A Methodology for Identifying & Quantifying Uncertainties (Seismic to First Phase Field Development) in Reservoir Simulation: Case Study of Two Fields in Saudi Arabia

Abstract

Understanding and management of subsurface uncertainties has become increasingly important for oil and gas companies to optimize reserve portfolios, make better field development decisions and improve day-to-day technical operations such as well planning. In this paper, the authors developed models, workflows and methodologies for multiple development scenarios that span the range of uncertainties for all stages of reservoir description and simulation for two fields (Field A and Field B) in Saudi Arabia. These processes are based on responses to uncertainty parameters in order to capture and quantify uncertainties. Uncertainty quantification for the two reservoirs was performed using experimental design (ED) approach taking into account seismic interpretation, geological uncertainty, and dynamic data. ED is an intelligent way of sampling parameter space by selecting combination of predefined variables to minimize the number of "experiments" to characterize the behaviour of a system, and to limit the number of models to be run. As a result, robust and responsive reservoir models were constructed to predict the field performance as well as to evaluate various future development strategies alongside better risk-assessments.