METHOD FOR ACCENTUATING SIGNAL FROM AHEAD OF THE BIT

摘要

A method for estimating a property of a portion of an earth formation ahead of a borehole penetrating the formation, the method includes: conveying a logging tool through the borehole; receiving one or more first signals from a previous depth of the logging tool; constructing a model of the earth formation using the one or more first signals; predicting one or more second signals from the portion of the earth formation ahead of the borehole using the model; receiving one or more third signals from the portion of the earth formation ahead of the borehole; calculating a difference between the one or more third signals and the one or more second signals; and estimating the property from the difference.