Sensor transportation apparatus and guide device

A method for conveying an elongate sensor assembly through a wellbore, the method comprising:

• connecting a sensor transportation apparatus to the elongate sensor assembly, the sensor transportation apparatus comprising a pair of 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, and an orientation structure comprising the pair of wheels and an orientation projection extending between the pair of wheels, wherein:
• lateral extremities of the pair of wheels and the orientation projection together defining a curve extending circumferentially around a portion of the circumference of the elongate sensor assembly, and
• a rotational centre of the curve is offset from a central axis of the elongate sensor assembly, and
• wherein a rotational axis of the pair of wheels is above the central axis of the elongate sensor assembly when the sensor transportation apparatus is substantially horizontal, and
• conveying the sensor transportation apparatus and the elongate sensor assembly through the wellbore with the sensor transportation apparatus causing the sensor transportation apparatus and elongate sensor assembly to orientate to a position in which the rotational axis of the pair of wheels is above the central axis of the elongate sensor assembly.

A sensor transportation apparatus to convey an elongate sensor assembly through a wellbore, the sensor transportation apparatus comprising:

• at least one engagement structure to connect the sensor transportation apparatus to the sensor assembly, and
• a pair of wheels comprising a first wheel and a second wheel 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, and
• an orientation structure comprising the first and second wheels and an orientation projection extending between the first and second wheels,
• the first wheel comprising a first curved lateral extremity extending circumferentially around a first portion of the elongate sensor assembly, and
• the second wheel comprising a second curved lateral extremity extending circumferentially around a second portion of the elongate sensor assembly, and
• the orientation projection comprising a third curved lateral extremity extending circumferentially around a third portion of the elongate sensor assembly,
• the first, second and third curved lateral extremities together defining a curve extending circumferentially around a portion of the circumference of the elongate sensor assembly when the sensor transportation apparatus is connected to the elongate sensor assembly, wherein a rotational centre of the curve is offset from a central axis of the elongate sensor assembly when the sensor transportation apparatus is connected to the elongate sensor assembly, and
• wherein a rotational axis of the pair of wheels is above the central axis of the elongate sensor assembly when the sensor transportation apparatus is connected to the elongate sensor assembly and the sensor transportation apparatus is substantially horizontal.