Class of borehole imaging tools that works on the principal of varying formation resistivity. Electrodes make resistivity measurements of the borehole wall as function of depth and orientation; these resistivity determinations are processed to form an oriented resistivity map of the borehole wall. Resistivity imaging tools fall into three categories. Multi-arm pad devices with tight arrays of microresitivity buttons; rotating electrodes fitted to a drill-collar and laterolog sensors arranged circumferentially. Most resistivy imaging devices require a conductive mud environment, but technological developments allow some newer tool types to function in oil-based fluids.
LUTHI, S. M. 2000. Geological Well Logs. Springer, Berlin, p373.
PRENSKY, S. E. 1999. Advances in borehole imaging technology and applications. In: LOVELL, M. A., WILLIAMSON, G and HARVEY, P. K. (eds.). Borehole Imaging: Applications and Case Histories. Geological Society Special Publication No. 159, 1-43.
See also borehole televiewers and density and photoelectric effect imaging devices.