geothermal resource potential of the safford-san simon basin, arizona

Whitlock Mountains Area
In 1927 and 1928 the Pinal Oil Company Whitlock Oil #1 State was unsuccessfully
drilled for oil in D-10-28-36AD. However, the hole encountered a
strong artesian flow of thermal water (4l o C)
from conglomerate below 440.4 m
to total depth at 586.7m.
Today artesian flow of thermal water from
this well continues.
An additional oil and gas test, the Bear Springs Oil
#1 Allen, formerly discharged "lukewarm" water (Knechtel, 1938). This well,
drilled to 473.9m, has since been destroyed.
The Badger Den well, D-10­
29-20AC, discharged 34.l o C water in the late 1970s (Swanberg and others, 1977).
Presently, this well is inoperative due to pump removal.
These thermal wells at the southern terminous of the Whitlock Mountains
indicate a significant low-temperature «100 o e) geothermal resource suitable
for direct-heat use in agricultural applications.
Total dissolved solids (TDS)
between 1,100 and 700 milligrams per liter (mg/l) are reported for water discharging
from thermal wells in the area (Table 2).
These thermal waters are
sodium chloride-sulfate composition and they contain fluoride concentrations
exceeding five mg/1 (see Table 2) •
Siltstone and clay to 440m provide a confining cap rock over conglomerate
aquifers in the vicinity of the Whitlock #1 well.
Fractured Tertiary
volcanic rock may host the thermal aquifer for the Badger Den well.
Chemical geothermometry, using the Na-K-Ca geothermometer, predicts 104
o
to 132 C deep subsurface temperature.
Caution is advised, however, in using
these results because further geochemical and geophysical studies are required
to confirm a deep intermediate-temperature (100-150 o C) resource. Additional
wells 457 to 610m depth are likely to encounter 40 to 50 0 C water and
may produce artesian flow exceeding 200 gallons per minute.
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