Laboratory investigation of steam adsorption in geothermal reservoir rocks

Technical Report · Mon Feb 01 04:00:00 EST 1988

DOI:https://doi.org/10.2172/7038730· OSTI ID:7038730

Luetkehans, J

Some vapor-dominated geothermal reservoirs and low-permeability gas reservoirs exhibit anomalous behavior that may be caused by surface adsorption. For example, geothermal reservoirs in the Larderello are of Italy and reservoirs in the Geysers Geothermal Field, California produce little, if any, liquid. Yet to satisfy material balance constraints, another phase besides steam must be present. If steam adsorption occurring in significant amounts is not accounted for, the reserves will be grossly under-estimated. In addition, well tests may be misinterpreted because the pressure response is delayed owing to be adsorbed material leaving or entering the gaseous phase. In the present research the role of adsorption in geothermal reservoirs in investigated. Two sets of laboratory equipment were constructed to measure adsorption isotherms of cores from Berea sandstone, Larderello, and The Geysers. Seven experimental runs were completed using nitrogen on the low temperature apparatus at -196/sup 0/C. Eight runs were conducted using steam on the high temperature apparatus at temperatures ranging from 150 C to 207/sup 0/C. The largest specific surface area and the greatest nitrogen adsorption isotherm were measured on the Berea sandstone, followed by a core from Larderello and then The Geysers. Difficulties in determining whether a system had reached equilibrium at the end of each step lead to questions regarding the magnitude of adsorption measured by the steam runs. Nevertheless, adsorption was observed and the difficulties themselves were useful indicators of needed future research.

• Research Organization: Stanford Univ., CA (USA). Stanford Geothermal Program
• DOE Contract Number: AS03-80SF11459; AS07-84ID12529
• OSTI ID: 7038730
• Report Number(s): SGP-TR-115; ON: DE88012261
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150904* -- Geothermal Engineering-- Geothermal Reservoir & Well Performance
BENCH-SCALE EXPERIMENTS
GEOLOGIC FORMATIONS
GEOTHERMAL SYSTEMS
Geothermal Legacy
PERMEABILITY
RESERVOIR ROCK
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE EFFECTS