CO Sub 2 and Carbonate Chemistry Applied to Geothermal Engineering. Guidance for Interpreting and Using Chemical Data About Geothermal Resources

摘要

The chemistry of high-HCO sub 3 resources is emphasized because they present special complications about data interpretation, development of vapor, and potential for scale deposition. Solubility of CO sub 2 and its exsolution from liquids is treated according to the unique context presented by geothermal resources. Contrasts between this approach and the treatment of CO sub 2 solubility in physical chemistry and other geochemical contexts are presented. Dimensional units for solubility coefficients different from those of physical chemists are presented to favor engineering application. The effects of CO sub 2 on wellbore flow, initiation of flashing, and depth of the 2-phase zone are described and illustrated with examples. To aid the understanding of fluid behavior and the interplay with the design process, specially constructed charts - chemical maps - are presented, examples given for their use, and directions given for their construction. (ERA citation 06:023399)