Patent ID: 7237613

Claim:
In a riser assembly for offshore drilling having a riser for fluid communication between a drilling platform and a subsea wellhead housing, the improvement comprising: an inner conduit that is run into and suspended in the riser, defining an annular space between the inner conduit and the riser; a seal assembly that seals the annular space at a point between a lower portion of the inner conduit and the riser, the seal assembly having a pressure area that is independent of the inner conduit so that any forces acting on the seal assembly due to pressure in the annular space below the seal assembly pass through the seal assembly to the riser and bypass the inner conduit; and wherein the seal assembly comprises a seal sleeve that is carried on the inner conduit for movement between a first position while running the inner conduit into the riser and an axially spaced second position after the inner conduit has landed in the riser.