Inter-well tracer tests in oil reservoirs using different optimization methods: A field case

Abstract

In the interpretation of inter-well tracer tests to determine reservoir properties in oil and geothermal reservoirs as well as in aquifers, different non-linear regression methods are used. Analytical flow models are employed to fit tracer breakthrough data in order to determine the free parameters in the models. Non-linearity can yield multiple solutions for the fitting parameters. Traditionally, a single optimization method and several initial parameter values are employed. This procedure is often cumbersome and computer time-consuming. Moreover, an initial point close to the global optimum must be provided, what in many field cases is not available. We propose an approach which employs several optimization methods simultaneously, using a few initial points. Thus, different solutions can be found in a relatively simple way, and the reliability of the solutions is improved.