Use of parameter gradients for reservoir history matching.

Abstract

This paper describes a rigorous analytical method for the computation of gradients. The gradient calculation has been implemented in the fully implicit, three phase, three dimensional reservoir simulator, SCORE, in a way which leads to significantly reduced computation time compared with other methods. The second part of the paper reports on a preliminary attempt at computer aided history matching, based upon a meta simulator which uses the calculated values of the gradients and a minimisation procedure together with several extrapolation laws. Two applications of the method are presented.