Apparatus, Tool and Method for Look-Ahead Advance Formation Evaluation which investigates the formation or formation characteristic in advance of the drill-bit before the formation or formation feature of interest has been penetrated or traversed.;A closed-loop real-time look-ahead formation evaluation tool which provides acoustic and/or electro-magnetic formation data beyond the drill-bit using a novel angular sensor orientation which also allows for optimized signal propagation and signal returns according to an axial plane and vertical depth.
展开▼