Structured Uncertainty Assessment for a Mature Field through the Application of Experimental Design and Response Surface Methods

Abstract

Abstract This study covers one of the largest and oldest oil fields in Oman. Despite over 35 years of production through various drive mechanisms, there remains an opportunity to realize additional value in the field.The scale and complexity of the uncertainties associated with such opportunity necessitates the use of experimental design and response surface methods to provide a framework for evaluating sensitivities and estimating impact of uncertainties on field performance. Since data sometimes are incomplete or inconsistent and measurements are ambiguous or inconclusive, the representation of reservoir and geological parameters are often sub optimal. This is especially true for heterogeneous fractured reservoir, such as this field, where the number and range of uncertainties is large.This paper presents the application of experimental design and response surface methods to the field development study of this field. The methodology uses an integrated approach, where cross discipline data is evaluated early in the study to identify and quantify uncertainties with the highest impact. After static and dynamic data are reviewed and quality checked, an initial ranking of uncertainties takes place. A selection of 3D simulation models, as defined by the experimental design approach, are run to construct response surface models, which are then used to assess the impact of these uncertainties on field behavior. The historical performance of the field is critical data used to constrain the range of some uncertainties. The results of this study are used to guide future development of the field.The methodology described in this paper highlights the value of a structured multiple realization approach, using experimental design and response surface modeling, for uncertainty estimation and management.