United States Patent (19) (11 Patent Number: 4,812,080

Urquhart et al. (45) Date of Patent: Mar. 14, 1989

(54) OFFSHORE PLATFORMJACKET AND 4,679,964 7/1987 Blandford ....................... 405/227 X
METHOD OF INSTALLATION 4,721,416 1/1988 Gracia ................................. 40.5/227
(75) Inventors: Richard G. Urquhart, Dallas; Adel S. Primary Examiner-Dennis L. Taylor
Tawfik, Houston, both of Tex. Attorney, Agent, or Firm-Michael E. Martin
(73) Assignees: Atlantic Richfield Company, Los 57 ABSTRACT
Angeles, Calif.; Brown & Root, Inc., Ajacket for supporting an offshore platform or the like
Houston, Tex. comprises at least one vertical column member, later
(21) Appl. No.: 77,481 ally and vertically spaced guide sleeves for piles to be
22 Filed: Jul. 24, 1987 driven into the sea floor and lateral bracing connecting
the guide sleeves to the column member. The jacket
(51) Int. Cl." .............................................. EO2B 17/00 may be installed with the piles prepositioned extending
(52) U.S. Cl. .................................... 405/227; 405/204; through the guide sleeves and temporarily secured
405/224 thereto until the jacket and pile assembly is in position
(58) Field of Search ............... 405/227, 203, 204, 195, on the sea floor and ready for pile driving. The vertical
405/205, 206, 207, 208, 224, 225 column member may receive a pile which may include
(56) References Cited a well casing. A method of installation for the jacket
may include drilling a well through the column member
U.S. PATENT DOCUMENTS after installation of the jacket and securement to the sea
4,422,805 12/1983, Sweatman ....................... 405/227 X floor by the piles which extend through the guide
4,493,592 l/1985 Knox ............................... 405/227X sleeves.
4,558,973 12/1985 Blandford ....................... 405/227 X
4,576,523 3/1986 Smetak ................................ 405/227 11 Claims, 4 Drawing Sheets
U.S. Patent Mar. 14, 1989 Sheet 1 of 4 4,812,080

A/G. 1
U.S. Patent Mar. 14, 1989 Sheet 2 of 4 4,812,080

(IsleMarietaristests Cistest(EE(EIts
U.S. Patent Mar. 14, 1989 Sheet 3 of 4 4,812,080
U.S. Patent Mar. 14, 1989 . Sheet 4 of 4 4,812,080
 1.
4,812,080
2
In accordance with another aspect of the present
OFFSHORE PLATFORM JACKET AND METHOD invention, there is provided an improved method of
OF INSTALLATION installing an offshore platform support jacket and the
like comprising a structure which serves as lateral brac
BACKGROUND OF THE INVENTION 5 ing for platform deck support piles and other column
1. Field of the Invention members, such as a well casing. In one preferred
The present invention pertains to a tower or so-called method of installation of the jacket, piling is preinstalled
jacket structure and a method of installation for Sup through pile guide sleeves on the jacket and each pile is
porting offshore oil and gas operations platforms. temporarily secured to the sleeves so that the jacket
2. Background 10 itself in assembly with the piling may be transferred
A wide variety of offshore support structures have from a barge or similar vessel to a selected position on
been developed for use in conjunction with the devel the sea floor, followed by removal of the temporary
opment and production of oil and gas from offshore connection between the piling and the jacket structure
wells. In water depths up to several hundred feet fixed and driving of the piling into its final position for sup
support structures known as "jackets' have been con 15 porting a deck or the like.
structed in the form of self-supporting, skeletal towers, Those skilled in the art will recognize further advan
basically comprising three or more vertical column or tages and superior features of the present invention
leg members which are interconnected by suitable brac upon reading the detailed description which follows in
ing. Such towers are typically secured to the sea floor conjunction with the drawing.
by piling which is driven through the hollow leg mem 20 BRIEF DESCRIPTION OF THE DRAWING
bers and secured to the leg members before installation FIG. 1 is a perspective view of an offshore platform,
of a deck or other structure to be supported by the including an improved support structure or jacket in
jacket.
The structural requirements of prior art jackets has 25 accordance with the present invention;
FIG. 2 is a view in somewhat schematic form show
been such that in order for the jackets to be self support ing one step in an improved method of installing a plat
ing prior to and after installation, that the plural leg form jacket in accordance with the present invention;
members are all made up of relatively large diameter FIG. 3 is a view showing the piling being installed
metal pipe, thereby adding to the weight and cost of the through
jacket structure. The bracing required to support the 30 FIG. 4the is a
jacket guide sleeves;
view showing a well being drilled through
pipe type leg members is also required to be relatively the column member of the installed jacket;
complex and the overall structure thereby is subject to FIG. S is a view showing the completed jacket and
greater wave loading when installed in the sea. In es platform installation;
sence, the construction of prior art jackets is such that FIG. 6 is a detail view showing one embodiment of a
the leg members are not efficiently utilized. The jacket 35 temporary
structure itself serves primarily as a guide and lateral guide sleevesconnection
for use
between a pile and one of the
during one method of installing the
support for piling which bears the actual vertical load of jacket;
the deck or other structure to be supported above the FIG. 7 is a perspective view of a first alternate em
surface of the sea.
bodiment of a jacket in accordance with the present
SUMMARY OF THE INVENTION 40 invention; and
The present invention provides an improved jacket FIG. 8 is a perspective view of a second alternate
or tower structure particuarly adapted for installation embodiment of a jacket in accordance with the present
invention.
on the sea floor for supporting a deck or similar struc
ture above the sea surface. In accordance with an im 45 DESCRIPTION OF PREFERRED
portant aspect of the present invention, an offshore EMBODIMENTS
platform support jacket is provided which is adapted to In the description which follows, like parts are
receive two or more piles as part of the support struc marked throughout the specification and drawing with
ture, which piles are extended through guide sleeves the same reference numeral, respectively. The drawing
formed at the nodes of the jacket braces and which piles 50 figures are not necessarily to scale and certain features
comprise at least some of the column or leg members of of the invention may be shown exaggerated in scale or
the jacket. in somewhat schematic or simplified form in the interest
In particular, in one preferred configuration of the of clarity and conciseness.
jacket, a generally vertical column member is provided Referring to FIG. 1, there is shown a completed
for receiving a pile or a well casing extending through 55 installation of an offshore platform utilizing the tower
the column member and into the sea floor. The column or jacket and method of the present invention. The
member is adapted to support plural guide sleeves by an offshore platform structure is generally designated by
arrangement of lateral and diagonal bracing and the numeral 10 and includes a platform deck 12 having
wherein the guide sleeves are adapted to receive elon depending support legs 14 and 16 which are suitably
gated piles which are operable to be driven through the braced by diagonal braces 18 depending also from the
sleeves and into the sea floor to form support structure deck 12. The deck 12 and its depending support legs 14
for a platform deck or the like. In effect, the jacket and 16 are shown in somewhat simplified form and
structure comprises lateral bracing for the piles. In this virtually all of the structure normally supported by the
way, the jacket structure is considerably lighter in deck has been eliminated from the drawing since it
weight than conventional skeletal frame jacket struc 65 forms no part of the present invention. Suffice it to say
tures with plural spaced apart column members, wave that the deck 12 may be adapted to support conven
loading on the jacket is reduced and the cost of manu tional production processing equipment for oil and gas.
facturing the jacket is also reduced. Moreover, the deck may support conventional handling
 4,812,080
3 4.
equipment, such as a crane, not shown, and may support be approximately 40 feet. The guide sleeves 26, 28, 30
a helicopter landing pad, also not shown. and 32, are preferably approximately 30 inch outside
The deck 12 is supported above the surface 20 of a diameter tubular steel sleeves having a nominal wall
body of water by a unique support structure comprising thickness of about 1.50 inches. The column member 24
a pile guiding and bracing jacket or tower 22 which is also constructed of the same structural steel tubular
includes a substantially vertically extending hollow material. The lateral braces 34, 36 and 38 are approxi
tubular column member 24 and spaced apart pile guid mately 16.0 inches outside diameter, 0.375 inch wall
ing sleeves 26, 28, 30 and 32. The sleeves 26, 28, 30 and thickness structural steel.
32 are suitably aligned with each other and canted at an The overall length of the guide sleeves 26, 28, 30 and
angle from the vertical at a slope of about one foot of 10 32 are each no more than about ten feet and are prefera
horizontal batter for approximately each seven to bly about seven feet long. As illustrated in FIG. 1, the
twelve feet of vertical run. The sleeves 26 and 28 are platform jacket is dimensioned such that the upper set
interconnected with each other and with the column of guide sleeves 26 and 28 extend above the surface of
member 24 by respective lateral braces 34 and 36 and by the water sufficiently that a typical expected wave zone
diagonal braces 38. The braces 34, 36 and 38 are con 15 is unlikely to encounter the upper set of lateral braces 34
nected to the respective sleeves at so-called "node and 36. Moreover, by eliminating column members
points' so that a set of braces 34 and 36 are coplanar. A which extend the full length of the jacket between the
second set of braces 34 and 36 is spaced from the first set upper and lower sets of braces and for housing the piles
and interconnect the sleeve 30 and 32 with each other 50 and 52, the weight of the jacket is substantially re
and with the member 24. The lower set of braces 34 and 20 duced and the expense of manufacturing the jacket is
36 may be interconnected by suitable gussets or mud likewise reduced. Although the piles 50 and 52 may be
mats 46. Moreover, suitable grating or decking 48 may of a heavier design, the overall structure or system will
be supported by and between the upper set of braces 34 be lighter than prior art jackets.
and 36, respectively. Referring now to FIGS. 2 through 5, one preferred
In the particular installation of the platform 10, the 25 method of installation of the jacket 22 is illustrated in
jacket 22 forms lateral support means for elongated somewhat schematic form. In the preferred method of
piles 50 and 52 which have been driven through the installation illustrated in the drawing figures, the piles
sleeves 26 and 30 and 28 and 32, respectively, and into 50 and 52 are preinstalled through the guide sleeves 26
the sea floor 53 to a sufficient depth so as to be capable and 30, and 28 and 32, respectively. The piles 50 and 52
of supporting the deck 12 and any structure supported 30 are each temporarily secured to their respective guide
by the deck. The platform 10 also includes a third pile sleeves by suitable retaining means such as illustrated in
56 which extends through the column member 24 and is FIG. 6. Referring briefly to FIG. 6, there is illustrated a
suitably driven into the sea floor. The pile 56 may, in detail of one method of securing the pile 52 to the guide
fact, comprise a casing for an oil or gas well, which sleeve 28 temporarily. A plurality of somewhat U
casing extends to the deck 12 and terminates in a well 35 shaped dog members 72 are welded to the outside sur
head 58. In the installation illustrated in FIG. 1, the piles face of the sleeve 28 and also to the outside surface of
50 and 52 are suitably secured to the guide sleeves, 26 the pile 52. This type of temporary connection is suit
and 28 by welds 60 which may be formed between the able for lifting and handling the piles when preinstalled
piles and the upper transverse edges of the respective in the sleeves, together with the jacket structure itself as
guide sleeves once the piles have been driven to their an integral unit. When the jacket 22 has been set on the
final depth. Welds 61 may also be provided between the sea floor with the piles 50 and 52 already extended
guide sleeves 30 and 32 and the respective piles 50 and through the guide sleeves, the dogs 72 may be removed
52 depending on pile weight and the cost of making or at least released from their connection with the piles
welds underwater. Suitable welds, not shown, may also by flame cutting or the like to free the piles for driving
be formed between the piles 50 and 52 and the lower 45 into the sea floor.
edges of the respective guide sleeves, 26, 28, 30 and 32. Referring to FIG. 2, the jacket 22, with the piles 50
In like manner, the casing 56 may also be secured to the and 52 preinstalled in the respective guide sleeves, may
column member 24 by a weld 62 or other suitable be transported to the installation site on a barge 80 and
means. The pile guide sleeves 26, 28, 30 and 32 may be prepared for installation on the sea floor by securing the
provided with guide funnels, not shown in FIG. 1, 50 jacket to a barge mounted crane 82. The crane 82 is then
which are useful in certain methods of installation of the operated to lift the jacket 22 in assembly with the piles
piles in conjunction with the improved jacket structure 50 and 52 off of the barge 80 while the barge 80 is then
22. The column member 24 may also be provided with moved away and the jacket 22 set down on the sea floor
Suitable funnel entry type guide sleeves 64 and 66 se into the position illustrated in FIG. 3. With the jacket 22
cured to the column member for guiding and laterally 55 in position on the sea floor 53 the dogs 72 are removed
Supporting a well casing or a pile extending substan and the piles driven into the seabed 83. Additional piles
tially parallel to the column member 24. The platform may be connected seriatum with the piles 50 and 52,
deck 12 is suitably secured to the piles 50 and 52 by such as the pile 51 illustrated secured to the upper end
welding the legs 14 and 16 to the respective piles 52 and of the pile 50, and driven into the sea floor through the
50 at welds 65 and 67. The deck 12 may also be secured 60 respective sets of sleeves. FIG. 3 illustrates a pile driver
to the casing type pile 56 in a suitable manner at the 86 suspended from the crane 82 or a similar apparatus,
deck itself. not shown, for driving the pile assembly 50, 51 to re
The particular installation illustrated in FIG. 1, in fusal or a predetermined depth. Accordingly, each of
cluding the jacket 22, is adapted for installation in water the piles 50 and 52 may be driven into the sea floor and
depths of up to about 50 feet above the mudline. For a 65 extension piles such as the pile 51 secured to each of the
jacket supporting a platform having approximately 50 original piles as required, depending on the total pile
tons gross weight, the lateral span between the column depth required. During the operation of pile driving as
member 24 and the guide sleeves 26, 28, 30 and 32 may illustrated in FIG. 3, a pile, not shown, may also be
 4,812,080
5 6
driven through the column member 24 to secure the the present invention is illustrated and generally desig
jacket 22 by a total of three piles. After the piles are nated by the numeral 130. The jacket 130 is of a configu
driven to final position, welds between the piles and the ration which may be preferred for embodiments which
guide sleeves, such as the welds 60, 61 and 62, shown in must be installed in water depths greater than 100 feet.
FIG. 1, are formed to secure the jacket and pile assem 5 The jacket 130 includes means forming a full length
bly. substantially vertical column member 132, an upper set
Further in accordance with one preferred method of of pile guide sleeves 134 and 136 and a lower set of pile
installing the jacket 22 and the platform 10, the jacket is guide sleeves 138 and 140. The guide sleeves 134 and
also anchored to the sea floor 53 by the well casing 56 136 are interconnected to each other and to the column
which is installed during a drilling operation to drill a 10 member 132 by lateral braces 142 and 144 and diagonal
well through the column member 24. As illustrated in braces 146. The guide sleeves 138 and 140 are intercon
FIG. 4, after installation of the jacket 22 to the extent nected to each other and to the column member 132 by
illustrated in FIG. 3, the crane 82 is moved off site and lateral braces 148 and 150 and diagonal braces 152. Due
a drilling rig 90 is moved into position for drilling a well to the substantial span between the upper set of guide
92 into the sea bed 83 through the column member 24. 15 sleeves 134 and 136 and the lower set 138 and 140 an
The drilling rig 90 is exemplary and is shown as a jack intermediate set of guide sleeves 135 and 137. The guide
up type rig with a cantilever derrick and floor assembly sleeves 135 and 137 are interconnected and their posi
91 arranged such that the drilling rig may move into tions strengthened by lateral braces 158 and 160 and
position over the jacket 22 for performing drilling oper diagonal braces 162. The pattern of guide sleeves and
ations through the column member 24. As part of the braces illustrated for the jacket 130 may also be re
drilling operation, the casing 56 is installed in a conven peated if the overall length or height of the jacket is to
tional manner and welded to the column member 24 to
further secure the jacket 22 in its working position. be extended for greater water depths. Both of the jack
After the drilling operation is complete for the well ets 100 and 130 enjoy the advantages of the jacket 22 as
92, the rig 90 is moved offsite and a suitable crane barge 25 set forth herein and their method of installation may be
or the like is moved into position for installing the plat similar in that piles may be preinstalled in the guide
form deck 12 whereby the completed installation is sleeves before setting the jacket on the sea floor or after
obtained, as illustrated in FIG. 5 and also FIG.1. Alter positioning of the jacket. In those instances when the
natively, the jacket 22 may be set in place on the sea piles are not preinstalled, each of the guide sleeves is
floor 53 by the crane 82 without the piles already in the 30 provided with a suitable upward facing guide funnel
guide sleeves wherein the crane would then hoist and 163, FIG. 8, to facilitate installation of the piling as
set each pile through its respective set of sleeves prior to illustrated.
a driving operation. Although preferred embodiments of an improved
Referring now to FIG. 7, one alternate embodiment offshore platform support jacket and unique methods of
of a platform jacket in accordance with the present 35 installation of same have been described herein, those
invention is illustrated and designated by the numeral skilled in the art will recognize that various substitu
100. The platform jacket 100 is adapted for installation tions and modifications may be made to the specific
in water depths ranging up to about 100 feet and in embodiments shown and described without departing
cludes spaced apart pile guide sleeves 102,104,106 and from the scope and spirit of the invention as recited in
108 through which suitable piles 110 and 112 may be the appended claims.
driven or preinstalled in the same manner as provided What we claim is:
for the jacket 22, Pile entry guide funnels 109 may be 1. A support jacket for supporting a deck of an off
provided on the sleeves 104 and 108 if the piles 110 and shore platform and the like above the surface of a body
112 are not preinstalled. The jacket 100 also includes of water, said jacket comprising:
means forming a vertical column member 114 through 45 a single substantially vertically extending hollow
which a pile 116 or well casing may be driven after column member extending above said surface for
installation of the jacket in its working position on the receiving means forming a first elongated pile ex
sea floor. tending through said column member;
The jacket 100 includes lateral braces 118 and 120 a plurality of vertically and laterally spaced guide
which are adapted to tie the guide sleeves 104 and 108 50 sleeves connected to said column member only by
together and to the column member 114. The vertical at least one of diagonal and generally horizontal
spacing of the guide sleeves 102 and 106 from the guide extending brace means, said guide sleeves being
sleeves 104 and 108 is such that respective sets of diago arranged to receive and guide respective second
nal braces 122 and 124 are provided which extend from and third elongated piles and for laterally bracing
a common node point 125 to the respective sets of guide 55 said second and third piles for supporting said deck
sleeves 104 and 108, and 102 and 106. Lateral braces 127 above said jacket, said guide sleeves including a
and 129 interconnect the guide sleeves 102 and 106 and first pair of laterally spaced part guide sleeves dis
Support grating 131. posed generally adjacent one end of said column
The jacket 100 may be installed in accordance with member and a second pair of said guide sleeves
the method described for the jacket 22 for configura 60 laterally spaced apart and adjacent the other end of
tions which are to be installed in water depths up to Said column member, each pair of said guide
about 100 feet. Moreover, the pattern of the structure of sleeves being interconnected to said column men
the guide sleeves, lateral braces, and diagonal braces for ber by said brace means, said guide sleeves extend
the jacket 100 may be repeated for jackets of greater ing generally vertically only a short distance from
overall height for installation in water depths exceeding 65 points of connection with said brace means to mini
100 feet. mize the weight of said jacket and reduce fores
Referring now to FIG. 8, a second alternate embodi imposed on said jacket due to wave action, and
ment of a platform support jacket in accordance with Selected ones of said guide sleeves being adapted to
 4,812,080
7 8
be secured to said second and third piles, respec support mat means secured to said lateral bracing of
tively. said lower guide sleeves for supporting said jacket
2. The jacket set forth in claim 1 wherein: during installation thereof on the sea floor.
said column member includes means forming spaced 8. The platform set forth in claim 5 wherein:
apart guide sleeves for guiding at least one of a well
5 said jacket and at least two piles are preassembled and
casing and a pile for securing said jacket in position temporarily secured to each other by extending
said piles through respective sets of said guide
for supporting said deck. sleeves and securing said piles to said guide sleeves
3. The jacket set forth in claim 1 including: for movement between a point of assembly of said
guide funnel means disposed on selected ones of said 10 piles with said jacket and the place of installation of
guide sleeves at the upper ends thereof, respec said jacket on the sea floor.
tively, for guiding a pile during installation thereof 9. A method for installing an offshore jacket for sup
through said guide sleeves, respectively. porting a platform deck and the like with respect to the
4. The jacket set forth in claim 1 including: sea floor comprising:
at least one pair of guide sleeves intermediate an
15 providing a piling support jacket comprising at least
one generally vertically extending tubular column
upper pair of guide sleeves and a lower pair of member and at least a pair of guide sleeves laterally
guide sleeves for stabilizing said piles. spaced apart from each other and from said column
5. An offshore platform and supporting jacket for oil member and interconnected to said column men
and gas operations comprising: ber by bracing means;
a platform jacket disposed substantially above the sea said guide sleeves being positioned such as to extend
floor, said jacket including a single generally verti above the sea surface when said jacket is installed
cal tubular column member, means forming a first on said sea floor;
elongated pile extending through said column 25 providing at least a pair of elongated piles extending
member and into said sea floor and secured to said through said guide sleeves and at least temporarily
column member at least two spaced apart guide secured to said guide sleeves, respectively;
transporting said jacket in assembly with said piles to
sleeves disposed laterally spaced from each other a point of installation on the sea floor and setting
and from said column member adjacent an upper said jacket in assembly with said piles on said sea
end of said column member and interconnected to 30 floor;
said column member only by at least one of sub disconnecting said piles from said jacket to the extent
stantially lateral and diagonal extending bracing, that said piles may be driven through said guide
and at least a pair of lower guide sleeves disposed sleeves into the sea floor;
laterally spaced apart form each other and from driving said piles into the sea floor;
said column member adjacent a lower end of said
35 securing said piles to respective ones of said guide
column member and also interconnected to said sleeves;
positioning a drilling rig over said column member
column member only by at least one of substan and drilling a well through said column member
tially lateral and diagonal extending bracing; including installing casing means through said col
elongated second and third pies extending through umn member; and
said upper guide sleeves and said lower guide securing said casing means to said column member.
sleeves, respectively, and into said sea floor, each 10. The method set forth in claim 9 wherein:
of said second and third piles being secured to at the step of securing said piles to said guide sleeves
least one of said guide sleeves, respectively; and 45 includes welding said piles to said guide sleeves,
a platform deck supported on and above said piles. respectively.
11. The method set forth in claim 9 wherein:
6. The platform set forth in claim 5 wherein: the step of securing said casing means to said column
said first pile comprises a well casing extending to a member comprises welding said casing means to
wellhead on said platform deck. said column member.
7. The platform set forth in claim 5 including: SO k k : :k k

55

60
 UNITED STATES PATENT AND TRADEMARK OFFICE
CERTIFICATE OF CORRECTION
PATENT NO. : 4,812,080
DATED : March 14, 1989
INVENTOR(S) : Richard G. Urquhart and Adel S. Tawfik
It is certified that error appears in the above-identified patent and that said Letters Patent is hereby
Corrected as shown below:

Column 6, 1ine 66, delete "fores" and insert --- forces ---.

Column 7, 1ine 40, delete "pies' and insert --- piles ---.

Signed and Sealed this

Nineteenth Day of September, 1989
Attest:

DONALD J. QUIGG

Attesting Officer Commissioner of Patents and Tradenotrks