What We Learned. History matching is one way to make intelligent guesses of grid block values in a simulation. History matching is the process of adjusting the simulator input so that its output matches some observed behavior, usually producing rate or cumulative recovery. This process gives substantial comfort to a prediction-after all, the simulator should be able to match behavior if it is realistic. But its disadvantages are considerable.
History matching obviously has no benefit whatever if there is no history.
Its use is limited to cases where some production already exists. It usually turns out that we find a particularly sensitive parameter or two and make the simulator match these, regardless of the true value of these or any other parameters. The geostatistical assignment procedure can obviously help here in reducing the data required. This time is largely nonproductive because it subtracts from time spent making predictions and evaluating alternatives. Practice has shown that the use of geostatistical assignments can vastly reduce the amount of time spent in history matching.