DISTRIBUTION OF CLAYS IN SANDSTONES BY IMAGE ANALYSIS: QUANTIFICATION,REPRESENTATIVITY AND EFFECTS ON PETROPHYSICAL PROPERTIES

摘要

Distribution of clays in sandstones was quantified using Scanning Electron Microscopy image analysis.Prior to estimation of mean values,representativity was checked using variograms,which gave the size of sample to be studied.Several parameters were calculated,either from granulometric or from geostatistical procedures.Attempt was made to correlate these parameters to permeability: straightforward use of well-known formalisms was likely to give acceptable values for model sandstones,but failed in the case of reservoir sandstones,where the spatial relationship between framework grains and clays is more complex.