jack ups in operation - types and differences

JACK UPS IN OPERATION –th OCTOBER 2013

PRESENTED BY NANDAKUMAR KUNNANCHATH

– TYPES AND DIFFERENCES

PRESENTED BY NANDAKUMAR KUNNANCHATH

PDF Creator - PDF4Free v3.0 http://www.pdf4free.com

http://www.pdfpdf.com/0.htm

Jack Ups in Operation

A jackup is a floating barge fitted with longlegs that can be raised or lowered. The jackupmaneuvered (self-propelled or by towing) intowith its legs up and the hull floating on theUpon arrival at the work location, the legs aredown onto the seafloor. Then "preloading"place, where the weight of the barge and additionalballast water are used to drive the legs securelythe sea bottom so they will not penetrate furtheroperations are carried out. After preloading,jacking system is used to raise the entire bargethe water to a predetermined height or "airthat wave, tidal and current loading acts onlyrelatively slender legs and not on the bargeModern jacking systems use a rack and pinionarrangement where the pinion gears are drivenhydraulic or electric motors and the rack is affixedthe legs.

Jackup rigs can only be placed in relativelywaters, generally less than 400 feet (120 m)However, a specialized class of jackup rigs knownpremium or ultra-premium jackups are knownhave operational capability in water depthsfrom 500 to 625 feet.


long supportjackup is

into locationthe water.are jacked

"preloading" takesadditional

securely intofurther while

preloading, thebarge above

gap", soonly on thebarge hull.pinion gear

driven byaffixed to

relatively shallowof water.

known asknown to

depths ranging




Mobile Offshore Drilling Units (MODUs)

capable of drillingEarth's crust.mud (slurry) throughannulus, for coolinga well is drilledtons of pipe. Otherinto reservoirsnatural gas; andpermanent livingcrews (which mayrigs may operatekilometres distantinfrequent crew

Jack Ups in Operation - Types

Mobile Offshore Drilling Units (MODUs)

drilling through thousands of metres of theLarge "mud pumps" circulate drilling

through the drill bit and up the casingcooling and removing the "cuttings" while

drilled. Hoists in the rig can lift hundreds ofOther equipment can force acid or sand

reservoirs to facilitate extraction of the oil orand in remote locations there can be

living accommodation and catering formay be more than a hundred). Marine

operate many hundreds of miles ordistant from the supply base with

crew rotation or cycle.




Liftboats


A liftboat is a self-propelled, selfelevating vessel with a relatively largeopen deck capable of carryingequipment and supplies in supportvarious offshore mineral explorationproduction or offshore constructionactivities. A liftboat also hascapability of rapidly raising its hull clearof the water on its own legs so asprovide a stable platform from whichmaintenance and construction workmay be conducted. Liftboats are usuallyoutfitted with at least one crane; marinecranes are usually designed tospecification 2C or the equivalentclassification society guidelines.




Jack Up WTIVs


Wind Turbine Installation Vesselsare deployed to install turbinesoffshore wind farms. On arrivalthe site of the wind turbine,vessel lowers its legs to standthe seabed, and then jacksabove the surface of the seaThis provides a stable platformhammer down a mono-pilethe sea bed and install the windturbine. When the turbinebeen installed, vessel lowersherself and sails to the nextposition to repeat the process




MOPUs

Mobility enables reduced installation,decommissioning costs, compared withups have the added advantage of relocationplatforms provide large flat deck areasfunctional topside arrangement.


Mobile offshore production units(MOPUs) are production units thatcan be relocated from site to siteThe jackup has proven itself anexcellent candidate for shallowwater early production applicationJackups offer a cost efficientsolution for short life fields,compared with jacket or subseaapplications.

installation, hook up, and commissioningwith a jacket structure. Production jack

relocation and re-use at less cost. Jackupareas offering flexibility for a safe and




Jack Up Construction & Accommodation Barges


Jack Up Construction & Accommodation Barges

Specialized jack ups usedas a base for servicingother structures such as oiland gas platforms duringtheir construction, operationand maintenance and alsofor accommodation ofoffshore crew during hookup and commissioning.



Jack Ups in OperationMajor Design ParametersThe overall jack up design optimizes thewould not desire a big deck area without a comparableelements to focus on:

1) Legs and PadsThe vast majority of jack ups are three-leggedthe cost of simply adding the cost of anotherlegs loaded diagonally is greater andoperationally, the setup time savings of aweigh the costs and benefits of three vs. fourProven to be a cost effective design, the vast(pipe legs). Columnar legs and pads provideare lowered to the sea floor. This buoyancyreduce the bottom bearing pressure on theliftboat pads are designed to reduce bottompenetration.Working water depth also affects the typemeters) of water, lattice legs are the norm.

Jack Ups in Operation - Differences

interrelationship of the key features, i.e.,comparable deck load. So there are certain

legged. The four-legged liftboat will cost moreanother leg, i.e., the jacking system to support

the hull structure is different/heavier.four-legged equates to money, so, one has

four legs.vast number of liftboats have three columnar

provide added buoyancy for the liftboat as thebuoyancy in both the legs and pads (spud cans) helps

pads. In combination with the buoyancy, largerbottom bearing pressure. This has the effect of

type of leg; for example, after about 220 feet




(2) Jacking System

The jacking system for a liftboat is veryup drilling rig. The two major differences

Speed of the liftboat jacking system is essentialelevates at two feet per minute, a liftboatand lower the legs at 14-18 feet per minuteon and off location significantly faster.

The jacking system for a liftboat encounterswould not be uncommon for a liftboat tonumber of times that a jack-up drilling rigthe wear factors, redundancy, materialbetween jack-ups and liftboats.


different than the jacking system for a jackdifferences center on speed and cycles.

essential. While a typical jack-up drilling rigliftboat could elevate at four to six feet per minute

minute. This gives the liftboat the ability to get

encounters a very different operational cycle.to jack up and down in one year the samerig would encounter in its entire lifetime. So,

material grades and shock loads are different




(3) Working Water Depth

The expected wind, wave and current (environmentalworking water depth need to be determinedthe liftboat design, such as, net deck load,depth. An area with moderate environmentalconditions will be a significantly differentjacking system and hull.

(4) Open Deck Area

The deck area is the unobstructed, openequipment and materials around and on toThere is a relationship among these variablescrane capacity. Furthermore, you need athe expected deck loads and deck area.


(environmental conditions) in the maximumdetermined. Although, other variables will go into

load, the starting point is still working waterenvironmental conditions vs. harsh environmental

different jackup design in all aspects, i.e., legs,

open area. The liftboat crane is used to moveto and off of the platform/offshore location.

variables – open deck area, net deck load andcrane capacity that is commensurate with




(5) Net Deck Load

The net deck load for a liftboat is whatthen jack up with on the deck. Consumablesetc.) are in addition to the net deck load.There is a definite relationship amongLiftboats are designed as multi-purposeAlso, one needs to consider the type ofthe deck, so that, various areas can beloadings, i.e., an area near the bow mayareas.


you have on your deck in transit and canConsumables (such as water, fuel, hydraulic fluid,

.deck area, deck load and crane capacityvessels.equipment and components that will be on

be designed to accommodate the variousmay have higher point loading than other




(6) Crane Capacity

There are a variety of cranes for liftboatscrane manufacturers specifically for liftboatsliftboat design, so, every considerationincluding the crane. Therefore, cranes forthan a comparable offshore crane.

Regarding types of liftboat cranes, thereboom, pedestal mounted, and leg encircling


liftboats. Cranes for liftboats are designed byliftboats. Weight is a key consideration in

consideration needs to be made in the overall designfor liftboats are typically structurally lighter

there are lattice boom, box boom, telescopicencircling cranes.




(7) Personnel Accommodations

The accommodations are anotheraccommodations are generally dividedcustomer/operational personnel. As liftboatscapacities, so have the requirements foraccommodation block would typicallyremaining 80 for customer/operational personnel

The type of job that the liftboat is performingrequirement, i.e., an offshore constructionpersonnel than a well intervention jobadditional modular living quarters on the


feature of liftboats. The personneldivided into two areas – navigation crew and

liftboats have gotten bigger with increasedfor more personnel. For example, a 100-man

have about 20 navigation crew and thepersonnel.

performing will dictate the accommodationconstruction job would generally require more

job. The construction job may even requirethe deck.




(8) Propulsion

Majority of liftboats are self-propelled. Thisliftboat or to set up on location. The liftboatmove. The larger liftboats have integratedwith DP2 capability are becoming more common

(9) Classification Society Rules

Classification Society rules are also differentexample, whilst most of the MODU rulesare different rules and guidelines avaialbleLloyds Register), etc.


This alleviates the need for tugs to move theliftboat can wait for a weather window and

integrated propulsion and bow thrusters. Liftboatscommon these days.

different for different types of jack ups. Forrules are applicable for Liftboats as well, there

avaialble for liftboats (MOUs for ABS, Liftboats for



Jack Ups in OperationIn today’s market place, there are more thanunits, each having certain design techniquesunits more economical to build, better to operate,of these features.

Pinion versus pin and hold jacking systemSingle sided versus opposed rackFixed versus floating jacking unitsElectric versus hydraulic jacking powerTransparent versus robust leg designJack support systems (a) Stiffness ofbalancing devicesGuide tolerances and lengthsLeg bracing patternsSlo-Rol systemsHeave absorption systems

With such a complex group of variables andto produce so many different possibleunderstand the purpose and functions of somequantitative manner, before owners andjackups for a specific operation.

Jack Ups in Operation - Differencesthan a dozen major active designers for jack

techniques and features that they feel make theiroperate, or both. The following is a brief listing

system

Units (b) Leg Locking Devices (c) Torsion

and their implications which may be combinedbenefits or problems, it is important

some of these features in both qualitative andoperators can decide the specification



Thank You for your attentionThank You for your attention



jack ups in operation - types and differences

Documents