Subsea drilling assembly

Claim 2

In an off-shore drilling assembly: a main body adapted to be positioned on the sea bottom and including an axially movable drill for rotating a drill string which includes a core barrel assembly provided with a detachable and replacable inner tube assembly for receiving and retaining a core, and a feeding device for displacing the drill axially, and a traveller body adapted to travel between a floating structure and the main body along a flexible guide, carrying a core-containing core barrel inner tube assembly from the main body to the floating structure and an empty core barrel inner tube assembly from the floating structure to the main body, means for releasably anchoring the traveller body to said main body, and a device in the traveller body arranged to be lowered from the traveller body into the borehole for retrieving a core-containing inner tube assembly from the core barrel.

Claim 3

A drilling assembly as claimed in claim 1 in which the retrieving device is adapted to lower an empty inner tube assembly into the borehole alternatively to fetching a core-containing inner tube assembly from the borehole.

Claim 4

A drilling assembly as claimed in claim 1 in which said flexible guide comprises at least two lines for lowering the main body from the floating structure to the sea bottom, means for sensing the horizontal direction are arranged on the main body, and a propelling means is arranged on the main body for preventing rotation of the main body during said lowering of the main body.

Claim 5

A drill assembly as claimed in claim 1 in which a flush-water pump has its intake of sea-water at the upper portion of the drill, said traveller body and said upper portion of the drill define a closed suction chamber when the traveller body is seated on the drill, said inlet of seawater ends in said closed suction chamber, and a back-pressure check valve is arranged to permit sea-water to said closed chamber, said flush-water pump thereby providing said anchoring of the traveller body to the main body.

Claim 6

A drilling assembly as claimed in claim 1 in which the core retrieving device is suspended in a wire, a flush water pump is arranged so as to supply flush water to the drill string, a valve is arranged in the flush water supply conduit, and the traveller body is arranged to shift the valve into connecting the flush water pump outlet to a space in said travelling body at the rear of said retrieving device so that said retrieving device is pumped down into the bore hole when the travel body seats on the drill.

Claim 7

A drilling assembly as claimed in claim 1 in which said feeding device comprises a vertical double-acting hydraulic jack which is mounted on the main body and carries the drill axially movably.

Claim 8

A drilling assembly as claimed in claim 6 in which an arm structure with an elbow-joint is pivotably connected between the unmovable part of the main body and the drill.

Claim 9

A drilling assembly as claimed in claim 6 in which the drill includes a drive rod onto the lower end of which a drill string element can be screwed, and a reversible rotation motor for rotating the drive rod, and the main body further comprises a freely rotatable chuck unit having two independently fluid actuated sets of chuck jaws, the upper of the sets of jaws being adapted for gripping the drive rod and the lower of the sets of jaws for gripping a drill string element when such a drill string element has been screwed to the lower end of the drive rod and the drill is in an upper position, said chuck unit being axially movable, a fluid actuated means for locking said chuck unit against rotation, a magazine below said chuck housing and arranged to store a casing tube and a number of drill string elements, a drill string clamp below said magazine, and a casing tube clamp below said drill string clamp.

Claim 10

A drilling assembly as claimed in claim 1 in which the main body is provided with sheave means and said flexible guide comprises a line deviated over the sheave means so that the main body can be lowered from the floating structure and lifted to the floating structure in the line.

Claim 11

A drilling assembly as claimed in claim 9 in which the traveller body is adapted to be clamped to one part of said line and guided on the other part so that it can be pulled up and down between the floating structure and the main body by means of the line.

Claim 12

In an off-shore drilling assembly: a remote controlled main body arranged to be positioned on the sea bottom from a floating structure and including a drilling device for rotating and feeding a drill string, a watertight housing filled with oil and being a part of the main body, an oil pump in the housing taking oil directly from the oil surrounding it and delivering pressure oil to a hydraulic motor, means for returning low pressure oil to the housing from the hydraulic motor, an electric motor in the housing driving the oil pump, an electric power line from the floating structure to the electric motor in the housing, and an oil accumulating device taking up the fluctuations in volume of the low pressure oil.

Claim 13

In an off-shore drilling assembly: a remote controlled main body arranged to be positioned on the sea bottom from a floating structure and including a drilling device for rotating and feeding a drill string, a watertight housing filled with oil and being a part of the main body, an oil pump in the housing taking oil directly from the oil surrounding it and delivering pressure oil to a hydraulic motor, means for returning low pressure oil to the housing from the hydraulic motor, an electric motor in the housing driving the oil pump, an electric power line from the floating structure to the electric motor in the housing, and an oil accumulating device taking up the fluctuations in volume of the low pressure oil.

Claim 14

A drilling assembly as claimed in claim 11 in which the accumulating device is a flexible wall member of the housing.

Claim 15

A drilling assembly as claimed in claim 11 in which at least one of the hydraulic jacks outside said watertight housing are supplied with pressure oil from said oil pump in the housing.

Claim 16

A drilling assembly as claimed in claim 11 in which the main body has three adjustable legs, and the housing is annular so as to allow the drill string to extend through the housing into the bore hole.

Claim 17

A drilling assembly as claimed in claim 14 in which the legs are adjustable by means of pressure oil delivered from said oil pump.

Claim 18

A drilling assembly as claimed in claim 14 in which a revolving magazine for a plurality of drill string elements extends into the opening of the housing.

Claim 19

A drilling apparatus arranged to be positioned on the sea bottom, lowered from a floating structure, and comprising: a frame work, means for supporting the frame work on the sea-bed, an axially movable drill including a drive rod onto the lower end of which a drill rod length can be screwed and a reversible rotation motor for rotating the drive rod, a feed motor for displacing the drill axially, a rotatable chuck unit mounted on said frame work and having two independently fluid actuated sets of chuck jaws, an upper of the sets of jaws being adapted for gripping said drive rod and the lower of the sets of jaws for gripping a drill rod length when such a drill rod length is screwed to the lower end of the drive rod and the drill is in an upper position, said chuck unit being axially movable, a fluid actuated means for locking said chuck unit against rotation, a magazine below said chuck housing and arranged to store a casing tube and a number of drill rods, a drill rod clamp below said magazine, and a casing tube clamp below said drill rod clamp.

Claim 20

A drilling apparatus arranged to be positioned on the sea bottom, lowered from a floating structure, and comprising: a frame work, means for supporting the frame work on the sea-bed, an axially movable drill including a drive rod onto the lower end of which a drill rod length can be screwed and a reversible rotation motor for rotating the drive rod, a feed motor for displacing the drill axially, a rotatable chuck unit mounted on said frame work and having two independently fluid actuated sets of chuck jaws, an upper of the sets of jaws being adapted for gripping said drive rod and the lower of the sets of jaws for gripping a drill rod length when such a drill rod length is screwed to the lower end of the drive rod and the drill is in an upper position, said chuck unit being axially movable, a fluid actuated means for locking said chuck unit against rotation, a magazine below said chuck housing and arranged to store a casing tube and a number of drill rods, a drill rod clamp below said magazine, and a casing tube clamp below said drill rod clamp.

Claim 21

A drilling apparatus as claimed in claim 17 in which the feed motor is an upright double acting hydraulic feed jack which is a part of the frame work, and the drill is mounted on the piston rod of the feed jack.

Claim 22

A drilling apparatus as claimed in claim 18 in which articulated struts for taking up reaction torque is mounted between the cylinder of the feed jack and the drill.