PARAMETERIZATION OF THE SPINE-AND-RIB PLOT FOR A DUAL-DETECTOR DENSITY TOOL

This paper demonstrates an empirical parameterization of the 'spine-an d-rib' plot for a dual-detector density tool for the purpose of develo ping an improved mudcake compensation algorithm for use in difficult c onditions with thick mudcakes. It is shown, using the results of Monte Carlo calculations, that a relatively simple equation provides a good fit to the detector responses for a wide range of mudcake and formati on densities, and for mudcake thicknesses up to 3 cm. A compensation a lgorithm based on these equations would take into account the divergen ce, at high mudcake thicknesses, of ribs measured for different mudcak e densities.