초록

The invention relates to an elongated buoyant arm mounted below the water line of a drilling vessel. The arm is of variable buoyancy and is attached to a drilling riser extending between the drilling vessel and the sea bottom to maintain tension on the riser.

대표청구항 ▼

An apparatus suitable for mounting on a drilling vessel and maintaining tension on a riser which traverses a depth of water comprising: an upper riser section having an upper end and a lower end, at least one lower riser section having an upper end and a lower end, an elongated arm having first and

An apparatus suitable for mounting on a drilling vessel and maintaining tension on a riser which traverses a depth of water comprising: an upper riser section having an upper end and a lower end, at least one lower riser section having an upper end and a lower end, an elongated arm having first and second ends and adapted to rotate vertically about said first end, pivot means affixed to said second end of said elongated arm, said pivot means being adapted to detachably hold the lower end of said upper riser section and the upper end of said lower riser section and further adapted to allow said lower riser section to pivot, at least one buoyancy tank mounted on said elongated arm a spaced distance from said first end and being adapted to be ballasted and deballasted, and upper tension means located at the upper end of said upper riser section and adapted to maintain said upper riser section in tension.