A component for a rock breaking system is magnetized into a state of remanent magnetization. The remanent magnetization of the component has a predetermined varying magnetization profile relative to geometry of the component, the varying magnetization profile describing varying magnetization intensity in the component relative to the geometry of the component.

The hydraulic rotary-percussive hammer drill includes a fluid injection portion including a fluid feed-in inlet and an annular inner groove fluidly connected to the fluid feed-in inlet; a shank including a fluid injection conduit fluidly connected to the annular inner groove; front and rear main sealing gaskets disposed on either side of the annular inner groove and configured to cooperate with a first shank portion of the shank; a rear backup sealing gasket located at the rear of the rear main sealing gasket and configured to cooperate with a second shank portion of the shank; a leakage passage defined between the shank and the fluid injection portion; pressure drop generation means configured to generate pressure drops in the leakage passage when a leakage flow flows in the leakage passage.

The hydraulic rotary-percussive hammer drill includes a fluid injection portion including a fluid feed-in inlet and an annular inner groove fluidly connected to the fluid feed-in inlet; a shank including a fluid injection conduit fluidly connected to the annular inner groove; front and rear main sealing gaskets disposed on either side of the annular inner groove and configured to cooperate with a first shank portion of the shank; a rear backup sealing gasket located at the rear of the rear main sealing gasket and configured to cooperate with a second shank portion of the shank; a leakage passage defined between the shank and the fluid injection portion; pressure drop generation means configured to generate pressure drops in the leakage passage when a leakage flow flows in the leakage passage.

A bottomhole assembly includes: a drill bit operable to vibrate when engaged with a formation and rotated; and a suspension sub including: a stator barrel for connection to a pipe string; a traveler barrel for connection to the drill bit; a slip joint longitudinally coupling the traveler barrel to the stator barrel while allowing movement of the traveler barrel between an extended position and a retracted position; a torsional joint connecting the traveler barrel to the stator barrel at and between the positions; and one or more springs disposed between the stator barrel and the traveler barrel. The suspension is tuned relative to the drill bit to: dampen the vibration of the drill bit when the BHA is rotated at a first angular velocity; and resonate the vibration of the drill bit when the BHA is rotated at a second angular velocity, thereby imparting percussive energy to the drill bit.

Various embodiments include methods and apparatus structured to increase efficiencies of a drilling operation. A drilling apparatus can be structured to include a hammer drill to move a hammer to impart impact force to a bit box in conjunction with a rotary drive shaft. The hammer drill can be arranged as a mechanical drive hammer capable of being applied to both fluid drilling and air drilling. Additional apparatus, systems, and methods are disclosed.

Various embodiments include methods and apparatus structured to increase efficiencies of a drilling operation. A drilling apparatus can be structured to include a hammer drill to move a hammer to impart impact force to a bit box in conjunction with a rotary drive shaft. The hammer drill can be arranged as a mechanical drive hammer capable of being applied to both fluid drilling and air drilling. Additional apparatus, systems, and methods are disclosed.

The present invention relates to a downhole wireline tool for performing a machining operation, such as milling, in a well having a top, the downhole wireline tool having a longitudinal axis, a first end configured to be connected to a wireline and a second end forming a front of the tool facing away from the wireline along the longitudinal axis, the downhole wireline tool comprising a tool housing, a holding section having projectable parts configured to prevent a part of the downhole wireline tool from moving in a direction towards the top, a machining tool arranged in the front of the tool, and a rotation unit for rotating the machining tool, wherein the downhole wireline tool further comprises an oscillation device having a rotational stationary part being connected with the rotation unit and a rotational part being connected to the machining tool, the oscillation device being configured to provide an oscillating movement of the machining tool by oscillating the rotational part in relation to the rotational stationary part.

The present invention relates to a downhole wireline tool for performing a machining operation, such as milling, in a well having a top, the downhole wireline tool having a longitudinal axis, a first end configured to be connected to a wireline and a second end forming a front of the tool facing away from the wireline along the longitudinal axis, the downhole wireline tool comprising a tool housing, a holding section having projectable parts configured to prevent a part of the downhole wireline tool from moving in a direction towards the top, a machining tool arranged in the front of the tool, and a rotation unit for rotating the machining tool, wherein the downhole wireline tool further comprises an oscillation device having a rotational stationary part being connected with the rotation unit and a rotational part being connected to the machining tool, the oscillation device being configured to provide an oscillating movement of the machining tool by oscillating the rotational part in relation to the rotational stationary part.

This hydraulic drilling apparatus including a casing comprising a front part, a shank including a fluid injection conduit and intended to be coupled to at least one drill rod equipped with a tool, the shank, a striking piston slidably mounted inside the casing along a striking axis (A) and configured to strike the shank, an extraction piston disposed around the shank and comprising an extraction portion configured to cooperate with the shank, and a cartridge removably mounted on the front part and disposed around the shank, the cartridge including an injection part configured to fluidly connect the fluid injection conduit to a fluid delivery conduit. The cartridge delimits a receiving housing in which the extraction piston is slidably mounted.

A downhole tool assembly for use in a drilling string includes a motor, a flow head, and a flow restrictor. The flow head is coupled to the motor and comprises a plurality of ports permitting fluid communication therethrough. The flow restrictor is in fluid communication with the flow head and comprises a plurality of ports permitting fluid communication therethrough. The flow restrictor is stationary with respect to the flow head, which rotates. As the flow head rotates, one or more of the plurality of ports of the flow head enters into and out of alignment with one or more of the plurality of ports of the flow restrictor such that fluid flow through the ports of the flow head and the flow restrictor is constrained to a cyclic, polyrhythmic pattern optionally including at least one interval where the fluid flow is substantially blocked by the flow restrictor.