Global, A New Approach to Computer-Processed Log Interpretation

Abstract

ABSTRACT A new computer-processed log interpretation chain, GLOBAL, uses a structure independent of model and logging suite. An error model is defined relating tool measurements to petrophysical parameters such as porosity, lithology, and fluid saturation. Then, using a minimization routine, GLOBAL searches for the solution with the minimum error. This solution is considered the most probable answer. A quality curve is presented indicating how well the answers fit the chosen model. The curve helps to determine if the model is inadequate, or if insufficient information is available to solve the interpretation problem. The main advantages shown by the examples analyzed are: Simultaneous use is made of all combination of logs, including experimental or recently introduced sensors.The approach works for very complex litholo-gies.It is adaptable to all kinds of models and local conditions.