| 摘要 |
A subsea drilling system comprises a pressurized drilling capsule that is sealed against the subsea environment and houses equipment for manipulating a drillstring that extends through an opening in the drilling capsule to the exterior of the capsule. A drilling fluid handling assembly is contained within the drilling capsule that communicates drilling fluid through the drillstring and returns the drilling fluid to the water's surface via a drilling fluid conduit. A seafloor unit engages the seafloor and the drilling capsule to position the drilling capsule relative to the seafloor, and includes an opening for passi ng the drillstring into the seafloor. A pressurized transport unit is movable between the drilling capsule and a support vessel at or near the water's surface for delivering personnel and supplies to the drilling capsule. A method of drilling using the subsea drilling system is achieved by pressurizing a drilling capsule assembly and maintaining the drilling capsul e assembly in a pressurized state suitable for human occupancy. The drilling capsule assembl y is submerged by altering its buoyancy. The drilling capsule assembly is secured to the formation by drilling a pilot hole in the formation from within the drilling capsule assembly and by inserting a portion of thedrilling capsule assembly into the pilot hole. A drillstring is delivered to the drilling capsule assembly, the drillstring including at lea st one length of 30--foot drillpipe. A bottomhole assembly is made up into the drillstring and rotated from within the drilling capsule to bore a hole in the formation. The drillstring is selectively removed from the hole and the drilling capsule assembly, wherein the drillstring remains assembled and includes at least one length of 30-foot drill pipe.
|
