Croucher, AdrianRenaud, TheoO'Sullivan, JohnO'Sullivan, MichaelRiffault, Jeremy2023-12-042023-12-042023-11-15(2023, November 15-17). [Conference item]. 45th New Zealand Geothermal Workshop, Auckland.https://hdl.handle.net/2292/66676In some geothermal systems there are high concentrations of chloride and some non-condensible gas (mainly CO2). For reservoir modelling, equation of state (EOS) modules that can handle non-isothermal mixtures of water, chloride and NCGs are required. In the TOUGH2 simulator, EWASG provides a suitable EOS. In this paper we describe a set of new EOS modules for modelling chloride-rich systems using the parallel, opensource geothermal flow simulator Waiwera. EOS modules for water & chloride, water, chloride & CO2 and water, chloride & air are provided. Shared code is used to give consistency between results from different EOS modules. The main physical properties of chloride are computed using the updated thermodynamic formulation of Driesner (2007) which also removes the low-temperature limitations of EWASG. As in the pure water and water & NCG EOS modules for Waiwera, primary variable interpolation gives improved phase transition performance and hence faster convergence of natural state simulations. Some results for theoretical test problems and real high- and low-temperature geothermal fields are presented. Keywords: Reservoir models, numerical modelling, flow simulator, Waiwera, chloride, non-condensible gasItems in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmConference Item2023-11-26Copyright: The authorshttp://purl.org/eprint/accessRights/RetrictedAccess