Shale Indicator Derived from Multivariate Statistical Analysis of Well Logs

In the paper a geostatistical approach is presented to estimate shale volume in shaly sand reservoirs. The factor analysis of well-logging data results in a new log, which correlates with the shale content of the formations. The connection between shale content and factor scores is quantified by an empirical relationship between the two variables. The nonlinear formula seems to be straight in different areas and gives consistent results both in water and hydrocarbon reservoirs. In the paper, statistical interpretation results of three different data sets originated from Hungary and the United States of America are compared. The results are verified by estimates of independent petrophysical interpretation.