U.S. patent number 3,828,561 [Application Number 05/368,236] was granted by the patent office on 1974-08-13 for drilling platform.
This patent grant is currently assigned to The Offshore Company. Invention is credited to William H. Moore, Floyd T. Pease, George T. Richardson.
United States Patent |
3,828,561 |
Moore , et al. |
August 13, 1974 |
DRILLING PLATFORM
Abstract
A floating vessel suitable as a drilling platform in which the
vessel has legs extending therethrough which in their upper
position are tightly held by the vessel and each leg includes a
footing which can be secured thereto or to the vessel when the legs
are lowered to raise the vessel into operating position to provide
the lower end of the legs with an extended bearing surface for
engagement with the bottom.
Inventors: |
Moore; William H. (Houston,
TX), Richardson; George T. (Houston, TX), Pease; Floyd
T. (Houston, TX) |
Assignee: |
The Offshore Company (Houston,
TX)
|
Family
ID: |
26897582 |
Appl.
No.: |
05/368,236 |
Filed: |
June 8, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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202350 |
Nov 26, 1971 |
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819623 |
Apr 28, 1969 |
3628336 |
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Current U.S.
Class: |
405/197; 403/362;
285/18; 403/306; 285/403 |
Current CPC
Class: |
E02B
17/021 (20130101); E02B 17/06 (20130101); E02B
2017/006 (20130101); Y10T 403/5741 (20150115); Y10T
403/7041 (20150115); E02B 2017/0082 (20130101) |
Current International
Class: |
E02B
17/02 (20060101); E02B 17/00 (20060101); E02b
017/00 (); F16l 037/14 (); F16b 012/40 () |
Field of
Search: |
;285/141,321,18,404,403
;287/DIG.7,119 ;61/46.5 ;403/362,306 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Shapiro; Jacob
Attorney, Agent or Firm: Springgate; Jack R. Edwards; Joe E.
Gay; M. H.
Parent Case Text
This application is a continuation of application Ser. No. 202,350
filed Nov. 26, 1971, and now abandoned, which was a divisional
application of Ser. No. 819,623 filed Apr. 28, 1969 now Pat. No.
3,628,336.
Claims
What is claimed is:
1. A floatable structure suitable for drilling, comprising
a floating vessel,
a plurality of legs,
each of said legs including a plurality of connectible sections,
and means for releasably connecting said sections together,
each of said sections including a plurality of tubular members and
a plurality of bracing members securing said tubular members in
generally parallel relationship to each other throughout the length
of said tubular members,
said vessel defining a plurality of holes through which said legs
are adapted to extend,
means associated with each of said holes for jacking said legs
through said holes, and
means associated with each of said holes for guiding said legs in
their movement through said holes,
said connecting means between sections releasably connecting the
tubular members of said sections together and being of a diameter
not larger than the diameter of said tubular members whereby said
connecting means allows desired coaction of said jacking and
guiding means throughout the movement of said legs through said
holes.
2. A floatable structure according to claim 1 wherein said tubular
members terminate in pin and box ends for mating between said
tubular members of adjacent sections and said connecting means
includes
at least one mating annular groove in each of said pin and box
ends,
a plurality of segments adapted to be wholly contained within the
grooves of one of said pin and box ends, and
means for moving said segments into a position partially in each of
the two mating grooves to secure the pin and box ends together.
3. An elongate structure according to claim 2, wherein said moving
means includes
at least one threaded screw secured to each of said segment members
and extending through the wall of said box end for rotation from
the exterior thereof to positively move said segment members to
their desired position.
Description
SUMMARY
The present invention relates to an improved structure for marine
drilling which is floatable and includes legs for raising the
structure to its desired position for drilling.
An object of the present invention is to provide an improved
drilling platform which provides stable footing under all
conditions of the bottom which may be encountered at the drilling
site.
Another object is to provide an improved drilling platform having
legs which are tightly secured in their upper position to prevent
vibration during movement of the platform.
Still another object of the present invention is to provide an
improved drilling platform having tank footings which may
alternately be secured to the hull and to the legs and which when
secured to the hull, provide a minimum of drag to the movement of
the platform through the water.
A still further object is to provide a vessel which includes its
own propulsion for movement on water to a marine drilling site and
may be jacked up on its legs to provide a stable drilling
platform.
A further object is to provide an improved vessel which can be
supported in drilling position on legs and which has a sufficient
low center of gravity to be stable when moving on the water.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects of the present invention are hereinafter
set forth and explained with reference to the drawings wherein:
FIG. 1 is a plan view of a drilling platform vessel constructed in
accordance with the present invention.
FIG. 2 is a side elevation of the drilling platform vessel shown in
FIG. 1.
FIG. 3 is a detail partial sectional view of one leg showing the
guides for the legs with the legs in their uppermost secured
position.
FIG. 4 is a partial schematic view of the vessel and showing the
improved leg and tank footing with the leg secured to the vessel
and the tank footing in position for movement of the vessel on the
water.
FIG. 5 is a similar schematic view of the vessel raised on the leg
with the tank footing secured to the lower end of the leg to
provide extended bearing surface for the lower end of the leg on
the bottom.
FIG. 6 is another similar schematic view showing the vessel raised
on the leg with the tank footing secured to the vessel.
FIG. 7 is an elevation view of a joint connection in one of the
legs.
FIG. 8 is a sectional view taken across one of the joints of the
leg along line 8--8 in FIG. 7.
FIG. 9 is a sectional view of the joint shown in FIG. 8 taken along
line 9--9.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The vessel 10 may have its own propulsion system as shown in FIGS.
1 and 2. The vessel is provided with the legs 12 which are adapted
to be lowered through the vessel 10 with suitable jacking
mechanisms. Also, the usual platform drilling equipment such as the
derrick D and the cranes C are mounted on the vessel 10. While four
legs 12 are shown, the vessel 10 may have three or more of such
legs without departing from the spirit of the present invention.
Each of the legs 12 extends through a well 14 in vessel 10. The
lower portion of vessel 10 surrounding the wells 14 defines the
recesses 16 in which the tank footings 18 are positioned during
movement of the vessel 10 on the water. Each of the footings 18 is
designed to receive the leg 12 therein or to allow the leg 12 to
move therethrough.
As shown in FIG. 3, each of the wells 14 includes the lower guides
20 and the upper guides 22. The lower end of the legs 12 are
slightly larger than the remainder of the legs so that when the
legs 12 are in their uppermost position they are held tightly
within the wells 14. In this position the legs 12 are secured
against movement and vibration during movement of vessel 10. To
further secure the legs 12, suitable wedges 23 are inserted between
the legs 12 and the upper guides 22.
The tank footings 18 each include the means 24 for releasably
securing the footing to its associated leg 12 and the means 26 for
releasably securing it to the vessel 10 within its recess 16.
Additionally, the means 28 is provided to releasably secure the
vessel 10 to each of the legs 12 and to positively move the legs 12
in both directions through their wells 14 in vessel 10. The means
28 includes the upper lock pins 30, the lower lock pins 32 and the
usual jacking means (not shown) for moving the pins 30 and 32
relative to each other. The legs 12 each include interconnected
structural members and the lower end of each of the legs 12
includes the integral tank footing 34.
The vessel 10 having its own propulsion is sailed to the drilling
site with the tank footings 18 secured in the position shown in
FIG. 4. The means 24 secures each tank footing 18 to the lower end
of its leg 12 and the legs 12 are secured by the means 28 in their
uppermost position so that the tank footings 18 are held within
their respective recesses 16. If desired, the tank footings 18 may
be held in their recesses 16 by the means 26 and the means 24 may
be in their released position. This position of the tank footings
18 minimizes the drag which the footings cause during the movement
of the vessel 10 through the water. With the vessel 10 in position
over the preselected drilling site, the type of bottom determines
whether the legs 12 should be lowered with the tank footings 18 as
shown in FIG. 5 or without the tank footings 18 as shown in FIG. 6.
When the bottom is relatively soft and has a limited bearing
capacity, the tank footings 18 are secured to the legs 12 as
hereinafter described to provide sufficient bearing capacity to
support the vessel 10 in a raised position. If the bottom
conditions are such that only a limited bearing area is needed to
support the raised vessel, then the tank footings 18 are held
secured to the vessel 10 in their recesses 16 while the legs 12 are
lowered.
If it is desired to lower the tank footing 18 with each of the legs
12, the tank footings 18 are first secured to the vessel 10 by the
means 26 and then their legs 12 are lowered a short distance to
project a few feet below the lower surface of tank footing 18.
Thereafter the means 24 are actuated to secure the tank footings 18
to their respective legs 12, and then the means 26 are released.
The legs may then be positively moved downwardly with respect to
the vessel 10. When the footings 34 and the tank footings 18 engage
the bottom, further relative movement of the legs 12 through the
wells 14 raises the vessel 10 above the water to the position shown
in FIG. 5. The projection of the lower end of the legs 12 below the
lower surface of the tank footings 18 causes a greater penetration
into the bottom and provides lateral stability. The extended lower
surface of the tank footings 18 greatly increases the bearing area
of the legs 12 in engagement with the bottom to thereby provide a
greatly increased stability of the vessel 10 in its raised drilling
position.
When the drilling site is over a bottom which is relatively hard,
the extended bearing area of the tank footings 18 may not be
desired. Under such conditions, the means 26 are actuated to secure
the tank footings 18 to the vessel 10 in their respective recesses
16 and then the means 24 are released to allow the legs 12 to be
positively moved downwardly through the wells 14 of vessel 10 and
the tank footings 18. As shown in FIG. 6, when the footings 34 of
legs 12 have firmly engaged the bottom, further jacking of the legs
12 through the vessel 10 raises the vessel 10 above the water
surface to provide a stable platform from which drilling operations
may be conducted.
The legs 12 normally are very long with a length of 350 feet being
expected. Since the projection of the legs 12 below the vessel 10
would cause drag on the movement of the vessel and may even ground
the vessel and the extension of the legs upwardly decreases the
stability of the vessel, a portion of the legs 12 is made to be
removable. This removable portion may be secured on the deck during
movement of the vessel 10. FIGS. 7, 8 and 9 illustrate a joint
between the removable section 36 and the main section 38. Each of
the longitudinal members 40 of the main section 38 has a pin end 42
adapted to be received in the box end 44 on the longitudinal
members 46 of the removable section 36. The pin end 42 is an
upstanding tubular portion having a reduced external diameter from
member 46 and the box end 44 is a tubular section of increased
thickness and an internal diameter slightly larger than the pin end
42. Securing means 48 is provided to maintain the pin end 42 in its
desired position within the box end 44. When the removable section
36 has been secured to the main section 38, the whole structure
functions as a unitary leg for supporting the vessel 10 as
previously described.
The securing means 48 includes the arcuate locking segments 50, the
screws 52 which control the position of the segments 50, the
grooves 54 defined around the interior of the box end 44 and the
grooves 56 defined around the exterior of the pin end 42. When the
segments 50 are retracted completely within grooves 54, then the
securing means 48 is released and the section 36 may be removed
from section 38. Actuation of screws 52 to move the segments 50
inwardly so that they are partially within grooves 56 and partially
within grooves 54 locks the sections 36 and 38 together. The upper
and lower edges of segments 50 are beveled to match with the
tapered shape of grooves 56. Thus when the segments 50 are forced
into the grooves 56, the bevels and tapers coact to bring the pin
end 42 and box end 44 into the desired secured relationship with
each other.
By having the removable sections 36 on the legs 12, the stability
of vessel 10 can be improved by storing the removable section 36 on
the deck which lowers the center of gravity of vessel 10. Also this
reduces the dynamic loading on legs 12 during movement of vessel
10.
From the foregoing description, it can be seen that the improved
structure of the present invention provides a stable marine
drilling platform in varied conditions of the bottom of the body of
water at the drilling site. This structure makes available an
extended bearing area which may be secured around the lower end of
the legs to engage the bottom and thereby increase the stability of
the structure. Additionally, the tank footings which provide this
extended bearing area are releasably secured within recesses
defined in the vessel so that drag during movement through the
water is minimized and may be releasably secured to the recesses
when the legs are lowered through the vessel. The vessel has its
own propulsion and is provided with wells having guides for the
movement of the legs therethrough and the legs are slightly
enlarged at their lower ends to fit tightly into the lower guides
so that the legs and tank footings are held secure during movement
of the vessel to prevent vibration of the legs.
* * * * *