Patent ID: 9260927
Filing Date: 2016-02-16
CPC Classification: B63B,E21B

Claim Text:
1. A method, comprising the steps of: pumping a fluid at a determined flow rate into a drill string disposed in a wellbore, the drill string being suspended from a drilling platform floating on a body of water; measuring a fluid pressure of the fluid returning from the wellbore within a fluid discharge line, the fluid discharge line having a variable length portion configured to vary the length of the fluid discharge line to correspond to a change in elevation of the drilling platform above a bottom of the body of water; determining a wellbore pressure at a selected position, the wellbore pressure being determined using at least the measured fluid pressure; and adjusting the determined wellbore pressure to account for changes in length of the fluid discharge line corresponding to changes in elevation of the drilling platform above the bottom of the body of water.