same as or different from the potential of the current electrodes insulation not shown is provided between the electrode and the conductive surface this makes it possible to focus the current in the formation away from any mudcake that may be present see u s pat no 6 348 796 to evans having the same assignee as the present disclosure implicit in the processing of the data is the use of a computer program implemented on a suitable machine readable medium that enables the processor to perform the control and processing the term processor as used in this application is intended to include such devices as field programmable gate arrays fpgas the machine readable medium may include roms eproms earoms flash memories and optical disks as noted above the processing may be done downhole or at the surface while the foregoing disclosure is directed to the preferred embodiments of the invention various modifications will be apparent to those skilled in the art it is intended that all variations within the scope and spirit of the appended claims be embraced by the foregoing disclosure the following definitions may be helpful in understanding the present invention electrode electric conductor usually metal used as either of the two terminals of an electrically conducting medium induction based on a relationship between a changing magnetic field and the electric field created by the change logging tool the downhole hardware needed to make a log the term is often shortened to simply u201c tool u201d machine readable medium something on which information may be stored in a form that can be.