Patent ID: 9388638
Filing Date: 2016-07-12
CPC Classification: B23P,E21B

Claim Text:
1. An expandable reamer apparatus for enlarging a borehole in a subterranean formation, comprising: a tubular body; at least one curved blade track carried by the tubular body; at least one blade engaged with the at least one curved blade track and configured to slide along the at least one curved blade track along a curved path between a first retracted blade position and a second expanded blade position, wherein the at least one blade is cantilevered beyond a lower longitudinal end of the at least one curved blade track in the second expanded blade position, the lower longitudinal end located below an upper longitudinal end of the at least one curved blade track when the expandable reamer apparatus is disposed vertically in a borehole; and wherein the expandable reamer apparatus has a retracted diameter defined as a maximum diameter of the expandable reamer apparatus when the at least one blade is in the first retracted blade position, and an expanded diameter defined as a reaming diameter of the expandable reamer apparatus when the at least one blade is in the second expanded blade position, and wherein a ratio of the expanded diameter to the retracted diameter is at least 1.25 to 1.0.