A downhole mud motor is formed of plural housings containing at least a drive section and a transmission section. At least a housing of the plural housings has a longitudinal axis and incorporates a reaming section with one or more rotary reamers. Each of the one or more rotary reamers is mounted in a respective pocket for rotation about a transverse axis relative to the longitudinal axis of the housing.

A downhole mud motor is formed of plural housings containing at least a drive section and a transmission section. At least a housing of the plural housings has a longitudinal axis and incorporates a reaming section with one or more rotary reamers. Each of the one or more rotary reamers is mounted in a respective pocket for rotation about a transverse axis relative to the longitudinal axis of the housing.

A drill head for expanding a pilot bore in order to create a borehole having a borehole wall as a result of loosening rock surrounding the pilot bore in the region of a working face, which extends in a substantially right-angled manner to the pilot bore, including a basic body including a connection element for a pilot bore string including at least two tool holders, in that at least one tool holder is at a greater spacing radially from the basic body than the at least one other tool holder such that there is at least one outer and one inner drilling tool which are movable into engagement with the working face, and the at least one inner drilling tool and the at least one outer drilling tool are each arranged offset at an angle in relation to the working face.

A drill head for expanding a pilot bore in order to create a borehole having a borehole wall as a result of loosening rock surrounding the pilot bore in the region of a working face, which extends in a substantially right-angled manner to the pilot bore, including a basic body including a connection element for a pilot bore string including at least two tool holders, in that at least one tool holder is at a greater spacing radially from the basic body than the at least one other tool holder such that there is at least one outer and one inner drilling tool which are movable into engagement with the working face, and the at least one inner drilling tool and the at least one outer drilling tool are each arranged offset at an angle in relation to the working face.

A downhole tool, for selectively reaming a wellbore or stabilizing drill string components within a wellbore, includes an elongate tool body adapted to receive reamer cartridges or stabilizer cartridges depending on the function desired. The reamer cartridges are radially insertable into corresponding pockets in the tool body, with each reamer cartridge having a reamer insert with an array of cutting elements. The reamer insert is disposed within a bushing and is rotatable relative thereto, about a rotational axis transverse to the longitudinal axis of the tool. However, the rotational axis is offset from the tool body axis, resulting in eccentric contact of the cutting elements with the wall of the wellbore, which in turn imparts rotation to the reamer insert when the tool is being moved axially through a wellbore without rotation. When the tool is to be used for stabilization, the reamer cartridges can be removed and replaced with stabilizer cartridges having stabilizer inserts with hard-faced stabilizer cones.

A downhole tool, for selectively reaming a wellbore or stabilizing drill string components within a wellbore, includes an elongate tool body adapted to receive reamer cartridges or stabilizer cartridges depending on the function desired. The reamer cartridges are radially insertable into corresponding pockets in the tool body, with each reamer cartridge having a reamer insert with an array of cutting elements. The reamer insert is disposed within a bushing and is rotatable relative thereto, about a rotational axis transverse to the longitudinal axis of the tool. However, the rotational axis is offset from the tool body axis, resulting in eccentric contact of the cutting elements with the wall of the wellbore, which in turn imparts rotation to the reamer insert when the tool is being moved axially through a wellbore without rotation. When the tool is to be used for stabilization, the reamer cartridges can be removed and replaced with stabilizer cartridges having stabilizer inserts with hard-faced stabilizer cones.

An apparatus and method for alleviating spiraling in boreholes is disclosed. The apparatus includes a sub, which adjusts the length of the bottom-hole assembly in response to tension/compression, flexural bending and/or torque measurements made above and below the reamer so that the drill bit and the reamer cut at the same depth rate. The sub is connected between the drill bit and the reamer. The apparatus further includes measurement devices disposed on the bottom-hole assembly above and below the reamer, which are capable of measuring the tension/compression, flexural bending and torque in the bottom-hole assembly. The method includes use of a data processor, which determines which operational output signals to supply to the sub in order to adjust its length and thereby accomplish the desired drilling rates.

An apparatus and method for alleviating spiraling in boreholes is disclosed. The apparatus includes a sub, which adjusts the length of the bottom-hole assembly in response to tension/compression, flexural bending and/or torque measurements made above and below the reamer so that the drill bit and the reamer cut at the same depth rate. The sub is connected between the drill bit and the reamer. The apparatus further includes measurement devices disposed on the bottom-hole assembly above and below the reamer, which are capable of measuring the tension/compression, flexural bending and torque in the bottom-hole assembly. The method includes use of a data processor, which determines which operational output signals to supply to the sub in order to adjust its length and thereby accomplish the desired drilling rates.

Disclosed is a well bore reamer for enlarging, stabilizing and/or cleaning portions of a drilled hole. An internal clutch system comprising pins and springs cause a helical blade segment of the disclosed device to rotate about its axis in a clockwise direction during its movement in a wellbore. When the device is situated in a fixed position in the wellbore, rotation of the drill pipe causes the clutch system to lock the helical blade segment of device in place, forcing the reamer to rotate with the drill string.

Disclosed is a well bore reamer for enlarging, stabilizing and/or cleaning portions of a drilled hole. An internal clutch system comprising pins and springs cause a helical blade segment of the disclosed device to rotate about its axis in a clockwise direction during its movement in a wellbore. When the device is situated in a fixed position in the wellbore, rotation of the drill pipe causes the clutch system to lock the helical blade segment of device in place, forcing the reamer to rotate with the drill string.