Abstract: A method for detecting a leak in a drill string valve used when drilling a subsea well. The method comprises measuring a first inlet pressure at a subsea mudlift pump while a subsea mudlift pump and a surface pump are operating and before a well is fully shut-in and measuring a second inlet pressure at the subsea mudlift pump after the mudlift pump and the surface pump are shut down and after the well is fully shut-in. The first and second subsea mudlift pump inlet pressure measurements are then compared, and a check is performed to determine if the subsea mudlift pump inlet pressure has increased by an amount greater than an estimated annular friction pressure.

Abstract: A method for controlling a subsea well that includes shutting at least one blowout preventer, opening at least one isolation line, and circulating an influx out of a well while an inlet pressure of a subsea mudlift pump is adjusted to maintain a substantially constant drill pipe pressure at an initial circulating pressure. After the influx is circulated out of the well, drilling mud with a kill mud weight is pumped into the well. The drill pipe pressure is reduced according to a preselected drill pipe pressure decline schedule until the kill mud weight drilling mud reaches the bottom of the well. The drill pipe pressure is then maintained at a final circulating pressure by adjusting the inlet pressure of the subsea mudlift pump. The kill mud weight drilling mud is then circulated from the well bottom to the surface at the final circulating pressure.

Abstract: A method for a dynamic shut-in of a subsea mudlift drilling system. The method comprises detecting a kick, isolating a wellbore, and adjusting a subsea mudlift pump and a surface mud pump to provide a selected wellbore pressure. Selected well parameters are measured and used to calculate a kick intensity.

Abstract: A method for controlling a subsea well that includes shutting at least one blowout preventer, opening at least one isolation line, and circulating an influx out of a well while an inlet pressure of a subsea mudlift pump is adjusted to maintain a substantially constant drill pipe pressure at an initial circulating pressure. After the influx is circulated out of the well, drilling mud with a kill mud weight is pumped into the well. The drill pipe pressure is reduced according to a preselected drill pipe pressure decline schedule until the kill mud weight drilling mud reaches the bottom of the well. The drill pipe pressure is then maintained at a final circulating pressure by adjusting the inlet pressure of the subsea mudlift pump. The kill mud weight drilling mud is then circulated from the well bottom to the surface at the final circulating pressure.

Abstract: A method for detecting a leak in a drill string valve used when drilling a subsea well. The method comprises measuring a first inlet pressure at a subsea mudlift pump while a subsea mudlift pump and a surface pump are operating and before a well is fully shut-in and measuring a second inlet pressure at the subsea mudlift pump after the mudlift pump and the surface pump are shut down and after the well is fully shut-in. The first and second subsea mudlift pump inlet pressure measurements are then compared, and a check is performed to determine if the subsea mudlift pump inlet pressure has increased by an amount greater than an estimated annular friction pressure.

Abstract: A method for a dynamic shut-in of a subsea mudlift drilling system. The method comprises detecting a kick, isolating a wellbore, and adjusting a subsea mudlift pump and a surface mud pump to provide a selected wellbore pressure. Selected well parameters are measured and used to calculate a kick intensity. The invention is also a method for a dynamic shut-in of a subsea mudlift drilling system including detecting a kick and isolating a wellbore. A first inlet pressure of a subsea mudlift pump and a first drill pipe pressure are measured. A rate of the subsea mudlift pump and a rate of a surface mud pump are adjusted to pre-kick circulation rates. A second inlet pressure of the subsea mudlift pump and a second drill pipe pressure are recorded. The measured values are used to calculate a kick intensity.