Poster Presentations

Abstract: The reservoir engineering design of waterflooding an oil reservoir is currently done by means of numerical simulators. These simulators need to be fed with relative permeabilities and capillary pressure functions. In this work, an inverse method has been developed to determine those functions from measurements taken during a laboratory experiment, in which oil and water flow through a core of reservoir rock. Our inverse method algorithm has four basic components. 1) An IMPES finite-difference numerical simulator of the unsteady one-dimensional oil-water flow through the core. 2) Functional representations of the relative permeability and capillary pressure curves in terms of a set of adjustable parameters (which are found by minimizing an objective function). 3) The objective function which is formed by the sum of the square of the differences between experimentally measured and numerically simulated data. 4) A non-linear regression algorithm (the Quasi-Newton Approximation for the Least-Squares Problem) to minimize that objective function. The inverse method algorithm is tested with simulated data and with actual experimental data. Convergent solutions are always found. Different objective functions must be used depending on the available measurements. The aim of this work is to analyze the effect of the objective function definitions upon the results of the inverse method.