Evaluation of uncertainty of the comprehensive interpretation of borehole logs by the multiple re-run statistical method

摘要

Measurements of various physical quantities in a borehole by geophysical well logging tools are designed to determine these quantities for underground geological formations. Then, the raw data (logs) are combined in a comprehensive interpretation to obtain values of geological parameters. Estimating the uncertainty of calculated geological parameters, interpreted in such a way, is difficult, often impossible, when classical statistical methods are used. The method presented here permits an estimate of the uncertainty of a quantity to be obtained. The discussion of the dependence between the uncertainty of nuclear and acoustic tool responses, and the estimated uncertainty of the interpreted geological parameters (among others: porosity, water saturation, clay content) is presented. (c) 2005 Elsevier Ltd. All rights reserved.