CA1066523A - Platforms for sea-bottom exploitation - Google Patents
Platforms for sea-bottom exploitationInfo
- Publication number
- CA1066523A CA1066523A CA293,938A CA293938A CA1066523A CA 1066523 A CA1066523 A CA 1066523A CA 293938 A CA293938 A CA 293938A CA 1066523 A CA1066523 A CA 1066523A
- Authority
- CA
- Canada
- Prior art keywords
- column
- base means
- base
- end region
- submerging
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
- E02B17/02—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
- E02B2017/0039—Methods for placing the offshore structure
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
- E02B2017/0056—Platforms with supporting legs
- E02B2017/0065—Monopile structures
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
- E02B2017/0056—Platforms with supporting legs
- E02B2017/0073—Details of sea bottom engaging footing
- E02B2017/0082—Spudcans, skirts or extended feet
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Revetment (AREA)
- Artificial Fish Reefs (AREA)
- Earth Drilling (AREA)
- Bridges Or Land Bridges (AREA)
- Foundations (AREA)
- Catching Or Destruction (AREA)
- Shovels (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A sea bottom off-shore exploitation platform comprising a column having an emerged portion and a base for said column, intended to be laid down and anchored on the sea bottom, wherein the improvement consists in that the base is designed in the form of as tank floating and supporting said column during transport ; said tank being sunk at the exploitation place.
A sea bottom off-shore exploitation platform comprising a column having an emerged portion and a base for said column, intended to be laid down and anchored on the sea bottom, wherein the improvement consists in that the base is designed in the form of as tank floating and supporting said column during transport ; said tank being sunk at the exploitation place.
Description
` ~0~5'~
The present in~ention relates to off-shore type platforms for oil-~i production units or installations ancl more particularly to platform~ of the type comprising at least one ool~n articulated on a base anchored to the sea bed whioh may be so designed as to allow for oil storage owing to its flui~-tightness.
Its purpose is mainly to permit the storage capaoity of the baae to be considerably increased and, at the same time, the sea carriage o~ the whole assembly to its place of submersion and anchoring to the sea bea to be facilitated.
It consists mainly in designing the base in the form of a tank of elongated shape capable of floating and of sufficient length to serve as a support for the column during the carriage to the anchoring location.
In the specific case where the column is artioulated on its base by ~- means of, in particular, a universal or Cardan joint, the articulation is advantageously provided in proximity to one of the small sides of the base i~ in the form of a rectangle or the like, so that during the carriage by sea f-" the column rests on the base lengthwise of the latter. During the ~ubmer-sion at the anchoring location use is made of ballasting means provided in ~- the base to cause the latter to first assume an inclined position until it contacts the ground, and then the platform is freed to allow it to assume : a substantially vertical position under the action of the ~hrust exerted by appro~riate floats. ~hereafter, there only remains to so balla~t the ba-se as to cause it to swing about its point of contac~ with the ground, un-til it entirely rests on the latter. ~-~ Of course several solutions may be contemplated in designing the base ; to be used as a tank.
According to a first alternatiYe it may be designea in the form of a t-~ vessel with heave-resisting walls.
Another alternatiYe consists in designing it in the form of a lighter container with means for allowing the access of sea water therein, during t'' the carriage, the floatability being obtained by means of floats internal and/or external to the wall of the said tank base.
In any case, when the submersion and anchoring to the ground axe com-plated (using any suitable ballasting means to ensure stability), there is obtained a large-capacity oil-storage tank, in combination, of course, with any valve system allowing the inflow of water or, on the contrary, ~ its expulsion by the oil to be stored, both i~ andf~m thetQ~k prQ~ d the j ~ floats if any.
r Apart from the above arran~ements the invention comprises some other 4 arrangements whirh are preferably used at the same time and will be refer-` red to more explicitely later.
,.,................................. 1 , --,'': - , . .. ~ . . ~ , :
--~ i s~;~
Also to be pointed out is the fact that the articu-lated column may not be used with ad~antage unless it is installed on development si-tes at relatively great depths of the order of one hundred meters or more. Indeed, such an articulated column must be provided with floats allowing it to be maintained in sub-stantially vertical relationship to its base lying on the sea bed.
In smaller depths the sizes of the floats must be increased to ;
ensure a sufficient righting moment on the column. This increased size of the floats, however, renders the column much more heave-. . ~ :
sensltlve, so that~/in medium depths of the order of from 40 to 60 m, the articulated column becomes much less advantageous.
,~,~, : .:
- On the other hand, the known system using mooring buoys -~ anchored by means of chains suffers from many drawbacks, including . ::: . .
- rapid wear of the chains and of the flexible oil-loading pipes.
~-~ Another type of column for sea bottom exploitation according to the present invention is remarkable in that it requires no moor-- ing chains for its installation, in that the oil-supply pipes ~ connected thereto are subjected to no strain or wear (they may ? be rigid) and in that it requires no righting floats, as an àrt--~ 20 iculated column does, since it is rigidly secured to its base.
- Such a platform structure or exploitation column is therefore ~--- an ideal solution on medium-depth exploitation or development ;~
sites.
` Specifically then, the present invention relates to a - ~
reservoir and articulated column assembly comprising elongated ~ ;
hollow base means for assuming a floating condition acting as a transporting vessel as well as for assuming a su~merged condi-. - .~ . .
tion resting on a sea bed and serving as a storage reservoir, said elongated base means having a length which is at least on the order of the depth of the sea at the location where the base ~. .
,. means is submerged to rest on the sea bed, elongated column means having a length which is at least almost as great as the length of said base means, said elongated column means having ~,,:: , ' opposed bottom and top ends, and connecting means fixedly car-ried by said base means at an upper surface thereof and ad~acent - one end region thereof, said connecting means being connected to ~: said bottom end of said column means for providing an articulated .. . .
, connection of said column means at sald bottom end thereof to sald base means according to which saicl column means is movable in all directions at said articulated connection with respect to said base means, so that said column means while connected by said con-~ necting means to said base means is capable of extending horizontal-:~i 10 ly along the upper surface of said base means with the top end of ~: said column means situated adjacent an end region of said base ~:~
. means which is opposed to said one end region thereof while said ; -base means assumes said floating condition acting as a vessel -`
for travelling to the location where said base means is to be . submerged while transporting said column means to the latter loc- :
ation, float means carried by said column means for causing the .,~,: -:"~
latter automatically to assume an upright condition when the base ~- means is submerged to engage the sea bed with said column means when in said upright condition having its top end situated above -~ .
20 the surface of the sea, so that upon submerging of the base means ~
.-~- to the sea bed at said location said column means will assume ~:
. . . : ~ .
~ its upright condition with its top end situated above the sur-;
face of the sea without changing the length of said column means, and ballast means carried by and operatively connected to said ;
:~ ' .. :' ' base means for controlling the submerging thereof.
. The present invention also specifically relates to a method for installing at an off-shore location an~assembly which ~:' -.
~: includes an elongated base means the length of which is on the . ;, . .
order of the depth of the sea at the latter location and an elon-Y~ 30 gated column means articulated to the base means at one end region ~.
, .: ,. .
.~` thereof, comprising the steps of initially placing said base means in a floating condition and transporting the column means ,.` connected to the base means to said off-shore location while said ~;
.~;..
~ ~ _3_ ;
~ -~0~6523 . .
base means is in said floating condition, and travels, while float-ing on the sea, to said off-shore location, said column means carrying float means for causing the column means to assume an ;~ :
upright conditlon upon submerging of the base means, and submerg- -~
ing said base means onto the sea bed at said off-shore location :~ :
while said float means provides for said column means an upright ~. . ,:
1 attitude extend.ing upwardly from said one end region of said base ,` means when the latter has been submerged, said oolumn means hav-ing a length sufficiently great for a top end thereof to be sit-uated above the surface of the sea when said base means is sub-merged.
,- The invention will be better understood and other pur-~: poses, details and advantages of the latter will appear more .
clearly from the following explanatory description of several exploitation platforms forming mooring and loading columns ac- ~.
`~ cording to the principles of the invention, given solely by way of example and made with reference to the appended non-limitat- ~ ~
. ive drawings wherein: --;
. Figures 1 and 2 are diagrammatic elevational and side , :.
views, respectively, of the whole articulated column and its base, - :`
designed to be installed on sea beds at relatively great depths ~ during sea transportation to the mooring location, -- Figures 3 and 4 are elevational views illustrating the `
. ~
; various operations involved in the installation of the column assembly on the sea bed, .
Figures 5 and 6 illustrate such an assembly in the !~ ~ transport position, according to a modification of the invention; -~
and - Figure 7 illustrates another modification of a gravity ;
-: , .
tank according to the invention.
According to a presently preferred form of embodiment ' of the invention, an off-shore platform of the type comprising ~:
-. columns articulated on a base by means of a universal or Cardan .'` ; '' .
.. , ~ - :
~ r 4 ''., ' ~', ", ;5'~3 joint, notably for oil-fields about 100 to 150 m deep, i5 designed and installed as follows or in a similar manner.
The base of such a platEorm is constituted by a tank capable of being used for oil storage on the sea bed, the said 1 tank being elongated in shape and its length being of the same ~ -,~ order of magnitude as the length of the articulated column, thus allowing the said tank to be used, during sea-borne transporta-,:~
tion, to support the column articulated thereto and resting on the said tank lengthwise thereof.
Sot according to the form of embodiment diagrammatically - illustrated in Figures 1 and 2, the said tank intended to serve '5~, as a base for the column is constituted by a parallelepipedic ~, fluid-tight container 1 the selected length L of which is a little greater than the height H of submersion at the anchoring loca-. - :
tion on the underwater ground.
The length L is therefore sufficient to allow the col-umn 2 to lie on the upper surface of the tank so as to be supported ` at its base end by a support 3 arranged in proximity to one of the smaller sides of the parallelepided, with the unversal or Cardan joint 4 possibly mounted from the outset, whereas it ~ - .
rests, at its other hand, on another temporary support such as 5. The platform is assumed to be equipped with tanks such as 6 and 7 serving as floats and possibly as ballasting means.
Moreover, it will be noted that the support 3 is ~n ; ;~
the form of a pedestal carried by the top surface of the base-v; reservoir 1 and extending upwardly to an elevation higher than ;
..... .
' the highest elevation of the top surface of the base-reservoir 1, with the universal joint 4 being situated at the top end of the :...
pedestal 3, so that in this way this universal joint 4 is sit- -`
uated at an elevation higher than the highest elevation of the top surface of the base-reservoir 1. In this way it is possible without diminishing the volume in the interior of the base-reservoir 1 and without complicating the structure thereof .:
~ 5~3 ., to accommodate the column 2 in the marlner shown in Figure 1 ex-;~ tending along the upper portion of the base-reservoir 1.
r;/ The said tank is provided at its ends with ballasting devices 8 and 9 intended to be used during the submersion as will be described later.
The tank, which must scrve as a means of sea-borne transportation between the shore building-yard and the drilling site or the storage location may be designed in various manners.
According to a first alternative, as assumed in Fig-10 ures 1 and 2, the tank (the length of which is therefore of the order of from 100 to 150 m or more) may be designed as a vessel whose upper portion is made fluid-tight. This solution may be perfectly contemplated, but it necessarily involves a heavy structure since the walls of the vessel must be capable of with- -' standing the heaving motion. -v ~ Another solution consists in ensuring the floatability of the tank not by itself but by means of appropriate float means provided either in the tank, as shown at 10 in Figures 5 and 6, ?
or above, as shown at 11 in Figure 6. These various methods may 20 be used jointly.
The latter solution is more advantageous, since the - -walls of the tank are not notably subjected to heave, of care is taken up to allow sea level to obtain within the tank through -- - inlets combined of course with valves, in which case the floats, " - constituted for example by cylinders 10 and/or 11, must be so ;~ designed as to support the apparent weight of the whole assembly.
In this case, the structure of the tank may be much lighter. -~
- The cylinders 10, 11 as well as the ballasting devices .. ~ . ~.
8 and 9 are combined with valve and pump systems to allow them to be emptied or filled with water at will.
A third solution is illustrated in Figure 7 where it is assumed that the structure of the tank consists of an assembly, e.g., welded, of longitudinal pipes 13 in combination with trans-.,j. ~:
- ~ -6- ~:
?J ~ S ~i 5 2 3 verse couples 14. Also in this case, the sea level can be al-lowed to obtain within the enclosed spaces thus formed (by means of suitable valves as in the previous case), so as to neutralize the heave effect, the floatability being obtained by means of pipes 13 either emptied or filled as described.
- Other forms of embodiment are of course possible.
:. .
In any case, whatever the form of embodiment adopted, the transportation and submission are effected as follows:
Figures 1 and 2 show the assembly constituted by the 10 tank and the column lying the length o* the upper wall of the said tank. The assembly floating in that position with a shallow draught is moved from the building workshop to the submersion site ~- either by means of an individual engine or by towage.
The ballasts 8 and 9 are empty or partially empty. So are the float cylinders where such floats are used. In this case, (Figures 5 to 7) sea water is allowed to enter the tank through suitably controlled valves or inlets.
The submersion is performed as follows. In a first stage, a preliminary lowering of the assembly is effe~ted by par-20 tially filling some of the ballast means 8, 9, while at the same ;~
tlme, of course, ensuring the transverse stability of the assembly owing to the said ballast means.
Thereafter, in a second stage, the filling is performed, more specially, of the ballast 8 which are nearest to the uni-versal joint 4, thus causing the tank to sink together with the ~- platform.
,.` A result of that operation, the tank lower end adjacent ,f~
~` to the bottom of the column sinks until it contacts the sea bed l 15 (Figure 3), whereas its other end continues to float. During s~ 30 - this movement, transverse stability is ensured by the unfilled ~ upper ballasts 9 or the unfilled cylindrical floats (Figures 5 ,- to 7) and also by the column main float 6 when submerged.
~-` In a third stage, the temporary attachment or fastening between the upper portion of the column and the tank 5 is released, r . 7 52~
;~
thus allowing the column to assume a substantially upright posi-tion under the action of its floats 7, while remaining connected - ;
to the tank through only the universal joint at its bottom end and so being allowed to oscillate freely tFigure 4).
In a four stage, the tank ballast chamber or chambers 9 opposite to the column bottom are filled. The tank then pivots about its lower edge 16 (Figures 3 and 4) which is in contact with the sea bed. The edge 16 thus bearing upon the sea bed along the full width of the tank ensures the transverse stability of the assembly during that time and prevents it from inclining lat- ~;
erally. The movement may thus continue until the tank lies en~
tirely on the sea bed. The articulated production column thus ;i-assumes its normal position (Figure 4).
It should be noted that, according to an advantageous ;
form of embodiment represented by phantom lines 161 in Figure 3, the lower end of the base tank may receive a rounded shape which, as is known both from experience and through calculations, allows the stability during the pivoting movement to be increased.
The tank being thus laid on the sea bed, it is to be noted that at that moment the said tank and its floats are filled ;;.: `; :
with water. It is furthermore desirable in order to ensure suf- - -~. . .
i ficient anchoring, to fill at least one of the compartment of the ,-~ tank or of the ballast chambers with sand, concrete or baryta ; ballast, whereas all the other compartments, floats or internal ~ spaces presently filled with water will be available later to ,`- receive storage oil.
To perform the storage use is made, as is known, of a ~' system of pumps and valves allowing the oil to enter by driving `~ the water before it.
In particular, these means will be connected to a pro-duction platform located at a distance and connected thereto by an oil pipeline. The platform 2 itself may be designed in the form of a loading platform allowing for ship mooring, according :; .~. ~, ~ - -8-~ , ~0~:i6~
. to the arrangements provided Eor, notably, in U.S. Patent No. . 3,980,037 in the name of the applicant company.
As su~ficiently appears from the foregoing description ~ of design and operation, the unit or installation according to 3 the invention offers over the already existing similar units a . great number of advantages:
- the possibility of maximum simplification o the opera-~` tions required to install the platform and its base, :~.
. - the possibility, owing to the considerable dimensions 10 of the base, the length of which is of the same order of magni-~ tude as the depth of the working site, of obtaining a large-size ~:~
s storage tank, ..
~. - and yet, the possibility of sea-borne transportation .
; with absolute safety owing to the relatively light floating as-sembly obtained, especially in those cases where water is allowed ; .
. to enter the floating tank during transportation, the floatability ,.being ensured by floats. ;~-.
Thus, the elongated base means 1 which is capable of serving as a storage reservoir as well as a floating transport-20 ing vessel, has the illustrated elongated configuration providing :
I this base means 1 with a length which is at least on the order of, . although actually somewhat longer than, the depth of the sea at .
-. the location where the base means is to be anchored to the sea bed, this base means 1 fixedly carrying at its upper surface . :.
adjacent one end region thereof the connecting means 3, 4 which ~:: serves to connect to the base means 1 the elongated column 2 in .--. a manner articulating the column 2 to the base means 1 for free movement in all directions with respect thereto with the column ,....... .
- means 2 being capable of extending along the upper surface of `~
;` 30 the base means 1 throughout the full length which the column . ..... means 2 has in its finally installed condition where the column ``
- means 2 will have an upper end region situated above the surface ~ :
.- of the sea. The column means 2 is releasably connected with the . ;.,,. . . . ... , ,,j ... . .. .
base means 1 at an end region of the latter distant from the end region where the connecting means 3, 4 is located by way of a releasable conecting means 5 so that when, due to operation of ~. :
the ballast means 8, which is carried by the base means 1, the structure has the condition indicated in solid lines in Figure 3, :
the releasable connecting means 5 can be opexated to release the column means 2 from the base means 1, so that the float means 6, 7 operatively connected to and carried by the column means 2 will then be operative to cause the column means 2 to assume its upright condition indicated in dot-dash lines in Figure 3. Thereafter, the ballast means 9 which is situated at an opposite end region .
of the base means 1 from the ballast means 8 can be operated to cause the base means to assume the position indicated in Figure 4, ~.
,.~: ., so that the base means 1 first turns downwardly in one direction ~;
to assume the position shown in solid lines in Figure 3, and ~:
~;; then turns downwardly in an opposite direction to assume the posi y~ tion shown in solid lines in Figure 4. --.J
.'.
~, 20 i:
~`' ~', '`~,:
;,'.'.
;' . ' , :
~.:` 30 ....
.,. :
': ~
'~ 10-:. - ~ .. , :
The present in~ention relates to off-shore type platforms for oil-~i production units or installations ancl more particularly to platform~ of the type comprising at least one ool~n articulated on a base anchored to the sea bed whioh may be so designed as to allow for oil storage owing to its flui~-tightness.
Its purpose is mainly to permit the storage capaoity of the baae to be considerably increased and, at the same time, the sea carriage o~ the whole assembly to its place of submersion and anchoring to the sea bea to be facilitated.
It consists mainly in designing the base in the form of a tank of elongated shape capable of floating and of sufficient length to serve as a support for the column during the carriage to the anchoring location.
In the specific case where the column is artioulated on its base by ~- means of, in particular, a universal or Cardan joint, the articulation is advantageously provided in proximity to one of the small sides of the base i~ in the form of a rectangle or the like, so that during the carriage by sea f-" the column rests on the base lengthwise of the latter. During the ~ubmer-sion at the anchoring location use is made of ballasting means provided in ~- the base to cause the latter to first assume an inclined position until it contacts the ground, and then the platform is freed to allow it to assume : a substantially vertical position under the action of the ~hrust exerted by appro~riate floats. ~hereafter, there only remains to so balla~t the ba-se as to cause it to swing about its point of contac~ with the ground, un-til it entirely rests on the latter. ~-~ Of course several solutions may be contemplated in designing the base ; to be used as a tank.
According to a first alternatiYe it may be designea in the form of a t-~ vessel with heave-resisting walls.
Another alternatiYe consists in designing it in the form of a lighter container with means for allowing the access of sea water therein, during t'' the carriage, the floatability being obtained by means of floats internal and/or external to the wall of the said tank base.
In any case, when the submersion and anchoring to the ground axe com-plated (using any suitable ballasting means to ensure stability), there is obtained a large-capacity oil-storage tank, in combination, of course, with any valve system allowing the inflow of water or, on the contrary, ~ its expulsion by the oil to be stored, both i~ andf~m thetQ~k prQ~ d the j ~ floats if any.
r Apart from the above arran~ements the invention comprises some other 4 arrangements whirh are preferably used at the same time and will be refer-` red to more explicitely later.
,.,................................. 1 , --,'': - , . .. ~ . . ~ , :
--~ i s~;~
Also to be pointed out is the fact that the articu-lated column may not be used with ad~antage unless it is installed on development si-tes at relatively great depths of the order of one hundred meters or more. Indeed, such an articulated column must be provided with floats allowing it to be maintained in sub-stantially vertical relationship to its base lying on the sea bed.
In smaller depths the sizes of the floats must be increased to ;
ensure a sufficient righting moment on the column. This increased size of the floats, however, renders the column much more heave-. . ~ :
sensltlve, so that~/in medium depths of the order of from 40 to 60 m, the articulated column becomes much less advantageous.
,~,~, : .:
- On the other hand, the known system using mooring buoys -~ anchored by means of chains suffers from many drawbacks, including . ::: . .
- rapid wear of the chains and of the flexible oil-loading pipes.
~-~ Another type of column for sea bottom exploitation according to the present invention is remarkable in that it requires no moor-- ing chains for its installation, in that the oil-supply pipes ~ connected thereto are subjected to no strain or wear (they may ? be rigid) and in that it requires no righting floats, as an àrt--~ 20 iculated column does, since it is rigidly secured to its base.
- Such a platform structure or exploitation column is therefore ~--- an ideal solution on medium-depth exploitation or development ;~
sites.
` Specifically then, the present invention relates to a - ~
reservoir and articulated column assembly comprising elongated ~ ;
hollow base means for assuming a floating condition acting as a transporting vessel as well as for assuming a su~merged condi-. - .~ . .
tion resting on a sea bed and serving as a storage reservoir, said elongated base means having a length which is at least on the order of the depth of the sea at the location where the base ~. .
,. means is submerged to rest on the sea bed, elongated column means having a length which is at least almost as great as the length of said base means, said elongated column means having ~,,:: , ' opposed bottom and top ends, and connecting means fixedly car-ried by said base means at an upper surface thereof and ad~acent - one end region thereof, said connecting means being connected to ~: said bottom end of said column means for providing an articulated .. . .
, connection of said column means at sald bottom end thereof to sald base means according to which saicl column means is movable in all directions at said articulated connection with respect to said base means, so that said column means while connected by said con-~ necting means to said base means is capable of extending horizontal-:~i 10 ly along the upper surface of said base means with the top end of ~: said column means situated adjacent an end region of said base ~:~
. means which is opposed to said one end region thereof while said ; -base means assumes said floating condition acting as a vessel -`
for travelling to the location where said base means is to be . submerged while transporting said column means to the latter loc- :
ation, float means carried by said column means for causing the .,~,: -:"~
latter automatically to assume an upright condition when the base ~- means is submerged to engage the sea bed with said column means when in said upright condition having its top end situated above -~ .
20 the surface of the sea, so that upon submerging of the base means ~
.-~- to the sea bed at said location said column means will assume ~:
. . . : ~ .
~ its upright condition with its top end situated above the sur-;
face of the sea without changing the length of said column means, and ballast means carried by and operatively connected to said ;
:~ ' .. :' ' base means for controlling the submerging thereof.
. The present invention also specifically relates to a method for installing at an off-shore location an~assembly which ~:' -.
~: includes an elongated base means the length of which is on the . ;, . .
order of the depth of the sea at the latter location and an elon-Y~ 30 gated column means articulated to the base means at one end region ~.
, .: ,. .
.~` thereof, comprising the steps of initially placing said base means in a floating condition and transporting the column means ,.` connected to the base means to said off-shore location while said ~;
.~;..
~ ~ _3_ ;
~ -~0~6523 . .
base means is in said floating condition, and travels, while float-ing on the sea, to said off-shore location, said column means carrying float means for causing the column means to assume an ;~ :
upright conditlon upon submerging of the base means, and submerg- -~
ing said base means onto the sea bed at said off-shore location :~ :
while said float means provides for said column means an upright ~. . ,:
1 attitude extend.ing upwardly from said one end region of said base ,` means when the latter has been submerged, said oolumn means hav-ing a length sufficiently great for a top end thereof to be sit-uated above the surface of the sea when said base means is sub-merged.
,- The invention will be better understood and other pur-~: poses, details and advantages of the latter will appear more .
clearly from the following explanatory description of several exploitation platforms forming mooring and loading columns ac- ~.
`~ cording to the principles of the invention, given solely by way of example and made with reference to the appended non-limitat- ~ ~
. ive drawings wherein: --;
. Figures 1 and 2 are diagrammatic elevational and side , :.
views, respectively, of the whole articulated column and its base, - :`
designed to be installed on sea beds at relatively great depths ~ during sea transportation to the mooring location, -- Figures 3 and 4 are elevational views illustrating the `
. ~
; various operations involved in the installation of the column assembly on the sea bed, .
Figures 5 and 6 illustrate such an assembly in the !~ ~ transport position, according to a modification of the invention; -~
and - Figure 7 illustrates another modification of a gravity ;
-: , .
tank according to the invention.
According to a presently preferred form of embodiment ' of the invention, an off-shore platform of the type comprising ~:
-. columns articulated on a base by means of a universal or Cardan .'` ; '' .
.. , ~ - :
~ r 4 ''., ' ~', ", ;5'~3 joint, notably for oil-fields about 100 to 150 m deep, i5 designed and installed as follows or in a similar manner.
The base of such a platEorm is constituted by a tank capable of being used for oil storage on the sea bed, the said 1 tank being elongated in shape and its length being of the same ~ -,~ order of magnitude as the length of the articulated column, thus allowing the said tank to be used, during sea-borne transporta-,:~
tion, to support the column articulated thereto and resting on the said tank lengthwise thereof.
Sot according to the form of embodiment diagrammatically - illustrated in Figures 1 and 2, the said tank intended to serve '5~, as a base for the column is constituted by a parallelepipedic ~, fluid-tight container 1 the selected length L of which is a little greater than the height H of submersion at the anchoring loca-. - :
tion on the underwater ground.
The length L is therefore sufficient to allow the col-umn 2 to lie on the upper surface of the tank so as to be supported ` at its base end by a support 3 arranged in proximity to one of the smaller sides of the parallelepided, with the unversal or Cardan joint 4 possibly mounted from the outset, whereas it ~ - .
rests, at its other hand, on another temporary support such as 5. The platform is assumed to be equipped with tanks such as 6 and 7 serving as floats and possibly as ballasting means.
Moreover, it will be noted that the support 3 is ~n ; ;~
the form of a pedestal carried by the top surface of the base-v; reservoir 1 and extending upwardly to an elevation higher than ;
..... .
' the highest elevation of the top surface of the base-reservoir 1, with the universal joint 4 being situated at the top end of the :...
pedestal 3, so that in this way this universal joint 4 is sit- -`
uated at an elevation higher than the highest elevation of the top surface of the base-reservoir 1. In this way it is possible without diminishing the volume in the interior of the base-reservoir 1 and without complicating the structure thereof .:
~ 5~3 ., to accommodate the column 2 in the marlner shown in Figure 1 ex-;~ tending along the upper portion of the base-reservoir 1.
r;/ The said tank is provided at its ends with ballasting devices 8 and 9 intended to be used during the submersion as will be described later.
The tank, which must scrve as a means of sea-borne transportation between the shore building-yard and the drilling site or the storage location may be designed in various manners.
According to a first alternative, as assumed in Fig-10 ures 1 and 2, the tank (the length of which is therefore of the order of from 100 to 150 m or more) may be designed as a vessel whose upper portion is made fluid-tight. This solution may be perfectly contemplated, but it necessarily involves a heavy structure since the walls of the vessel must be capable of with- -' standing the heaving motion. -v ~ Another solution consists in ensuring the floatability of the tank not by itself but by means of appropriate float means provided either in the tank, as shown at 10 in Figures 5 and 6, ?
or above, as shown at 11 in Figure 6. These various methods may 20 be used jointly.
The latter solution is more advantageous, since the - -walls of the tank are not notably subjected to heave, of care is taken up to allow sea level to obtain within the tank through -- - inlets combined of course with valves, in which case the floats, " - constituted for example by cylinders 10 and/or 11, must be so ;~ designed as to support the apparent weight of the whole assembly.
In this case, the structure of the tank may be much lighter. -~
- The cylinders 10, 11 as well as the ballasting devices .. ~ . ~.
8 and 9 are combined with valve and pump systems to allow them to be emptied or filled with water at will.
A third solution is illustrated in Figure 7 where it is assumed that the structure of the tank consists of an assembly, e.g., welded, of longitudinal pipes 13 in combination with trans-.,j. ~:
- ~ -6- ~:
?J ~ S ~i 5 2 3 verse couples 14. Also in this case, the sea level can be al-lowed to obtain within the enclosed spaces thus formed (by means of suitable valves as in the previous case), so as to neutralize the heave effect, the floatability being obtained by means of pipes 13 either emptied or filled as described.
- Other forms of embodiment are of course possible.
:. .
In any case, whatever the form of embodiment adopted, the transportation and submission are effected as follows:
Figures 1 and 2 show the assembly constituted by the 10 tank and the column lying the length o* the upper wall of the said tank. The assembly floating in that position with a shallow draught is moved from the building workshop to the submersion site ~- either by means of an individual engine or by towage.
The ballasts 8 and 9 are empty or partially empty. So are the float cylinders where such floats are used. In this case, (Figures 5 to 7) sea water is allowed to enter the tank through suitably controlled valves or inlets.
The submersion is performed as follows. In a first stage, a preliminary lowering of the assembly is effe~ted by par-20 tially filling some of the ballast means 8, 9, while at the same ;~
tlme, of course, ensuring the transverse stability of the assembly owing to the said ballast means.
Thereafter, in a second stage, the filling is performed, more specially, of the ballast 8 which are nearest to the uni-versal joint 4, thus causing the tank to sink together with the ~- platform.
,.` A result of that operation, the tank lower end adjacent ,f~
~` to the bottom of the column sinks until it contacts the sea bed l 15 (Figure 3), whereas its other end continues to float. During s~ 30 - this movement, transverse stability is ensured by the unfilled ~ upper ballasts 9 or the unfilled cylindrical floats (Figures 5 ,- to 7) and also by the column main float 6 when submerged.
~-` In a third stage, the temporary attachment or fastening between the upper portion of the column and the tank 5 is released, r . 7 52~
;~
thus allowing the column to assume a substantially upright posi-tion under the action of its floats 7, while remaining connected - ;
to the tank through only the universal joint at its bottom end and so being allowed to oscillate freely tFigure 4).
In a four stage, the tank ballast chamber or chambers 9 opposite to the column bottom are filled. The tank then pivots about its lower edge 16 (Figures 3 and 4) which is in contact with the sea bed. The edge 16 thus bearing upon the sea bed along the full width of the tank ensures the transverse stability of the assembly during that time and prevents it from inclining lat- ~;
erally. The movement may thus continue until the tank lies en~
tirely on the sea bed. The articulated production column thus ;i-assumes its normal position (Figure 4).
It should be noted that, according to an advantageous ;
form of embodiment represented by phantom lines 161 in Figure 3, the lower end of the base tank may receive a rounded shape which, as is known both from experience and through calculations, allows the stability during the pivoting movement to be increased.
The tank being thus laid on the sea bed, it is to be noted that at that moment the said tank and its floats are filled ;;.: `; :
with water. It is furthermore desirable in order to ensure suf- - -~. . .
i ficient anchoring, to fill at least one of the compartment of the ,-~ tank or of the ballast chambers with sand, concrete or baryta ; ballast, whereas all the other compartments, floats or internal ~ spaces presently filled with water will be available later to ,`- receive storage oil.
To perform the storage use is made, as is known, of a ~' system of pumps and valves allowing the oil to enter by driving `~ the water before it.
In particular, these means will be connected to a pro-duction platform located at a distance and connected thereto by an oil pipeline. The platform 2 itself may be designed in the form of a loading platform allowing for ship mooring, according :; .~. ~, ~ - -8-~ , ~0~:i6~
. to the arrangements provided Eor, notably, in U.S. Patent No. . 3,980,037 in the name of the applicant company.
As su~ficiently appears from the foregoing description ~ of design and operation, the unit or installation according to 3 the invention offers over the already existing similar units a . great number of advantages:
- the possibility of maximum simplification o the opera-~` tions required to install the platform and its base, :~.
. - the possibility, owing to the considerable dimensions 10 of the base, the length of which is of the same order of magni-~ tude as the depth of the working site, of obtaining a large-size ~:~
s storage tank, ..
~. - and yet, the possibility of sea-borne transportation .
; with absolute safety owing to the relatively light floating as-sembly obtained, especially in those cases where water is allowed ; .
. to enter the floating tank during transportation, the floatability ,.being ensured by floats. ;~-.
Thus, the elongated base means 1 which is capable of serving as a storage reservoir as well as a floating transport-20 ing vessel, has the illustrated elongated configuration providing :
I this base means 1 with a length which is at least on the order of, . although actually somewhat longer than, the depth of the sea at .
-. the location where the base means is to be anchored to the sea bed, this base means 1 fixedly carrying at its upper surface . :.
adjacent one end region thereof the connecting means 3, 4 which ~:: serves to connect to the base means 1 the elongated column 2 in .--. a manner articulating the column 2 to the base means 1 for free movement in all directions with respect thereto with the column ,....... .
- means 2 being capable of extending along the upper surface of `~
;` 30 the base means 1 throughout the full length which the column . ..... means 2 has in its finally installed condition where the column ``
- means 2 will have an upper end region situated above the surface ~ :
.- of the sea. The column means 2 is releasably connected with the . ;.,,. . . . ... , ,,j ... . .. .
base means 1 at an end region of the latter distant from the end region where the connecting means 3, 4 is located by way of a releasable conecting means 5 so that when, due to operation of ~. :
the ballast means 8, which is carried by the base means 1, the structure has the condition indicated in solid lines in Figure 3, :
the releasable connecting means 5 can be opexated to release the column means 2 from the base means 1, so that the float means 6, 7 operatively connected to and carried by the column means 2 will then be operative to cause the column means 2 to assume its upright condition indicated in dot-dash lines in Figure 3. Thereafter, the ballast means 9 which is situated at an opposite end region .
of the base means 1 from the ballast means 8 can be operated to cause the base means to assume the position indicated in Figure 4, ~.
,.~: ., so that the base means 1 first turns downwardly in one direction ~;
to assume the position shown in solid lines in Figure 3, and ~:
~;; then turns downwardly in an opposite direction to assume the posi y~ tion shown in solid lines in Figure 4. --.J
.'.
~, 20 i:
~`' ~', '`~,:
;,'.'.
;' . ' , :
~.:` 30 ....
.,. :
': ~
'~ 10-:. - ~ .. , :
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A reservoir and articulated column assembly com-prising elongated hollow base means for assuming a floating con-dition acting as a transporting vessel as well as for assuming a submerged condition resting on a sea bed and serving as a storage reservoir, said elongated base means having a length which is at least on the order of the depth of the sea at the location where the base means is submerged to rest on the sea bed, elongated column means having a length which is at least almost as great as the length of said base means, said elongated column means hav-ing opposed bottom and top ends, and connecting means fixedly carried by said base means at an upper surface thereof and adja-cent one end region thereof, said connecting means being connected to said bottom end of said column means for providing an articu-lated connection of said column means at said bottom end thereof to said base means according to which said column means is movable in all directions at said articulated connection with respect to said base means, so that said column means while connected by said connecting means to said base means is capable of extending hori-zontally along the upper surface of said base means with the top end of said column means situated adjacent an end region of said base means which is opposed to said one end region thereof while said base means assumes said floating condition acting as a ves-sel for traveling to the location where said base means is to be submerged while transporting said column means to the latter loca-tion, float means carried by said column means for causing the latter automatically to assume an upright condition when the base means is submerged to engage the sea bed with said column means when in said upright condition having its top end situated above the surface of the sea, so that upon submerging of the base means to the sea bed at said location said column means will assume its upright condition with its top end situated above the surface of the sea without changing the length of said column means, and ballast means carried by and operatively connected to said base means for controlling the submerging thereof.
2. The assembly of claim 1, and wherein a releasable connecting means releasably connects said column means to said base means at a location distant from said one end region there-of for maintaining said column means in a position extending along the upper surface of said base means while the latter assumes its floating condition as a transporting vessel and also during at least part of the submerging of said base means, said releas-able connecting means being operable to release said column means for movement to its upright position extending upwardly from said one end region of said base means.
3. The assembly of claim 2, and wherein said releas-able connecting means is situated adjacent said top end of said column means when releasably connecting said column means to said base means.
4. The assembly of claim 1, and wherein said ballast means includes a pair of ballast portions respectively situated adjacent the opposed end regions of said base means and capable of being independently operated for controlling the submerging of said base means.
5. An assembly as recited in claim 4, and wherein said portion of said ballast means adjacent said one end region of said base means is operatively connected thereto for first submerging said one end region of said base means until said one end region engages the sea bed.
6. An assembly as recited in claim 5, and wherein said one end region of said base means has a lower convexly curved surface for engaging the sea bed to provide for rocking movement of said base means with respect to the sea bed at said one end region of said base means.
7. An assembly as recited in claim 1, and wherein said elongated base means has a streamlined configuration similar to that of a boat.
8. An assembly as recited in claim 1, and wherein said base means includes hollow float means for controlling the float-ing and submerging of said base means.
9. An assembly as recited in claim 1, and wherein said base means is in the form of a plurality of elongated tubular mem-bers fixed to each other and forming an outer hull for said base means.
10. An assembly as recited in claim 1, and wherein said connecting means includes a pedestal fixedly carried by said base means at said one end region thereof and extending upwardly therefrom to an elevation higher than any part of said upper sur-face of said base means, said connecting means including a uni-versal joint carried by an upper end of said pedestal and connect-ing said bottom end of said column to said pedestal.
11. An assembly as recited in claim 10, and wherein the elevation of said universal joint is sufficiently above the highest part of said upper surface of said base means to provide for situating said column means horizontally along the upper surface of said base means in a condition where said column means in its entirety is situated at an elevation no lower than the uppermost part of the upper surface of said base means.
12. A method for installing at an off-shore location an assembly which includes an elongated base means the length of which is on the order of the depth of the sea at the latter loca-tion and an elongated column means articulated to the base means at one end region thereof, comprising the steps of initially placing said base means in a floating condition and transporting the column means connected to the base means to said off-shore location while said base means is in said floating condition and travels, while floating on the sea, to said off-shore location, said column means carrying float means for causing the column means to assume an upright condition upon submerging of the base means, and submerging said base means onto the sea bed at said off-shore location while said float means provides for said column means an upright attitude extending upwardly from said one end region of said base means when the latter has been sub-merged, said column means having a length sufficiently great for a top end thereof to be situated above the surface of the sea when said base means is submerged.
13. A method as recited in claim 12, and including the step of maintaining the column means releasably connected with the base means during at least part of the submerging thereof, and then releasing the column means after the base means has been partially submerged so that the float means will then cause the column means to assume its upright attitude while the submerging of the base means to the sea bed is completed.
14. A method as recited in claim 13, and including the step of first submerging to the sea bed that end region of said base means to which the bottom end of the column means is arti-culated, and then submerging the opposite end region of the base means to the sea bed, so that the base means tilts first in one direction and then in an opposite direction while being sub-merged.
15. A method as recited in claim 14, and including the step of releasing the column means to assume its upright atti-tude after submerging to the sea bed that end region of the base means to which the bottom end of the column means is articulated, and thereafter submerging the opposite end of the base means to the sea bed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA329,160A CA1068497A (en) | 1977-06-24 | 1979-06-06 | Platforms for sea-bottom exploitation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7719480A FR2395359A2 (en) | 1977-06-24 | 1977-06-24 | IMPROVEMENTS MADE TO THE SEA BASE OPERATION PLATFORMS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1066523A true CA1066523A (en) | 1979-11-20 |
Family
ID=9192554
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA293,938A Expired CA1066523A (en) | 1977-06-24 | 1977-12-28 | Platforms for sea-bottom exploitation |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5410502A (en) |
| AR (1) | AR217097A1 (en) |
| BR (1) | BR7708670A (en) |
| CA (1) | CA1066523A (en) |
| DE (1) | DE2758339A1 (en) |
| ES (1) | ES465480A1 (en) |
| FR (1) | FR2395359A2 (en) |
| GB (1) | GB1596400A (en) |
| NL (1) | NL7714334A (en) |
| NO (1) | NO148819C (en) |
| SU (2) | SU882421A3 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2143269B (en) * | 1983-07-13 | 1986-07-23 | Dinardo And Partners | Bridges for traversing waterways |
| GB2476276B (en) | 2009-12-18 | 2015-10-21 | Alstom Renewable Technologies | Foundation structure |
| GB201015218D0 (en) | 2010-09-13 | 2010-10-27 | Aubin Ltd | Method |
| FI20126086L (en) * | 2012-10-18 | 2014-04-19 | Stx Finland Oy | OFFSHORE STRUCTURE |
| WO2016042173A1 (en) * | 2014-09-15 | 2016-03-24 | Drace Infraestructuras, S.A. | Gravity foundation for the installation of offshore wind turbines and meteorological towers |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2924946A (en) * | 1954-12-03 | 1960-02-16 | Jerome L Goldman | Submersible barge for off-shore drilling |
| US2937006A (en) * | 1957-05-17 | 1960-05-17 | Sun Oil Co | Underwater drilling rig |
| DE1064002B (en) * | 1957-09-18 | 1959-08-27 | Saburo Okabe | System for opening up an oil field lying under water |
| GB819857A (en) * | 1958-03-07 | 1959-09-09 | Guy Anson Maunsell | Marine drilling tower |
| GB1366770A (en) * | 1972-04-04 | 1974-09-11 | Taylor Woodrow Const Ltd | Submersible structures |
| JPS49116801A (en) * | 1973-03-12 | 1974-11-08 |
-
1977
- 1977-06-24 FR FR7719480A patent/FR2395359A2/en active Granted
- 1977-12-23 GB GB53821/77A patent/GB1596400A/en not_active Expired
- 1977-12-23 NL NL7714334A patent/NL7714334A/en not_active Application Discontinuation
- 1977-12-26 SU SU782558953D patent/SU882421A3/en active
- 1977-12-26 SU SU772558953A patent/SU1064874A3/en active
- 1977-12-27 DE DE19772758339 patent/DE2758339A1/en not_active Ceased
- 1977-12-27 ES ES465480A patent/ES465480A1/en not_active Expired
- 1977-12-27 BR BR7708670A patent/BR7708670A/en unknown
- 1977-12-28 NO NO774476A patent/NO148819C/en unknown
- 1977-12-28 CA CA293,938A patent/CA1066523A/en not_active Expired
- 1977-12-29 JP JP15868277A patent/JPS5410502A/en active Granted
- 1977-12-30 AR AR270595A patent/AR217097A1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5410502A (en) | 1979-01-26 |
| DE2758339A1 (en) | 1979-02-22 |
| NO148819B (en) | 1983-09-12 |
| SU882421A3 (en) | 1981-11-15 |
| NO148819C (en) | 1983-12-21 |
| AR217097A1 (en) | 1980-02-29 |
| JPS5626727B2 (en) | 1981-06-20 |
| BR7708670A (en) | 1979-07-17 |
| NL7714334A (en) | 1978-12-28 |
| FR2395359B2 (en) | 1982-03-19 |
| SU1064874A3 (en) | 1983-12-30 |
| ES465480A1 (en) | 1978-09-16 |
| NO774476L (en) | 1978-12-28 |
| GB1596400A (en) | 1981-08-26 |
| FR2395359A2 (en) | 1979-01-19 |
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