Full-Field Gas Storage Simulation Using a Control-Volume Finite-Element Model

Abstract

Abstract This paper presents the actual case history of Saint-Clair-sur-Epte (France), a fourteen year old underground gas storage in a very large aquifer. This gas storage shows two topics of interest: it is partially filled with inert gas; the economical interest and the technical feasibility of injecting a significant quantity of inert gas prior to filling the storage with natural gas have been shown.Its geological structure is made with two partially connected reservoirs; the understanding and quantification of gas moving across the two reservoirs are crucial for the management of this gas storage. The second item, as above, is the subject of this paper. Simulations and history-matches have been performed initially with a finite-difference model using a cartesian local grid refinement technique. Following this, a general-purpose model including a control-volume finite-element (CVFE) method has been used. The purpose is to check and confirm the ability of this method to perform real reservoir studies, i.e. simulating large 3-dimensional full-field multi-phase reservoirs. As far as we know, it is the first published full-field study performed with a control-volume finite-element method simulator, and it confirms previous conclusions from theoretical and specific pattern example papers. This type of simulator can be an excellent alternative to flexible gridding techniques used in finite-difference simulators. The following shows some of the advantages over the finite-difference techniques: The entire reservoir can be gridded as required without using any special techniques for local grid modifications.The numerical diffusion is as isotropic as possible, so that the grid-orientation effect is controlled.The representation of zones of interest, singularities and discontinuities is more accurate and flexible.