Patent ID: 7850398

Claim:
A jackup oil rig comprising: a hull as a working platform; a plurality of jackup modules being disposed on the hull; a buoyant mat being rested on the seabed when the jackup oil rig is in operation; a plurality of legs coupling the hull and buoyant mat, wherein one end of each of the plurality of legs is fixed onto the buoyant mat, and the remaining is operably engaged with the hull; thereby when the legs are disengaged, they move freely through the hull; and when the legs are locked, they are engaged with hull maintaining the distance between the hull and the buoyant mat; wherein each of the plurality of legs is coupled with at least one of the plurality of jackup modules, thereby the hull is driven up and down along the legs by the jackup modules; a plurality of sloped, trapezoidal or pyramidal structures being attached to the underside of the hull for breaking ice formation around the legs; wherein the plurality of the sloped, trapezoidal or pyramidal structures is disposed circumferentially around the legs; thereby when the hull is jacked down by the jackup module, the sloped, trapezoidal or pyramidal structures break the ice formation around the legs; wherein the upper surface of the buoyant mat around the legs has a recess that is complementary to the sloped, trapezoidal or pyramidal structures for receiving the sloped, trapezoidal or pyramidal structures during operation and storage; and a plurality of piles slidably attached to the hull, wherein when they are driven into seabed, they provide additional support of the hull, and wherein each of the plurality of piles has complementary recesses at intervals.