Abstract: A wellbore imaging tool is provided which is sensitive to magnetic permeability changes in the wellbore wall. In one embodiment, the measuring array comprises a transmitter coil, an array of receiver coils, and a signal processor. The transmitter coil generates an oscillating magnetic field in the wellbore wall, and each of the receiver coils generates a voltage indicative of a direct inductive coupling strength between the receiver coil and the transmitter coil. Variations in the magnetic permeability of the wellbore wall will cause the direct inductive coupling strength between the transmitter and receiver coils to vary accordingly. The signal processor is coupled to each of the receiver coils to determine the direct inductive coupling strength and configured to convert it into a pixel value for each of the receiver coils. The pixel value may represent the magnetic permeability of a wall region proximate to the receiver coil, or it may represent the direct inductive coupling strength.

Abstract: A method and apparatus for retrieving logging data from a downhole logging tool is presented. The tool includes a plurality of sensors which acquire data which is stored in memory. Upon receiving an appropriate signal from a surface control unit, the logging tool transmits the logging data from memory. This can be accomplished when drilling has paused; for example, while the well is being conditioned.