Abstract: A guide device for a tool string to guide the tool string down a wellbore, the guide device comprising: a coupling to connect the guide device to an end of a tool string, a mandrel and a tip at a leading end of the mandrel, a centralising device supported by the mandrel, and a joint (a flexible joint or articulation joint) between the mandrel and the coupling allowing angular displacement of the mandrel relative to the tool string so that the tip can displace from a longitudinal axis of the tool string.

Abstract: A sensor transportation apparatus for conveying a sensor assembly through a wellbore comprises at least one engagement structure to connect the sensor transportation apparatus to the sensor assembly, at least one axle, a bearing connected to the axle, and a wheel connected to the bearing and provided with a shaft seal to prevent or reduce debris from the wellbore entering the bearing, and a lubrication delivery system to provide a lubricant to the bearing at a pressure which is greater than ambient wellbore pressure. The lubrication system comprises a bellows formation, and the apparatus comprises a housing to contain the lubricant, the housing in fluid communication with the bearing, the bellows formation sealingly mounted to the housing with at least a portion of the bellows received within the housing.

Abstract: The disclosure relates to a carriage apparatus for carrying a tool string down a wellbore in a wireline logging, and an orientation apparatus and hole finder device for a wireline logging tool string. In some embodiments the carriage includes a protection structure which extends longitudinally around a wheel of the apparatus to thereby prevent a side of the wheel from contacting a wall of the wellbore. In some embodiments an orientation apparatus and hole finder are arranged so that the orientation apparatus orientates the hole finder device in the wellbore so that a tip of a nose section of the hole finder is elevated above a low side of the wellbore by a height and offset from and above a longitudinal axis of the tool string.

Abstract: A logging tool assembly comprises an elongate sensor assembly, a plurality of sensor transportation apparatuses for transporting the elongate sensor assembly through a wellbore, and an orientation structure. The sensor transportation apparatuses are spaced apart along the elongate sensor assembly. Each sensor transportation apparatus comprises an engagement structure to connect the sensor transportation apparatus to the elongate sensor assembly and prevent relative rotation between the sensor transportation apparatus and the elongate sensor assembly, and one or more pairs of wheels arranged to rotate on an axis of rotation substantially perpendicular to a longitudinal axis of the elongate sensor assembly. The axes of rotation of the pairs of wheels of said transportation apparatuses are parallel. The orientation structure is connected to the elongate sensor assembly to prevent relative rotation between the orientation structure and the elongate sensor assembly.

Abstract: A sensor transportation apparatus to convey a sensor assembly through a wellbore. The apparatus comprising has an engagement structure to connect the sensor transportation apparatus to the sensor assembly, and one or more wheels arranged to rotate about an axis of rotation substantially perpendicular to a longitudinal axis of the sensor assembly when the transportation apparatus is connected to the sensor assembly. An orientation structure defining a form having a transverse outline which has a rotational center, wherein the rotational center is offset from a centroidal axis of the elongate sensor assembly.

Abstract: A logging tool assembly comprises an elongate sensor assembly, a plurality of sensor transportation apparatuses for transporting the elongate sensor assembly through a wellbore, and an orientation structure. The sensor transportation apparatuses are spaced apart along the elongate sensor assembly. Each sensor transportation apparatus comprises an engagement structure to connect the sensor transportation apparatus to the elongate sensor assembly and prevent relative rotation between the sensor transportation apparatus and the elongate sensor assembly, and one or more pairs of wheels arranged to rotate on an axis of rotation substantially perpendicular to a longitudinal axis of the elongate sensor assembly. The axes of rotation of the pairs of wheels of said transportation apparatuses are parallel. The orientation structure is connected to the elongate sensor assembly to prevent relative rotation between the orientation structure and the elongate sensor assembly.

Abstract: A sensor transportation apparatus to convey a sensor assembly through a wellbore. The apparatus comprising has an engagement structure to connect the sensor transportation apparatus to the sensor assembly, and one or more wheels arranged to rotate about an axis of rotation substantially perpendicular to a longitudinal axis of the sensor assembly when the transportation apparatus is connected to the sensor assembly. An orientation structure defining a form having a transverse outline which has a rotational centre, wherein the rotational centre is offset from a centroidal axis of the elongate sensor assembly.

Abstract: A sensor transportation apparatus to convey a sensor assembly through a wellbore. The apparatus comprising has an engagement structure to connect the sensor transportation apparatus to the sensor assembly, and one or more wheels arranged to rotate about an axis of rotation substantially perpendicular to a longitudinal axis of the sensor assembly when the transportation apparatus is connected to the sensor assembly. An orientation structure defining a form having a transverse outline which has a rotational center, wherein the rotational center is offset from a centroidal axis of the elongate sensor assembly.

Abstract: A sensor transportation apparatus to convey a sensor assembly through a wellbore. The apparatus comprising has an engagement structure to connect the sensor transportation apparatus to the sensor assembly, and one or more wheels arranged to rotate about an axis of rotation substantially perpendicular to a longitudinal axis of the sensor assembly when the transportation apparatus is connected to the sensor assembly. An orientation structure defining a form having a transverse outline which has a rotational centre, wherein the rotational centre is offset from a centroidal axis of the elongate sensor assembly.