Resistivity Log At Valles Caldera - Sulphur Springs Geothermal Area (Wilt & Haar, 1986)
Exploration Activity: Resistivity Log At Valles Caldera - Sulphur Springs Geothermal Area (Wilt & Haar, 1986)
|Exploration Activity Details|
|Location||Valles Caldera - Sulphur Springs Geothermal Area|
|Exploration Technique||Single-Well and Cross-Well Resistivity|
|Activity Date||- 1986|
The generalized resistivity log (Fig. 8) indicates a multilayer section with considerable resistivity contrast between the layers. The near-surface layer varies from 2 to 10 ohm-m; the lower values are indicative of regions of hydrothermal alteration, and the higher values are representative of alluvium and caldera fill in higher elevations where sediments are undersaturated. The resistivity of the Bandelier Tuff, which underlies the surface layer, is variable. Upper sections show a resistivity of 100-500 ohm-m, which is consistent with the tight, well-cemented rocks; but at depths greater than 1 km in the production region, the resistivity in the tuff is quite low (10-70 ohm-m). This lower resistivity is probably caused by K766hot saline reservoir fluid, by increased porosity due to fracturing and dissolution of minerals, and by high subsurface temperatures. The resistivity contrast between this unit and surrounding units presents a good target for surface geophysical prospecting.
- Michael Wilt, Stephen Vonder Haar (1986) A Geological And Geophysical Appraisal Of The Baca Geothermal Field, Valles Caldera, New Mexico