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Effect of geothermal fluid composition on power production

Nagasree Garapati, Stuart DC Walsh, Allan MM Leal, Philipp Schaedle, Martin O Saar

Research output: Contribution to conferenceAbstractpeer-review

Abstract

Energy extraction from geothermal reservoirs requires an understanding of the thermodynamic and thermophysical properties of the geothermal fluid, which are themselves dependent on the fluid's chemical composition.
The composition of geothermal fluids varies over time throughout the reservoir and differs from well to well, as a result of injection of other fluids (brine, CO2) or due to changes in local chemical and thermal equilibrium as heat is extracted.
Therefore, numerical models should account for such spatial and temporal chemical changes to calculate fluid properties accurately.
While several thermodynamic and thermophysical models exist for predefined fluid compositions, numerical methods are needed that can accommodate fluids of arbitrary chemical composition.
In this work, we present a numerical simulation framework that accounts for such composition-dependency in geothermal power production modeling. The framework couples species-based thermodynamic and thermophysical models, with a non-linear system solver (KINSOL) and a chemical system solver (Reaktoro).
We first demonstrate accuracy of the approach by comparing the predictions of thermodynamic and thermophysical properties of various aqueous solutions (single, binary, and multiple salt solutions) with experimental data.
We then use the solver to model geothermal heat extraction from different geothermal sites and examine the effects of salinity and fluid composition on the amount of energy produced.
Original languageEnglish
Publication statusPublished - 2016
Externally publishedYes
EventFall Meeting of the American-Geophysical-Union 2016 - San Francisco, United States of America
Duration: 12 Dec 201616 Dec 2016

Conference

ConferenceFall Meeting of the American-Geophysical-Union 2016
Abbreviated titleAGU
Country/TerritoryUnited States of America
CitySan Francisco
Period12/12/1616/12/16

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