Gradients Method Constrained by Geological Bodies for History Matching

Abstract

Conventional gradient methods have already been applied to reservoir engineering for matching the history of former field performances. The key point of these methods is to select the best areal reservoir zoning for reduction of the amount of reservoir parameters to be identified. In this paper we propose a zoning based on reservoir lithofacies, thus making a more natural than geographical choiee. By introducing gradients to numrmze an objective function that measures the difference between observed and simulated well pressure responses, we can effectively achieve the inversion of petrophysical lithofacies parameters. By fixing the value of petrophysical parameters, the influence of the geometry can be studied by varying the geologie body's dimensions. Several examples of inversion are given at the end of the artiele to illustrate the effectiveness of this gradient method.

Ensemble Kalman filter for automatic history matching of geologic facies

“…The problem of history matching of reservoir models with unknown geologic facies boundaries has been studied less frequently than the problem of history matching to rock properties (Rahon et al, 1996;Bi, 1999;Landa et al, 2000). Liu and Oliver (2003) applied a gradient-based method to the problem of conditional simulation of facies boundaries generated from the truncated pluri-Gaussian method.…”

An analysis of history matching errors

“…It is very likely for commonly used search algorithms (such as gradient methods) to pick any of these local minima instead of the true model. Here we chose arbitrary forms for the standard deviations ' w and ' o , equations(2,3). Changing these parameters would alter the shape of the objective functions.…”