Emergency well-control vessel

Abstract

The emergency well-control vessel is capable of being moved above an offshore live oil or gas well, over which all normal controls have been lost. The vessel carries special purpose equipments and specially trained personnel for the purpose of bringing the erupted well under control, thereby stopping the pollution of the water body with the ejected formation fluids which form a so-called "plume". Such equipment is adapted to allow the vessel to move over and continue to dispel the plume while simultaneously attempting to regain control of the well. In one aspect, control of the abandoned wellhead and blowout preventers is established with divers working from the vessel or from an auxiliary craft. After control of the blowout preventer stack is confirmed and the same is fully operational, a kill string is lowered through the open blowout preventer stack and as deep down into the well as necessary. Thereafter, weighted fluid is circulated down the kill string and up through the annulus to thereby eventually overcome the formation fluid pressure with greater hydrostatic pressure. In other aspects, the flow can be sealed off with packoffs established against the well casing or against the formation.

Dependencies are inferred from the claim text.