Patent ID: 6457529
Filing Date: 2002-10-01
Classification: E21B

Abstract:
In an apparatus for drilling a subsea well, the apparatus having a subsea wellhead assembly enclosing a drill pipe, the drill pipe having a bore through which drilling fluid is delivered and a drill pipe annulus between the drill pipe and a bore of the well, an improved pump assembly for returning drilling fluid flowing up the drill pipe annulus to a surface vessel, the pump assembly comprising:a submersible pump having an inlet and an outlet, the inlet being in fluid communication with seawater surrounding the wellhead assembly; a conduit extending from the outlet of the pump to the surface vessel for delivering seawater to the surface vessel; a venturi in the conduit for creating a lower pressure area due to the seawater flowing though the venturi; and a passage extending from the drill pipe annulus to the venturi for drawing drilling fluid from the drill pipe annulus into the conduit.