A flow diversion sub for a down-the-hole drill comprising a housing assembly that includes a housing body, a cap extending from the housing body, and a drive shaft having an upper central blind hole and a lower central blind hole spaced from the upper central blind hole, wherein the drive shaft is received within the housing assembly. In operation, one of the housing assembly and drive shaft moves between a first position and a second position relative to the other of the housing assembly and drive shaft. In the first position the upper central blind hole is in fluid communication with the lower central blind hole, and in the second position the upper central blind hole is blocked from being in fluid communication with the lower central blind hole.

A device for generating pressure waves in a well or a wellbore. The device includes a housing containing an impact-generating mechanism for generating the pressure waves and a connector for connecting the housing to a conveyor for transporting the device to any desired location within the well or the wellbore. The device may be used for a number of downhole applications such as cleaning perforations, fracturing processes, vibration of a casing to prevent fluid flow in a cemented annulus, hydraulic jar operations for freeing stuck downhole objects, generating data to optimize pumping parameters and as an enhancement to percussion drilling techniques.

A device for generating pressure waves in a well or a wellbore. The device includes a housing containing an impact-generating mechanism for generating the pressure waves and a connector for connecting the housing to a conveyor for transporting the device to any desired location within the well or the wellbore. The device may be used for a number of downhole applications such as cleaning perforations, fracturing processes, vibration of a casing to prevent fluid flow in a cemented annulus, hydraulic jar operations for freeing stuck downhole objects, generating data to optimize pumping parameters and as an enhancement to percussion drilling techniques.

A hydraulic hammering device is capable of sufficiently transmitting blow energy to bedrock while further strengthening cushioning action and suppressing damage to equipment. The device includes a pushing piston disposed behind a transmission member and having a smaller propulsive force than that of a main body, a damping piston positioned behind the pushing piston to slide reciprocally forwards and backwards and having a greater propulsive force than that of the main body, a direction-restrictor in a high-pressure circuit between pushing and damping chambers, to which hydraulic fluid is supplied for providing the pistons with propulsive forces, and a fluid supply source. The direction-restrictor restricts an outflow from the chambers side to the fluid supply source side while allowing fluid inflow from the fluid supply source side to the chambers and the pushing chamber sides. A throttle in a drain circuit discharges leaked fluid from a sliding contact location to a tank.

A down the hole rock drilling machine and a method of drilling rock. The drilling machine includes a reciprocating piston, which has a sleeve-like configuration. Inside a central opening of the piston is arranged one or more fluid passages for conveying pressurized fluid during the work cycle of an impact device of the drill machine.

A down the hole rock drilling machine and a method of drilling rock. The drilling machine includes a reciprocating piston, which has a sleeve-like configuration. Inside a central opening of the piston is arranged one or more fluid passages for conveying pressurized fluid during the work cycle of an impact device of the drill machine.

A method of monitoring a rock drilling and a rock drilling device includes generating a stress wave, which propagates in a tool of the rock drilling device, measuring the stress wave propagating in the tool and measuring a drilling parameter indicating a drilling penetration rate. The method further includes identifying, from the measured stress wave propagating in the tool, at least one of a compressive stress wave and a tensile stress wave of a reflected stress wave reflected from a rock to be drilled back to the tool, determining at least one property of the at least one of the compressive stress wave and the tensile stress wave of the reflected stress wave, detecting, on the basis of a change in the at least one property of the at least one of the compressive stress wave and the tensile stress wave, that the tool is approaching the cavity.

For clearing of the bore liners of geothermal wells, disclosed is a clearing tool that can be used without a drive motor, but with a drive hammer, to clear mineral deposits from the inside of the bore liners of geothermal wells. A forward end clears unwanted material from a live well. An aft end engages with a hammer device. The tool also has working surfaces to bear against and to cut through or to break up the unwanted material, at least one bypass passage conveying fluid from the live well through the clearing tool, and at least one exhaust passage communicating with the hammer device and conveying exhaust gases from the hammer to exhaust exit ports. The location of at least one exhaust exit port is a location that is situated aft of a forward face of the forward end of the clearing tool.

For clearing of the bore liners of geothermal wells, disclosed is a clearing tool that can be used without a drive motor, but with a drive hammer, to clear mineral deposits from the inside of the bore liners of geothermal wells. A forward end clears unwanted material from a live well. An aft end engages with a hammer device. The tool also has working surfaces to bear against and to cut through or to break up the unwanted material, at least one bypass passage conveying fluid from the live well through the clearing tool, and at least one exhaust passage communicating with the hammer device and conveying exhaust gases from the hammer to exhaust exit ports. The location of at least one exhaust exit port is a location that is situated aft of a forward face of the forward end of the clearing tool.

A device for generating pressure waves in a well or a wellbore. The device includes a housing containing an impact-generating mechanism for generating the pressure waves and a connector for connecting the housing to a conveyor for transporting the device to any desired location within the well or the wellbore. The device may be used for a number of downhole applications such as cleaning perforations, fracturing processes, vibration of a casing to prevent fluid flow in a cemented annulus, hydraulic jar operations for freeing stuck downhole objects, generating data to optimize pumping parameters and as an enhancement to percussion drilling techniques.