LOOK-AHEAD OF THE BIT APPLICATIONS

摘要

Various embodiments include apparatus and methods of operation with respect to well logging. Apparatus and methods can include a tool having an arrangement of spaced apart transmitter antennas and receiver antennas in transmitter-receiver antenna pairs to make shallow measurements and deep measurements. The signals acquired from the shallow measurements and deep measurements can be processed to provide a look-ahead signal in a drilling operation. The transmitter and receiver antennas can be oriented to cancel or substantially cancel out signals from layers between the transmitter antenna and the receiver antenna in response to the transmitter being operated downhole in a well. Additional apparatus, systems, and methods are disclosed.

主权项

1. A method comprising:
controlling activation of a tool disposed downhole, the tool having an arrangement of transmitter antennas and receiver antennas spaced apart operable in selected transmitter-receiver pairs; acquiring a deep signal from a deep measurement using a transmitter-receiver pair and one or more shallow signals from one or more shallow measurements using one or more other transmitter-receiver pairs; processing the one or more shallow signals, generating a modeled signal relative to regions adjacent sides and back of the tool; and forming a look-ahead signal substantially without contributions from the regions adjacent the tool by processing the deep signal with respect to the modeled signal.