How do jack-ups work?
Since the first jack up was built in 1954, jack-ups have become the most popular type of mobile offshore drilling unit (MODU) for offshore exploration and development purposes. In fact, there are hundreds of self elevating jack up stationed around the world performing drilling and workover operations in just about every environment.
One forms of bottom-supported MODUs, jack up rigs rest on the seafloor as opposed to going with the flow. The premise of a jack-up rig is that it is self-elevating; right here, the legs are stationed on ocean ground and the drilling device is jacked up above the water’s floor.
Providing very stable drilling surroundings, in contrast to other forms of offshore drilling rigs, jack-ups can drill in waters up to 350 toes deep. Once drilling is required in waters which might be deeper than the competencies of a jack-up, semisubmersibles and drillships become an extra-logical preference for exploration and development operations.
When their legs are not deployed, jack-ups float, which makes those styles of MODUs pretty easily transported from one drilling location to another. While some are capable of self-propulsion and do no longer need an outside source for movement, most jack-ups are transported through tugboats or submersible barges. While towing is effortlessly achieved, barges are the transportation of choice while the jack-up wishes to be moved quickly or over an extended distance.
Jack up legs
Whether a jack-up design entails 3 or 4 legs, there are primary varieties of legs which can be used on jack-ups. The first contains open-truss legs into the design that resemble electrical towers. Open-truss legs are manufactured from tubular steel sections which can be crisscrossed, making them robust, but lightweight.
Jack-ups can have columnar legs fabricated from big steel tubes. While columnar legs are much less high priced than open-truss legs to manufacture, they’re less stable and cannot adapt to stresses within the water as well as open-truss legs. For this cause, columnar-legged jack-ups are not utilized in waters that degree greater than 250 ft deep.
In addition to their legs, jack-ups are supported through distinct structures of stabilization. Jack up legs are supported on the sea floor via either mats or spud cans.
Usually used on unbiased-legged jack-ups, spud cans are cylindrically formed metal footwear with pointed ends, just like a cleat. Spud cans are attached to the lowest of each leg, and the spike within the can is driven into the ocean floor, adding balance to the rig all through operations.
Additionally, there are two sorts of raising devices. Once the jack-up is on vicinity, the legs are diminished to the sea’s ground and the rig hull and drilling system is extended properly above the water’s floor and far away from any capacity waves.
The first kind of raising device uses hydraulic cylinders ready with shifting and stationary pins. These cylinders expand and retract to climb up and down the legs of the jack-up. The different kind of elevating device employs a rack and two pinion gears which might become to move the legs up and down.
Whichever form of leg this is used within the layout, the legs of the jack-up upward thrust up through holes in the hull of the drilling rig. Here, a deck is used to help the drilling derrick and different system.
There are methods to mount the drilling gadget at the hull. The maximum famous layout for drilling equipment is a cantilevered jack up. Here, the drilling derrick is hooked up on an arm that extends outward from the drilling deck. With a cantilevered jack up, drilling can be finished thru present structures, in addition to without them. Because of the variety of movement that the cantilever provides, maximum jack up built in the last 10 years had been cantilevered jack-ups.
The different kind of jack-up is the slot-type jack up, additionally referred to as a key way jack up. Drilling slot jack-ups are built with a gap within the drilling deck, and the derrick is placed over it. While exploration wells may be drilled with drilling slot jack-ups, the rig also can be jacked up over some other smaller facility, drilling via its hull. To find out more about our self elevating jack Up Vessels Visit Thong Yong Marine Group!.