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Report on geographical and television explorations in City of Jacksonville water wells ( FGS: Information circular 64 )
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 Material Information
Title: Report on geographical and television explorations in City of Jacksonville water wells ( FGS: Information circular 64 )
Series Title: ( FGS: Information circular 64 )
Physical Description: iii, 15 p. : illus. ; 23 cm.
Language: English
Creator: Leve, Gilbert W ( Gilbert Warren ), 1928-
Geological Survey (U.S.)
Publisher: State of Florida, Dept. of Natural Resources
Place of Publication: Tallahassee
Publication Date: 1970
 Subjects
Subjects / Keywords: Aquifers -- Florida -- Jacksonville   ( lcsh )
Wells -- Florida -- Jacksonville   ( lcsh )
Geophysical well logging   ( lcsh )
Genre: non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by G. W. Leve.
General Note: "Prepared by U.S. Geological Survey in cooperation with the Bureau of Geology, Division of Interior Resources, Florida Department of Natural Resources, and the City of Jacksonville, Florida, Duval County."
Funding: Digitized as a collaborative project with the Florida Geological Survey, Florida Department of Environmental Protection.
 Record Information
Source Institution: University of Florida
Rights Management:
The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier: aleph - 001048706
oclc - 01287477
notis - AFD1784
lccn - 70633653 //r872
System ID: UF00001124:00001

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Table of Contents
    Title Page
        Page i
        Page ii
    Table of Contents
        Page iii
        Page iv
    Introduction and data description
        Page 1
        Page 2
        Page 3
    Results
        Page 4
        Page 3
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Copyright
            Main
Full Text




STATE OF FLORIDA
DEPARTMENT OF NATURAL RESOURCES






BUREAU OF GEOLOGY
Robert O. Vernon,Chief






INFORMATION CIRCULAR NO. 64





REPORT ON GEOPHYSICAL
AND TELEVISION EXPLORATIONS IN
CITY OF JACKSONVILLE WATER WELLS




By
G.W. Leve





Prepared by
U.S. GEOLOGICAL SURVEY
in cooperation with the
BUREAU OF GEOLOGY
DIVISION OF INTERIOR RESOURCES
FLORIDA DEPARTMENT OF NATURAL RESOURCES
and the
CITY OF JACKSONVILLE, FLORIDA, DUVAL COUNTY


Tallahassee
1970





























































Completed manuscript received
March 21, 1969
Printed by the
Florida Department of Natural Resources
Division of Interior Resources
Bureau of Geology
Tallahassee








CONTENTS


Introduction ................
Description of data obtained . .
Electric logs ..............
Gamma logs ..............
Caliper logs and current meter traverses
Television traverses . . .
Results .. ... .. .. .. .. .
General ................
Analyses of data from individual wells
Main Street well field . .
Well number 5 ...........
Well number 7 ........ .
Well number 13 . . .
Well number 28 . . .
Well number 44 . . .
McDuff well field . . .
Well number 39 . . .
Hendricks Ave. well field . .
Well number 35 .........
River Oaks well field ........
Well number 34 .........


Page
S 1
. 1
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S3
S3
S3
. 3
. 3
S4
S4
S4
S4
S4
S9
S9
S9
S9
S12


. . . . . 12
. . . . . 14
. . . . . 14


ILLUSTRATIONS

Figure
1. Map showing the location of the wells described in this report ........


Page


2. Photograph of television image showing caved-in zone at 440 feet in city v ell 5. View
looking vertically down into the hole when the television camera was about 3 feet
above the caved-in material. A, back of light source; B, smooth side of well bore; C,
material which has collapsed into the open hole . . . . 6
3. Geophysical data obtained in well no. 7 . . . ..... .. 7
4. Geophysical data obtained in well no. 13 . . . ..... .. 8
5. Geophysical data obtained in well no. 28 . . . ..... ... 10
6. Geophysical data obtained in well no. 44 . . . .. ... 11
7. Geophysical data obtained in well no. 39 . . . .. ... 12
8. Geophysical data obtained in well no. 35 . . . .. ... 13
9. Geophysical data obtained in well no. 34 . . . .. ... 15

TABLES

Table Page
1. Tabulation of data obtained from wells . . . ..... .. 5


.I...
....o
. .








REPORT ON GEOPHYSICAL
AND TELEVISION EXPLORATIONS IN
CITY OF JACKSONVILLE WATER WELLS
by
G. W. Leve
INTRODUCTION
During November 1968 the U.S. Geological Survey conducted geophysical
and television explorations in eight City of Jacksonville water production wells.
The purpose of this investigation was to aid the City and the City's consulting
engineers (Reynolds, Smith, and Hills) in appraising the physical condition of
each well and to gain more information on the hydrologic properties of the
aquifer.
The explorations in these wells were made as a part of a comprehensive
investigation to fully appraise the water resources in the Jacksonville area. The
investigation is being conducted by the U.S. Geological Survey in cooperation
with the Division of Geology, Florida Board of Conservation, the City of
Jacksonville, and Duval County.
This report describes the findings of the well explorations and includes the
basic data obtained from these explorations. The locations of the wells explored
are shown on figure 1.
DESCRIPTION OF DATA OBTAINED
Conventional well-logging techniques combined with measurements of flow
velocity in the borehole can provide valuable information on the geology and
water-bearing characteristics of the subsurface rocks penetrated by a well. In
addition, the logs and flow velocity traverses obtained from each well can be
used to correlate the regional relationship of the rocks. However, the purpose of
this report is to present the hydrologic data that was collected during the well
explorations and to briefly describe these data to help the City determine the
physical condition of the wells. Therefore, a detailed analysis of the data and
regional correlations is beyond the scope of this report.
ELECTRIC LOGS
The different rocks adjacent to a well bore will have varying effects on an
artificial electrical current that passes through them. An electric log is a graphic
portrayal of the electric current as it passes through the rock. Resistivity logs are
graphs of the resistivity of the fluid-saturated rocks expressed in ohmmeters.
Spontaneous potential (SP) logs, expressed in millivolts, show the
electro-chemical effect of media of different nature (i.e., rocks of different
lithology or different texture, or two different types of liquid) and the
elcctrokinctic effect of fluids moving through permeable rock in a well. Both the






2 BUREAU OF GEOLOGY






























EXPLANATION

yl City well explored and
well number
S--+ Direction of seoawrd



C. COUNTY.. I

\I y 0 I 4 MILES




Figure I. Map showing the location of the wells described in this report.


resistivity logs and spontaneous potential logs can be used to determine the
depth of casing in a well, to interpret lithology and permeability of the rocks in
a well and to estimate the chemical character of fluid in the pore spaces of the
rocks. Correlations of the hydrologic and geologic properties of the rocks can be
made throughout the area by comparing the electric logs of each well. The
electric log is useful only in the uncased part of the well (open-hole).




INFORMATION CIRCULAR NO. 64


GAMMA LOGS

The gamma log is a graph of the relative natural gamma radiation of rocks
penetrated by the well. Natural gamma radiation is due to the presence of
unstable isotopes of uranium, thorium, and potassium and their various decay
products within the rocks. The radioactivity is measured by a slowly moving
instrument probe which houses a gamma detector, usually a scintillation
counter. The gamma log indicates the depth, thickness and lithology of the
various types of rocks similar to the electric logs, but it is valuable in
determining these characteristics in the cased part of the well which is not
possible with an electric log. In general, carbonaceous shales will have a high
gamma activity whereas limestone, dolomite and evaporites tend to have low
activities.

CALIPER LOGS AND CURRENT METER TRAVERSES
A caliper log is a continuous graph of the diameter of the well bore at
different depths (cased and uncased parts) and the current meter traverse
measures the relative velocity of flow of water at various depths in the well bore.
The quantity of .water flowing at different depths in the well bore may be
calculated by comparing the velocity of flow from the current meter data and
the cross-sectional area from the caliper log at that depth. From this information
the location, thickness, and yield of the water-bearing zones in tile aquifer
penetrated by a well may be determined.
TELEVISION TRAVERSES
An underwater television camera lowered into a well bore affords direct visual
observation of physical conditions in the well. The depth and condition of the
casing seat can be determined and-any incrustation, cracks and perforations in
the casing can be seen and located. Obstructions, cavities or any other
irregularities in the open-hole portion of the well can be observed and located.
Video tapes of the television traverses can be played back and the video picture
compared to electric, gamma, and caliper logs and to current meter data to
obtain additional knowledge of the structure and texture of the rocks penetrated
by the wells.
RESULTS
GENERAL
Electric and gamma logs of the wells show that relatively hard beds of rock
are present in the aquifer between about 700 and 950 feet below the surface.
Relatively soft porous rock is present in the aquifer above and below these hard
beds of rock although there are relatively thin beds of hard rock below about
950 feet. Current meter data indicate that little or no water enters the wells





4 BUREAU OF GEOLOGY
from the hard zones between 700 and 950 feet. Most of the water enters the
wells from soft porous zones between about 500 to 700 feet or between about
950 to 1,200 feet.
Television traverses in the wells showed badly corroded casing in one well and
casing not firmly seated and cemented in the aquifer in two wells. An
obstruction in one well was shown to be caused by a cave-in of clay above the
aquifer. Table I lists the wells examined during the investigation, shows the
kinds of data collected, and lists the diameter and depth of the well.
ANALYSES OF DATA FROM INDIVIDUAL WELLS
MAIN STREET WELL FIELD
WELL NO. 5
(Corner Ist and Laura Streets). This well is reported to be 1,270 feet deep,
but instrument probes could not be lowered below 442 feet because of an
obstruction in the well bore. The television camera showed that the well is cased
to 420 feet, which is about 100 feet above the top of the Floridan aquifer, and
that poorly consolidated silty clay below the casing has collapsed and partially
blocked the well bore. When the well is discharging, water from the underlying
aquifer flows through the restricted opening below the casing at relatively high
velocities and carries some silt and clay to the surface in suspension. Figure 2 is a
photo of the television screen showing the caved-in zone at a depth of 440 feet
in city Well Number 5.
WELL NO. 7.
(Hubbard Street and Confederate Park). Electric and caliper logs were run in
this well to about 1,229 feet; however, because of technical difficulties the
current meter traverse was made to a depth of only 925 feet. The data obtained
indicates that about 70 percent of the water flowing from the well at the surface
enters the well bore below 925 feet. The data also indicates that no water enters
the well between about 750 feet and the bottom of the casing, and in fact some
water is lost back into permeable zones in the aquifer between about 700 feet
and the bottom of the casing, which is 485 feet below land surface. The caliper
log also shows a probable break in the casing between 90 and 120 feet.
The geophysical logs and a bar graph indicating the percentage of the total
natural flow that enters the well at different depth intervals are shown on figure
3.-
WELL NO. 13.
(8th Street and Hogans Creek). This well drilled in 1918 is one of the oldest
water wells owned by the City. Water has been leaking around the outside of the
casing for a number of years, indicating that either the casing is perforated below
land surface or the casing is not properly seated in the aquifer and water is
leaking upwards around the bottom of the casing. Electric logs were made to
locate the bottom of the casing and to obtain geologic and hydrologic
information on the rocks penetrated by the well. A television camera traverse
was made to inspect the casing seat and to locate any perforations in the casing.




INFORMATION CIRCULAR NO. 64


GAMMA LOGS

The gamma log is a graph of the relative natural gamma radiation of rocks
penetrated by the well. Natural gamma radiation is due to the presence of
unstable isotopes of uranium, thorium, and potassium and their various decay
products within the rocks. The radioactivity is measured by a slowly moving
instrument probe which houses a gamma detector, usually a scintillation
counter. The gamma log indicates the depth, thickness and lithology of the
various types of rocks similar to the electric logs, but it is valuable in
determining these characteristics in the cased part of the well which is not
possible with an electric log. In general, carbonaceous shales will have a high
gamma activity whereas limestone, dolomite and evaporites tend to have low
activities.

CALIPER LOGS AND CURRENT METER TRAVERSES
A caliper log is a continuous graph of the diameter of the well bore at
different depths (cased and uncased parts) and the current meter traverse
measures the relative velocity of flow of water at various depths in the well bore.
The quantity of .water flowing at different depths in the well bore may be
calculated by comparing the velocity of flow from the current meter data and
the cross-sectional area from the caliper log at that depth. From this information
the location, thickness, and yield of the water-bearing zones in tile aquifer
penetrated by a well may be determined.
TELEVISION TRAVERSES
An underwater television camera lowered into a well bore affords direct visual
observation of physical conditions in the well. The depth and condition of the
casing seat can be determined and-any incrustation, cracks and perforations in
the casing can be seen and located. Obstructions, cavities or any other
irregularities in the open-hole portion of the well can be observed and located.
Video tapes of the television traverses can be played back and the video picture
compared to electric, gamma, and caliper logs and to current meter data to
obtain additional knowledge of the structure and texture of the rocks penetrated
by the wells.
RESULTS
GENERAL
Electric and gamma logs of the wells show that relatively hard beds of rock
are present in the aquifer between about 700 and 950 feet below the surface.
Relatively soft porous rock is present in the aquifer above and below these hard
beds of rock although there are relatively thin beds of hard rock below about
950 feet. Current meter data indicate that little or no water enters the wells











Table 1. Data obtained from wells.


Gamma Caliper
Log Log


Current Television
Meter Traverse


Main Street Well Field

1st & Laura Sts.
Hubbard and
Confederate Park
8th & Hogan Creek
4th & Pearl Sts.
Union & Ionia Sts.


McDuff Well Field

39 Gilmore St. east
of McDuff

Hendricks Avenue Well Field

35 LaRue St. & Playground

River Oaks Well Field

34 Pumping Station Yd.


10 1,270


1,250
1,071
1,242
1,063


992


X
CX


X


I




0%



A\


10 1,286


10 1,335 X X


City
Well
No.


Location


Diam
(in.)


Total
Depth
(ft.)


Electric
Log


X t ,





BUREAU OF GEOLOGY


Figure 2 Photograph of television image showing caved-in zone at 440 feet in
city well 5. View looking vertically down into the hole when the television
camera was about 3 feet above the caved-in material. A, back of light source; B,
smooth side of well bore; C, material which has collapsed into the open hole.

The electric logs and television camera show that the well is cased to about
443 feet below land surface, and that the casing is seated in clay about 60 feet
above the aquifer. The television camera shows that the entire casing is badly
pitted and corroded and that large longitudinal cracks occur in the casing below
about 300 feet below land surface. Water is probably leaking from the casing at
many depths below the surface. Although only a small amount of water leaking
from the casing reaches the surface, much greater amounts are probably leaking
through perforations and cracks in the casing into the surrounding rocks below
land surface. Geophysical logs of Well No. 13 are shown on figure 4.




INFORMATION CIRCULAR NO. 64


CALIPER LOG
WELL DIAMETER
0 10" 20" 30"
1 1 1


CITY WELL 7


COMPUTED
FLOW METER LOG


PERCENT OF FLOW


Figure 3. Geophysical data obtained in well no. 7.


ELECTRIC
SP
25 MV
400-- r


LOGS
RESISTIVITY


(n
UJ
o 700



0
-J
I
m 800
w
U-
-J
' 900

I--
0


i




BUREAU OF GEOLOGY



CITY WELL 13
ELECTRIC LOGS
SP RESISTIVITY
10 MV 100
1 I I ohms I


Figure 4. Geophysical data obtianed in well no. 13.





INFORMATION CIRCULAR NO. 64


WELL NO. 28.

(Corner of 4th and Pearl Streets). This well flows about 900 gallons per
minute at land surface. Geophysical data indicates that more than 50 percent of
this water comes from soft, porous zones in the aquifer between the bottom of
the casing at 498 feet below land surface and about 700 feet below land surface.

Although this well is 1,242 feet deep the data indicates that no water enters the
well bore below 1,120 feet. Geophysical and flow meter logs are shown on figure
5.
WELL NO. 44.
(Corner of Union and Ionia Streets). This well flows about 1,070 gpm at land
surface. Current meter data indicates that most of this water enters the well bore
from two major water-bearing zones, between about 550 and 700 feet below
land surface and below about 900 feet. The zones above 550 feet and between
700 and 900 feet yield only small quantities of water.
Electric logs indicate numerous alternating soft, porous and hard, nonporous
zones occur in the aquifer between 780 and 940 feet below land surface. The
caliper log and the television camera indicate that there are many small cavities
or fractures in the rock between these depths. Geophysical and flow meter logs
are shown on figure 6.
McDUFF WELL FIELD
WELL NO. 39.

(On Gilmore Street east of McDuff Avenue). The water from this well
contains large quantities of green clay and sand. Geophysical and television
explorations were made in the well to locate the source of this sediment. The
logs and television data show that the casing of this well is seated in limestone at
the top of the Floridan Aquifer about 500 feet below land surface. About 1 to 2
feet below the bottom of the casing there is a cavity about 8 feet in height and
at least 14 inches larger in diameter than the diameter of the casing. This cavity
is the probable source of the sand and clay. Water entering the well bore through
this cavity is probably carrying in poorly consolidated material from above the
top of the limestone. The television camera showed that while the well was
flowing, large quantities of sand were being held in suspension in the well bore
below the cavity. When this sand enters the well bore through the cavity, the
lighter particles are carried to the surface when the well is flowing and the
heavier particles either drop to the bottom of the well or are held in suspension
in the bore. When the well is pumped the water moves up the well bore at faster
velocities and carries these heavier particles to the surface in suspension. Current
meter data indicates that 70 percent of the water discharged at the surface by
gravity flow enters the well from this cavity, and that no water enters the bore
between 810 feet and the bottom of the well at 992 feet (the last 180 feet).
Geophysical logs and current meter data are shown in figure 7.





BUREAU OF GEOLOGY


CAMPER LOG
WELL DIAMETER
O


30C
ELECTRIC LOGS
SP RESISTIITY
25 v 100
SI I Ohm I










S E- -




0




0
No-


CITY WELL 28





COMPUTED
FLOW METER LOG


(Well flowing of surface)











































0 10 20 30
PERCENT OF FLOW


Figure 5. Geophysical data obtained in well no. 28 .


100--

200- -




INFORMATION CIRCULAR NO. 64




CITY WELL 44


ELECTRIC LOGS
SP RESISTIVITY
25 MV 50 ohms
L.I I I


CALIPER LOO
WELL DIAMETER
0 18"
..L..L J


COMPUTED
FLOW METER LOG


10 20
PERCENT OF FLOW


Figure 6. Geophysical data obtained in well no. 44.


-7





BUREAU OF GEOLOGY


CITY WELL 39


ELECTRIC LOGS
RESISTIV"TY
ov 100
._. itai


CALIPER LOG
WELL DIAMETER
0 I5 24"
W


COMPUTED
FLOW METER LOG


PERCENT OF FLOW

Figure 7. Geophysical data obtianed in well no. 39 .



HENDRICKS AVENUE WELL FIELD

WELL NO. 35.

(On LaRue Street between Nira and Cedar Streets).This well flows 1,200 gpm
and current meter data indicates that more than 80 percent of this water enters
the well from two major water-producing zones in the aquifer: between the
bottom of the casing at 508 feet and about 750 feet below the surface and
between about 1,150 feet and 1,250 feet below the surface. Only a relatively
small amount of water enters the well in the intervals between about 750 and
950 feet and between 1,050 feet and 1,150 feet below the surface. The electric
logs show relatively large increases in resistivity in these non-producing zones,
which indicates that the rocks in these zones are relatively hard and
impermeable. Geophysical logs and flow meter data are shown in figure 8.


SP


d


500




600




1000




6o0




st




,O -




INFORMATION CIRCULAR NO, 64


CITY WELL 35


ELECTRIC LOGS
SP RESISTIVITY
50 MV 100
L J I I ohms I



Bottom of IO"co






















0D



0



0
)0
_ S


CALIPER LOG
WELL DIAMETER
0 10"
r---- r


COMPUTED
FLOW METER LOG


10 20
PERCENT OF FLOW


Figure 8. Geophysical data obtained in well no. 35 .




14 BUREAU OF GEOLOGY

RIVER OAKS WELL FIELD
WELL NO. 34.
(In River Oaks Pumping Station yard). Current meter data shows that while
the well is flowing at the surface all of the water enters the well from below 900
feet beneath land surface. These data also indicate that there is internal
circulation of water in the well bere and some of the water that enters the well
below 900 feet is lost back into the aquifer between about 800 feet and the
bottom of the casing at 508 feet. Although the loss of water is slight while the
well is flowing at the surface a current meter traverse made while the well was
closed at the surface shows that a comparatively large quantity of water from
below 900 feet is lost back into the aquifer above 800 feet. Current meter data
in fig. 9 also shows that no water enters the well bore below about 1,240 feet
and the bottom of the well at 1,335 feet (the last 95 feet). Geophysical logs and
current meter data are shown on figure 9.




INFORMATION CIRCULAR NO. 64


in radiation


GAMMA







































0



0



0
I

o-t-

-I-


0)^-

15 r -


SP
,10 MV
LW


II


RESISTIVITY
100
I ohms I






















tO

^-


PERCENT OF FLOW


Figure 9. Geophysical data obtained in well no. 34.


COMPUTED
FLOW METER LOG


CITY WELL 34

ELECTRIC LOGS


RAY LOG
ncreose


z










FLRD GEOLOSk ( IC SUfRiW


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