SG179303A1 - Raised cantilever for easy access (rcea) used on self elevating drilling rigs (offshore energy sector) - Google Patents

Abstract

RAISED CANTILEVER FOR EASY ACCESS (RCEA)USED ON SELF ELEVATING DRILLING RIGSThis invention. Raised Cantilever for Easy Access (RCEA), is a novel concept and design thatallows and improves personnel or man-handled material access to and from either side of thecantilever on a self-elevating drilling rig, platform or vessel used in oil and gas industry.The idea, through special physical re-arrangement of the components involved, is unique andinnovative when compared with typical cantilevers found in self elevating drilling rigs and bringsForth several advantages to improve operational efficiency of the rigSketches which support the explanations and typically illustrate the invention's novelty are:Figure IFigure [AFigure 2I11RAISED CAN 1'I [.EVER FOR EASY ACCESS (RCEA)USED ON SICt.F ELEVATING DRILLING RIGS(O1-'h'S11ORE ENERGY SECTOR)DESCRIPTIONField of the Inventionf his invention relates to an arras •crncnt of an apparatus so as to improve personnel access toand from cilher side of this apparatus during its operation. Such an apparatus is normally calledthe cantilever o1 a self-elevating drilling rig used in the offshore energy scclor. This inventionis applicable to self elevating drilling rigs. non-drilling platforms or vessels in offshoreapplications. 1=undamentally, it is innovative in idea enabling personnel access from either sideof the apparatus (or cantilever) so as to significantly improve operational efficiency of thedrilliig rig.The idea, through special physical rc-arrangement of the eunipnnenls involved. is unique andinnovative when compared with typical cantilevers found in self elcvaling drilling rigs orVessels.Because its application is essentially more pragmatic, the invention of this arrangement iscalled "Raised Cantilever for Easy Access" or R(TA. the conventional arrangement ofsiinilar cantilevers found in self-elevating drilling rigs is not raised to a point which allows easypersonnel movements between both sides ^f the rig. Amilher added feature of this invention ofarrangement is that it creates more space below the cantilever for installations of deck itemsincluding ventilators which otherwise arc required to he placed at the sides of the rig. Theventilators when properly arranged and located below the cantilever, in turn can provide an air1

Description

RAISED CANTILEVER FOR EASY ACCESS (RCEA)

USED ON SELF ELEVATING DRILLING RIGS

(OFFSHORE ENERGY SECTOR)

DESCRIPTION Field of the Invention

This invention relates to an arrangement ol an apparatus so as W improve personnel aceess (o and trom either side of this apparatus during is operation. Such an apparatus is normally called the cantilever of a sclf-elevating drilling fg used in the offshore energy scetor. This invention applicable to self elevating drilling gs. non-drilling platforms or vessels in offshore applications. Fundamentally, it is innovative in idea cnabling personnel access from cither side of the apparatus (or cantilever) so as to significantly improve operational efficiency of the drilling rig.

The idea, through special physical rearrangement of the components involved. is unique and innovative when compared with typical cantilevers found in self elevating dolling rips or vissels,

Hecause its application 1s essentially more pragmatic, the invention of this arrangement is called “Raised Cantilever for Easy Access” or RCEA. The conventional arrangement of similar cantilevers found in self-clevating drilling rigs is nol rused to a point which allows casy personnel movements between both sides of the rig. Another added feature of this invention of arratigement 3s that it creates more space below the cantilever for installations of deck nems including venolators which otherwise are required to he placed at the sides of the rig. The ventitalors when properly arranged and located below the cantilever, in um can provide an air drafl that can enhance safely aspect of vemiilaton ae the dell Toor and BOP (blow oul preventer) vicinity,

A typical cantilever on a sell-clevatng drilling rig 15 depicwed in figure § The following terminologies common in a drilling rp are defined for the better understanding of the application of the invention, ! Terminology Description ;

Cantilever The part of a self elevating drilling rig which is made movabic and 1s able to exiend aft-ward so that the dill (oor Tecated above the canilever can perform its drilling function over a space envelope afi al the rig transom.

Push-Up structure This refers to a support structure located av afl of the nig to held up the camilever, When the cantilever is stowed or extended afl-wand. (this structure performs a push-up reaction to the cantilever. This simagiore comes in as a pair and they support the side beams of the cantilever throughout its longimdinal travel (zee Figure 14).

Hold-Down structure This refers 0 a structure located forward of the push-up structure and provides support of the cantilever when stowed in forward position. When the cantilever is extended aft-ward [ beyond a point where its centrg-of-gravity (CG) is behind the rig ransom, this structure holds down the cantilever and prevents it from tipping over the transom. The structure comes in as a pair and they support or hold-down the side beans of the cantilever during its longimdinal wavel (sce Figure 14).

Background vf the Invention

Cantilever is a commen feature of self-elevaring drilling rigs. while nor so common on vesscls or offshore plationes. ts purpose 1s Ww carry the drill Neor located above it at the aft-end snd move the doll floor over a drilling area envelope described by the cantilever and doll floor movements. The cantilever moves longitudinally whereas the drill floor moves transversely,

While such apparatus described above and other variations of such design achieve their objective in drilling over an area envelope. the cantilever is normally located low close to the main deck of the hull body (see figure I. The clearance between cantilever and hull main deck is normally between 0.8-1.2m in height or thereabout, Since the cantilever, in its stowed position lakes up quite a long and central arca of (the hull, personnel or man-handled materials crossing between port and starboard sides of the rig is relatively ineffective and requires a person or the material to move forward, turn around the forward end of the cantilever and reach back to» other side of the hull. Even when the cantilever extends aft-ward, there 1s snl] this blockage of access between port/starboard sides.

Further, the long and central space occupicd by the cantilever close to man deck takes away valuable space for deck outfits {air vents, sounding heads, remote-operated valve deck handles, ventilators ete.) which are pushed to the sides when they could be installed in the puddle portion of the rg.

The background of the Invention lies in a re-armangement of the components by raising the cantilever vertically up w a suitable height from the main deck thus allowing boner and easier access of personnel reaching [rom one side of the nig 0 the sther side (see figure 2). AL the same Ime, it creates more deck space for outfits 0 be msialled in the central portion of the nig.

First significant dificrence and substantial advantage of the present vention is that the Raised

Cantilever Tor Easy Access (RCEA) provides for better movement of personnel between pon and starboard sides of the rig.

Second significant difference and substaniial advantage of the present invention 1s that RCEA frees the coniral portion deck space allowing outfits to be located and operated in relation w tanks or space directly below the deck (eg. Air vent, sounding pipe. remote-operated valve deck handle, ventilator ete). This has cost and space savings impact.

A_third significant difference and substantial advantage of the present invention is that if the ventilators are amanged for nara) exhaust as is the case iF the exhaust ventilator is directly above the compartment below, cost savings from eliminating the necessity 10 provide forced exhaust is achieved. Al the same time, a stream of exhaust air below the cantilever can he directed 1oward the afi-end of the rig thus reducing or preventing any hazardous or (oxic pases to Mow forward to living quarters,

A fourth significant difference and substantial advantage of the present vention is that the raised cantilever results in more air gap from sea level. Without further mising the hull, the cantilever can be made to reach over a production platform to perform work-over activilivs,

Needless to say a RCEA amangement optimizes apparatus-miy (or vessel or platform} engagement utilization. As a result, operational efficiency is improved.

The Objective of the Invention

The objective of the invention 1s to provide an imewvative, improved and altemative arrangement for ease of personnel and material access and movement between pon and starhoard of the rig. along with which comes other usefulness as mentioned in the preceding chapter.

The RCEA ammanpement design wall obviate or mitigate the aforementioned sitation of less operational efficiency, lack of usage optimization and space sharing, or one which will at least provide the public with a uselul, operationally more clfective and cost saving choice.

Statement of the Invention.

The RCEA works on rearmanging certain components thus elevating the whole cantilever vertically and creating space below the cantilever for useful operational advantages.

Roth the “push-up” and “hald-down’ structures are reinforced and increased in height so that the whole canlibever when supported is about 2m to 3m above the main deck of the ng. In other words, the cantilever will operate at this height wom the mam deck inoall positions when it moves longitudinally {see figure 2)

The raising of the cantilever is done purposely so as Wo achieve some advantayeous results.

The ead-result of this myvenbon manifests the followmy advantages:

I. The mised cantilever provides better movement of personnel between port and starhoard sides of the rig.

2. The raised cantilever trees the central portion deck space allowing outfits to be located and yet atend-able by men for mainenance or during operation, 3. In the treed-up space below the cantilever, ventilators can be located and if the ventilators are arranged for natural exhaust as is the case if the exhaust ventilator is directly above the comparnment below, cost savings from eliminating the necessity 10 provide forced exhaust is achieved. At the same time, a stream of exhaust air below the cantilever can be directed wward the alt-end of the rig thes reducing or preventing any hazardous or wxic gases to flow forward to living quaners, 4. The rised cantilever results wm more air gap rom sea level and without further rising the hull. the cantilever can be made to reach over prduction platform easier in performing work-over activities.

Results and Discussion

The following wble highlights and compares the RUCEA advanwges over typical sinular cantilevers of other scelf-clevating dnlling mgs. The table 1s in no way meant 0 be an exhaustive exploration of all of the features of the invention, and many of those not discussed will hecome readily apparent to a skilled reader once the [ull scope of the invention is understood.

No. Features Invention Conventicenal 1. Raised cantilever io | This innovative concept and re- | Similar cantilever on self a height of about design of the push up’ and “hold | elevating drilling rigs sis dm to 3m from down” structures immediately | close wo deck level and Lhis main deck level provides a free vertical space for | impedes acccssihility personnel and matenal access & | between port and starboard

O movement between port amd | sudo of the np oo starboard side ol the rig. 2 | The treed-up lmmoedinely, deck oudits such | Without usable central space vertical space also | as wir vents and sounding pipes | being made weailabie, deck clears up deck telodimeg tank dump valve fittings such us air vents and j space that can he remot deck handles | sounding pipes including i utilized for concerning tanks directly below | dump vale deck handles installation of need nob be rated Ww sides of rig have to be routed wo sides of wvulfits directly and this saves mater] and ps and coneesting valuable relevant br tank or | space. deck space al rig sides. space below deck 3. Ventilators for Natural cxhaust ventilators can Ventilators for conipartments compartments tony be used and (his reduces the directly below cantilever ned threctly below can | number of forced ventilators ww be routed to rig sides and bo nstalled inthis | required (forced supply and forced ventilators (forced central deck space | natural exhaust) supply and loreed exhaust) must be used and this increases cost. 4. | Exhaust vemilawors | These exhavst ventilators can Cellar deck hazardous or arranged in central | provide a strong air draft and oxic gases. when present, deck space when directed aft-wand, it can can move lorward into improve ventilation around BOP caniilever and forward to and cellar deck area.

Hazardous living quarters. or luxe gases, when present, can be partially prevented from tervinyge forward te living quarters by lus continuous aft- ward air deati.

| Increased The arsed canulever height of | To reach over the plafoms, cantlever air-gap 2m-3m from main deck provides | te rigs will Base wo hee mem fromm sea level the additonal air gap for the lwll air gap exposing the nig cantilever to work over oe more environmental loads production platform withow increasing hull air gap. Reduced hull air wap improves the rigs performance against forces of the envirenment (wind, wave ele)

Modifications of the Preferred Embodiments

While the invention has been described with particular reference tw certain embodiments thereat. it will be understood that various modifications can be made to the above-mentioned embodiment without departing from the spirit and scope of the present invention, The examples and the particular proportions set forth are imended (© be illustrative only.

Information Niselosure References

Information relating to inventions that may have been previously fled in by others and that 1s of similar invention can only be determined after a search by the authority, hd

Claims (1)

THE INVENTORS CLAIM

1. A self elevating dnlling rg, platform, vessel or system suitable lor off-shore oil and gas drilling or production and other operations comprising: a cantilever thin is xed on the hull main deck and is able 10 nye longitudinally while carrying # drill floor above to provide a drilling envelope when extended aft of the ng transom ang the conventional design is to have the cantilever fixed vertically close w the main deck and supported by the ‘push-up’ and “hold-down’ structures, and the mir gap between the cantilever and the main deck is insufficient for persomnel acvess between port and starboard sides of the np: characterized in that the cantilever is now raised up by re-designing the “push-up” and ‘hold-duwn” structures to enable the cantilever to be fixed at a vertical height of about 2m to Im from the main deck level that is novel in the amangement design and this frees up a large space below the cantilever, which allows not only personnel and man- handled material access between port and starboard sides of the rig but also creales several advantages ww be realized to improve operational efficiency of the rig. ug