A rotary steering tool includes a steering member configured to move between a retracted configuration and an extended configuration. The rotary steering tool also includes a pump configured to pump a fluid, a power source independent of the downhole motor, the power source configured to power the pump, and a piston in fluid communication with the pump. The piston is configured to apply a force to the steering member to move the steering member from the retracted configuration to the extended configuration when the pump pumps the fluid at an operating system pressure. The rotary steering tool includes a controller to operate the pump at a range of operating system pressures, and a variable pressure control valve. The variable pressure control valve adjusts the operating system pressure between the range of operating system pressures to adjust the force applied to the steering member.

A method to provide support within a wellbore includes underreaming a section of the wellbore at a depth spanning a layer of an unstable formation. The method also includes deploying a bistable structure within the wellbore at the depth of the layer of the unstable formation. Additionally, the method includes actuating an expandable packer within the bistable structure to expand the bistable structure in a radially outward direction from a longitudinal axis of the bistable structure. The bistable structure is in contact with walls of the underreamed section of the wellbore upon expanding in the radially outward direction.

An apparatus is positioned within a wellbore in a subterranean formation. The apparatus includes a housing, a guide shaft, a follower, multiple underreamer blades, and a hydraulic chamber. The housing defines a track including multiple catch points. The guide shaft is disposed within the housing. The follower protrudes radially outward form the guide shaft and is received by the track. The follower and the track are cooperatively configured to restrict movement of the guide shaft relative to the housing. A rate of flow to the guide shaft is adjusted to adjust a relative position of the guide shaft with respect to the housing until the follower is located at one of the catch points. A pressure within the hydraulic chamber is adjusted to adjust a level of radially outward protrusion of the underreamer blades. The underreamer blades are rotated to cut into the subterranean formation.

A method to provide support within a wellbore includes underreaming a section of the wellbore at a depth spanning a layer of an unstable formation. The method also includes deploying a bistable structure within the wellbore at the depth of the layer of the unstable formation. Additionally, the method includes actuating an expandable packer within the bistable structure to expand the bistable structure in a radially outward direction from a longitudinal axis of the bistable structure. The bistable structure is in contact with walls of the underreamed section of the wellbore upon expanding in the radially outward direction.

A rotary steering tool includes a steering member configured to move between a retracted configuration and an extended configuration. The rotary steering tool also includes a pump configured to pump a fluid, a power source independent of the downhole motor, the power source configured to power the pump, and a piston in fluid communication with the pump. The piston is configured to apply a force to the steering member to move the steering member from the retracted configuration to the extended configuration when the pump pumps the fluid at an operating system pressure. The rotary steering tool includes a controller to operate the pump at a range of operating system pressures, and a variable pressure control valve. The variable pressure control valve adjusts the operating system pressure between the range of operating system pressures to adjust the force applied to the steering member.

An over-bit backreamer. The backreamer is configured to be placed over a bit without detaching the bit from a drill string associated with a pilot bore. The backreamer has an internal surface that conforms to a steering surface of the bit. Rotation is transferred from the bit to the backreamer at the internal surface. The backreamer further defines a flange which interacts with a feature, such as a heel, on the bit. The flange and heel form a shoulder which transfers pullback force to the bit. The backreamer comprises a pullback eye that pulls a product pipe back through the borehole.

A drilling device for drilling a hole in the ground and/or rock and having in its drilling head a plurality of drilling wing bits arranged at equal distribution with their mutual position being adjustable such that the wing bits are located within a minimum diameter dimension and, on the other hand, adjustable such that they are located to drill a hole with a maximum size diameter and that the drilling device is arranged to pull, during drilling, a protective pipe into the hole at least when drilling the hole in the ground. An outer circumference of the wing bits includes a circumferential groove arranged to receive a ring belonging to a front part of the protective pipe, to an inner surface thereof, when the wing bits are adjusted to a diameter size substantially larger than the minimum diameter dimension in order to pull the protective pipe via the wing bits.

An over-bit backreamer. The backreamer is configured to be placed over a bit without detaching the bit from a drill string associated with a pilot bore. The backreamer has an internal surface that conforms to a steering surface of the bit. Rotation is transferred from the bit to the backreamer at the internal surface. The backreamer further defines a flange which interacts with a feature, such as a heel, on the bit. The flange and heel form a shoulder which transfers pullback force to the bit. The backreamer comprises a pullback eye that pulls a product pipe back through the borehole.

This cutting assembly provides a radially grooved body insert upon which cutter arms with complementary radial grooves may translate to extend the cutter arms in a radial fashion from a body of a downhole drilling assembly. This improved cutting assembly design can be incorporated into an underreamer, hole opener, drill bit, or section mill.

Using a rock crushing system for widening a pilot hole on rocky terrain includes taking a plurality of crushing elements, for example roller bits and/or cutter discs, pressing the crushing elements against the lateral wall of the pilot hole and at the same time rolling the crushing elements along a cylindrical portion of the lateral wall, widening the pilot hole. The crushing elements, free to rotate with respect to an axis thereof, are radially pushed by hydraulic cylinders. Stabilising means exemplarily include a basket abutting the lateral wall to keep a main body bearing the hydraulic cylinders centered with respect to an axis of the pilot hole during the rock crushing.