Patent ID: 9062498
Filing Date: 2015-06-23
Classification: E21B

Abstract:
1. Drilling system for drilling subsea wells from a floating mobile offshore drilling unit (MODU), the system comprising: a subsea BOP attached to a well below a seabed, the BOP not being connected to the MODU by a marine riser; flexible choke and kill lines arranged between the subsea BOP and the MODU; a drill string guiding and cleaning apparatus, configured for guiding a drill string when inserting or taking out the drill string from the well, the guiding and cleaning apparatus being further configured for drill string cleaning when pulling the drill string out from the well; a recovery funnel arranged below the drill string guiding and cleaning apparatus, but above the well; a seawater leakage control system configured for pressure control that enables controlled leakage of seawater into the recovery funnel while inhibiting polluted seawater from flowing out of the recovery funnel; and a fluid return system configured for return from the recovery funnel to the MODU of drilling fluid and seawater leaked into the recovery funnel, said fluid return system including separate drilling fluid and polluted water outlet lines extending from the recovery funnel, said outlet lines being in fluid communication with separate drilling fluid and polluted water pumps and return lines.