Patent ID: 7185714
Filing Date: 2007-03-06
Classification: E21B

Abstract:
1. An apparatus for adjusting the traction of a downhole tractor moveable within a borehole, the apparatus comprising: at least one drive module including at least one drive unit, said at least one drive unit being engageable with and moveable relative to a wall of the borehole, said at least one drive module being capable of determining the velocity of the at least one drive unit in the borehole, said at least one drive module being capable of applying normal force to said at least one drive unit to cause said at least one drive unit to engage and move with respect to the wall of the borehole; and at least one measuring unit capable of determining the velocity of the tractor in the borehole, whereby said at least one drive module is capable of varying the normal force on said at least one drive unit based upon the velocity of the tractor and the velocity of said at least one drive unit, wherein said at least one drive unit determines the velocity of said at least one drive unit.