Laboratory investigation of steam adsorption in geothermal reservoir rocks
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
- Resource Relation:
- Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GEOTHERMAL SYSTEMS
RESERVOIR ROCK
SORPTIVE PROPERTIES
BENCH-SCALE EXPERIMENTS
GEOLOGIC FORMATIONS
PERMEABILITY
SANDSTONES
TEMPERATURE EFFECTS
ROCKS
SEDIMENTARY ROCKS
SURFACE PROPERTIES
Geothermal Legacy
150904* - Geothermal Engineering- Geothermal Reservoir & Well Performance