Prediction of thermal front breakthrough due to fluid reinjection in geothermal reservoirs
Chemically reactive tracers can be used to measure reservoir temperature distributions because of their extreme sensitivity to temperature. If a reactive tracer flows through a reservoir from an injection well to a production well, then early in the production history the tracer will contact mostly high temperatures and experience a high percentage of decomposition. As more energy is extracted from the reservoir, subsequent reactive tracer tests will show less decomposition. Tracers must be chosen which have reaction kinetics appropriate to the temperature patterns expected in the reservoir under consideration. If kinetics are too slow, no significant reaction occurs. If kinetics are too fast, essentially all of the tracer will react. In neither case can useful information be obtained. Seventeen chemically reactive tracers have been identified which are appropriate for geothermal reservoirs in the 70 to 275/sup 0/C range. Of the 17 tracer reactions investigated, 5 are hydrolysis of esters, 3 are hydrolysis of amines, and 9 are hydrolysis of aryl halides. A method for choice of the appropriate reactive tracer for a given reservoir is also presented. The method requires measurement of the residence time distribution (from a conservative tracer test), an estimate of reservoir temperature, and some simple geochemistry measurements and calculations. Several examples of choosing reactive tracers for existing geothermal reservoirs are given.
- Research Organization:
- Los Alamos National Lab., NM (USA); Mechanical Design Services, Los Alamos, NM (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 5859042
- Report Number(s):
- LA-UR-87-3071; CONF-880103-1; ON: DE88000524
- Resource Relation:
- Conference: Symposium on geothermal energy, New Orleans, LA, USA, 10 Jan 1988; Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GEOTHERMAL SYSTEMS
TEMPERATURE MEASUREMENT
GEOTHERMOMETRY
TRACER TECHNIQUES
AMINES
ESTERS
FLUID INJECTION
HALIDES
HALOGENATED AROMATIC HYDROCARBONS
REACTION KINETICS
AROMATICS
HALOGEN COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
Geothermal Legacy