U.S. patent application number 10/078610 was filed with the patent office on 2003-08-21 for expandable drilling template system.
Invention is credited to Crain, Jack.
Application Number | 20030155119 10/078610 |
Document ID | / |
Family ID | 27732864 |
Filed Date | 2003-08-21 |
United States Patent
Application |
20030155119 |
Kind Code |
A1 |
Crain, Jack |
August 21, 2003 |
Expandable drilling template system
Abstract
A template that can be used for drilling subsea wells in
proximity at the seafloor is provided. The template is first placed
over an existing protuberance above the seafloor, which is usually
the conductor casing of an existing well. The template has a
plurality of cans or guide slots, of which one has a J-slot that
can be engaged by a running tool. The template is placed near the
seafloor and plates are released to rest on the seafloor and
support the template. After wells are drilled through the slots,
the template can be rotated or moved to additional well casings for
the drilling of additional wells.
Inventors: |
Crain, Jack; (Broussard,
LA) |
Correspondence
Address: |
BAKER BOTTS, LLP
910 LOUISIANA
HOUSTON
TX
77002-4995
US
|
Family ID: |
27732864 |
Appl. No.: |
10/078610 |
Filed: |
February 19, 2002 |
Current U.S.
Class: |
166/245 ;
166/243 |
Current CPC
Class: |
E21B 43/017 20130101;
E21B 41/08 20130101 |
Class at
Publication: |
166/245 ;
166/243 |
International
Class: |
E21B 043/00; E21B
043/30 |
Claims
What I claim is:
1. A drilling template for subsea drilling, comprising: a plurality
of cans supported by a frame and cross-supports, one of the cans
having a J-slot therein for support of the template in a horizontal
plane and being adapted to be lowered over a selected protrusion
extending from a seafloor location; a plurality of leveling plate
rod guides affixed to the frame and a plurality of leveling plate
rods, each of the leveling plate rod guides having a mechanism for
controlling movement of one of the leveling plate rods through the
rod guide; and a leveling plate affixed to each of the leveling
plate rods.
2. The template of claim 1 further comprising a level-measuring
device attached to the frame and cross-supports for determining if
the frame is horizontal.
3. The template of claim 1 wherein each of the cans adapted to be
lowered over the protrusion is adapted by gussets affixed
therein.
4. The template of claim 1 wherein the mechanism for controlling
movement of the leveling plate rods is a bracket having bolts
therein.
5. The template of claim 1 wherein the plurality of cans is three
cans.
6. The template of claim 1 further comprising a shipping bracket
attached to the frame.
7. A running tool for placing a subsea drilling template,
comprising: a body, the body having an outside diameter and an
inside surface and being sized to be lowered inside a selected can
of the drilling template, the can having a J-slot therein; a
plurality of lugs attached to the outside diameter of the body, the
lugs being adapted to move inside the J-slot; and a support
attached to the body.
8. The running tool of claim 7 further comprising a stripe painted
on the inside surface for adjusting the position of a TV camera in
the body.
9. A method for placing a drilling template over a protrusion
extending above a seafloor location, comprising: assembling the
template, the template having a frame, a plurality of cans
including a can adapted for lowering over the protrusion, the can
having a J-slot therein, and a plurality of leveling plates
attached to a plurality of leveling plate rods, each of the
leveling plate rods being attached to the frame by a mechanism to
control movement of the leveling plate rods with respect to the
frame; lowering the template with drill pipe, the drill pipe
supporting the template by a J-mechanism, to place the can having
the J-slot therein over the protrusion with the template a selected
distance above the seafloor location; operating the mechanism to
control movement of the leveling plate rods to release the
plurality of leveling plate rods such that the plurality of
leveling plates rest on the seafloor location; operating the
mechanism to control movement of the leveling plate rods to prevent
further movement of the leveling plate rods; and operating the
J-mechanism to release the drill pipe from the template.
10. The method of claim 9 further comprising determining if the
frame of the template is in a horizontal plane before operating the
J-mechanism to release the drill pipe from the template.
11. The method of claim 9 further comprising operating an orienting
device to determine compass orientation of the drilling
template.
12. The method of claim 9 further comprising operating a TV camera
while lowering the drill pipe.
13. The method of claim 9 further comprising operating a jet sub to
assist in the step of placing the can having the J-slot therein
over the protrusion.
14. The method of claim 9 wherein the protrusion is a conductor
casing of a well.
15. A method for drilling a plurality of subsea wells through a
drilling template, the drilling template comprising a plurality of
cans supported by a frame and cross-supports, one of the cans
having a J-slot therein for support of the template in a horizontal
plane and being adapted to be lowered over a conductor casing
extending from a seafloor location, a plurality of leveling plate
rod guides affixed to the frame and a plurality of leveling plate
rods, each of the leveling plate rod guides having a mechanism for
controlling movement of one of the leveling plate rods through the
rod guide, and a leveling plate affixed to each of the leveling
plate rods, comprising: assembling the template, lowering the
template with drill pipe, the drill pipe supporting a running tool
having lugs to engage the template by the J-slot, to place the can
having the J-slot therein over the conductor casing with the
template a selected distance above the seafloor location; operating
the mechanism to control movement of the leveling plate rods to
release the plurality of leveling plates and leveling plate rods
such that the leveling plates rest on the seafloor location;
operating the mechanism to control movement of the leveling plate
rods to prevent further movement of the leveling plate rods;
operating the J-mechanism to release the drill pipe from the
template and retrieving the drill pipe; drilling at least one well
through at least one of the cans and placing an added conductor
casing therein; running the running tool with drill pipe and
engaging the running tool and the can having the J-slot therein;
rotating the template through a selected angle by rotating the
drill pipe; operating the J-mechanism to release the drill pipe
from the template and retrieving the drill pipe; and drilling at
least one well through at least one of the cans and placing an
added conductor casing therein.
16. The method of claim 15 further comprising running drill pipe
with the running tool and engaging the running tool and the can
having the J-slot therein, removing the template from the conductor
casing and placing a can of the template not having a J-slot
therein on the added conductor casing; and drilling at least one
well through one of the cans.
17. The method of claim 15 further comprising operating a jet sub
to assist in the step of placing the can having the J-slot therein
over the added conductor casing.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention pertains to subsea wells. More particularly,
a template for drilling wells on the seafloor and apparatus and
method for placement of the template are provided.
[0003] 2. Description of Related Art
[0004] Offshore oil and gas well drilling is usually conducted by
placing multiple wells in close proximity where they penetrate the
seafloor. To assist in placing the wells at a known location
closely spaced, a drilling template is usually employed. The
template is used for guiding drill strings, tubulars and tools into
the seafloor. Templates may be placed directly on the seafloor and
held in place by their mass or they may be affixed to piles or
other equipment. Submerging or uneven settling of templates has
caused problems in some areas.
[0005] U.S. Pat. No. 4,706,757, discloses a template that is
supported by a wellhead. A central support member of the template
engaged with the wellhead is supported above the seafloor. A number
of guide slots are attached to the central support member, which
may be prevented from rotating on the wellhead. The central support
member fits coaxially over the upper portion of the wellhead. In
one embodiment, a running tool is used to install the template,
with J-slots engaging lifting dogs on the central support member.
The running tool is cylindrical and fits over an upper portion of
the central support member.
[0006] U.S. Pat. No. 5,244,312, discloses a method for installing a
drilling template that is supported on preset piles. The template
is leveled while supported on the piles. U.S. Pat. No. 4,784,527
discloses a modular template. In one embodiment, the template is
secured to the seafloor by piles and is leveled by adjustment of
gimbaled jack mechanisms associated with individual latches.
[0007] What is needed is a versatile template system that can be
used to drill closely spaced wells on the seafloor and that can be
deployed and re-positioned simply to allow drilling of a selected
number of closely spaced wells, thereby effectively making the
template expandable.
SUMMARY OF THE INVENTION
[0008] A template having guide slots or cans supported in a frame
is provided. In a preferred embodiment, the template is first
placed over casing of an existing well on the seafloor. Leveling
plates attached to rods are placed on the seafloor when rod guides
release and then re-grip the rods. Devices on the template can
determine if it is horizontal. A running tool that can be attached
to drill pipe and is sized for attaching to the template by a
J-mechanism is also provided. A TV camera can be placed in the
running tool and used, along with a jet sub, to place the template.
A gyroscope can be used to determine compass direction of the
template. The template can be rotated around the original well and
can be moved to other well casings to drill additional wells.
BRIEF DESCRIPTION OF THE FIGURES
[0009] FIG. 1 is a top view of the disclosed subsea template.
[0010] FIG. 2 is an elevation view of the disclosed subsea
template.
[0011] FIG. 3 is a detailed view of a rod guide and leveling plate
assembly of the disclosed template.
[0012] FIG. 4 is an elevation view of a running tool for placing a
subsea template disclosed herein on the seafloor with drill
pipe.
[0013] FIG. 5 is a top view of a template before and after
re-positioning for drilling additional wells.
DETAILED DESCRIPTION
[0014] A top view of one embodiment of the subsea template
disclosed herein is shown in FIG. 1 at 10. Beams 12 form a frame in
which cans (or guide slots) 14, 16 and 18 are held in place by
cross support members 20. Center can 14 includes top funnel guide
22 and gussets 24. Gussets 24 are sized such as to center can 14
over a protrusion extending from the seafloor, which is normally a
conductor casing. The sizing of center can 14 including gussets 24
can be adjusted to allow centering of can 14 over a protuberance
extending above the seafloor. Cans 16 and 18 are sized such as to
allow conductor casing of adjacent wells to be run through the
cans. Pad eyes 26 may be placed on frame 12 for use in lifting the
template. Preferably, the structure of template 10 is symmetrical
with respect to orthogonal planes that extend through the center of
can 14. This allows template 10 to be suspended in a horizontal
plane when the template is supported only through can 14.
[0015] Leveling plate rod guides 28, 29 and 30 are extended from
frame 12 and are used to receive leveling plate rods (not shown)
used for leveling and supporting template 10 on leveling plates
(not shown). Each rod guide includes a mechanism for controlling
movement of leveling plate rods through the rod guide. An enlarged
view of one embodiment of such mechanism for rod guides 28, 29 and
30 is shown in the inset below rod guides 30. By applying torque to
bolts 33, bracket 31 can be adjusted to control friction on a rod
that is sized for passing through the rod guide. Level devices 32
are used for leveling template 10. The levels may be simple devices
based on the location of a bubble, which must be observed by a
diver or a TV camera, or may be an electronic device.
[0016] Although three cans are shown in template 10, it should be
understood that only two cans may be used or more than three cans
may be used and the same principles can be applied as described
herein. The template should be weight-balanced such that it lies in
a horizontal plane when supported. The distance between cans can be
adjusted by varying the length of members of frame 12 between the
cans. For example, members can be inserted such that the cans have
spacings of 7.5 feet, 8.5 feet or 10 feet, which correspond to
distances between wells often used on platforms. Other distances
may be selected, depending on the design of a structure to be used
for drilling through the template.
[0017] Dimensions of can 14 may be as follows: funnel guide 22 may
have an outside diameter of 61.5 inches, an inside diameter of 41
inches and a sloping surface 10 inches wide; gussets 24 may have a
protrusion distance into the can of 3 inches, a thickness of 0.75
inch and a length of 1.5 feet, with slope angles of 45.degree.. The
body of can 14 may have an OD of 42 inches and an ID of 40.75
inches, which provides a diameter within the gussets of 34.75
inches. Cans 16 and 18 may have an OD of 36 inches and an ID of
34.75 inches. These cans would be suitably sized for 30-inch OD
conductor casing extending through the cans. Funnel guides on cans
16 and 18 may have an OD of 55.5 inches, an ID of 35 inches and a
sloping surface 10 inches wide. Lower funnel guides (not shown) may
be added to these cans.
[0018] In one embodiment, distances between cans 14 and 16 are 9
feet center-to-center The overall length of frame 12 is 25.5 feet
and the width is 9 feet to the exterior of the frame. Pad eyes 26
may be placed at a distance 5 feet from the ends of frame 12. The
frame may be made of 8-inch schedule 40 pipe having a wall
thickness of 0.322 inch. The frame and cans may be joined using
conventional welding techniques.
[0019] FIG. 2 depicts an elevation view of template 10. Center can
14 has upper funnel guide 22 and lower funnel guide 25. Lower
funnel guide 25 is used for guiding center can 14 over a protrusion
from the seafloor and upper funnel 22 is used for guiding tubulars
or tools into can 14. Center can 14 also includes J-slot 54, which
is used in placing template 10 on the seafloor, as will be
described below. Frame 12 of template 10 is supported on or near
the seafloor by leveling plate rods that pass through rod guides
28, 29 and 30. The rods may be held in place by friction caused by
tightening of bracket 31, which is shown in more detail in FIG.
1.
[0020] FIG. 3 shows details of a leveling plate assembly that may
be adapted for use in rod guides 28, 29 and 30 of FIGS. 1 and 2.
Rod 34 may be placed through the rod guides before template 10 is
deployed subsea. The rod may be lifted using eye 35. Leveling plate
38 may be attached to leveling plate rod 34 using pin 39. Leveling
plate 38 is stabilized by gussets 40. Leveling plate rod 34 may
have a length of 10 feet. Leveling plate 38 may be rectangular in
shape with sides of 3 feet and 4 feet, for example. Larger area of
a leveling plate is desirable when softer seafloor is expected.
Leveling plate rod 34 may be made of 5-inch drill pipe, for
example.
[0021] FIG. 4 illustrates running tool 42. Running tool body 44 is
sized to be placed over a protrusion extending above the seafloor,
such as 30-inch conductor casing. Body 44 of the running tool may
have a diameter of 36 inches and a wall thickness of 5/8 inch, for
example. Body 44 is attached to tubular support 46, which may be
41/2 inch-drill pipe terminating in box 47. Gussets 48 are used in
attaching support 46 to body 44. The top of the body is preferably
open around the gussets, providing for passage of a TV camera and
cable into running tool 42. At the lower end of body 44 are gussets
50, which may have a thickness of about 2 inches in the radial
direction and a thickness of about 0.75 inch and a length along the
radius of body 44 of about 1.3 feet, for example. Lugs 52 protrude
from gussets 50. Normally, gussets 50 are spaced at 90.degree.
angles around body 44. Painted stripes 54 may be provided on the
inside surface of body 44 to assist a TV camera operator in keeping
a camera within the body as the running tool is lowered on drill
pipe.
[0022] For this size protrusion, running tool body 44 should have
an OD of 36 inches with a 5/8-inch wall. Gussets 50 have a depth of
2 inches, a width of 3/4 inch and a length of about 1.5 feet. They
may be placed at 45.degree.(90.degree. shown in FIG. 4). Lugs 52
are sized to be used in J-slot 54 (FIG. 2). The lugs may have a
diameter of 2.5 inches and a length of 3.5 inches. The running tool
gussets then extend to an outside diameter of 40 inches and can be
accommodated in can 14, having a J-slot and an inside diameter of
40.75 inches. Lugs 52, having an OD of 43 inches, are accommodated
within the 3-inch slot width of J-slot 54.
[0023] The following procedure may be used to place template 10 on
a casing or other protrusion from the seafloor. The dust cover on a
casing is first removed. A trash cap is then preferably placed on
the casing. The height of the casing or other protrusion above the
seafloor should be determined so as to insure that the running tool
is long enough to go over the protrusion and set a template at the
desired height off the seafloor. The template is then moved to the
cellar deck on the drilling vessel. Leveling pads including rods 34
and leveling plate 38 are installed in guide sleeves 28 and 30 and,
optionally, guide sleeves 29. Running tool 42 may be made up with
muleshoe sub 49 for orientation of template 10, using a gyroscope
landed in the sub, and jet sub 51, which may be used to force the
running tool over the protrusion on which it is to be placed. The
J-slot running tool is then placed in center can 14 of template 10
and the template is then lowered on drill pipe to about 20 feet
above the mud line. Preferably, center can 14 is observed going
over the protrusion, such as a 30-inch drive pipe or casing, with a
remotely operated vehicle (ROV) or a diver and by a TV camera
suspended on a cable passing into the top of body 44. The template
is then preferably lowered to about 3 feet above the mud line.
Preferably, a single shot gyroscope is used to align the template
in the desired direction by landing the gyroscope is mule shoe sub
49. The alignment may be verified by re-running a single shot
gyroscope. Then the template is lowered to tag bottom and leveling
devices 33 are checked with an ROV or diver to determine if the
template is level. If necessary, the drill pipe and template are
raised slowly until the template is observed to be level. At this
point, torque is applied to bolts 33 of brackets 31 around the
template, using a diver or ROV. This allows leveling pads 38 to
drop to the seafloor. Then bolts 33 on each of the leveling pads
are re-tightened using a diver or ROV. The drill pipe is then
lowered until the J-slot running tool is at the bottom of the "J".
Again the bubble leveling device or devices are checked to
determine if the template is level. If it is not, the template is
pulled up slowly until the template is level and the leveling pad
lock bolts are again released and re-tightened as explained above.
After a check of the leveling device with the J-slot running tool
at the bottom of the J shows that the template is level, the
running tool is then "unjayed" from center can 14 of template 10
and retrieved on the drill pipe. Although the J-mechanism is the
common method for attaching and releasing such loads, it is clear
that other mechanical mechanisms may be used to achieve the same
result.
[0024] The entire apparatus can be conveniently assembled for
shipment by clamping legs 34 within frame 12, attaching leveling
plates 44 to the bottom of frame 12 and storing running tool 42 on
posts 17 that protrude above frame 12. The entire assembly then can
be lifted and located using a clevis which is attached to cables
and inserted in each pad eye 26 with a pin.
[0025] When more wells are to be drilled from a subsea location
than the number of cans in the template, template 10 can be
successively rotated or moved from the first wells drilled.
Rotation is accomplished by lowering a running tool, such as shown
in FIG. 4, on drill pipe with muleshoe sub 49 and jet sub 51
present between the running tool and the drill pipe. Preferably, a
TV camera is placed in body 44 of running tool 42 before the
running tool is placed subsea. As the running tool is lowered on
drill pipe, cable supporting the TV camera is reeled off to
maintain the camera within body 44. Preferably, stripes 54 of black
and white are placed on the inside surface of body 44 to assist the
cable operator in maintaining the camera within body 44. Using the
camera to locate body 44 with respect to the J-slot of the can to
be engaged by lugs 52 of running tool 42, jet sub 51 can be
operated to move body 44 in the direction necessary to place lugs
52 in the J-slot of the can. After the J-mechanism is engaged,
drill pipe at the surface is rotated, usually by 90 degrees, to
rotate the template. A one-shot gyroscope may then be run through
drill pipe to muleshoe sub 49, where a measurement can be made to
verify direction of the template after its rotation. Two additional
wells can then be drilled from the cans 16 and 18, as shown in FIG.
5. This allows a total of five wells to be drilled using template
10.
[0026] If additional wells are to be drilled in the selected
location, template 10 can be lifted off the original well (well 1,
which is drilled before template 10 is deployed) using the same
technique as described before. Center can 14 can then be placed on
one of the wells drilled off the line of the original wells, such
as well 5. Wells 6 and 7 (not shown) could then be drilled such
that wells 5, 6 and 7 are aligned in the same direction as wells 1,
2 and 3. Similarly, template 10 may be placed over well 4 and wells
8 and 9 (not shown) could be drilled with the same alignment as
wells 1, 2 and 3. A jackup platform can usually accommodate nine
wells. Template 10 may then be recovered from the seafloor before
the wells are tied back
[0027] If more than nine wells are to be drilled, such as from a
semisubmersible rig, using techniques described before, template 10
can be placed such that an end can, such as can 16 of FIG. 2, is
around well 3, for example. Template 10 can then be aligned in the
direction of wells 1, 2 and 3, and the direction verified using a
gyroscope. Additional wells can be drilled as described before.
Preferably, if more than nine wells are to be drilled, a lower
funnel, such as funnel 25 of FIG. 2, is also placed on cans 16 and
18 (not shown) to facilitate lowering of one of these cans over the
conductor casing of an existing well.
[0028] Although the present invention has been described with
respect to specific details, it is not intended that such details
be regarded as limitations upon the scope of the invention, except
as to the extent they are included in the following claims.
* * * * *