A directional casing drilling system includes a casing string, a drilling rig and a retrievable Bottom Hole Assembly (BHA). The drilling rig includes a casing drive for rotating the casing string in the borehole, a control system for controlling the casing drive, and a mud pump for pumping a continuous flow of drilling mud into the casing string. The BHA includes a torque transfer section, with which it is secured in the casing string, and a drill bit section held in a drilling position in the torque transfer section. It further includes a mud drive that rotates the drilling position of the drill bit section about the longitudinal axis of the torque transfer section, and a communicating device for communicating the orientation of the drill bit to the control system. The BHA is steered by adjusting the rotational speed of the casing string.

A caisson or casing 107 for installing a sheet 102/103 into a ground or underwater location, the caisson 107 having a shaped wall 107.1, which is open for a predetermined length and is adapted to receive and connect to an excavation means 3 within the confines of the caisson or casing 107. In at least one embodiment, the system includes a drilling assembly 3 for insertion of a caisson or casing 1, the drilling assembly 3 having one or more expanding drill bits 4 which are adapted to be driven by a drilling or rotation motive device 5, the expanding drill bits 4 being adapted to be arranged with respect to the caisson or casing 1 in use, so as form a hole or bore which substantially conforms to, or substantially overlaps with, the shape of the caisson or casing 1.

A drill string apparatus includes an upper casing section having a port collar. The port collar provides a controllable opening from an interior of the upper casing section to an annulus around the upper casing section. A lower casing section is coupled to the upper casing section through a swivel. The lower casing section includes an external casing packer and a casing pad coupled to an external portion of the lower casing section. The external casing packer is expandable to an annulus around the lower casing section before a cement operation to avoid cement loss circulation to weak formation below the packer. Methods and systems are also disclosed.

A method of controlling fluid flow between two tubulars includes disposing a sealing member in an annular area between two tubulars, wherein the two tubulars partially overlap; moving the sealing member to a lower position where it is not in contact with one of the tubulars, thereby allowing fluid flow through the annular area; and moving the sealing member to an upper position where it is in contact with both of the tubulars, thereby preventing fluid flow through the annular area.

In an assembly for lowering and expanding a tubular element in a borehole on an expansion string, at least part of the weight of the tubular element is transmitted to the expansion string via an internal upset and support means protruding from an outer surface of the expansion string below the internal upset.

A method of forming a wellbore includes providing a drilling assembly comprising one or more lengths of casing and an axially retracting assembly having a first tubular; a second tubular at least partially disposed in the first tubular and axially fixed thereto; and a support member disposed in the second tubular and movable from a first axial position to a second axial position relative to the second tubular, wherein, in the first axial position, the support member maintains the second tubular axially fixed to the first tubular, and in the second axial position, allows the second tubular to move relative to the first tubular; and an earth removal member disposed below the axially retracting assembly. The method also includes rotating the earth removal member to form the wellbore; moving the support member to the second axial position; and reducing a length of the axially retracting assembly.

A caisson or casing 107 for installing a sheet 102/103 into a ground or underwater location, the caisson 107 having a shaped wall 107.1, which is open for a predetermined length and is adapted to receive and connect to an excavation means 3 within the confines of the caisson or casing 107. In at least one embodiment, the system includes a drilling assembly 3 for insertion of a caisson or casing 1, the drilling assembly 3 having one or more expanding drill bits 4 which are adapted to be driven by a drilling or rotation motive device 5, the expanding drill bits 4 being adapted to be arranged with respect to the caisson or casing 1 in use, so as form a hole or bore which substantially conforms to, or substantially overlaps with, the shape of the caisson or casing 1.

Disclosed is a drillable adaptive turbine guide shoe, including an adaptive booster component and a power casing shoe component; the adaptive booster component includes a supercharging hollow shaft, a supercharging shell, a disc spring group, a shunt head, a jet oscillator and a semi-cylindrical ring, the supercharging hollow shaft is slidably connected to the supercharging shell, one end of the supercharging hollow shaft is a liquid inlet end and the other end is closed, a cavity is formed between the supercharging hollow shaft and the supercharging shell, and the disc spring group is built in the cavity, the jet oscillator and the semi-cylindrical ring are mounted on the inner wall of the supercharging shell, and one side of the jet oscillator and the semi-cylindrical ring abuts against the shunt head, the shunt head is sleeved on the outer wall of the supercharging hollow shaft; this disclosure solves the problem that the casing cannot be effectively run when the wellbore has sand bridges or wellbore necking.

An arrangement and a method for installing a casing in a borehole are described. The arrangement includes a casing, a boring pipe, which is adapted within the casing, and the boring pipe includes flow channels for compressed air and a flushing medium. The flushing medium flow channel is arranged to lead the flushing medium to the bottom of the borehole. The arrangement also includes a percussion hammer, which includes a compressed air operated percussion piston adapted in a cylinder of the percussion hammer, as well as hole drilling means for drilling a hole for the casing. The flushing medium flow channel is adapted to bypass the percussion piston or which flushing medium flow channel is adapted to pass through the percussion piston, and in which arrangement the drilling means additionally includes splines transmitting a rotating motion and adapted to conduct the compressed air that used the percussion piston through the splines.

Disclosed is a drillable adaptive turbine guide shoe, including an adaptive booster component and a power casing shoe component; the adaptive booster component includes a supercharging hollow shaft, a supercharging shell, a disc spring group, a shunt head, a jet oscillator and a semi-cylindrical ring, the supercharging hollow shaft is slidably connected to the supercharging shell, one end of the supercharging hollow shaft is a liquid inlet end and the other end is closed, a cavity is formed between the supercharging hollow shaft and the supercharging shell, and the disc spring group is built in the cavity, the jet oscillator and the semi-cylindrical ring are mounted on the inner wall of the supercharging shell, and one side of the jet oscillator and the semi-cylindrical ring abuts against the shunt head, the shunt head is sleeved on the outer wall of the supercharging hollow shaft; this disclosure solves the problem that the casing cannot be effectively run when the wellbore has sand bridges or wellbore necking.