| 摘要 |
An expandable reamer apparatus and methods for reaming a borehole, wherein a laterally movable blade 112,114 carried by a tubular body 132 may be selectively positioned at an inward position and an expanded position. The movable blade, held inwardly by blade-biasing elements 124,126,128,130, may be forced outwardly by transmission of force or pressure from the drilling fluid to the movable blade via a separation element 560. Alternatively, a chamber in communication with the movable blade may be pressurized by way of a downhole turbine or pump. A ridged seal wiper, compensator, movable bearing pad 152,154, fixed bearing pad preceding the movable blade, or an adjustable spacer element to alter expanded blade position may be included within the expandable reamer. In addition, a drilling fluid pressure response indicating an operational characteristic of the expandable reamer may be generated. |
