Patent ID: 9157287
Filing Date: 2015-10-13
Classification: E21B

Abstract:
1. A system for conveying along a wellbore, comprising: a tractor having a plurality of wheels oriented to engage a surrounding wellbore wall such that rotation of the plurality of wheels causes movement of the tractor with respect to the surrounding wellbore wall via a tangential force and a radial force created between each wheel and the surrounding wellbore wall, each wheel comprising teeth having a wheel tooth geometry which cooperates with the tangential force and the radial force to push debris out of the teeth during rotation of the wheel along the surrounding wellbore wall, wherein the teeth of each wheel: are oriented in an alternating angular pattern, are arranged in a square tooth tread pattern oriented to eject debris laterally to both sides of the wheel, are mounted on a slanted root oriented at a non-parallel angle with respect to a rotational axis of the wheel, are mounted on a slanted root oriented at a non-parallel angle with respect to a rotational axis of the wheel, comprise non-symmetrical sloping teeth, or combinations thereof.