Note: Descriptions are shown in the official language in which they were submitted.
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"LARGE DIAMETER FLUSH JOINT PIPE HANDLING SYSTEM"
BACKGROUND OF THE IIWENTION
Flush joint (or 'near flush joint') pipe used for riser pipe in offshore
drilling and/or
used for conductor pipe for deep well drilling is often too Large in diameter
to be
handled by conventional die-grip casing handling tools. The most commonly
available
die-grip tools for handling large pipe have a maximum diameter capacity of
approximately 24 in. Riser pipe and conductor pipe can have a substantially
larger
diameter, frequently in excess of 36 in.
The present invention relates to special equipment and procedures for handling
and
running Large diameter flush joint pipe in offshore wells and/or other
drilling sites
requiring pipe having diameters exceeding the capacity of conventional running
tools.
BRIEF SLT.NIN1ARY OF THE INVENTION
In one embodiment, an elevator for assembling a plurality of a large diameter
pipe
joints into a pipe string with a drilling rig is disclosed. A first one of the
plurality of
large diameter pipe joints is adapted to threadingly engage a second one ofthe
plurality
of large diameter pipe joints. The elevator is detachably securable to an
upper end of
the first joint and adapted to both lift and position the first joint while it
is stabbed and
tightened onto the string. After stabbing and tightening, the elevator is
lowered with
the joint where it is further adapted to co-operatively engage the rotary
table of the
drilling rig to rotatably tighten the second joint to the first joint as the
second joint is
added to the string.
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Also disclosed is an elevator clamped to the joint with a colt on collar, or
it rnay be
bolted around an annular groove formed in an external surface of the pipe
joint. The
collar may have a plurality of Keystone-shaped recesses that extend over
corresponding keystone shaped projections attached to the external surface of
a pipe
joint. In addition the groove in the joint may frictionally engage a
complimentary,
annular, centrally extending projection developed along an inner
circumferential
surface of the collar. Also disclosed is the groove in the joint with a
reverse angle
shoulder adapted to engage and rest upon a similarly angled projection in the
collar.
As the collar supports a weight of the string from the rotary table, a surface
of the
projection in the collar may be slightly spaced axially from a groove surface
in the joint
whereby the surface of the projection engaging the groove surface supports a
substantial amount of the vertical Load imparted to the collar by the weight
of the
string.
In addition, the elevator may have a plurality of lifting pad eyes for
attachment to lift
lines on the drilling rig, and one rotary table lugs may extend from the
lifting pad eyes
to engage the rotary table.
Also disclosed is an elevator having two halves, each half comprising a
plurality of bolt
ears adapted to receive bolts for clamping the collar.
BRIEF DESCRIPTION OF THE DRAWFVGS
Figures 1-3 are general views of bolt on elevators (collars) of the present
invention.
Figures 4 illustrates cylindrical rotary table of figures 1-3.
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Figure 5 illustrates a rotary support table having openings of the type used
in the
present invention.
Figures 6-12 are views of various arrangements of bolt on elevators (collars)
of the
presentinvention.
Figures 13-16 are views of an alternate embodiment of bolt on elevators
(collars) of the
present invention.
Figures 17-20 are views of alternate keystone plates for the collars of
figures 13-16.
Figure 21 is an enlarged view of the welding of the plates of figures 17-20.
Figures 22-25 are views of a permanent lug plate of an alternate embodiment of
the
present invention.
Figure 26 is a cross section illustrating a connecting fixture secured to a
lug plate in
accordance with the present invention.
Figures 27-37 represent various steps in the transfer of a pipe joint of the
present
invention from storage to a position ready for use.
2S Detailed Description of the Illustrated Embodiments
A large diameter pipe joint 11 is moved from a storage location on a drilling
rig to a
vertical orientation in the drilling rig derrick to be run through the
drilling rig floor 12
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into the sea or into the well bore below the rig. The lower end of the pipe
joint 11
terminates as a threaded pin and the upper end terminates as a connector 1 la
in the
form of an internally threaded box. Multiple pipe joints, such as the joint
11, are
assembled to form a continuous flush joint pipe string of pipe that extends
from the rig
and through the sea to the sea bottom ox into a well bore below the rig.
In assembling the pipe string, a pipe elevator (collar) I 3 is attached to the
upper end
area 14 of an individual joint of the pipe to assist in bringing the pipe to
the vertical
running position. In one form of the Invention, the elevator 13 provides one
of the
attachment fixtures for the lines 16 and 17 used to lift and/or move the pipe
to the
vertical orientation. Additional positioning and restraint lines, such as the
snub line 18
are attached to a fixture 20 that is removably secured to an attachment plate
21 bonded
to the pipe. Once the joint 11 is in its vertical position, the elevator 13
supports the
joint 11 vertically so that it may be added to a string of the pipe 22
extending through
the rotary table 24 on the drilling rig floor 12.
One embodiment of the elevator 13 is a bolt-on collar with an internal annular
projection. (Figures 4, 6-12). The collar is bolted around an annular groove
machined
into the external surface of an internally threaded connector l la at the top
of the joint
11. The connector 1 la may be welded onto the tubular body of the joint 11 to
provide
an internally threaded box connection at the upper end of the joint or it may
be
otherwise secured to, or formed at, the end of the tubular body. The groove is
machined or otherwise suitably formed in the outer surface of the connector 11
a.
Machining is preferred to provide uniform surface contact between the elevator
projection and the connector groove.
A second embodiment of the elevatox is a bolt-on collar having axially
extending
Keystone-shaped recesses that extend over corresponding Keystone shaped
projections
welded to the external surface of the internally threaded connector. (Figures
13-16).
_q._
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The terms "collar" and "elevators" are used interchangeably in the description
of the
presentinvention.
An elevator 25 is connected to the top of the assembled pipe string 22
extending below
the rotary table. The elevator 25 rests on the rotary table 24 to support the
string 22.
The elevator 25 is identical to the elevator 13 that supports the joint of
pipe 11 being
added to the string.
The new joint 11 being added to the string is threaded into the string 22 by
rotating the
suspended string 22 with the rotary table 24 while holding the new joint
stationary with
a snub line 18 secured to the removable handling fixture 20. The rotary 24 is
rotated in
a counterclockwise direction to cause the right hand threads of the joint 11
and the
string 22 to engage. The opposite end of the snub line 18 is secured to a
stationary
point (not illustrated) on the rig.
Once the joint 11 is properly engaged to the string 22, the lift lines 17
extending
between the uppermost collar 13 and the top drive or traveling block of the
rig (not
illustrated) are raised to lift the joint 11 and attached string 22. Lifting
the string 22
permits the lower collar 25 to be removed from the string. Once the collar is
removed,
the string 22, including the newly added joint I1, is then lowered until the
upper collar
13 is resting on the rotary table 24 where it may support the entire string
full. The
process is repeated until the full string of pipe is run into the well.
Figure 4 illustrates cylindrical rotary table lugs 26 and 27 that extend
downwardly from
lifting pad eyes 28 and 29, respectively, of the elevator 13. The cylindrical
rotary table
lugs 26 and 27 are received in openings 30 and 31 respectively formed in the
top
surface of the rotary table 24. The engagement of the lugs 26 and 27 in the
openings
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30 and 31 transmits the rotary motion of the rotary table 24 to the collar 13,
which in
turn transmits the rotation to the connector 1 la at the top of the joint 11.
Figure 5 illustrates a conventional rotary support table 35 having openings 36-
39 of the
type used to receive the rotary table lugs extending from the elevator 13.
Figures 6 and 7 illustrate, in perspective view, two halves 13a and 13b of the
elevator
13. Bolt holes 40-47 are provided in bolt ears extending radially from the two
elevator
halves for receiving bolts (not illustrated) used to securely clamp the
elevator halves
13a and 13b about a pipe connection such as the connector l la. The rotary
table lug 26
extends axially away from the elevator half 13a while the rotary table lug 27
extends
axially from the collar half 13b.
Figure 8 illustrates the rotary lug 27 projecting from the bottom surface of
the collar
half 13b.
As illustrated by joint reference to Figures 4, 9 and 11, when the pipe
connector 1 la of
the joint 11 is engaged by the collar 13, the pipe joint 11 is supported by an
annular,
centrally extending projection 50 developed along the inner circumferential
surface of
the clamp 13a and 13b of the collar 13. The external circumferential bearing
surface
51 of the projection 50 conforms to the internal circumferential bearing
surface 52
formed within an annular recess 54 formed about the external surface of the
connector
11 a. The cross-section of the connector 11 a and the cross section of the
projection 50
extending from the elevator 13 have conforming profiles.
With the collar securely bolted about the pipe connector 11a, the elevator
projection
surface 51 engages the groove surface 52 to effect a large radially directed
gripping
force against the connector 1 la. The gripping force works with the surface
friction
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between the two contacting surfaces to prevent relative rotation between the
elevator
and the connector during the process of adding joints to the string.
In a preferred embodiment of the Invention, illustrated in Figures 9 and 10,
with the
collar 13 securely clamped about the connector 11 a and supporting the weight
of the
pipe string 22 from the rotary table, the projection surface 51 is slightly
spaced axially
from the groove surface 52a. The result is that the projection surface 51 b
engaging the
groove surface 52b supports a substantial amount of the vertical load imparted
to the
collar by the weight of the string 22.
A modified form of the invention is illustrated in Figures 1 l and 12. A
projection 60
extending from the elevator 13 is adapted to be received within an annular
recess 62
formed in the external surface of the connector 11 a. The projection 60 and
recess 62
are similar to the projection and recess of Figures 9 and 10 with the
exception of the
change in dimensions and cross sectional profile of the components.
The dimension A of the projection 60 is less than the dimension B at the entry
to the
groove 62 so that the elevator 13 can be closed circumferentially about the
connector
l la with the projection 60 received within the groove 62. The recess 62
includes a
reverse angle shoulder 64a adapted to engage and rest on a similarly angled
surface 65
on the annular projection 60.
When the elevator 13 is gripped around the connector 11a, circumferential
surfaces 68
on the connector 11 a and 69 on the elevator 13 are brought together with a
strong
radially directed bearing force exerted by the bolts holding the elevator
halves together.
The resulting bearing pressure and surface friction between the surfaces 68
and 70
prevent the elevator 13 from rotating relative to the connector 11 a when the
connector
and its associated pipe joint 11 are being added to the pipe string 22.
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The inclined angles of the contact surfaces 64 and 65 cooperate with the
weight of the
string 22 to pull the elevator 13 radially inwardly to enhance the
circumferential
gripping force exerted by the elevator against the pipe connector 1 I a. The
inclined
surfaces 64 and 65 also cooperate to hold the collar circumferentially about
the pipe
section 1 la in the event of failure of the bolts or other parts of the
elevator.
A feature of the form of the Invention Illustrated in Figures 11 and 12 is
that the string
weight pulls the elevator 13 into compression rather than forcing it into
tension.
Breakage or loss of the bolts holding the elevator halves together or partial
breakage of
parts of the elevator will not necessarily release the pipe from its support
at the rotary
table because of the trapping action provided through the mating inclined
surfaces
between the elevator projection and the connection groove.
The form of the invention illustrated in Figures 9-12 is a preferred design in
that it
requires no radial protrusions on the external surface of the pipe joints and
is
inexpensive to fabricate and employ. The system of Figs. 9-12 also permits the
pipe to
be handled without requiring an increase in the outside diameter of the flush
joint pipe.
The elevator 13 described in Figures 9-12 is inexpensive to fabricate and one
such
elevator may be attached to each joint of pipe before the pipe is delivered to
the
location where it is to be run into the well. This procedure allows the
elevator to be
secured to each pipe joint in a controlled environment, ensuring that the
bolts are
probably torqued up and that the collar is properly secured to the connector
11a.
Placing the elevator on the pipe before it is delivered to the well location
reduces the
amount of time required to maneuver the pipe from its on-site storage location
and run
the pipe into the well. Personnel safety is also enhanced in that the collar
application
may be performed in the controlled environment of an indoor shop rather than
the
extreme, outside environment of an offshore drilling rig.
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Figure 13 illustrates an elevator, indicated generally at 70, similar to the
elevator 13
previously described but intended to be used with pipe joints having permanent
external radial protrusions adapted to be received within accommodating
recesses in
the elevator 70. The elevator 70 is designed for reuse at the well site. When
an
elevator 70 is removed from its support of the string 22, it is used to secure
and remove
a new joint from the storage rack and add the new joint into the string.
The elevator 70 is similar to the elevator 13 except that the central internal
circumferential projection of the elevator 13 is replaced by Keystone shaped
recesses
72 and 74 adapted to engage similarly shaped Keystone plates or projections 76
and 78
permanently secured to the external surface of the pipe section 11 a. Figures
15 and 16
illustrate elevator halves 70a and 70b in position about a pipe connector 1 la
to which
Keystone projections 76 and 78 have been permanently welded.
Figure 17 is an elevation illustrating a Keystone plate that is welded to the
external
surface of the connector 11 a. Figure 18 is a top view of the Keystone plate,
illustrating
its arcuate shape, taken along the line 18-18 of Figure 17. Figure 19 is a
side elevation
of the Keystone plate taken along the line 19-19 of Figure 17.
Four internally threaded bolt holes 81-84 are provided on the broad part of
the
Keystone plate 76. The bolt holes are used to secure handling fixtures that
secure lines
used in positioning and making up the pipe joints. The fixtures are removed
before the
joint is lowered into the well. Three weldment areas 86, 87 and 88 are
provided for
providing welding contact lines for welding the Keystone plate 76 to the
external
surface of the connector 11 a. The lower end of the plate 76 is tapered as
indicated at
90 to reduce the probability of hanging up the pipe joint to which it is
secured as the
pipe joint is lowered into the well.
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Figure 21 illustrates welding W extending around the contact lines provided by
the
weldment areas. The welding W along the internal weldment areas secures the
Keystone plate 76 to the pipe connector 11 a without requiring placement of
welding
material along the external surfaces 92 and 94 of the Keystone. The external
surfaces
92 and 94 are thus allowed to mate exactly with the engaging surfaces of the
Keystone
recesses in the elevator 70.
The provision of Keystone shapes for the elevator recesses 72 and 74 and the
permanently secured pipe connector projections 76 and 78 facilitates placement
of the
elevator about the pipe section 11 a and also equalizes the distribution of
support forces
exerted on the elevator when the elevator is holding the entire string weight.
Figures 22-25 illustrate a permanent lug plate 21 to be welded to a pipe joint
11 to
assist in handling and making up the pipe joint. Figure 22 is a front
elevation of the Iug
plate 21. Figure 23 is a top view taken along the line at 23-23 of Figure 22
illustrating
the curvature of the lug plate. Figure 24 is a side view taken along the line
24-24 of
Figure 22 illustrating the bottom taper 101 of the lug plate. Figure 25 is a
front
elevation of the lug plate 21 welded onto a pipe joint 11.
The lug plate 21 is provided with four internally threaded bolt holes 102-105.
A
weldment area 106 cut into the lug plate 21 provides an increased welding
contact line
for welding the lug plate to the pipe joint 11. Welding W along the external
lug edge
and along the edges of the weldment area 106 is illustrated in figure 25
securing the lug
plate 21 to a pipe joint 11.
Figure 26 is a cross sectional view illustrating a connecting fixture 20
secured to the
lug plate 21 welded to the pipe 11. Two of four bolts 110 and 112 axe
illustrated seated
in the bolt holes 104 and 105, respectively. The connecting fixture 20 is
provided with
a circumferentially extending arxn 20a and a pad eye plate 20b with a pad eye
opening
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20c. The arm 20a assists in distributing reaction forces exerted through the
restraining
line 18 as the joint 11 being added to the string 22. The pad eye 20c provides
an
attachment point for the restraining and/or control line 18 used in the
positioning
and/or makeup of the connection.
Figures 27 through 37 illustrate various steps in the transfer of a joint 11
from its
storage location to a vertical orientation in preparation for being.added to a
string of
pipe to be run into the well. Figure 27 illustrates positioning lines 16 and
18 secured
respectively to a connecting fixture 120 secured to a Keystone projection 76
and the
connecting fixture 20. The connecting fixture 120 is similar to the connecting
fixture
and is bolted into place in the bolt holes 81-84 of the Keystone plate. The
lines 16
and 18 are illustrated lifting the joint 11 from its horizontal storage
location in
preparation to moving the pipe to the drilling rig floor.
15 Figure 28 illustrates the elevator 70 being positioned about the pipe 11.
The elevator
70 is suspended from lines 122 and 123 respectively connected to one of the
two
elevator halves 70a and 70b. The lines 122 and 123 hold the elevator 70 in the
open
position illustrated in Figure 29. A stop in the hinge 70c prevents the
elevator from
opening further to facilitate placement of the elevator about the pipe 11.
20 Figures 30 and 31 illustrate the elevator 70 loosely bolted around the pipe
joint 11 prior
to being moved axially into engagement with the Keystone projections 76 and
78.
Figures 32-34 illustrate the elevator 70 being rotated around the pipe joint
11 by
releasing the line 122 and raising the line 123 to align the Keystone
projections on the
pipe with the Keystone recesses in the elevator.
Figure 35 illustrates the lift lines 17 being secured to the lift eyes 28 and
29 extending
radially from the sides of the elevator 70. Once the lift lines 17 are
properly attached to
the lift eyes 28 and 29, the fixture 120 may be released from the Keystone
projection
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76 by removing the four bolts (riot illustrated) holding the fixture to the
Keystone
projection. Once the joint 11 has been added to the string, the fixture 20 may
be
removed from the attachment pad 21. The provision of removable handling
fixtures
120 and 20 on the Keystone plate and on the pipe body, respectively, provides
safe and
secure attachment points for moving and making up the connection and also
permits
the rapid removal of the fixtures to reduce the outside dimensions of the pipe
joint for
facilitating its introduction into the well.
Figures 36 and 37 illustrate the pipe joint 11 being moved to its vertical
position with
the use of the lift lines 17 and the snub line 18.
Whereas the present invention has been described in particular relation to the
drawings
attached hereto, it should be understood that other and further modifications
apart from
those shown or suggested herein, may be made within the scope and spirit of
the
present invention.
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