Measurement and modeling of stress changes caused by underground pressurization of gas

Robert Walsh, Othman Nasir, Nicola Calder, Sean Sterling, John Avis

In the proceedings of: GeoOttawa 2017: 70th Canadian Geotechnical Conference; 12th joint with IAH-CNC

Session: Rock Mechanics II

ABSTRACT: Underground storage of gas allows us to store energy when supply exceeds demand, and quickly deliver energy when needed. In Ontario, natural gas is stored in spent reservoirs during reduced demand (typically summer) and delivered in winter. Renewable wind and solar energy is produced inconsistently, but excess energy can be stored underground as compressed air. In both, pressurized gas is injected into subsurface formations changing the effective stresses in and around the storage formation or cavern. To maximize capacity, operators want to maximize pressure, while avoiding hydraulic fracturing. Here we describe two modeling studies. In the first, data was obtained from a deep borehole, providing indirect observations of the geomechanical response of the caprock. In the second, open boreholes intersected thin caprock units above the reservoir, allowing gas flow into a shallower unit. At both sites, the mechanical response of the caprock was modeled using combined two-phase flow and geomechanical models.

RÉSUMÉ: demande et de fournir de l'énergie lorsque nécessaire. En Ontario, le gaz naturel est emmagasiné dans des réservoirs épuisés, en période de demande réduite (généralement l'été) puis libéré en hiver. nergie renouvelable tel que une production variable, mais peuvent aussi être emmagasinée sous terre dans des systèmes de stockage sous pression. Dans les deux cas, un gmodifiera les stresses de la formation ou de la caverne. Pour maximiser la capacité, les opérateurs veulent optimiser la pression et éviter la fracturation hydraulique. Nous décrivons ci-dessous, deux études, dans le premier cas, les données ont été obtenues à partir d'un forage, ce qui nous a fourni des observations sur la réaction géomécanique du caprock. Le seconde étude, un forage ouvert, entre coupant unités du caprock, permis au gaz de migré. La réponse mécanique du caprock a été modélisée à l'aide d'un modèle de flux ainsi que géomécanique.

Access this article:
Canadian Geotechnical Society members can access to this article, along with all other Canadian Geotechnical Conference proceedings, in the Member Area. Conference proceedings are also available in many libraries.

Cite this article:
Robert Walsh; Othman Nasir; Nicola Calder; Sean Sterling; John Avis (2017) Measurement and modeling of stress changes caused by underground pressurization of gas in GEO2017. Ottawa, Ontario: Canadian Geotechnical Society.

@article{geo2017Paper214,author = Robert Walsh; Othman Nasir; Nicola Calder; Sean Sterling; John Avis,title = Measurement and modeling of stress changes caused by underground pressurization of gas,year = 2017}