Patent ID: 7451822
Filing Date: 2008-11-18
Classification: E21B

Abstract:
1. A method for preparing to move a floating structure away from a wellbore drilled below the bottom of a body of water, comprising: filling a riser extending from the bottom of the body of water to the floating structure with water; displacing the water in the riser to a first selected depth below the water surface, the displacing including discharging the water through a selectively controllable outlet in hydraulic communication with an interior of the riser at a depth below the first selected depth, an elevation difference between the first selected depth and a second selected depth shallower than the first selected depth providing the riser, when filled with gas, sufficient buoyancy to buoyantly support all the riser in the water below the second selected depth; closing the selectively controllable outlet; sealing the riser at the second selected depth; and withdrawing the portion of the riser above the second selected depth onto the floating structure.