GB2203782A - An arrangement in connection with a drilling platform - Google Patents
An arrangement in connection with a drilling platform Download PDFInfo
- Publication number
- GB2203782A GB2203782A GB08808474A GB8808474A GB2203782A GB 2203782 A GB2203782 A GB 2203782A GB 08808474 A GB08808474 A GB 08808474A GB 8808474 A GB8808474 A GB 8808474A GB 2203782 A GB2203782 A GB 2203782A
- Authority
- GB
- United Kingdom
- Prior art keywords
- drilling
- extension unit
- platform
- arrangement
- existing
- 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.)
- Granted
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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
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Earth Drilling (AREA)
- Foundations (AREA)
Abstract
The invention relates to an arrangement and a method for providing extended drilling programs in connection with existing fixed drilling and production platforms. Instead of providing a completely new, fixed installation with complete equipment for drilling and production, the present invention suggests the use of at least one drilling extension unit (11) comprising a plurality of conductor pipes (12a...12n) contributing to the structural strength of the extension unit (11) and allowing for drilling to be performed therethrough. By including extended skid beams (10c, 10d) in the extension unit (11) and by the connection thereof to the existing skid beams (10a, 10b) on the fixed platform (1), the existing drilling module (6) including derrick (7) and drilling equipment can be transferred to the extension unit (11) without the use of hoisting equipment for thereby extending the drilling programs by means of existing drilling equipment of the fixed platform structure (2). <IMAGE>
Description
An arrangement in connection with a drilling platform
The present invention relates to an arrangement in connection with a drilling platform, especially a substantially permanently installed offshore drilling platform.
The invention also relates to a method for providing additional drilling wells for a drilling platforn, especi-'- ly a substantially permanently installed offshore drills platform.
In connection with substantially permanently installed offshore constructions, in which both drilling and production takes place there wrll sooner or Later arise need for extended drilliung programs, i.e. extended drillin in the vicinity of the drilling area of the fixed drilling platform.
Previous solution. suggest that another fixed platform including at least expensive drilling equipmen installed in the vicinity of existing fixed dri.ilisg platforms for thereby constituting a completely equipped drilling unit including derrick, hoisting means, storage facilities for drilling pipes etc. as ell as conductor pipes extending between the drilling deck and the sea bed on which the drilling unit is permanently anchored.
An object of the present invention is to provide an arrangement and a method which in a simple and inexpensive manner can meet the need for extended drilling programs on existing fixed drilling platforms.
Another object of the present. invention is to provide an arrangement and a method which replace the need of a new, fixed installation with complete and expensive equipment for drilling and production in connect ion with an extended drilling program.
A further object of the present invention is to provide an arrangement and a method in which existing drilling equipment on a fixed installation can be utilized for extended drilling programs.
Yet another object of the present invention is to provide an arrangement and a method in which an existing drilling module can be transported for the extended drilling programs independently of heavy and expensive hoisting devices.
till another object of the invention is to provide an arrangement and a method for extended drilling programs which require a mInimum of structural elements since existing trilling equipment can be utilized to a substantial decree for the implementation thereof.
The above and other objects are achieved in an arr2nse,.e.: as stated In the preamble of the main claim, which according to the present inventIon is characterized in that the platform includes at least one drilling extension unit, including a plurality of conductor pipes contributing to the structural strength of the extension unit and allowing for drilling to be performed therethrough.
Preferably, the extension unit can be substantially composed of a truss structure, including said conductor pipes, it being understood that the extension unit can either take the form of a tripod in which the third pod is composed of said conductor pipes, or it could take the form of a substantial rectangular structure including said conductor pipes.
In order to allow for the utilization of existing drilling equipment of the fixed installation said extension unit may approprIately comprise means for being connected to the permanently installed main platform, for example by extended skid beams allowing for the displacement of the drilling module between said main platform and any extension unit.
To further extend the flexibility of the extension unit this may include means for quick connection and disconnection to any existing drilling and production platform.
This flexibility may be further extended by making the extension unit self-supported but including therein means for being linked to the deck of an existing main platform to allow transfer of a drilling module.
In order to reduce the amount of steel in the extension lt to a m:.nimum, the extension unit may preferably be attached to the main platform structure, for example by having the supporting legs thereof braced to the existing structure, or example by means of clamping connections.
It should be noted that the structure of the extend on may comprise vertical legs extending to the bottom. and including one or two bays or supporting trarnes.
Further, It t s to be understood that the bottom bay may provide a transition between the tower aid or the group or conductors, and a large base should be sizes to minimize pile requirements.
A method according to the present invention for providing additional drIllIng wells for a drilling platform, especially a substantially permanently installed offshore drilling platform, is characterized by providing a drilling extension unit in which a plurality of drilling conductor pipes are included to constitute a substantial part of said extension unit and allowing for drilling to be performed therethrough.
The extension unit may be constructed close to or on shore and may be loaded out and transported to the area of the existing drilling and production platform in a substantially vertical position, said extension unit then being lifted in position at the installed platform.
As an alternative the extension unit may be transported horizontally and upended using two cranes, this structure creating the greatest foundation requirements.
The flouting of said extension unit is facilitated by means of quick connect/disconnect links relative to the existing platforms.
The invert ion will now be further described with reference to the appended drawings illustrating preferred embodiments of the arrangement according to the present invention arc being an aid In explaining the method involved therein.
Figure 1 is a side view of a fixed offshore platform ircuding a derrick and heavy hoisting devices.
FIgure 2 is a perspective view of the drilling platfcrn according to Figure 1.
Figure 3 is a perspective view of a first embodiment of a drilling extension unit according to the present invention.
Figure 4 is â side view similar to Figure 1, but including the drilling extension unit of Figure 3.
Figure 5 is a perspective view of the drilling platform according to Figure 4, including the drilling extension unit, and showing the derrick still positioned on the drilling platform.
Figure 6 is a side view similar to Figure 4, but with the derrick displaced from the main drilling platform to the drilling extension unit.
Figure 7 is a perspective view similar to Figure 5, but showing the derrick in a parked position on the drilling extension unit as in Figure 6.
Figure 8 is a top view of the fixed main drilling platform including the drilling extension unit with the derrick parked on the latter.
Figure 9 is section through the bottom part of the combined fixed main platform and the drilling extension unit.
Figure 10 is a perspective view of a combined fixed main drilling and production platform and an extension unit according to the present invention, in whIch the drilling module or derrick is still parked on the main drilling platform.
Figure 1' is perspective vie similar t Figure ;D, illustrating the drilling module parked on rhe extension unit.
Figure 12 is a schematic top view Illustrating the main dimensions at drilling deck level of the combined structure according to Figures 10 and 11.
Figure 13 is a perspective vie of a combined main fixed drilling and production platform having a drilling extension unit according to the present invention fixed thereto, and wherein the drilling module is still parked on the fixed drilling and production platform, and wherein the drilling extension unit has been mounted on the opposite side of the fixed platform as compared with the embodiment of Figures 10 and 11.
Figure 14 is a perspective view similar to Figure 13 and illustrates the drilling module parked on the drilling extension unit and displaced somewhat from the central position thereof.
In Figures 1 and 2 which are a side view and a perspective view, respectively, of a drilling platform, especially a substantially permanently installed offshore drilling platform, the fixed platform structure itself is designated generally by 1, said platform structure 1 comprising a first truss structure 2 extending from the sea bed 3, and supporting at its top a lower deck or production deck 4 as well as a drilling deck 5.
On the drilling deck 5 there is provided a drilling module 6, including a derrick 7, and in the area below the drilling nodule 5, there is provided a cluster of conductor pipes 7a...7n through which drilling can be performed by means of drilling strings controlled by the derrick and its not illustrated turn-table. The cluster of conductor pipes covers a first drIllIng area designated by Al.
The fixed platform structure otherwise comprises equipment for efecting drilling programs through said conductor plies, as well as other devices which are necessary for a corbired drilling and production platform, i.e. hoisting cranes such as those designated by 8 and 9, respective'y.
When drilling programs have been executed through the conductor pipes 7a...7n, the area of drilling may possibly be extended by moving the drilling module 6 via appropriate skid beams 10a, 10b to the area beside the cluster of conductor pipes, i.e. to the area designated A2 in Figure i, in which area h2 there may be provided a further cluster of conductor pipes which possibly may include conductor pipes from the cluster of said first area Al.
In order to extend drilling programs beyond the areas of the fixed platform structure 2, i.e. beyond the areas Al and A2, it is according to the present invention suggested to provide this extension by means of at least one drilling extension unt, for example of the type which Is especial illustrated in Figure 3 showing a perspective view thereof, but which is also illustrated in connection with the fixed platform 1 in Figures 4 to 9.
Thus, in Figures 4 to 9 there is illustrated substantially permanently installed offshore drilling platform 1 including a drilling extension unit which is generally designated by 11, and which favourably includes a plurality of conductor pipes 12a....12n contributing to the structural strength of the extension unit 11, and allowing for drilling to be performed therethrough.
In the embodiment illustrated in Figures 3 to 9 the extension unit 11 is substantially composed of a truss structure including said conductor pipes 12a...12n, said extension unit substantially taking the form of a tripod, in which two of the pods 13a and 13b, respectively, take the form of substantially vertical piles, whereas the third pod is composed of said conductor pipes 12a...12n.
As illustrated in Figures 4 to 9 the extension unit 11 comprises means for being connected to the fixed platform 1, especially by means of extended skid beams lOc and lOd allowing for displacement of the drilling module 6 between the fixed main platform 1 and the or any extension unit 11.
It should be understood that the extension unit 11 may include means for quick connection and disconnection to any existing platform.
It should further be understood that the extension unit 11 may be made self-supported, which means that the main connection to the fixed platform 1 should be constituted by the extended skid beams lOc and lOd, whereas the bottom foundation should then be designed to appropriately give ample anchorage for the self-supporting extension unit 11.
However, it should also be understood that the extension unit 11 could be more or less substantially permanently attached to the main platform structure 2, for example by having the supporting legs or piles 13a and 13b braced to the existing permanently installed platform structure 2, but also here preferably by means of clamping connections.
It should be noted that the extension unit 11 can be manufactured in a plurality of ways, and that there exist a plurality of manners in which the extension unit can be installed.
However, the main aspect of the present invention resides in providing a drilling extension unit in which a plurality of drilling conductor pipes are included to constitute a substantial part of said extension unit and to allow for a drilling therethrough.
Said extension unit may be partly assembled close to or on shore, whereafter the assembly is loaded out and transported in for example a substantially vertical position to the main platform structure, at which the extension unit is lifted in position by means of appropriate lifting means.
Alternatively, the extension unit can be loaded out and transported in a substantially horizontal position, it being noted that this manner of transportation requires maximum area for foundations.
If a tripod structure with one vertical face is used, this structure could be transported horizontally and upended whilst using two cranes. This structure involves a design having the greatest foundation requirements.
After the extension unit 11 has been installed on site, i.e.
as illustrated in Figures 4 and 5, and after the extended skid beams lOc and lOd of the extension unit il have been connected to the skid beams lOa and lOb, respectively, on the fixed main platform 1, the drilling module 6 can, as best illustrated in Figures 6, 7 and 8 be moved to the area of the extension unit 11, where extended drilling programs beyond the areas Al and A2 of the main platform structure 2 can be executed, the transfer of said drilling module 6 being effected without any expensive and time consuming lifting procedures.
Thus, the extension unit can extend the drilling programs considerably, without the necessity of providing a completely new, fixed installation with complete equipment for drilling and production.
In Figures 10 to 14 there is illustrated a further extended concept of the present invention. As regards the extension unit 11 and the main platform structure 2, Figures 10 and 11 substantially correspond to previously discussed Figures 5 and 7, respectively, with the exception that the main platform structure 2 of Figures 10 and '1 supports alternative embodiments of equipment for drilling and production.
However, Figure 10 illustrates the extension unit 11 being mounted in close proximity to the main platform structure 2, the drilling module 6 with its derrick 7 being parked in the area of the main platform structure 2. In Figure 11 the drilling module 6 has been transferred to the extension unit 11 along the skid beams lOa, lOb and lOc, lOd, and is parked in an offset position after having been displaced along a third pair of transversally arranged skid beams iOe and lOf, constituting a skid base for the drilling module 6.
Figure 12 gives an outline of the main dimensions of the drilling deck for the main platform 1 and the extension unit 11, respectively.
Figures 13 and 14 illustrate the further extended concept of the present invention, in which another extension unit lla has been provided, or has been moved from its first sideposition illustrated in Figures 10 and 11 to the second opposite side-position as illustrated in Figures 13 and 14, for thereby allowing for a further extension of the drilling programs which can be carried out in the vicinity of the main platform 1..
In the extension unit there may be arranged for a number of 16 welis to be drilled, said wells being arranged in a 4 x 4 fashion and located on either side of any existing fixed drilling and production platform. The total distance from well center te well center of for example the northernmost to the southernmost slot could be 20' . Slot spacing ill then be -6 2/3 in both directions.
This arrangement will render a light structure for supporting the conductors and the deck size could be minimized For this kind of extension structure installation could be executed in one lift.
The outline measures of the extension structure could for example be 18 x 15 x 100 meters, including a top deck so ze of 18 x 16 meters.
The illustrated embodiments should be considered in connection with a self supporting conductor supported extension unit which can be installed adjacent to any existing drilling and/or production platform.
The concept of the present invention is developed fron the premise of providing facilities for drilling/maintaining sixteen wells using the drilling rigs currently working on the existing platforms. Whilst the conductor supported structure would be self-supporting, it should be linked to the deck of the existing platform during rig transfer. This rig transfer or drilling module transfer operation should be performed during calm weather and the structural link between the extension unit and the main platform structure should be disconnected subsequent to the transfer operations.
It should be understood that the extension unit not necessarily should take the form of a tripod designed as a steel jacket, but could also take the form of a rectangular structure including said conductor pipes.
Installation of the extension unit could most appropriately be effected as lift installation using a crane barge.
If vertical piles are used this ould reduce potential foundation congestion and contribute to an overall favourable economy.
The extension unit should be provided with a standard deck which could either be installed separately or together with the jacket.
ith the dimensions outlined above link beams wOld be necessary to bridge a gap of approxmately 15 tween te primary trusses of the proposed extension unit.
It shoud also oc noted that other platform extension concepts are to be considered, for example in connectior.
with transfer of some wave load to the existing structure, and in connection with a design providing additional strength and stiffness to the existing structure. To achieve this additional strength, the additional support legs would be properly braced to the existing structure using clamps to achieve the connections. This interbraced constellation could reduce the steel weight compared to the stand alone structure and also give a more favourable protecting economy.
On the basis of the above scheduled dimensions approximately installation weight would amount to 1064 tonnes, and this weight should not pose any problem for existing semisubmersible crane barges, for example Micoperi, Mc Dermot DB 102, Hermod/3alder.
If leg piles are used this would minimize the jacket lift weight and provide extra resistance to boat impact. It would require constant large leg diameter. Depending on the low brace diameter/leg diameter ratio at the top of the jacket, the joint strength/fatigue would be more critical.
Due to low skin fraction, underreaming and provision of â bell foundation would probably be required.
Installation cost should be considered in relation to additional time required for handling and welding pile additional onshore, which could require that the extension unit be installed as two separate lifts, i.e. jacket and deck separately.
As regards any cluster piles leg diameter should be minimized, as this will minimize wave load/joint strength and fatigue problems, and the structure of the extension unit can be installed as an integral unit.
If piles are installed as complete units using the underwater hammer, no offshore welding should be necessary.
Vertical piles can be used to minimize appurtenance and foundation footprint.
In connection with structural concept alternatives the base of the structure should be designed so as to minimize pile requirement. The structure should be loaded out and transported in a vertical position and lifted into place.
If the structure is provided with vertical legs to bottom, including one or two bays, the bottom bay should provide a transition between the 12 m x 12 m tower aid. A large base should be sized to minimize pile requirements. This arrangement should enable the structure to be loaded out/ transported horizontally whilst generating maximum area for foundation requirements.
These structures could all be used in connection with the quick connect/disconnect link to the existing platforms.
Claims (16)
1. An arrangement in connection with a drilling platform, especially a substantially permanently installed offshore drilling platform , c h a r a c t e r i z e d i n that the platform includes at least one drilling extension unit comprising a plurality of conductor pipes contributing to the structural strength of the extension unit and allowing for drilling to be performed therethrough.
2. An arrangement as claimed in claim 1, c h a r z c t e r ' z e d i n that the extension unit is substantially composed of a truss structure including said conductor pipes.
3. An arrangement as claImed in claim 1 or 2, c h. â r a c t e r . z e d i n that the extension unit substantially takes the form of a tripod, in which the third pod is composed of said conductor pipes.
4. An arrangement as claimed in claim 1 or 2, c h a r a c t e r i z e d i n that the extension unit substantially takes the form of a rectangular structure including said conductor pipes.
5. An arrangement as claimed in any of the claims 1 - 4, c h a r a c t e ri z e d i n that said extension unit comprises means for being connected to the permanently installed main platform , for example by extended skid beams allowing for displacement of the drilling module between the main platform and any extension unit
6. An arrangement as claimed in any of the claims 1 - 5, c h a r a c t e r i z e d i n that the extension unit includes means for quick connection and disconnection to any existing platform.
7. An arrangement as claimed in any of the claims 1 - 6, c h a r a c t e r i z e d i n that the extension unit is made self-supported and includes means for being linked to the deck of a main existing platform
to allow transfer of a drilling module.
8. An arrangement as claimed in any of the claims 1 - 7, c h a r a c t e r i z e d i n that the extension unIt is substantially permanently attached to the main platform structure , for example b having the supporting legs of the extension unit braced to the existing platform structure , preferably by means of clawing connections.
9. An arrangement as claimed in any c the claims 1 - 8, c h a r a c t e r i z e d i n that the extensor.
unit includes vertical legs to bottom, and one or two bays.
10. .n arrangement as claimed in claim 9, c h a r a c t e r i z e d i n that the extensor unit includes a bottom bay to provide a transmissior. between te tower aio.
11. A method for providing additional drilling we: for a drirlin platform especially a substantially permanently installed offshore drilling and production platform, c h a r a c t e ri z e d b y providing a drilling extension unit in which a plurality of drilling conductors are included to constitute a substantial part of said extension unit.
12. A method as claimed in claim 11, c h a r a c t e r i z e d b y manufacturing said extension unit close to or on shore, and by loading out and transporting said extension unit in a substantially vertical position, and by lifting said extension unit in position at the installed fixed platform.
13. A method as claimed in claim 12, c h a r a c t e ri z e d b y manufacturing said extension unit close to or on shore, and by loading out and transporting said extension unit in a substantially horizontal position, for example by using two cranes.
14. A method as claimed in any of the claims 11 - 13, c h a r a c t e r i z e d b y mounting said extension unit
in relation to said fixed platform structure by means of quick connect/disconnect links.
15. An arrangement as defined in claim 1, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
16. A method for providing additional drilling wells to a drilling platform substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO871538 | 1987-04-10 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8808474D0 GB8808474D0 (en) | 1988-05-11 |
| GB2203782A true GB2203782A (en) | 1988-10-26 |
| GB2203782B GB2203782B (en) | 1991-10-09 |
Family
ID=19889856
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8808474A Expired - Lifetime GB2203782B (en) | 1987-04-10 | 1988-04-11 | An arrangement in connection with a drilling platform |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2203782B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2241925A (en) * | 1990-02-06 | 1991-09-18 | Brian Mcleod | Floating flight deck |
| US7419006B2 (en) * | 2005-03-24 | 2008-09-02 | Wzi, Inc. | Apparatus for protecting wellheads and method of installing the same |
| GB2501089A (en) * | 2012-04-11 | 2013-10-16 | Britannia Operator Ltd | Extension for an offshore structure |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2187778A (en) * | 1986-03-03 | 1987-09-16 | Earl & Wright Ltd | Offshore platform with two jacket portions |
-
1988
- 1988-04-11 GB GB8808474A patent/GB2203782B/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2187778A (en) * | 1986-03-03 | 1987-09-16 | Earl & Wright Ltd | Offshore platform with two jacket portions |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2241925A (en) * | 1990-02-06 | 1991-09-18 | Brian Mcleod | Floating flight deck |
| US7419006B2 (en) * | 2005-03-24 | 2008-09-02 | Wzi, Inc. | Apparatus for protecting wellheads and method of installing the same |
| GB2501089A (en) * | 2012-04-11 | 2013-10-16 | Britannia Operator Ltd | Extension for an offshore structure |
| WO2013153373A2 (en) * | 2012-04-11 | 2013-10-17 | Britannia Operator Limited | Offshore structure |
| WO2013153373A3 (en) * | 2012-04-11 | 2014-04-17 | Britannia Operator Limited | Offshore structure |
| GB2501089B (en) * | 2012-04-11 | 2014-08-27 | Britannia Operator Ltd | Offshore structure |
| AU2013246716B2 (en) * | 2012-04-11 | 2017-09-14 | Chevron North Sea Limited | Offshore structure |
| US9945087B2 (en) | 2012-04-11 | 2018-04-17 | Conocophillips (U.K.) Britannia Limited | Offshore structure |
| US10260210B2 (en) | 2012-04-11 | 2019-04-16 | Conocophillips (U.K.) Britannia Limited | Offshore structure |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2203782B (en) | 1991-10-09 |
| GB8808474D0 (en) | 1988-05-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19940411 |