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.