(1) The distance between the logging tool [[measure point|measure points]] for various parameters measured by a [[combination logging tool]]. Also, the correction necessary to record all parameters at the same depth reference.

(2) Pertaining to the [[dipmeter]], it is the vertical distance in the hole between equivalent responses measured at different quadrants in the hole.

(3) Also refers to the replacement of a portion of the interstitial fluids by borehole fluids, near the borehole, during the invasion process.