Method for controlling a well in a subsea mudlift drilling system
First Claim
1. A method for controlling a subsea well, the method comprising:
- shutting at least one blowout preventer;
opening at least one isolation line;
circulating a formation fluid influx out of a well while an inlet pressure of a subsea mudlift pump is adjusted to maintain a drill pipe pressure at a substantially constant initial circulating pressure;
pumping drilling mud with a kill mud weight from a water surface into the well;
reducing the drill pipe pressure according to a preselected drill pipe pressure decline schedule until the kill mud weight drilling mud reaches a bottom of the well;
maintaining the drill pipe pressure at a substantially constant final circulating pressure after the kill mud weight drilling mud reaches the bottom of the well by adjusting the inlet pressure of the subsea mudlift pump; and
circulating the kill mud weight drilling mud from the bottom of the well to the water surface while maintaining the substantially constant final circulating pressure.
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Accused Products
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.
82 Citations
45 Claims
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1. A method for controlling a subsea well, the method comprising:
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shutting at least one blowout preventer;
opening at least one isolation line;
circulating a formation fluid influx out of a well while an inlet pressure of a subsea mudlift pump is adjusted to maintain a drill pipe pressure at a substantially constant initial circulating pressure;
pumping drilling mud with a kill mud weight from a water surface into the well;
reducing the drill pipe pressure according to a preselected drill pipe pressure decline schedule until the kill mud weight drilling mud reaches a bottom of the well;
maintaining the drill pipe pressure at a substantially constant final circulating pressure after the kill mud weight drilling mud reaches the bottom of the well by adjusting the inlet pressure of the subsea mudlift pump; and
circulating the kill mud weight drilling mud from the bottom of the well to the water surface while maintaining the substantially constant final circulating pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for controlling a subsea well, the method comprising:
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shutting at least one blowout preventer;
opening at least one isolation liner;
circulating a formation fluid influx out of a well while an inlet pressure of a subsea mudlift pump is adjusted to maintain a drill pipe pressure at a substantially constant initial circulating pressure;
pumping drilling mud with a kill mud weight from a water surface into the well;
holding the inlet pressure of the subsea mudlift pump substantially constant until the kill mud weight drilling mud reaches a bottom of the well;
adjusting the inlet pressure of the subsea mudlift pump to maintain the drill pipe pressure at a substantially constant final circulating pressure after the kill mud weights drilling mud reaches the bottom of the well; and
circulating the kill mud weight drilling mud from the bottom of the well to the water surface while maintaining the substantially constant final circulating pressure. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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Specification