IMMERSED MOVABLE CAISSON PROVIDED WITH ICE RESISTANCE FOR SEA OIL WELL DRILLING IN ARCTIC Russian patent published in 1996 - IPC

FIELD: mining in Ocean with complex ice conditions. SUBSTANCE: caisson includes a structure formed by immovable vertical front, lateral and back walls. A pool is provided inside the caisson. The caisson has decks. Upper deck is placed over water level when in immersed position. Inclined section at outer surface is provided that is above or over water level when in immersed position to guide incoming ice upwards. Cut is originated in caisson back wall. Caisson height is more than Ocean depth. The caisson is provided with a base in the form of support and bottom placed along caisson perimeter under its walls. The bottom is made of solid reinforced building material. The caisson is provided also with input gate installed in back wall cut. Lower part of the cut is restricted with the base, and internal walls too. The decks are placed between internal and external walls. Outer surface of the caisson is reinforced to withstand forces allied by floating ice. Height of caisson walls is adequate to ward off maximum design wave when in immersed position. Ballast compartments are provided in caisson base and between internal and external walls. Majority of a compartment is under water level when in immersed position. Upper deck provided along each side has at least one equipment hole for drilling and/or production. Each lateral side of caisson circular support is provided with a system of drill shafts passing through it. The shafts are matched with appropriate equipment hole. Caisson base is placed so about upper deck as to provide entrance and exit of drill and/or production oil rigs when in floating position with closed gate. EFFECT: high efficiency. 15 cl, 20 dwg