Denise M. Onyskiw , P.E. Onyskiw Engineering, LLC Water Management for Shale Plays

May 30, 2014

# Agenda

 History of injection induced seismicity

 Current injection

- induced seismic events

 Review of major publications

 Going forward

– best practices

# History of Injection Induced Seismicity

 Rocky Mountain Arsenal, CO

 Basel, Switzerland

 Rangely Field, CO

 Paradox Valley, CO

# Rocky Mountain Arsenal, CO

 12,045 feet deep

 Bottomed into 75 feet of highly fractured pre

Cambrian gneiss

 Injection pressure peaked at 1050 psi

 Maximum rate was 300 gallons per minute

 710 Denver

- area earthquakes

 Most with epicenters within 5 miles of injection well

# Earthquake Frequency vs. Waste Injected

From National Academy of Sciences Induced Seismicity Potential in Energy Technologies

# Rangely Field, CO

 Tertiary recovery field

 Injection pressures were in excess of 3730 psi

 Earthquake occurrence was reduced after pressures were reduced below 3450 psi

 Today, pressures are below 2000 psi

# Paradox Valley, CO

 16,000 feet deep

– world’s deepest injection well

 Desalinates the Colorado and Dolores rivers in order to meet water usability agreement with Mexico

 Inject 110,000 tons of salt per year

 Injection pressure is 5350 psi

 Injection rate was 345 gallons per minute and 70% brine/30% water

 Injection protocol altered to 230 gallons per minute and 100% brine to reduce earthquake occurrence

# Paradox Injection Well

From Bureau of Reclamation UC Today February 2013

# Current Injection

- induced Seismic Events

 West Virginia

 Texas

 Arkansas

 Ohio

# Major Publications

 National Academy of Science Report

– Induced Seismicity Potential in Energy Technologies

 Environmental Protection Agency

– Minimizing and Managing Potential Impacts of Induced

- Siesmicity from Class II Disposal Wells: Practical Approaches

– still in draft

# Sample Risk Analysis

From National Academy of Sciences Induced Seismicity Potential in Energy Technologies

# Davis and Frohlich Ten

- Point Checklist

– Background Seisimicity

 Are large earthquakes (M >=5.5) known in the region (within several hundred km)?

 Are earthquakes known near the injection site (within 20 km)?

 Is rate of activity near the injection site (within 20 km) high?

# Davis and Frohlich Ten

- Point Checklist

– Local Geology

 Are faults mapped within 20 km of the site?

 If so, are these faults known to be active?

 Is the site near (within several hundred km of) tectonically active features?

# Davis and Frohlich Ten

- Point Checklist

– State of Stress

 Do stress measurements in the region suggest rock is close to failure?

# Davis and Frohlich Ten

- Point Checklist

– Injection Practices

 Are (proposed) injection practices sufficient for failure?

 If injection has been ongoing at the site, is injection correlated with the occurrence of earthquakes?

 Are nearby injection wells associated with earthquakes?

# Example of Traffic Light System Used for Hydraulic Fracturing in 

# England

# Traffic Light System

 Green

- injection proceeds as planned

 Yellow

– injection proceeds with caution, possibly at reduced rates; monitoring is intensified

 Red

– injection is suspended immediately

# Induced Seismicity

- Primer

 Human activity that causes seismic events (energy release) beyond ‘historical’ baseline level.

 Elevated pore pressure causing shear failure

– potential scenario associated with fluid injection into existing fault.

Source: DOE, LBNL http://esd.lbl.gov/research/projects/induced_seismicity/ Confirmed prior instance of induced seismicity in immediate area/formation

 Any recognized Neogene (< 25 mya ) faults in the area?

 Linear elements in surface topography suggesting possible unmapped faults?

 Any historic earthquakes recorded in the area?

 Fault character relative to depth of proposed injection and stratigraphy

 Peak ground acceleration (PGA)

 Existing injection wells and historical volumes 

# Induced Seismicity Risk EvaluationKnown Faults & Historical Earthquakes

• CGS Late Cenozoic Fault, Fold & Earthquake Database http://geosurvey.state.co.us/hazards/Earthquakes/Pages/Maps.aspx • USGS Quaternary Fault & Fold Database http://earthquake.usgs.gov/hazards/qfaults/Induced Seismicity Risk Evaluation

– Example

# Seismic Risk

– Recommendations

 Seismic monitoring might be prudent if earthquake triggering is deemed possible.

 Mitigation strategies might be considered prior to injection.



###  

### If significant changes in baseline seismic activity are recorded at any point after an injection 

### program begins, a more detailed seismicity investigation may be warranted.Denise M. Onyskiw, P.E. Onyskiw Engineering, LLC 720 - 260

- 2963 denise@onyskiwengineering.

com