Induction Conductivity and Natural Gamma Logs at the Osage Skiatook Research Sites “A” and...
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Transcript of Induction Conductivity and Natural Gamma Logs at the Osage Skiatook Research Sites “A” and...
Induction Conductivity and Natural Gamma Logs at the Osage Skiatook Research
Sites “A” and “B”, Northeastern, Oklahoma
By
Marvin M. Abbott, Bruce D. Smith, Robert A Zielinski,James K. Otton, and James J. Thordsen
17 wells
9 wells
Number of wells logged
Skiatook Lake
normal pool
Surface
and
Subsurface
Salty
Area
A-site
A-site
Well not near salt area
Well near salt area
Unit 3
Unit 2
Unit 4
25
25
Greater conductivity in the near surface section of all well logs
Greater conductivity on the logs from wells near surface salt area
Natural Gamma Ray correlated stratigraphic units across the area
Natural Gamma Ray Identified lithologic changes within the units
A depth of 25 feet was selected to test for a statistically significant difference between the near surface and deeper units conductivity values
CO
ND
UC
TIV
ITY
, M
S/M
Grouped Box Plots of Borehole Conductivity Log Data
1. All sets are statistically significantly different for conductivity data grouped by depths <25 feet and >25 feet 2. Location, lithology, and proximity to salty areas have little
affect on the significance of the difference between the data sets.
3. The change in conductivity data is probably associated with a natural depth of weathering for the region.
Location Lithology Proximity to Salty Areas
Depth
Borehole Geophysical Data and
•Surface DC-Resistivity Geophysical Data
•Aqueous Core-Extract Chemistry Data
•Water-Quality Chemistry Data
9
6 7
8
Location of 4 DC Resistivity Survey Points
A-site
AA02AA04
AA03
Conductivity Logs near DC Resistivity Survey Line
Conductivity, mS/m
Borehole Geophysical Data and
•Surface DC-Resistivity Geophysical Data
•Aqueous Core-Extract Chemistry Data
•Water-Quality Chemistry Data
Example Log
Core ExtractChloride <100 mg/L
25 Feet
Core Extract Chloride >100 mg/L
DC-07
Unit 3
Unit 4
100
PROFILE OF WELLS REMOVED FOR SURFACE SALT AREA
C C’
SOUTH NORTH
PROFILE OF WELLS REMOVED FROM SURFACE SALT AREA
DATUM 25 Feet Depth of Weathering
Core Extract Data
Sulfate is dominate anion species in shale and sandstone at <25 feet or >25 feet
AA-11 has greater chloride values.
• Located at surface drainage from pit area but not in the surface salt area.
• 25 foot weathering zone intersects Unit 3, a sandstone section.
Unit 3
Unit 2
Unit 4
PROFILE OF WELLS NEAR SURFACE SALT AREA
D D’
PROFILE OF WELLS NEAR SURFACE SALT AREA
DATUM 25 Feet Depth of Weathering
<25 Feet, Chloride Dominate Anion Species
Chloride found at greater depths,where 25 foot weathering zone intersects Unit 3, sandstone section
Unit 3
Unit 2
Unit 4
Water Quality Samples Total Dissolved Solids mg/L
Core Extract Chloride <100 mg/L
Core Extract Chloride >100 mg/L
25 Feet, 8 Meters
Land Surface
Core Extract Chloride <100 mg/L
Core Extract Chloride >100 mg/L
25 Feet, 8 Meters
Water Quality Samples Total Dissolved Solids mg/L
Land Surface
Summary
• Log conductivity values were greater near surface, <25 feet.
• Salt leachate can percolate through near-surface sandstone, shale, siltstone, and limestone.
• Borehole logs data are comparable with surface geophysics, aqueous core-extract methods, and water quality sampling.
• Core salt leachate was found at depths greater than the regional weathered zone 25 foot if permeable units were present near surface.