Patent ID: 8085049

Claim:
A method of evaluating an earth formation during a drilling operation, comprising the acts of: providing a resistivity logging tool configured for incorporation into a drill string, the logging tool comprising, a tool body having a longitudinal axis, a first transmitter coil antenna extending in a cutout around the tool body, a first receiver coil antenna extending in a cutout around the tool body, a rotational position indicator that comprises at least one of: an inclinometer, a gyroscope, and a fluxgate magnetometer, and a processor assembly, and wherein the first transmitter antenna is oriented at a first angle relative to the longitudinal axis of the tool body, and wherein first receiver antenna is oriented at a second angle relative to the longitudinal axis, and wherein the first and second angles are not the same; during the drilling operation, rotating the logging tool relative to the longitudinal axis; transmitting an electromagnetic wave into the earth formation through use of the first transmitter antenna; receiving electromagnetic energy from the earth formation at the first receiver antenna; and using said processor assembly to provide an advance indication of a bed boundary based at least in part on the received electromagnetic energy at the first receiver antenna and information from the rotational position indicator, said advance indication being indicative of a difference or ratio of the received electromagnetic energy at opposite azimuths in the tool's rotation.