Patent ID: 9556682
Date: 2017-01-31
CPC Classifications: E21B

Claim:
1. An underreamer for increasing a diameter of a wellbore, comprising: a body having an axial bore extending at least partially therethrough; an electromagnetic activation system disposed at least partially within the bore of the body; a valve disposed within the axial bore of the body and coupled to the electromagnetic activation system, the valve including a mobile element and a static element, the mobile element being coupled to the electromagnetic activation system and being arranged and configured to move from a first position where the mobile element obstructs fluid flow through the valve to a second position where the mobile element permits fluid flow through the valve; a fluid pressure-activated locking mechanism arranged and configured to selectively prevent rotation of the movable element relative to the static element; and a cutter block movably coupled to the body and configured to move radially-outward as the mobile element moves from the first position to the second position.