History Matching Using the Method of Gradients: Two Case Studies

Abstract

Abstract We have successfully history matched two reservoirs using the method of gradients. This was achieved by defining an objective function which is the sum of the squares of the differences between calculated variables, such as a shut-in bottom hole pressures, from the reservoir simulator and their measured values. The objective function is minimised using a non-linear regression algorithm. This requires the derivative, or gradient, of the calculated variables with respect to the history matching parameters. Our reservoir simulator is able to calculate these derivatives efficiently during a simulation run. Both reservoirs had previously been matched by hand. Our results compare well with the hand matches.