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Formation dry‐out from CO 2 injection into saline aquifers: 2. Analytical model for salt precipitation
Author(s) -
Pruess Karsten
Publication year - 2009
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2008wr007102
Subject(s) - saturation (graph theory) , salinity , aquifer , mechanics , materials science , thermodynamics , soil science , hydrology (agriculture) , environmental science , groundwater , mathematics , geology , geotechnical engineering , physics , combinatorics , oceanography
From a mass balance for water dissolved into the flowing CO 2 stream and a consideration of saturation profiles from the Buckley‐Leverett fractional flow theory, we derive an equation that directly relates gas saturation S g,d at the dry‐out front to temperature, pressure, and salinity dependence of fluid properties. The equation is easily solved by iteration or interpolation. From gas saturation at the front we derive the average gas saturation in the dry‐out region, from which we obtain the “solid saturation” S S , i.e., the fraction of pore space filled with solid precipitate. Values of S S derived from this theory show excellent agreement with numerical simulations presented in the preceding companion paper. Thus, from relative permeabilities and fluid properties at in situ conditions prior to CO 2 injection, it is possible to directly make an accurate estimate of solids precipitation, without having to perform a numerical simulation of the injection process.