CPC E21B 17/1057 (2013.01) | 20 Claims |
1. A downhole tool operable to connect to a tool string and reduce friction between the tool string and a sidewall of a wellbore through which the tool string is conveyed, wherein the downhole tool comprises:
a frame operable to connect to the tool string;
a first wheel connected to the frame;
a second wheel connected to the frame; and
a hump disposed at least partially between the first wheel and the second wheel, wherein the hump comprises a plurality of holes extending therethrough between opposing sides of the hump, and wherein, when the downhole tool is connected to the tool string:
the first wheel, the second wheel, and the hump collectively define a curved outer profile extending circumferentially around at least a portion of a circumference of the tool string;
the curved outer profile has a geometric center that is offset from a central axis of the tool string; and
the weight of the tool string and the offset between the geometric center and the central axis cause a torque that urges rotation of the connected downhole tool and tool string within the wellbore toward a position in which the central axis is below the geometric center.
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