Method for controlling directional drilling in response to horns detected by electromagnetic energy propagation resistivity measurements

摘要

The disclosed method is applicable for use in conjunction with an earth borehole drilling apparatus that typically includes: a drilling rig; and a drill string operating from said drilling rig for drilling an earth borehole, the drill string including a bottom hole arrangement comprising a drill bit and a downhole resistivity measuring subsystem for measuring downhole formation resistivity near the bit by propagating electromagnetic energy into earth formations near the bit, receiving electromagnetic energy that has propagated through the formations and producing measurement signals that depend on the received signals. A method is set forth for directing the drilling of a well bore with respect to a geological bed boundary in the earth formations, including the steps of: producing from the measurement signals a recording of downhole formation resistivity as a function of position; determining the presence of a horn in the resistivity recording; and implementing a change in the drilling direction of the drill bit in response to said determination of the presence of a horn.