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The West Virginia Thermal Anomaly - West Virginia Department of ...

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<strong>West</strong> <strong>Virginia</strong> <strong>The</strong>rmal <strong>Anomaly</strong><br />

Zachary Frone<br />

May 22, 2012


Outline<br />

• 2004 Geothermal Map <strong>of</strong> North America (GMNA)<br />

• Heat Flow<br />

• 2010 Study Details<br />

• Temperatures<br />

• Energy Potential<br />

• Future Work


2004 GMNA-Eastern US subset<br />

Important Features:<br />

• <strong>West</strong> <strong>Virginia</strong> data<br />

only in Northern<br />

portion <strong>of</strong> state<br />

• Very Low data density<br />

– This led to funding for<br />

additional data analysis


Heat Flow<br />

• Q – Heat Flow mW/m 2<br />

• K – <strong>The</strong>rmal Conductivity W/m*K<br />

dd<br />

•<br />

dd<br />

- <strong>The</strong>rmal Gradient °C/km<br />

• Inverse relationship between<br />

gradient and conductivity<br />

• Heat flow is constant with depth


Heat Flow<br />

• Traditionally heat flow is<br />

determined from equilibrium<br />

temperature logs<br />

• Changes in gradient reflect<br />

changes in lithology<br />

• <strong>The</strong>rmal conductivity<br />

measured on core or cuttings<br />

• Low conductivity lithologies<br />

(shale) have high gradients<br />

and visa versa<br />

• No equilibrium logs like this in<br />

WV


Heat Flow<br />

• Traditionally heat flow is<br />

determined from equilibrium<br />

temperature logs<br />

• Changes in gradient reflect<br />

changes in lithology<br />

• <strong>The</strong>rmal conductivity<br />

measured on core or cuttings<br />

• Low conductivity lithologies<br />

(shale) have high gradients<br />

and visa versa<br />

• No equilibrium logs like this in<br />

<strong>West</strong> <strong>Virginia</strong>


2010 Research<br />

• Funded by Google.org (RE


New Data<br />

• Temperature<br />

@ Depth data


Spicer Data<br />

• Compilation <strong>of</strong> temperature<br />

data collected in the 1920s-<br />

1930 across the U.S.<br />

• 15 logs in <strong>West</strong> <strong>Virginia</strong><br />

• Maximum reading<br />

thermometer<br />

• Quality checked with modern<br />

temperature logs


New Data<br />

• Bottom Hole<br />

Temperature<br />

Data (BHT)<br />

• 1673 data<br />

points


BHT Corrections<br />

• Correction for thermal<br />

effects caused by drilling<br />

Harrison Correction<br />

• Circulation <strong>of</strong> drilling mud<br />

generally cools the<br />

borehole<br />

– At shallower depths<br />

borehole may be heated<br />

• BHTs normally recorded a<br />

short time after mud<br />

circulation is completed


Calibration


Calibration


Lithologic Information<br />

• Correlation <strong>of</strong> Stratigraphic<br />

Units <strong>of</strong> North America<br />

(COSUNA) AAPG, 1985<br />

• Coarse lithology model<br />

• Used averaged thermal<br />

conductivity values for<br />

Paleozoic sediments<br />

• Specific depth and thickness<br />

data collected for evaporites<br />

Rock Type<br />

<strong>The</strong>rmal<br />

Conductivity<br />

Evaporite 4.7<br />

Dolomite 4.4<br />

Sandstone 4.2<br />

Chert 4.0<br />

Conglomerate 4.0<br />

Limestone 2.9<br />

Limestone/Shale 2.0<br />

Shale 1.4<br />

Unconsolidated<br />

Sediment<br />

1.2<br />

Coal 0.6


Swezey, 2002


Heat Flow Calculation<br />

1. Scale lithologic column to<br />

sediment thickness<br />

2. Calculation <strong>of</strong> thermal<br />

resistance (1/K) then summed<br />

entire sedimentary column<br />

3. Calculate resistance to the<br />

depth <strong>of</strong> the BHT, convert this<br />

back to conductivity<br />

4. Conductivity X Gradient=<br />

Heat Flow<br />

<strong>The</strong>rmal Resistance is similar<br />

to Electrical Resistance


2010 Heat Flow map


Error – Bullard Plot<br />

Eastern <strong>West</strong> <strong>Virginia</strong><br />

Temperature °C<br />

0.0<br />

10.0<br />

20.0<br />

30.0<br />

40.0<br />

50.0<br />

60.0<br />

70.0<br />

80.0<br />

90.0<br />

100.0<br />

Resistance<br />

0 400 800 1200<br />

y = 0.0665x + 13.6<br />

Values below 50 and<br />

above 85 removed<br />

Temperature °C<br />

0.0<br />

10.0<br />

20.0<br />

30.0<br />

40.0<br />

50.0<br />

60.0<br />

70.0<br />

80.0<br />

90.0<br />

100.0<br />

<strong>West</strong>ern <strong>West</strong> <strong>Virginia</strong><br />

Resistance<br />

0 400 800 1200<br />

y = 0.044x + 14.4<br />

Values below 40 and<br />

above 55 removed


Temperature Explanation<br />

1.<br />

2.<br />

• Q o = Surface Heat Flow<br />

• K = <strong>The</strong>rmal Conductivity<br />

• A s = Heat Production in<br />

sediments<br />

NOT AN EXTRAPOLATION OF GRADIENT<br />

• A b = Heat Production in<br />

basement<br />

• X = Depth <strong>of</strong> calculation<br />

• Q m = Mantle Heat Flow<br />

• b = Thickness <strong>of</strong> heat<br />

producing zone


Temperatures<br />

(~11,500ft)<br />

(~14,750ft)<br />

(~18,000ft)<br />

(~21,325ft)


Note: Vertical<br />

exaggeration<br />

Cross section<br />

from Ryder et al.<br />

2009


Note: Vertical<br />

exaggeration<br />

Cross section from<br />

Ryder et al. 2008


Electrical Potential<br />

• Estimates based on Beardsmore<br />

et al. 2011<br />

Process for estimating Technical Potential<br />

• Calculation includes:<br />

– Base Temperature (Surface<br />

temperature + 80°C)<br />

– <strong>The</strong>rmal Cycle Efficiencies<br />

– Drawdown Temperature (10°C)<br />

– Recoverability Factor<br />

– Exclusion <strong>of</strong> “inaccessible” land<br />

– Limits depth to 6.5 km (~21,000ft)


Generation Capacity<br />

Energy Potential ~4,700 EJ (US energy consumption ~14EJ annually)<br />

Installed electricity capacity for WV is 17,700 MW<br />

(EIA, 2010)


Future work<br />

• Re-evaluation <strong>of</strong> heat flow and<br />

temperatures-at-depth<br />

– <strong>The</strong>rmal conductivity<br />

measurements on lithologies<br />

within the state (WVU)<br />

– Additional BHT data from<br />

WVGES online database<br />

– More detailed<br />

lithology/structure basin model<br />

incorporating work from<br />

WVGES<br />

– Hopefully multiple equilibrium<br />

temperature logs in eastern<br />

part <strong>of</strong> the state


Special Thanks

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