Calibration of logging data from mudstone washout intervals and its application in Chunxiao Field

P-impedance is partly superimposed in sandstone and mudstone in Chunxiao field due to hole washout at part of mudstone intervals. To solve this problem, the mudstone density at hole washout inter-vals is calibrated with the regression relationship between GR and density at washout intervals, and the in-terval transit time at washout mudstone intervals is calculated through matching with Gardner formula of the study area. Though comparison of logging data before and after calibration, and analysis of cross plot, rock properties, modeling and inversion results, it is believed that the characteristics of washout mudstone can be reflected in calibrated logging data. P-impedance differences are obvious between sandstone and mudstone, which provide reliable information for inversion and analysis of sand body distribution.