METHOD FOR LOCATING AN ANOMALY AHEAD OF A DRILL BIT

摘要

A method and a system are provided for allowing determination of a distance from a tool to anomaly ahead of the tool. The apparatus for performing the method includes at least one transmitter and at least one receiver. An embodiment of the method includes transmitting electomagnetic signals from t he at least one transmitter through the formation surrounding the wellbore and detecting voltage responses at the at least one receiver induced by the electromagnetic signals. The method includes calculating apparent conductivi ty or apparent resistivity is monitored over time, and the distance to the anomaly is determined from the apparent conductivity or apparent resistivity values