TY - JOUR
T1 - Water adsorption at high temperature on core samples from The Geysers geothermal field, California, USA
AU - Gruszkiewicz, Miroslaw S.
AU - Horita, Juske
AU - Simonson, John M.
AU - Mesmer, Robert E.
AU - Hulen, Jeffrey B.
N1 - Funding Information:
The authors would like to thank their colleague David Cole for providing pure mineral samples and carefully reviewing the manuscript. Research sponsored by the Office of Geothermal Technology (now the Office of Geothermal and Wind Technologies), the Office of Power Technologies, and the Division of Chemical Sciences, Office of Basic Energy Sciences, U.S. Department of Energy, under contract DE-AC05-96OR22464 with Oak Ridge National Laboratory, managed by Lockheed Martin Energy Research Corp. The critical comments of two anonymous Geothermics reviewers led to a greatly improved final version of this paper. X-ray diffraction analysis of the core samples was completed by Louise Spann, of EGI.
PY - 2001/4
Y1 - 2001/4
N2 - For the first time, water sorption on representative geothermal reservoir rocks from The Geysers steam field has been determined in the laboratory at actual reservoir temperature. The Oak Ridge National Laboratory (ORNL) isopiestic apparatus has been used to measure quantities of water retained at various temperatures and relative pressures by plug samples of three representative reservoir metagraywacke cores. The measurements were made at 150, 200 and 250°C as a function of relative pressure in the range 0.00 ≤ p/po ≤ 0.98, where po is the saturated water vapor pressure. Both adsorption (increasing pressure) and desorption (decreasing pressure) runs were made in order to investigate the phenomenon of hysteresis. Low-temperature gas adsorption analyses were completed on the same rock samples. Nitrogen or krypton adsorption and desorption isotherms at 77 K were used to obtain BET (Brunauer, Emmet, Teller) specific surface areas and pore volumes and their distributions with respect to pore sizes. Mercury-intrusion porosimetry was also used to obtain similar information extending to very large pores (macropores). A qualitative correlation was found between the surface properties obtained from nitrogen adsorption and the mineralogical and petrological characteristics of the solids. In general, however, there is no direct proportionality between BET specific surface areas obtained from nitrogen adsorption and the capacity of the rocks for water adsorption at high temperatures. An analysis of the temperature dependence of adsorption/desorption indicates that multilayer adsorption rather than capillary condensation is the dominant water storage mechanism in The Geysers reservoir rocks at high temperatures.
AB - For the first time, water sorption on representative geothermal reservoir rocks from The Geysers steam field has been determined in the laboratory at actual reservoir temperature. The Oak Ridge National Laboratory (ORNL) isopiestic apparatus has been used to measure quantities of water retained at various temperatures and relative pressures by plug samples of three representative reservoir metagraywacke cores. The measurements were made at 150, 200 and 250°C as a function of relative pressure in the range 0.00 ≤ p/po ≤ 0.98, where po is the saturated water vapor pressure. Both adsorption (increasing pressure) and desorption (decreasing pressure) runs were made in order to investigate the phenomenon of hysteresis. Low-temperature gas adsorption analyses were completed on the same rock samples. Nitrogen or krypton adsorption and desorption isotherms at 77 K were used to obtain BET (Brunauer, Emmet, Teller) specific surface areas and pore volumes and their distributions with respect to pore sizes. Mercury-intrusion porosimetry was also used to obtain similar information extending to very large pores (macropores). A qualitative correlation was found between the surface properties obtained from nitrogen adsorption and the mineralogical and petrological characteristics of the solids. In general, however, there is no direct proportionality between BET specific surface areas obtained from nitrogen adsorption and the capacity of the rocks for water adsorption at high temperatures. An analysis of the temperature dependence of adsorption/desorption indicates that multilayer adsorption rather than capillary condensation is the dominant water storage mechanism in The Geysers reservoir rocks at high temperatures.
UR - http://www.scopus.com/inward/record.url?scp=0035313876&partnerID=8YFLogxK
U2 - 10.1016/S0375-6505(00)00049-3
DO - 10.1016/S0375-6505(00)00049-3
M3 - Article
AN - SCOPUS:0035313876
SN - 0375-6505
VL - 30
SP - 269
EP - 302
JO - Geothermics
JF - Geothermics
IS - 2-3
ER -