U.S. patent number 3,895,677 [Application Number 05/434,651] was granted by the patent office on 1975-07-22 for riser pipe stacking method.
This patent grant is currently assigned to Dolphin International, Inc.. Invention is credited to Donald G. Bokenkamp.
United States Patent |
3,895,677 |
Bokenkamp |
July 22, 1975 |
Riser pipe stacking method
Abstract
An offshore drilling rig that embodies a means for vertical
stacking of riser pipe sections and blowout preventors below a
derrick floor and includes riser pipe manipulating mechanisms for
transporting units in a vertical condition between a storage area
and the operational area. In the operational area, the cellar floor
is provided with a sliding door mechanism which is selectively
capable of supporting either the blowout preventor and riser
weight, or the blowout preventor. The transportation system
includes means for lifting and supporting a riser pipe section
vertically and movable in transverse and longitudinal, horizontal
directions for transporting pipe sections in a vertical
condition.
Inventors: |
Bokenkamp; Donald G. (Houston,
TX) |
Assignee: |
Dolphin International, Inc.
(Houston, TX)
|
Family
ID: |
23725089 |
Appl.
No.: |
05/434,651 |
Filed: |
January 18, 1974 |
Current U.S.
Class: |
166/359; 166/380;
175/52; 175/85 |
Current CPC
Class: |
E21B
19/14 (20130101); E21B 19/143 (20130101); E21B
19/002 (20130101) |
Current International
Class: |
E21B
19/00 (20060101); E21B 19/14 (20060101); E21B
019/14 (); E21B 019/16 (); E21B 007/12 () |
Field of
Search: |
;166/.5,315,775
;175/5,7,52,85,171 ;214/2.5 ;114/.5D |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Purser; Ernest R.
Claims
What is claimed is:
1. In an offshore drilling system on location in a body of water, a
method for manipulating riser pipe sections between a stored
condition of individual sections in a storage area in a drilling
rig and an operational condition of sections coupled to one another
to define a riser string where said riser string extends downwardly
from the drilling rig toward the floor under the water, said method
comprising the steps of
coupling the draw works of a drilling rig to the riser string and
lifting the riser string through an opening in a riser storage
floor until at least the upper end of said riser string is below
the rotary table on the rig floor and at least one riser section is
above the riser storage floor,
releasably supporting the riser string at said opening in said
riser storage floor,
releasably coupling a horizontally movable transfer means to the
upper end of a riser section just below the rotary table,
disconnecting the draw works from the riser string and
disconnecting such riser pipe section from the riser string at a
location above said opening,
raising such uncoupled riser pipe section on the horizontal
transfer means to clear the end of the supported riser string and
transferring such uncoupled riser pipe section in a horizontal
direction while in a vertical condition to a storage area on the
same level,
at such storage area, lowering such uncoupled riser pipe section
with respect to the horizontal transfer means into a storage
position on a pipe rack, and
securing such uncoupled riser pipe section to said pipe rack.
2. The method as defined in claim 1 snd further including the
performance of the following steps while a riser pipe section is
being moved to the storage area,
coupling the draw works of the drilling rig to the supported riser
string immediately following the initiation of the transfer of an
uncoupled riser pipe section to the storage area,
releasing the support of said riser string at said opening and
lifting the riser string through said opening to position at the
next riser section in the riser string above the riser storage
floor, and
releasably supporting the riser string at said opening in said
riser storage floor.
3. In an offshore drilling system on location in a body of water, a
method for manipulating riser pipe sections between a stored
condition of individual sections in a storage area in a drilling
rig and an operational condition of sections coupled to one another
to define a riser string where said riser string extends downwardly
from the drilling rig toward the floor under the water, said method
comprising the steps of
moving a riser pipe section from a storage area to a location below
a draw works,
coupling the draw works to such riser pipe section and raising the
riser pipe section into the drilling rig,
moving a blow out preventer from a storage area to a location below
the draw works,
supporting the blow out preventer at the opening in a riser pipe
storage floor, and lowering the raised riser pipe section to said
blow out preventer,
coupling said riser pipe section to said blow out preventer,
coupling the blow out preventer to the riser pipe section,
releasing the support for the blow out preventer and lowering the
riser pipe section and blow out preventer through the opening in
the riser storage floor until at the upper end of said riser pipe
section is just above the riser storage floor,
releasably supporting the riser pipe section at said opening in
said riser storage floor,
releasably coupling a horizontally movable transfer means to the
upper end of another riser section, disconnecting the draw works
from the riser pipe section, and connecting such other riser pipe
section to the riser section in the opening to define a riser
string depending from said opening,
coupling the draw works to said riser string, releasing the support
at said opening and lowering said riser string to a location where
the upper end of the riser string is just above said opening,
and
releasably securing such riser string in said opening.
4. The method as defined in claim 3 and further including the
performance of the following steps while the riser pipe string is
lowered through said opening, the steps of
coupling a horizontally movable transfer means to a pipe section in
a storage area on the riser storage floor and transferring such
pipe section toward said opening while said pipe string is being
lowered through said opening.
Description
BACKGROUND OF THE INVENTION
This invention relates to offshore drilling rigs and more
particularly, to structures in a rig for storing riser pipe
sections and blowout preventors in a vertical condition below the
derrick floor and for transporting such units in vertical condition
between storage and operational areas.
In offshore drilling rigs, it is customary to have a string of
interconnected tubular pipe sections extending from the rig to a
blowout preventor means (sometimes hereinafter referred to as BOP)
set on the ocean floor. The drilling string is then inserted
through the tubular pipe string (called a "riser") for the drilling
of the earth formations below the ocean floor.
On most rigs during the installation or removal of a riser pipe
system, the riser is set or supported dependently on the rotary
table and connections of riser pipe sections are made at the rig or
derrick floor level. When not in use, the lengths of riser pipe
sections are usually passed through a V-door and supported
horizontally on a pipe rack by means of a rig crane. This
manipulation of riser pipe sections between a horizontal position
on a pipe rack and a vertical passage through the rotary table is
similar to the operation required for running casing strings. The
operation requires virtually the full drilling crew as well as
crane operators and roustabouts.
During rough weather, the riser sections are hard to control while
hanging on the crane-sling lines. Tag lines are an aid but the
chance for injury to personnel or damage to the riser is great.
Actually, the problem of retrieving riser sections often comes
about because of bad weather where it is desired to pull the riser
string.
In the present invention, enough clearance is provided between a
lower cellar deck and the derrick floor to rack or store the riser
sections vertically under the derrick floor. The advantages of this
concept include:
1. The need to lay down the riser pipe joints on the pipe rack is
eliminated;
2. Wind or dynamic loading on the derrick is not increased as it
would be if the riser were racked in the derrick;
3. More pipe rack area is available for other tubulars;
4. The hazard to equipment and personnel created by frequent crane
handling is eliminated;
5. The same storage area is used for transit that is used while
pulling or running;
6. The number of personnel required to handle the riser is
reduced;
7. The time necessary to run or pull the riser is decreased;
and
8. The capability for handling the riser in more severe weather is
increased.
SUMMARY OF THE INVENTION
The present invention includes the provision of a cellar floor
below a drilling floor with a clearance greater than the length of
a riser pipe section. Vertically stacked on the cellar floor in
storage area are riser pipe sections necessary for the drilling
operation. Each riser pipe has its lower open end receive a stub
fixed to the floor and its upper end is supported between upper
channel arms. A transportation mechanism is provided for movement
to and from an opening in the cellar floor to the riser storage
area. In this regard, the transportation system has capability for
transverse and longitudinal, horizontal directional movement and
vertical lifting movement. Means are provided for independent
motion in any of the three coordinate directions. The
transportation means include a bridge type crane mounted for
movement on a pair of rails. A vertical lifting device is mounted
for sliding movement along a transverse beam of the crane. At the
cellar floor opening is a first pair of supporting arms for
engaging and supporting blowout preventors where the supporting
arms are spaced at appropriate distances relative to blowout
preventors sizes. At the cellar floor opening also is a second pair
of supporting arms for engaging and supporting riser pipe sections.
The separate pair of supporting arms utilize the same space but can
be selectively employed.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more apparent when the following
description is taken in connection with the drawings in which:
FIG. 1 is a schematic representation of an offshore rig embodying
the riser pipe handling system of the present invention;
FIGS. 2-4 are plan views of the door and opening in extended and
retracted positions;
FIG. 5 is a view taken along line 5--5 of FIG. 3;
FIG. 6 is a side view taken along line 6--6 of FIG. 7;
FIG. 7 is a plan view of the transporting system for riser pipe and
BOP means; and
FIG. 8 is a schematic illustration of the cellar floor plan for
transporting and storing riser pipe sections.
DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, an offshore rig or drilling barge 10 which
can be a semi-submersible which supports a drilling floor 11 above
the surface 12 of the ocean 13. Below the drilling floor 11 is a
cellar deck or floor 14. The clearance between the cellar floor 14
and drilling floor 11 is made adequate to permit vertical stacking
of riser pipe sections between the two floors 11 and 14. On the
drilling floor 11 is a derrick 15 equipped with a traveling block
16, draw works 17, and a rotary table 18. Vertically aligned with
the rotary table 18 is an opening 19 (sometimes called a moon pool
opening) in the cellar floor 14. A special two-stage horizontally
movable door 20 is movable between an extended position over the
opening to support selectively either a riser pipe section or a
Blow Out Preventor (hereinafter referred to as BOP). The door 20 is
powered by suitable hydraulic or mechanical means which is
schematically illustrated by the numeral 21. The door powering
means 21 is capable of horizontally reciprocating the door 20
relative to the opening 19 between an extended position over the
opening or a retracted position where the opening is entirely
clear. As illustrated in FIG. 1, a riser pipe string 22 is extended
from the cellar floor 14 to the ocean floor 23. The riser string 22
is comprised of the usual tubular riser pipe sections or joints
which are connected to one another. At the bottom of the riser
string is a BOP means 24 which attaches to the ocean floor well
head connection. The BOP means 24, as illustrated, has an enlarged
cross-section as compared to the cross-section of a riser pipe
section. The vertical clearance between the cellar floor and
derrick floor is such that one of the riser pipe sections 25 can be
vertically disposed in the clearance between the rotary table 18 in
the drilling floor and opening 19 in the cellar floor. The riser
pipe sections and BOP means have support means (to be explained
later) which are engagable by the door 20 to support the riser
string 22 while a riser pipe section 25 is added or subtracted from
the riser pipe string.
Means for moving a riser pipe section in the space between the
drilling rig floor and cellar floor include a bridge crane 27 which
is mounted for movement in one horizontal direction by spaced apart
guide rails 28 (only one shown). The crane includes wire lines 29
for moving the BOP means vertically with respect to the cellar
floor. A transverse beam 30 on the bridge crane extends between the
guide rails 28. A fork lift type device 31 is mounted for movement
along the length of the beam 30 and is also capable of vertical
movement relative to the transverse beam 30. The purpose of this
arrangement is to transport riser pipe sections or BOP means in a
vertical condition between the cellar opening 19 and storage areas.
The storage area for the BOP means is to either side of the opening
as shown by the illustration of upper and lower BOP stacks 32 and
33. The storage area for the riser pipe sections includes upper
fingers 35 which are arranged to receive the upper portion of the
riser pipe sections and stubs 36 set along the cellar floor for
receiving the open lower end of each riser pipe section.
In the overall operation of the system, the crane 27 first picks up
the lower section 33 of a BOP and moves it to the opening 19. The
BOP portion 33 is lowered partially through the opening with the
door 20 in a retracted condition. Then, the door 20 which has beams
for supporting the BOP 33, is moved to an extended position where
the door arms support the BOP portion 33 relative to the cellar
floor. The bridge crane 27 is then used to move the upper BOP
section 32 over the lower section and the BOP sections are
connected. After connection of the upper BOP section 32 to the
lower BOP section 33, a single joint of riser pipe that has been
pre-positioned on the hook of the traveling block 16 by means of a
running tool (not shown) is lowered through the rotary table 18 and
connected to the top of the assembled BOP stack. The BOP stack is
then picked up sufficiently for clearance and the sliding door 20
is retracted to allow passage through the cellar deck opening 19 of
the BOP. After the BOP has been sufficiently lowered to clear the
cellar deck opening 19, a second pair of door arms are engaged to
the first set of door arms that previously supported the BOPs. The
interconnection of the two sets of arms is accomplished while the
door is in the retracted position. The door 20 is then manipulated
again to an extended position with the now interconnected second
set of arms that are spaced apart sufficiently to provide clearance
for the riser and to support a riser spider 37 which will support
the riser section and BOP connected to it. The riser spider 37 is
then installed around the riser and supported by the second set of
arms. The riser is then set in it. The running tool (not shown) is
then released and pulled up sufficiently to provide clearance for
the next joint of riser. The fork lift device 31 is moved to the
riser pipe section storage area and another riser pipe section is
picked up vertically and transported in a vertical condition to the
cellar opening 19 where it is lowered and coupled to the riser
joint setting in the riser spider. The running tool (not shown)
attached to the traveling block 16 is lowered through the rotary
table 18 to attach to the connected riser pipe section. After
connection with the running tool, the assembled stack is picked up
sufficiently to release the spider and then is lowered until the
second riser pipe section is in position to be supported by the
riser spider 37. This sequence is repeated for the other riser pipe
sections as needed. The operation is reversed for pulling the riser
string.
Referring now to FIGS. 2-5, the door 20 and opening 19 are shown in
greater detail. The opening 19 is defined by a rectangular shaped
frame comprised of frame components 19(A-D) which attach to the
cellar floor. The side frame components or members 19a and 19c are
elongated and attached to an end frame member 19e. In FIG. 2, the
door 20 is in a retracted position and rests upon the frame members
19e, 19a, 19c and 19d. The door 20 includes two sets of generally
U-shaped gate members. A first U-shaped member 40 is shown most
clearly in FIG. 3. The gate member 40 has a length greater than the
span between the frame members 19d and 19e, and its open end lies
on the transverse frame member 19d in the retracted position of the
gate member. The U-shaped gate member 40 includes a pair of
longitudinally extending bar members 40a and 40b which are spaced
apart a distance compatable with the outer diameter of a riser pipe
section so that a riser pipe section can be supported by a riser
spider installed on the gate member 40. For supporting riser pipe
sections, a conventional riser pipe spider is also employed but is
not shown for clarity of illustration.
The other U-shaped gate member 50 is also shown most clearly in
FIG. 3. The gate member 50 has its open end facing the opening 19
where the open end is defined by parallel bar members 50a and 50b.
The bar members 50a and 50b are spaced apart a distance compatable
with the outer diameter of a BOP. The bar members 50a and 50b
attach to a pair of spaced transverse bars 50c and 50d which extend
across the width of the frame member 19d. Side support bar members
50e and 50f extend along the length of the frame members 29a and
19c and attach to the BOP supporting bars 50a and 50b. As
illustrated in FIGS. 2 and 3, the gate member 50 is movable between
a retracted and extended position relative to the cellar opening
19. Mean (such as tongue and groove connections not shown) are
provided for suitable guiding of the gate members relative to the
frame. The gate member 50 has its transverse members 50c and 50d
disposed above the bars 40a and 40b (see FIG. 5) of the gate member
40 so that the gate members 40 and 50 may move horizontally between
retracted and extended positions independently of one another.
Selective locking means in the form of openings 40c and 50g are
respectively provided in the bars 40a and 40b and the transverse
bars 50c and 50d. Pins (not shown) are used to couple the gate
members to one another. Hence, as shown in FIG. 4, both gate
members 40 and 50 can be retracted and extended relative to the
opening 19 in unison.
A riser spider 37 is conventional and is shown schematically in
FIG. 4. The spider 37 includes hinged semi-cylindrical members with
four equidistantly spaced latching fingers 37a. The latching
fingers 37a releasably engage latching slots in a riser section for
supporting the depending pipe load.
Referring now to FIGS. 6 and 7, the riser pipe manipulating or
transporting means are illustrated in side and plan view. The guide
rails 28 are spaced from one another in a parallel fashion at the
height above the cellar floor adequate to permit transportation of
a riser pipe section in a vertical condition. Elongated end frame
members 61 and 62 extend along the rails and carry journaled pairs
of wheels 63. The frame members 61 and 62 are connected to
transverse beam members 64 and 65 which can have box type
cross-sections. The frame and beam members 61, 62, 64 and 65 form a
generally rectangular configuration which is movable in a
horizontal direction by virtue of the wheels 63 and the track 28. A
longitudinal rack 66 can be attached to one or both of the rails
28. A pinion 67 on the wheel shaft 68 engages the rack 66 for
driving purposes. A motor and transmission means 69 on the beam 64
can be used to drive the shaft 68. As shown in FIG. 6, one or more
hooks 29 attached to cable and spooling means 70 can be provided on
the frame for picking up equipment such as the BOP means.
On the forward transverse beam 65, its upper and lower surfaces are
provided with longitudinally extending guides 71, 72 and 73. A
U-shaped frame member 74 has an upper arm with a vertically
journaled set of rollers 75 which engage a side of the guide 71
facing away from the front of the beam 65. Horizontally journaled
sets of rollers 76 in the frame 74 engage the upper surfaces of the
guides 71 and 73. A vertically journaled roller in the lower arm of
the frame member 74 engages an outer side of the lower guide 72.
The guides and rollers provide a cantilevered rolling support for
the frame member 74 on the transverse beam 65. A motor 77 on the
frame member operates a pinion on the frame member 74 which engages
a longitudinal rack 78 on the beam 65. Operation of the motor 77
traverses the frame member 74 relative to the beam member 65 in a
horizontal direction transverse or perpendicular to the direction
of travel of the beam member 65 on the rails 28.
The foward portion of the frame member 75 is provided with parallel
vertical trackways 80 in opposing sides of the frame member. Guide
rollers 81 are received in the guideways and are attached to a
lifting frame 82. Additional side rollers 83 are provided so that
the lifting frame 82 is movable vertically with respect to the
frame member 74. Hydraulic means 84 are coupled between the frame
member 74 and lifting frame 82 to accomplish relative vertical
motion between the units. The lifting frame 82 has a generally flat
upper surface 86 which has a U-shaped recess 87 sized to pass
around the outer diameter of a riser section. A riser pipe section
24 has diametrically opposed pin members 88 perpendicularly
arranged relative to the axis of a riser pipe and supported by
plate members 89 welded to the upper sides of the pins 88 and to
the sides of a riser pipe section. The surface 82 of the frame 82
has recesses 90 therein to receive the pins 88 so that a riser
section is interlocked by the pins to the lifting frame.
As shown in FIG. 8, the arms 35 which provide the upper support for
the riser pipe sections can include transverse locking bars 92 to
retain the upper portion of the pipes in a steady condition. The
crane 27 can move to the stored riser pipe sections and the fork
lift device can be lowered below the crane 27 to engage the pins 88
of a riser pipe section. The arms 35 for storage are located
relative to the pins 88 so that the lifting portion of fork lift
device can be inserted between the arms 35 and pins 88. The riser
pipe sections are stacked and removed one at a time from side to
side of the racking arms 35.
In summary of the overall operation of the system, the crane 27
first picks up the lower end 33 of a BOP and moves it to the
opening 19. The BOP portion 33 is lowered partially through the
opening 19 with the door sections 40 and 50 in a retracted
condition. Then, the door section 50 which has beams for supporting
the BOP 33, is moved to an extended position where the door section
50 supports the BOP portion 33 relative to the cellar floor. The
bridge crane 27 is then used to move an upper BOP section 32 over
the lower section 33 and the BOP sections 32 and 33 are connected.
After connection of the upper BOP section 32 to the lower BOP
section 33, a single joint of riser pipe that has been
pre-positioned on the hook of the traveling block 16 by means of a
running tool (not shown) is lowered through the rotary table 18 and
connected to the top of the asembled BOP stack. The BOP stack is
then picked up sufficiently for clearance and the door section 50
of the sliding door 20 is retracted to allow passage through the
cellar deck opening 19 of the BOP. After the BOP has been
sufficiently lowered to clear the cellar deck opening 19, a second
pair of door arms 40 are engaged to the first set of arms 50 that
previously supported the BOPS. The interconnection of the two sets
of arms 40 and 50 is accomplished by inserting pins in the holes
40c and 50g while the door is in the retracted position. The door
20 is then manipulated again to an extended position with the now
engaged second set of arms 40 that are spaced apart sufficiently to
provide clearance for the riser and to support a riser spider 37
which will support the riser and BOP connected to it. The riser
spider 37 is then installed around the riser and supported by the
second set of arms 40. The riser is then set in it. The running
tool (not shown) is then released and pulled up sufficiently to
provide clearance for the next joint of riser. The fork lift device
31 is moved to the riser pipe section storage area and another
riser pipe section is picked up vertically and transported in a
vertical condition to the cellar opening 19 where it is lowered and
coupled to the riser joint setting in the riser spider. The running
tool (not shown) attached to the traveling block 16 and is lowered
through the rotary table 18 to attach to the connected riser pipe
section. After connection with the running tool, the assembled
stack is picked up sufficiently to release the spider and then is
lowered until the riser pipe section is in position to be supported
by the riser spider which is supported by the door section 40. The
door section 40 then supports the depending stack by support of the
riser pipe section by the door sections 40 and 50 coupled to one
another.
While particular embodiments of the present invention have been
shown and described, it is apparent that changes and modifications
may be made without departing from the invention in its broader
aspects; and therefore, the aim in the appended claims is to cover
all such changes and modifications as fall within the true spirit
and scope of this invention.
* * * * *