What is a punch through jack-up?

Punch-through is a sudden and uncontrolled penetration of the spudcan often causing structural damage of the unit. It may occur when the load becomes equal to bearing capacity for the spudcan while within a soil layer having relatively higher bearing capacity than the soil underlying that layer.

How big is a jack-up rig?

The legs on a jack-up rig can be up to 500 ft. in height. Considering a 100 ft air space between the waves and hull of the rig, this allows for water depths of approximately 400 ft for drilling operations. The rotary rig on a jack-up rig can either be a conventional kelly drive rig or a top-drive rig.

How many jack-up pillars legs are there in a jack-up rig?

The number of these legs depends on the type and functionality of the barge but is usually 3, 4, 6, or 8. The buoyancy of the hull means that the structure can lift objects out of the water, such as turbines, smaller vessels, or offshore drilling platforms.

What is preloading of a jack-up?

Upon arrival at the work location, the legs are jacked down onto the seafloor. Then “preloading” takes place, where the weight of the barge and additional ballast water are used to drive the legs securely into the sea bottom so they will not penetrate further while operations are carried out.

What is the biggest jack-up rig in the world?

The Maersk Invincible ultra harsh environment jack-up rig is an MSC CJ70-X150-MD, designed for year-round operation on the Norwegian and Continental Shelf, is one of Maersk Drilling’s I-class rigs – the world’s largest and most advanced jack-up drilling rigs.

What does a jack-up boat do?

Liftboats are commonly used to perform maintenance on oil and gas well platforms. The liftboat usually moves on location on a side of the platform where no obstructions or pipelines are observed, lowers its legs and jacks up out of the water.

What is an accommodation jack-up?

Jack-ups, also known as self-elevating platforms (SEPs), are barges, propelled or non-propelled, which rise above the water on hydraulically powered legs or piles.

What is a platform jacket?

Platform jacket refers to a single physical component and includes any type of offshore exploration, development, or production structure or component thereof, including platform jackets, tension leg, or SPAR platform superstructures (including the deck, drilling rig and support utilities, and supporting structure).

What is preloading of a jack-up why and how is it carried out?

The preloading of a jack-up is carried out in fair weather. Initially, the legs are lowered to touch the seabed. As the hull is gradually raised from water, vertical compressive load i.e. self-weight of the jack-up is transferred to the foundations.

What is one purpose of pre loading a support system with a jacking device?

Pre-loading ensures a rigid contact between interacting members and is accomplished by inserting a hydraulic jack as each side of an individual pipe strut between the wale beam and a special jacking pblate welded to the strut (Xanthakos, 1994).

Where is the Maersk Highlander?

The current position of MAERSK HIGHLANDER is at North Sea (coordinates 55.47653 N / 8.41224 E) reported 1 min ago by AIS.

How long are the legs on a lift boat?

335 feet long
The legs are 335 feet long (102 m) and it has a main crane and three auxiliary cranes. The vessel uses electro-hydraulic jacking systems, and the cranes are all driven from the segregated machinery spaces.

What is a jack-up leg?

Since the first jack-up was built, jackups have become the most popular type of mobile offshore drilling unit (MODU) for offshore exploration and development purposes in shallow water. The most pivotal component of the jack-up unit is the leg, which can directly affect the global performance of the unit.

How many legs does a jack up rig have?

JACK-UP LEG STRUCTURAL DESIGN PARAMETERS. The conventional jack-up design has three vertical legs. Each leg is normally being constructed of a triangular framework. The triangular column lattice structure for a jack-up rig consists of three chords, horizontal braces and diagonals.

How deep can a jack-up rig extend?

Therefore, the jack-up Constellation II, may extend the three legs by 84 ft to reach a leg length of 631 ft. This will enable the unit to drill in water depth of 462 ft and replace old generation semisubmersibles. The jack-up rig day rate is affected by changing the water depth.

How many legs does a jack up tower have?

Jack-up designs varying from being monotower structures (single leg designs) to multiple leg designs, e.g. up to six legs, although units with sixteen legs are not unknown, Boswell (1986). The supporting leg structures may be a framework design, or, may be plate profile design.