| 摘要 |
The invention describes a method for drilling in the floor of an ocean from a floating structure. A seal housing (20) having a rotatable seal connected above a portion of a riser R which is fixed to the floor of the ocean. The seal rotates with tubular to allow the riser R and seal housing (20) to maintain a predetermined pressure. A flexible conduit is used to compensate for relative movement of the seal housing (20) and the floating structure because the floating structure moves independent of the seal housing (20). The drilling fluid is pumped from the floating structure into an annulus of the riser R, allowing the formation of a mud cap (1330) downhole in the riser R, or allowing reverse circulation of the drilling fluid down the riser R, returning up the rotatable tubular to the floating structure.
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