Systems and Methods for Investigating A Formation Surrounding A Borehole

摘要

A method, a system, and an apparatus are described for the data acquisition in the well-logging of a borehole wall during the investigation of formation properties. Data acquisition is conducted by either an adaptive phase compensation processing or a modulus mode processing, both of which use in-phase and out-of-phase current components to obtain current values. Adaptive phase compensation employs a calculation of a phase shift compensation value, which may then be applied to subsequent acquisitions and can be further processed in the generation of an image of the borehole wall.

主权项

1. A method of investigating a formation surrounding a borehole, comprising:
computing both an average in-phase current and an average out-of-phase current for each pad disposed on a down-hole tool by repeatedly acquiring in-phase and out-of-phase current data from the formation relative to a voltage applied to one or more electrodes disposed on said pad over multiple depths within a depth window; averaging the acquired in-phase and out-of-phase current data over the one or more electrodes to obtain the average in-phase current and the average out-of-phase current for each pad at each depth of the multiple depths within the depth window; determining an average phase shift compensation angle from each respective phase shift compensation angle calculated for each pad of the down-hole tool; applying the average phase shift compensation angle determined to in-phase and out-of-phase current data subsequently acquired by each pad of the down-hole tool from the formation over a depth of the borehole to be measured to obtain phase shift compensated current values over the depth of the borehole to be measured; and forming an image of the borehole based on the phase shift compensated current values.