Comparing reactive and non reactive tracers to measure changes in liquid dominated, fractured geothermal reservoirs

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:494389

Du Teaux, R; Callahan, T J ^[1]

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1. Los Alamos National Lab., NM (United States)

Tracer test data collected during the 1992 and 1995 flow tests of the Hot Dry Rock (HDR) reservoir at Fenton Hill, NM reveal that significant dynamic flow changes occurred with heat mining. Temporally changing tracer residence times, reservoir fluid volume, and broadening fluid residence time distributions were measured with two different tracers used simultaneously during both flow tests. The tracers employed were p-toluene sulfonic acid (p-TSA) and sodium fluorescein (NaFl). While p-TSA is considered non reactive, fluorescein degrades at high temperature. Differences in the recovery of the two tracers measured at Fenton Hill suggest the circulating fluid may have increasingly accessed higher temperature flow paths as energy was extracted. However, the reactive and adsorptive properties of fluorescein are not well characterized for the geochemistry of the Fenton hill reservoir, so further study of tracer properties should be conducted before making firm conclusions. Reservoir simulation with GEOCRACK, a computer model that couples thermal deformation with fluid flow and heat transfer, aids in understanding the tracer response with heat extraction. Simulation of non reactive and reactive tracers illustrates how a comparison of these tracers could be employed to characterize fracture surface area and predict thermal breakthrough in liquid dominated, fractured geothermal reservoirs.

• OSTI ID: 494389
• Report Number(s): CONF-960913--
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
99 GENERAL AND MISCELLANEOUS
FLUID FLOW
FRACTURED RESERVOIRS
G CODES
GEOTHERMAL HOT-WATER SYSTEMS
GEOTHERMAL RESOURCES
HOT-DRY-ROCK SYSTEMS
NEW MEXICO
RESOURCE POTENTIAL
TRACER TECHNIQUES