FLOATING SPAR FOR SUPPORTING PRODUCTION RISERS

• Main Authors: SKEELS, HAROLD, B, FITZGERALD, JOHN, A
• Format: Patent
• Language: English; French; German
• Published: 27.03.2002
• Edition: 7
• Subjects: EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; EQUIPMENT FOR SHIPPING; FIXED CONSTRUCTIONS; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS; PERFORMING OPERATIONS; RELATED EQUIPMENT; SHIPS OR OTHER WATERBORNE VESSELS; TRANSPORTING

A subsea system is provided for producing a number of subsea wells which may be arranged in groups. Each of the groups of subsea wellheads is connected to deliver production flow to a subsea manifold and each subsea manifold is connected to deliver production flow to a production riser. A plurality of production risers each being connected to receive production flow from one of said subsea manifolds extend from the subsea manifolds for groups of wells. A deep draft floating spar is located generally above the subsea wellheads with mooring lines and has a production platform located above the sea surface and has buoyancy and ballast chambers to control floatation. The spar structure defines a riser bore receiving the production risers extending from the subsea wellheads to the production platform. The spar is also capable of being shifted laterally by its mooring lines for positioning above a selected well to thus permit well intervention activities as needed. The subsea wells are each provided with wellheads having a removable cap to permit ROV actuated cap removal and replacement as needed to permit well intervention.