Numerical Simulation of Mud Discharge after Drilling Riser Emergency Disconnection

摘要

After emergency disconnection of a drilling riser, drilling mud mostlydischarges directly from riser bottom and generates a fast-openingwaterhammer. A new numerical procedure is developed to simulate theflow of mud discharge, in which WENO scheme and TVD Runge-Kutta scheme are applied to discrete the governing equation, and LevelSet method is adopted to track the top level of mud column during mudfalling and seawater refilling. Also, a whole fluid column model isintroduced as a contrast. Case calculation shows variations of flowvelocity, acceleration, fluid pressure and flow friction force of drillingmud during discharging.