Asymptotics, saturation fronts, and high resolution reservoir characterization

Using an asymptotic methodology we formulate a fast, accurate algorithm for the inversion of multi-phase flow data. The approach is appropriate for ma ny common reservoir production strategies such as CO2 and water flooding. T he technique compares well to a purely numerical method with a significant reduction in computation time. In an application to fractional flow data fr om the North Robertson field in West Texas, 100,000 permeability and porosi ty parameters are determined on a workstation. Generally, higher permeabili ty, approaching 1 milli-Darcy, is found in the eastern portion of the reser voir. The permeability estimates agree with type curve analysis for materia l and volumetric balances and a previous numerical pilot-point inversion.