METHOD FOR MAINTAINING WELLBORE PRESSURE.

摘要

A method for maintaining wellbore pressure includes reducing flow rate of a drilling fluid pump fluidly connected to a drill pipe in the wellbore. Flow out of the well is enabled into a first auxiliary line associated with a drilling riser. A seal around the drill pipe is closed. Fluid is pumped down a second auxiliary line at a rate selected to maintain a specific pressure in the wellbore. Drilling fluid flow through the drill pipe is stopped.