rig floor, the pipe segment will generally not hang
vertical due to the
force of gravity, and it is difficult and awkward to maneuver the pipe segment
into a vertical
position atop the pipe string suspended in the borehole. Finally, once the
pipe segment is
threadably coupled to the pipe string in the borehole, the single joint
elevator must be removed
from the path of the string elevator or top drive, and rig personnel are
required to carry the
elevator back to the receiving door or other location on the rig floor.
[006]An improved method and apparatus are needed for manipulating segments to
be made up
into a pipe string. The method and apparatus would preferably provide more
precise, safe and
efficient manipulation of segments and save time in making up the string. The
apparatus would
preferably be light-weight, so that it can be easily removed from the path of
the string elevator or
top drive, but sufficiently robust to support and manipulate tubular segments.
SUMMARY OF THE PRESENT INVENTION
[007] One embodiment of the present invention comprises a single joint
manipulator arm having
a swing arm supporting a single joint elevator for securing a pipe segment to
the swing arm. The
swing arm is a strong and generally light-weight arm positionable with one or
more cylinders or
other actuators for rotatably aligning the segment with the string. In a first
embodiment, the
present invention provides a single joint manipulator arm that is pivotably
securable to one or
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more bails that support a string elevator for lifting and lowering the pipe
string into the borehole
after each joint or stand of new pipe is threadably coupled into the string.
The present invention
provides a light-weight single joint manipulator arm that is easily and
efficiently removed from
the path of the string elevator or spider elevator. In a second embodiment,
the present invention
provides a single joint manipulator arm that is pivotably securable to a sub
threadably coupled to
a top drive shaft or quill. In this embodiment, the manipulator arm is
pivotably secured to the
sub above other components, such as a fill-up and circulation tool, or it is
pivotably secured to a
sub positioned below a top drive shaft and above a casing running tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[008]Fig. 1 is a side elevation view of one embodiment of a single joint
manipulator arm of the
present invention in its aligned position and suspended from the bails on a
rig.
[009]Fig. 2 is a side elevation view of the single joint manipulator of Fig. 1
in its removed or
"luffing" position.
[0010]Fig. 3 shows the single joint manipulator arm of Fig. 1 coupled to a
casing segment at the
staging area.
[0011]Fig. 4 shows the single joint manipulator arm of Fig. 1 after the bails
and the string
elevator are elevated and the single joint manipulator arm and casing segment
controllably
rotated clockwise from its position shown in Fig. 3.
[0012]Fig. 5 is a side elevation view of the single joint manipulator arm of
Fig. 1 after the bails
and the string elevator are elevated from the position in Fig. 4, and the
single joint manipulator
arm and casing segment controllably rotated further clockwise to suspend the
casing segment
adjacent to the axis of the well.
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[0013]Fig. 6 is a side elevation view of the single joint manipulator arm of
Fig. 1 after being
rotated further clockwise from its adjacent position shown in Fig. 5 to
generally suspend the
segment in a vertical position aligned with the string in the well.
[0014]Fig. 7 is a side elevation view of the single joint manipulator of Fig.
1 illustrating a safety
fuse used for preventing tool failure from excessive load being applied.
[0015]Fig. 8 is a perspective view of the single joint manipulator arm of Fig.
1 showing a
bifurcated pivoting attachment to the bails and powered rotation using a pair
of actuators.
[0016]Fig. 9 is a perspective view of a modified lower portion of the single
joint manipulator
arm of the present invention comprising a slew actuator for angular
displacement of the stand-
offs to position a tubular segment secured within the single joint elevator.
[0017]Fig. 10 is a perspective view of an alternative embodiment of the single
joint manipulator
arm of the present invention pivotably supported by a sub that is threadably
coupled to and
suspended from a top drive. The sub also supports a casing running tool that
is operated by the
top drive to releasably engage and support the pipe string and a fill-up and
circulation tool.
[0018]Fig. 11 is a perspective view of another alternative embodiment of the
single joint
manipulator arm of the present invention pivotably supported by a sub that is
threadably coupled
to and suspended from a top drive. The sub supports a fill-up and circulation
tool that is aligned
with the top drive and positioned to enter the proximal end of a pipe string
secured within the
string elevator.
[0019]Fig. 12 is a high-level method flowchart describing one embodiment of a
method of the
present invention.
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DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0020]The present invention provides an apparatus and method for manipulating
casing
segments to assemble a casing string in a borehole. A single joint manipulator
arm may be used
to safely and reliably manipulate casing segments as they are made up into a
casing string and
installed in a well. The embodiments disclosed below describe the manipulation
of casing
segments to assemble a casing string using the present invention. It is to be
understood,
however, that other types of tubular segments, including drill pipe and
production tubing, may be
similarly manipulated to assemble strings without departing from the scope of
the invention. For
the reason, the terms "pipe", "tubular" and "casing" are used interchangeably,
as are the terms
"segment" and "joint."
[0021]In one embodiment, an apparatus and method of the present invention are
used to
assemble and run a casing string. Once assembled, the casing string will
include a plurality of
casing segments threadedly coupled end-to-end and installed in a well. The rig
on which this
embodiment may be used includes a hoist movably suspending a pair of bails
that, in turn,
suspend a string elevator. A swing arm, having a proximal end, and a distal
end is pivotally
coupled at its proximal end to the bails at a location above the string
elevator. The swing arm
supports a single joint elevator at its distal end, which may be a hinged-body
type elevator or a
horseshoe elevator. The pivoting swing arm is angularly positionable relative
to the bails using
one or more actuators, such as cylinders. Control of the swing arm and the
hoist enable the
operator to efficiently retrieve a casing segment from a staging area and to
move the casing joint
into abutting alignment with the string for being threadably coupled into the
string.
[0022]A segment of large casing to be lifted using the manipulator arm may
weigh 2,000 pounds
(980 kg). A casing string may weigh 400,000 pounds (181,600 kg). The string
elevator is very
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heavy compared to the single joint manipulator arm, and the moment imposed on
the bails by the
light-weight single joint manipulator arm and the casing segment do not
significantly deflect the
string elevator and the heavy bails from the vertical orientation.
[0023]Fig. 1 is a side elevation view of one embodiment of a single joint
manipulator arm 10 the
present invention. A perspective view of this same embodiment is shown in Fig.
8. A string
elevator 12 is secured to a pair of bails 14, 114 at lifting ears 16, 116. The
string elevator 12 is
sized and configured for coupling to and supporting a casing string by
securing the proximal end
of the casing string (not shown in Figs. 1 or 8 - see element 36 in Figs. 3-
6). The bails 14, 114
are configured for supporting the weight of the string elevator and the casing
string, and are
coupled at their supported ends to a block suspended by a draw works (not
shown).
[0024]The single joint manipulator arm 10 of the present invention comprises a
swing arm 18
pivotally coupled at swing arm pivots 28b, 128b to bails 14, 114. The swing
arm 18 includes an
upper portion 20 that forms an angle to the swing arm and provides offset
clearance around the
string elevator 12 when the swing arm 18 is generally vertical (see Fig. 6).
Single joint elevator
22 is supported from stand-off members 52 and 152 pivotally coupled to the
distal end 17 of the
swing arm 18 for releasably securing and supporting a casing segment (not
shown in Figs. 1 and
8 see Figs. 3-6).
[0025]Typically, an internally threaded coupling is used to threadably couple
two casing
segments end-to-end. This coupling structure provides an external
circumferential shoulder that
a single joint elevator 22 may engage to support the add-on casing segment.
However, it is
within the scope of the present invention to use a single joint elevator
adapted for securing
integral connection segments by clamping along the length of the body of the
pipe segment in
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place of the horseshoe elevator shown in Fig. 1 or the hinged-body type
elevator shown in Fig. 9.
The string elevator, horseshoe elevator and hinged-body type elevator shown in
the drawings are
included in the disclosed embodiment of the present invention for illustration
only.
[0026] The generally light-weight swing arm 18 of the single joint manipulator
arm of the present
invention may be extendable, such as by axially telescoping. As shown in Figs.
1 and 8, the
length of the swing arm 18 may be adjustable in length by telescoping an inner
beam member 26
from within an outer beam member 24, then securing the outer and inner beam
members 24, 26
by, for example, inserting a pin 28 through a pair of alignable holes 27. The
use of tubular or
squared tubular steel may provide a good strength to weight ratio.
[0027] The swing arm 18 is controllably rotatable about the pivots 28b, 128b
using an actuator,
such as a pair of pneumatic or hydraulic cylinders 21, 121. The cylinders 21,
121 each comprise
a piston (not shown) coupled to selectively extendable and retractable rods
23, 123, respectively,
that are axially positionable with respect to cylinders 21, 121. The rods 23,
123 in Figs. 1 and 8
are shown in the extended condition to position the swing arm 18 in a
substantially vertical
position generally parallel to the bails 14, 114.
[0028]Fig. 2 is a side elevation view of the single joint manipulator arm 10
in a substantially
horizontal or luffing position. The rods 23 and 123 (the latter not shown in
Fig. 2) are shown
retracted into the cylinders 21 and 121 (the latter not shown in Fig. 2) to
position the swing arm
18 generally perpendicular to the bails 14 and 114 (the latter not shown in
Fig. 2). The luffing
position illustrated in Fig. 2 serves two purposes. Casing segments are
sometimes presented to
the rig floor at a receiving door in a substantially horizontal condition. The
luffing position
shown in Fig. 2, or a position near horizontal, may be suitable for coupling
the elevator 22
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supported by the single joint manipulator arm 10 to casing segments presented
in this condition.
Also, the luffing position removes the single joint manipulator arm 10 and the
supported elevator
22 from obstructing the full descent of the string elevator 12 (or, in other
embodiments, a casing
running tool or a top drive) as it lowers a casing string into the borehole
after an add-on casing
segment is made up into the casing string.
[0029]Receiving doors, or staging areas, on some rigs present add-on pipe
segments to the rig
floor in a position angled between vertical and horizontal (see Fig. 3). In
use on these rigs, the
cylinders 21 and 121 (the latter not shown in Fig. 3) may be used to position
the elevator 22
supported by the single joint manipulator arm 10 to a suitable angled position
between vertical
and horizontal for coupling to the presented casing joint 30. When the single
joint manipulator
arm 10 is moved to the desired initial position, a presented casing segment 30
is secured to the
single joint manipulator arm 10 at the presented end 32 by securing the
segment in the single
joint elevator 22.
[0030]Figs. 3-6 are sequential side elevation views of the single joint
manipulator arm 10 of Fig.
1 showing the process of manipulating a casing segment from an initial
position in a staging area
(Fig. 3) to an aligned position for rotatably coupling to a casing string in a
well (Fig. 6). To
retrieve a casing segment from the staging area of a rig, an actuating member
first moves the
swing arm outwardly away from vertical to position an end of the swing arm in
proximity to a
staging area wherein casing joints are presented. Fig. 3 shows one embodiment
of the single
joint manipulator arm 10 in an initial position for retrieving a casing
segment 30 from a rig
staging area 35. The horseshoe elevator 22 is engaged just below a collar 32
of the presented
casing segment 30. Once the segment is secured to the swing arm 18, the hoist
raises the bails
14, 114 (the latter not shown in Fig. 3) the swing arm 18 and the casing
segment 30. As the
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casing segment 30 is raised, it slides along ramp 37, and the swing arm 18
controllably rotates in
the clockwise direction against the damping force of cylinders 21 and 121 (the
latter not shown
in Fig. 3). This clockwise rotation of the swing arm 18 against the damping
force controllably
moves the casing segment 30 in the direction of the casing string 34 (see Fig.
6). A damping
member, such as a hydraulic, pneumatic or inert gas-charged cylinder, is used
to dampen and
control movement of the swing arm as it rotates from the initial position the
equilibrium position.
The damping member provides controlled and manageable movement in manipulating
the casing
segment.
[0031]Fig. 4 is a side elevation view of the single joint manipulator arm 10
of Fig. 3 showing the
bails 14 and 114 (the latter not shown in Fig. 3) elevated from their initial
position shown in Fig.
3, and the single joint manipulator arm 10 rotated further clockwise against
the damping force of
the cylinders. The casing segment 30 in Fig. 4 is shown substantially raised
along ramp 37 from
its initial position shown in Fig. 3. As the bails 14 and 114 (the latter not
shown in Fig. 3) raise
the single joint manipulator arm 10 and the casing segment 30 along ramp 37 in
staging area 35,
the weight of the casing segment 30 increasingly urges the swing arm 18 to
rotate clockwise.
The cylinders 21 and 121 (the latter not shown in Fig. 4) dampens the rate of
clockwise swing of
the swing arm 18, and the damping action provided by cylinders 21 and 121 will
prevent rapid or
uncontrolled swing of the casing segment 30 across the rig floor after the
casing segment 30
clears the ramp 37.
[0032]Fig. 5 is a side elevation view of the single joint manipulator arm 10
of Figs. 3 and 4
showing the bails 14 and 114 (the latter not shown in Fig. 5) raised from the
position shown in
Fig. 4 and the swing arm 18 rotated further clockwise from its position shown
in Fig. 4. The
casing segment 30 shown in Fig. 5 hangs from single joint elevator 22
substantially vertically in
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an equilibrium position, but it is not aligned with the casing string 34 in
the well supported by
the spider 36 because of the offset provided by the angled portion 20 at the
top of the swing arm
18. As shown in Fig. 5, this equilibrium position is not aligned with the
casing string 34, and the
casing segment 30 hangs offset from alignment with the top connection with the
casing string 34.
The casing segment 30 hangs slightly suspended from the single joint elevator
22 like a
pendulum, and the single joint elevator 22 imparts generally negligible torque
on the casing
segment 30. The equilibrium position of the swing arm 18 shown in Fig. 5 and
the amount of
offset is determined by the dimensions and weights of both the single joint
manipulator arm 10
and the casing segment 30 when cylinders 21 and 121 (the latter not shown in
Fig. 5) are
inactive. Since the casing segment 30 is generally significantly heavier than
the swing arm 18,
the casing segment 30 will generally hang near vertically below the pivots 28b
and 128b (the
latter not shown in Fig. 5) securing the pivot arm 18 to the bails 14 and 114
(the latter not shown
in Fig. 5).
[0033]Fig. 6 is a side elevation view of the single joint manipulator arm 10
of Figs. 3-5 with the
casing segment 30 vertically positioned above and axially aligned with the
casing string 34,
positioned to be lowered by the hoist (not shown in Fig. 6) to engage the
casing string 34. The
swing arm 18 has been rotated slightly further clockwise from its equilibrium
position shown in
Fig. 5 by energizing the cylinders 21 and 121 (the latter not shown in Fig. 6)
to extend the rods
23 and 123 (not shown in Fig. 6) to rotate the swing arm 18 from its
equilibrium position of Fig.
to the aligned position shown in Fig. 6. Energizing the cylinders 21, 121 to
extend the rods 23,
123 rotates the swing arm 18 further clockwise from its position shown in Fig.
5 and slightly
vertically lifts the casing segment from its equilibrium shown position of
Fig. 5 as it vertically
aligns the single joint elevator 22 and the casing segment 30 with the casing
string 34. The
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capacity to rotate the single joint manipulator arm 10 clockwise from its
equilibrium position
shown in Fig. 5 provides substantially all of the rotational movement required
to position casing
segment 30 may be alignment with the casing string 34. A lower, distal end 33
of the casing
joint 30 is positioned to be threadably coupled with the proximal end of
casing string 34. The
string elevator 12 is substantially axially aligned with casing string 34 so
that the hoist (not
shown) and bails 14 and 114 may be lowered, along with the string elevator 12,
to provide
abutting contact for casing make up.
[0034]Once the casing segment 30 has been brought into aligned contact with
the casing string
34, a power tong or other torquing device engages and axially rotates casing
segment 30 to make
up the threaded connection between the casing segment 30 and the casing string
34. After the
connection is made, the single joint elevator 22 is released from the casing
segment 30 and the
swing arm 18 is rotated counterclockwise using cylinders 21 and 121 to its
luffing position
shown in Fig. 2. The hoist (not shown in Fig. 2) and bails 14 and 114 may then
be lowered to
bring the string elevator 12 to the proximal end 32 of the casing joint 30.
The string elevator 12
may be engaged with the proximal end 32 of the casing segment 30, and the
entire casing string
34 is lifted by the hoist (not shown) and the string elevator 12 to allow
disengagement of the
spider 36. The string elevator 12 is then lowered until the proximal end 32 of
the casing segment
30 reaches the same elevation as previously occupied by the proximate end of
the casing string
34 shown in Fig. 6. The spider 36 is then engaged to support the casing string
34 in the well, and
the string elevator 12 may be disengaged from the casing segment 30.
[0035]The process described above in connection with Figs. 3-6 is repeated
with additional
casing segments until the casing string 34 achieves the desired length.
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[0036]To further enhance safety, the apparatus may include a safety fuse, such
as a shear pin,
that will audibly shear if the swing arm supports a load that is substantially
heavier than a
segment of the casing being made up and run into the well. Fig. 7 is a side
elevation view of one
embodiment of the single joint manipulator arm 10 for illustrating a load
safety fuse 50. A pair
of stand-offs 52, 152 (the latter not shown in Fig. 7) are secured at their
first ends 52a, 152a (the
latter not shown in Fig. 7) to the lower portion 17 of the swing arm 18 at
pivot 54. A
sacrificially failing safety link 58 is pivotally coupled to the swing arm 18
at pivot 58a located
generally intermediate the pivotal coupling 54 of the stand-offs 52, 152 and
angled portion 20.
The safety link 58 is coupled between pivot 58a and shackle 57 which is, in
turn, coupled to the
first ends 56a, 156a of cables 56 and 156 (elements 156a and 156 not shown in
Fig. 7 - see Fig.
8). The second ends 56b and 156b of cables 56 and 156 are coupled and
supported to the second
ends 52b and 152b of stand-off members 52 and 152. The safety link 58
generally is held by
stand-offs 52, 152 at an angle to the swing arm 18. As shown in Fig. 7, that
angle is about 20
degrees, with the stand-offs 52, 152 being supported substantially in
positions perpendicular to
the swing arm 18. The weight of the single joint elevator 22 biases the stand-
offs 52, 152
generally downwardly when the single joint manipulator arm 10 is vertical,
pulling cables 56 and
156 taut.
[0037]The safety link 58 comprises a sacrificially failing member that is
designed to fail under a
predetermined load. Thus, the safety link 58 is designed to withstand the load
produced in cables
56 and 156 when the weight of segment of casing is supported by the single
joint elevator 22. A
load significantly heavier than that of a casing segment plus the elevator 22
will cause the
sacrificial member to fail, such as a shear failure, without dropping the
load. The sound of the
sacrificial failure is loud enough to alert the rig operator. In response to
the sacrificial failure of
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the safety link 58, the stand-offs 52, 152 will slightly rotate about pivot 54
counterclockwise (in
Fig. 7) but will remain coupled by safety link 58 to avoid dropping the casing
segment coupled
to the single joint elevator 22.
[0038]Fig. 8 is a perspective view of the embodiment of the single joint
manipulator arm 10 in
Figs. 1-7. The lifting ear 16 on the bail 14 is accompanied by a second
lifting ear 116 on bail
114. These bails are movably suspended from a block (not shown), and are
capable of
supporting very heavy loads, such as a casing string. The angled portion 20 of
the swing arm 18
comprises a pair of generally parallel prongs 18a, 18b that are pivotally
coupled to bail clamps
29, 129, respectively, at swing arm pivots 28b, 128b, respectively. The bail
clamps 29, 129 are
secured to bails 14, 114, respectively, using fasteners. The hydraulic
cylinder 21 is accompanied
by a second generally parallel hydraulic cylinder 121 for balanced damping of
swinging loads
applied to swing arm 18. The cylinders 21 and 121 comprise extendable and
retractable piston
rods 23, 123 that are pivotally coupled to swing ears 25, 125, respectively,
of the swing arm 18.
Cylinders 21, 121 are each pivotally coupled to bail clamps 29, 129,
respectively, at pivots 28a,
128a, respectively. These pivoting cylinder couplings on bail clamps 29, 129
are each secured to
the bails at a spaced distance above swing arm pivots 28b, 128b that pivotally
secure the prongs
18a, 18b of swing arm 18 to the bail clamps 29, 129, respectively. The swing
ears 25, 125 are
offset from the swing arm so that pivoting of the swing arm 18 toward its
equilibrium position
(see Fig. 5) under the force of gravity rotates the swing ears 25, 125 away
from the cylinders 21,
121 and requires substantial extension of the rods 23, 123 from cylinders 21,
121, respectively,
for rotation. The resistance to extension of the rods 23, 123 from cylinders
21, 121 substantially
dampens the rate of rotation of the swing arm 18 as compared to unrestrained
swinging of the
swing arm 18. Similarly, force imposed by powered retraction of rods 23, 123
into the cylinders
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21, 121 pulls against swing ears 25, 125, respectively, to controllably rotate
the swing arm 18 to
the desired angular orientation, either to an initial position (see, for
example, Fig. 3) for coupling
the single joint elevator 22 to a presented casing segment 30, or to the
luffing position (see Fig.
2) for either coupling the single joint elevator to a horizontally presented
casing segment or for
removing the swing arm 18 from obstructing the descent of the string elevator
12 to the spider
36.
[0039]In the embodiments discussed in connection with Figs. 1-8, hydraulic
cylinders 21, 121
provide a dual function. According to a first function, the cylinders 21, 121
substantially slow
and dampen movement of the swing arm 18 under the load of a casing segment
secured in the
elevator 22 as the single joint elevator and the load is lifted from a staging
area. According to a
second function, cylinders 21, 121 are used as actuators to rotate the swing
arm 18 beyond its
equilibrium (shown in Fig. 5) to selectively position the swing arm 18 and
thereby align the
casing segment with the casing string, and also to rotate the swing arm 18 to
the luffing position
or to an angle for securing the elevator to a presented casing segment. Other
embodiments may
employ independent devices to actuate the swing arm 18 to align with the
casing string and to
dampen movement of the swing arm under load. For example, it is within the
scope of the
present invention for one cylinder may be used as an actuator to rotate the
swing arm and another
cylinder may used to dampen swing rotation of the swing arm.
[0040]As previously mentioned, the swing arm 18 may comprise a telescoping
portion. The
outer beam 24 may slidably receive an inner beam 26. In other embodiments, a
swing arm may
be axially extendable without these beams being concentric as in the
embodiments of Figs. 1-8.
For example, it is within the scope of the present invention for one beam to
secure to the other
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using a slot on one beam and a bolt or pin on the other beam that is
receivable and securable
within the slot to lock the beams together to form a single load-bearing
member.
[0041]An advantage of an extendable swing arm is that it provides the ability
to adjust the length
of the swing arm to manipulate different lengths of casing segments, to adjust
the single joint
manipulator arm to cooperate with the height of the spider at the rig floor,
or generally to
accommodate different drilling rig configurations. Additional versatility is
realized by use of the
embodiments of the tool of the present invention shown in Figs. 9-12. The
single joint
manipulator arm can be adapted for use with fill-up and circulation tools,
pipe gripping
assemblies and slew actuators that enhance the capacity of the tool to
manipulate and position
tubular segments for make-up into a tubular string.
[0042]Fig. 9 is a perspective view of a modified lower portion of the single
joint manipulator
arm of the present invention comprising a slew actuator for angular
displacement of the stand-
offs to position a tubular segment secured within the single joint elevator.
Fig. 9 shows an
alternate embodiment of the single joint manipulator arm 10 of the present
invention having
enhanced capacity to manipulate and position tubular segments supported in the
single joint
elevator 22. Fig. 9 shows a lower portion 20 of the single joint manipulator
arm of the present
invention equipped with a slew actuator. A pair of stand-offs 52 and 152 are
pivotally secured at
their first ends 52a, 152a (the latter not shown in Fig. 9) to the lower
portion 17 of the swing arm
18. The second ends 56b and 156b of cables 56 and 156 are coupled to the
second ends 52b and
152b of stand-offs 52 and 152. The stand-offs 52, 152 are supported by cables
56 and 156 in
positions generally perpendicular to the swing arm 18. The weight of the
single joint elevator 22
and any tubular segment secured therein biases the stand-offs 52, 152
generally downwardly
when the single joint manipulator arm 10 is vertical, thereby pulling cables
56 and 156 taut.
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[0043]The enhanced capacity for manipulation and positioning of tubular
segments provided by
the slew actuator shown in Fig. 9 is best understood by consideration of the
ranges of controlled
movement, relative to a classic x-y-z three-dimensional coordinate system,
provided by the
single joint manipulator arm. As seen in Figs. 3 - 6, the cylinders 21 and 121
provide controlled
rotation of the swing arm 18 and the supported casing segment 30 in the x-y
plane. This
movement of the tubular segment 30 secured in the elevator 22 is primarily
along the x-axis
when the cylinders 21 and 121 position the swing arm 18 in the generally
vertical orientations
shown in Figs. 5 and 6. Vertical displacement of the tubular segment secured
in the elevator 22
along the y-axis is provided by the rig hoist (not shown) that raises and
lowers the drawworks,
block and the sub and/or bails to which the single joint manipulator arm is
secured. The slew
actuator shown in Fig. 9 provides for controlled movement along the z-axis.
[0044]Fig. 9 shows the components of one embodiment of the single joint
manipulator arm
equipped with a slew actuator providing enhanced positioning and manipulation
of the
suspended tubular joint. The slew actuator housing 42 generally surrounds a
slew actuator 43,
which may be a cylinder, for positioning a slew rod 44 generally perpendicular
to the pivotable
stand-offs 52 and 152. While the actual movement of stand-offs 52 and 152 is
radial about
stand-off pivots 46a and 46b, respectively, the movement of a tubular segment
(not shown in
Fig. 9) secured in the elevator 22 upon actuation of the slew actuator 43 is
substantially along the
z-axis as defined above. Accordingly, this embodiment of the present invention
provides
superior control and manipulation of casing segments for being made up into a
casing string.
[0045]Fig. 10 is a perspective view of one embodiment of the single joint
manipulator arm 10 of
the present invention secured to and supported by a top drive and supporting a
fill-up and
circulation tool and a pipe gripping assembly. The single joint manipulator
arm 10 is pivotably
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secured to an enlarged portion of a sub 88 that is threadably coupled at its
inlet 88a (above the
sub 88) to a top drive and supports a casing running tool 104 from its
discharge 88b (below the
sub 88). In this embodiment, the discharge 88b of the sub 88 supports a casing
running tool 104
having a gripping assembly sized for being received into a casing segment (not
shown). The
casing running tool 104 comprises a plurality of pipe gripping shoes 105 that
are deployable and
retractable radially outwardly to grip and release the internal wall of a
casing segment to support
the casing string or to rotate the casing segment to make up the connection
with the casing string.
[0046]The embodiment in Fig. 10 also comprises a fill-up and circulation tool
100 supported
underneath the casing running tool. The elastomeric seal 103 is sized for
engaging the internal
wall of a casing string (not shown in Fig. 10) upon insertion. The seal
enables pressurization of
the casing string so that pressurized fluid introduced into the bore of the
casing string through the
bore 101 of the fill-up and circulation tool 100 can be circulated down the
casing string and back
to the surface through the annulus formed between the casing string and the
borehole.
[0047]Fig. 11 is a perspective view of another embodiment of the present
invention. The single
joint manipulator arm 10 of the present invention is secured to and supported
by a top drive, and
supports a fill-up and circulation tool 100 comprising an elastomeric seal
103. A bore 101
formed by aligned bores in the top drive, sub 88 and the fill-up and
circulation tool 100 provides
a conduit for introducing fluid into the casing string. The single joint
manipulator arm 10 is
pivotably secured to an enlarged portion of a sub 88 that is threadably
coupled at its inlet 88a
(above the sub 88) to a top drive and supports the fill-up and circulation
tool 100 from its
discharge 88b (below the sub 88). In this embodiment, a pair of bails 14, 114
is suspended from
a support ring 89 that is rotatably supported by the top drive.
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[0048] Fig. 12 is a flowchart describing one embodiment of a high-level method
of
manipulating casing segment to assemble a casing string. In step 60, the swing
arm is rotated to
an initial position. A hydraulic cylinder or other actuator is used to rotate
the pivot arm away
from vertical and to a desired angle according to the orientation of a
selected joint in the staging
area. In step 62, the hoist is lowered as necessary to position a first
elevator, such as a horseshoe
elevator, near a proximate end of the targeted casing segment. In step 64, the
single joint
elevator is coupled to the proximate end of the targeted joint. In step 66,
the hoist is raised to
begin moving the joint into a suspended position. As the joint is lifted along
the ramp to leave
the staging area, the swing arm rotates clockwise toward an equilibrium
position, and the rotation
is dampened in step 68. Once the swing arm and the casing segment are
substantially vertical
and the joint is suspended in the offset position, the joint is then aligned
with the casing segment
by powered rotation of swing arm and lowered to abut the casing string in
steps 70 and 72. Once
the distal end of the joint is in contact with the upper end of the casing
string, the joint is
threadably coupled to the casing string in step 74. A power tong may be used
to rotate the joint
to threadedly couple the joint to the casing string. Then, in step 76, the
hoist is lowered while the
single joint elevator is disengaged from the proximate end of the joint.
Lowering the hoist brings
the string elevator near the proximate end of the casing string and, in step
78, the string elevator
engages the proximate end of that uppermost joint of the casing string. In
step 80, the casing
string is lifted up slightly. This releases the load on the spider so the
spider is released according
to step 82. In step 84, with the casing string released by the spider, the
hoist is lowered to install
the casing string further into the borehole to about the position of the
casing string prior to
connecting the additional joint in step 74. The spider slips are moved into
contact with the
casing string to support it in the well. In the step 86, if the string has
achieved the desired length,
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work stops. Otherwise the process repeats as the swing are is rotated to an
initial position in step
60.
[0049] Embodiments of the invention provide a safe and efficient way to
assemble a casing
string. A highly maneuverable single joint manipulator arm retrieves a casing
joint from a
variety of angles to access a staging area. The single joint manipulator arm
then positions the
casing joint into alignment with the casing string in a controlled manner
using a damper. A
casing string may also be assembled quickly and efficiently, minimizing the
time and expense
associated with casing make up.
[0050]The terms "comprising," "including," and "having," as used in the claims
and
specification herein, shall be considered as indicating an open group that may
include other
elements not specified. The terms "a," "an," and the singular forms of words
shall be taken to
include the plural form of the same words, such that the terms mean that one
or more of
something is provided. The term "one" or "single" may be used to indicate that
one and only
one of something is intended. Similarly, other specific integer values, such
as "two," may be
used when a specific number of things is intended. The terms "preferably,"
"preferred,"
"prefer," "optionally," "may," and similar terms are used to indicate that an
item, condition or
step being referred to is an optional (not required) feature of the invention.
[0051]The terms "segment" and "joint" are used interchangeably to refer to
individual portions
of casing. The term "casing" is used to refer to casing, production tubing,
drill pipe and all other
tubulars that may be coupled end-to-end and installed in a well.
[0052] While the invention has been described with respect to a limited number
of embodiments,
those skilled in the art, having benefit of this disclosure, will appreciate
that other embodiments
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can be devised which do not depart from the scope of the invention as
disclosed herein.
Accordingly, the scope of the invention should be limited only by the claims.
