Subsurface Geologic Investigation of Fountain Hills - AZGS ...
Subsurface Geologic Investigation of Fountain Hills - AZGS ...
Subsurface Geologic Investigation of Fountain Hills - AZGS ...
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changes. Short-normal and long-normal logs are used to determine the resistivity close<br />
to the borehole and away from the borehole, respectively, and presumably beyond the<br />
influence <strong>of</strong> the drilling fluid. The spontaneous potential curve (SP) measures the<br />
naturally occurring borehole potential, or voltage, that arises due to differences between<br />
the borehole fluid and the formation fluid. Because water is a good conductor <strong>of</strong><br />
electricity, where the water is high, the conductance is high; if the water content is low,<br />
the conductance is low. The resistivity and spontaneous potential curves are usually read<br />
together and are compared. The geophysical logs for the four ASR wells and five<br />
monitor wells are found in Figures A-2 through A-II.<br />
CROSS SECTIONS<br />
Three geologic cross-sections shown in figure A-I were constructed based on the<br />
lithologic logs derived from borehole drilling samples and geophysical logs collected<br />
during the drilling process. <strong>Geologic</strong> cross-section A-A' (Figure A-I2) was constructed<br />
from north to south, west <strong>of</strong> <strong>Fountain</strong> Lake. This cross-section includes, from north to<br />
south, wells ASR-4, FHMW-2, ASR-I, and FHMW-S.<br />
Cross-section B-B' (Figure A-l3) lies from north to south, east <strong>of</strong> <strong>Fountain</strong> Lake.<br />
This cross section includes from north to south wells, ASR-2, FHMW-4, FHMW-I and<br />
FHMW-3.<br />
Cross-section C-C' (Figure A-I4) spans west to east and includes wells FHTW-3,<br />
FHMW-2, ASR-I, and FHMW-4.<br />
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