The invention relates to an underwater drilling apparatus comprising a lowerable platform configured for setting down on a waterbody bottom, at least one support tube axially displaceable and rotatably mounted on the platform, at least one tubular drive arranged on the platform and configured for rotationally driving the support tube, in order to rotationally introduce the support tube into the waterbody bottom, and an in-hole drilling rig arranged in the support tube, wherein the in-hole drilling rig comprises: a rig base body, at least one clamping device for bracing and securing the in-hole drilling rig in the support tube, and a drill head which is axially displaceably and is rotatably mounted on the rig base body and can be rotationally driven by means of a drill drive. According to the invention, it is provided that, when the support tube is rotationally driven, the in-hole drilling rig is arranged in the support tube and is axially clamped thereto.

A valve arrangement in a tubular having a first one way valve configured to prevent fluid flow in the tubular in a first direction; and a second one way valve configured to prevent fluid flow in the tubular in a second, opposite direction.

The invention is directed to a detachable fluidisation device for use in a vertical positioned tubular foundation pile having a pile axis and comprising of a central element and radially extending fixing means. The radially extending fixing means can have a first position wherein, in use, the central element is radially fixed to the interior of the tubular foundation pile and a second position which allows the fluidisation device to axially move along the length of the tubular foundation pile. The central element has at its lower end a rotating lower end provided with horizontally extending arms. The arms are each provided with high pressure water injection nozzles and with mechanical cutting elements extending from the arm in the direction of rotation.

In one embodiment, a casing bit drive assembly may be used with a casing drilling system. The casing bit drive assembly may include one or more of the following: a retrievable drilling motor; a decoupled casing sub; a releasable coupling between the motor and casing bit; a releasable coupling between the motor and casing; a cement diverter; and a casing bit.

A method and system for directional drilling while conveying a liner, with latching parking capabilities for multiple trips, is disclosed. As the wellbore is drilled, each casing and liner is installed having upper and lower interior latch couplings. A liner to be installed below a parent casing includes an exterior latch assembly dimensioned for connection to the interior latch couplings of the parent casing. A bottom hole assembly may include upper and lower exterior inner string latch assemblies for connection to the upper and lower interior latch couplings of the liner to be installed. Such arrangement allows the liner to be conveyed and installed with the bottom hole assembly while directional drilling and for the liner to be temporarily hung from the parent casing for bottom hole assembly change-out while drilling. Float plugs dimensioned to be landed at lower liner interior latch couplings may be provided for cementing operations.

The drilling tool includes a circular-cylindrical casing pipe; an annular ring bit disposed at a leading end of the casing pipe so as to be coaxial with the casing pipe and rotatable around a central axis of the casing pipe; and a pilot bi inserted into the casing pipe and has a leading end disposed at an inner peripheral part of the ring bit. The ring bit is engaged with the pilot bit in a rotational direction, and thereby is rotatable integrally with the pilot bit and is locked to the leading end of the pilot bit. Drilling tips are mounted on the leading ends of the pilot bit and the ring bit, and first drilling tips at an outermost periphery of the pilot bit and second drilling tips at an innermost periphery of the ring bit overlap each other in a rotational trajectory around the central axis.

A casing drilling system includes a casing having a bore therethrough; a drilling member coupled to the casing; a retrievable motor releasably coupled to the casing and includes a power section configured to rotate the drilling member relative to the casing; and a cementing tube in selectively fluid communication with the bore of the casing for diverting cement from the power section of the drilling motor.

A reaming tool includes a housing having a connection at one end for coupling to a pipe string. The housing defines at least one of a rotor and a stator of a turbine. A rotor shaft is rotatably supported on the housing. The rotor shaft has an interior passage and defines the other of a stator and a rotor of the turbine. The rotor shaft has a coupling at one end to attach a well intervention tool. A flow diverter is disposed within the housing. The flow diverter comprises ports to selectively direct flow of fluid from an interior of the housing to either (i) an annular space between the housing and the rotor shaft, or (ii) the interior passage of the rotor shaft. The flow diverter is operable to change direction of the flow of fluid by changing a flow rate of the flow of fluid.