WSP12268

• File Number: 8509
• Description: San Luis Valley
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 6/1/1987
• Title: Interim Task 5 Report Deep Well Testing & field Investigation - San Luis Valley Confined Aquifer Study - Phase 1
• Water Supply Pro - Doc Type: Report/Study

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~~difficulty in getting the logging probe to drop below that depth. The logging
t;..;jprobe would not go below a depth of 284 feet, even after repeated attempts.

Because of the desirability of obtaining geophysical logs from the Hooper
Pool Well, a downhole-TV camera survey of the well was performed on August 28,
to attempt to determine why the logging probe would not drop below 284 feet.
The TV survey found that eight-inch diameter casing begins at 156,5 feet in
the well, and is off-center inside the 16-inch casing. At 161.5 feet inside
the eight-inch casing is a grillwork iron or steel basket, with slots
approximately ~ne-half inch wide and four to six inches in length, through
which water is moving upward. Whether the grillwork was welded in place
intentionally, or whether this is a pump-intake screen which had fallen to
this depth, could not be determined. No attempt was made to remove the
grillwork basket.

Between the 8-inch and the 16-inch casing, at a depth of 162.5 feet, is a
plug of what appeared to be cement. Along one side, the cement evidently had
cracked and fallen away, because there was a crescent-shaped hole through
which water could be seen to move upward toward the surface. This was the
hole through which the geophysical logging probe dropped to a depth of 284
feet, at which point either there is a break in the 16-inch casing, or that
casing ends, or there is another obstruction, That hole was not large enough
for entry of the downhole TV camera.

From the geophysical logs it is apparent that there is water entering the
well from a depth of approximately 200 to 280 feet. The water which flows at
the surface evidently is a mixture of shallow confined aquifer (HSU-2) ground
water from outside the 8-inch casing, and ground water from an unknown depth
inside the 8-inch casing. This has been inferred from an abrupt change in
temperature and fluid resistivity which occurs in the depth interval 200 to
280 feet.

2.3.2 Carroll Well Logging
Geophysical logging of the Carroll Well took place between August 27 and

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