Comparison of an Expert System to Human Experts in Well Log Analysis and Interpretation

':omparisons of the results produced by the expert system to ,hose produced by experts proficient in the field of log analysis are discussed using case histories from a variety of wells from many countries. The results, in general, have exceeded initial ex­ pectations for the expert system, with the system showing surpris­ ingly "intelligent" behaviour in some circumstances and actually highlighting mistakes made by the human experts. In other ex­ amples the expert system fails to closely emulate the human ex­ pert. This failure is shown to be the result of application of knowledge gathered from outside the realm of log analysis or in­ formation that was not considered for input into the expert sys­ tem. An important facet of a knowledge-based system is the development of an understanding of its own limitations, as the refusal by the system to perform an analysis in circumstances that it does not understand is critical to its overall success.