Fracking and Earthquakes

Alastair Muir, President Muir&Associates Consulting

Who am I?

• Data since 1979

Who cares?Why do they care?

What is their problem?

The Domain - Seismic Mechanisms in the WCSB

Factors relevant to induced seismicity have been determined for the WCSB:

• Region (pre-existing faults)

• Hydraulic fracking

• Water disposal

• Pore overpressure

Risk and Hazard ManagementThe risk model is based on factors that are observable and can be monitored externally. This will allow continuous risk assessment and mitigation.

The model allows for future amendments to components while retaining the overall structure. It allows the introduction of new technologies for exploitation without major changes.

The model is objective and defines responsibilities for the licensee and the regulator

Components include:

• Data requirements (seismic catalogue and monitoring)

• Rate and magnitude models specific to geological regions

What data do you need?What data do you have?

Public Data Sources

• Hydraulic fracturing records (>10,000 pdf files)

– MER – RGE – TWP – SEC – LSD

• Well locations ( >500,000 wells)

– UWI

• Earthquake data

– Latitude, longitude

Induced Seismic Activity in WCSB

Seismicity increase between April 2009 and December 2011 in the Horn River Basin

Activity is regionally confined and associated with deployment of new resource development technologies; horizontal drilling and multistage hydraulic fracturing

Induced Seismic Activity in WCSB

Fox Creek, Duvernay Zone, AER Subsurface Order No 2

BC Alberta

Total 31,609 587,243

Non Abandoned 24,445 501,897

Candidate HF 15,786

Candidate Disposal 3,840

Associated HF 50

Associated Disposal 52

Affected Producers(Alberta)

• Encana has four times the number of applications as the next licensee

• 20 out of 252 licensees (8%) account for 50% of applications

• Seismic and operations timing data are required

• 1 year embargo on other operational data

Modelling

Managing Risk

Monitor the process to identify changes before they cause a problem or a shutdown. Data should be quantitative and timely.

The risk model is based on factors that are observable and can be monitored externally. This will allow continuous risk assessment and

mitigation.

Seismic Risk Assessment

1. Determine seismic catalogue and ongoing real time data collection and update process

• CASC catalogue(Atkinson, et al.)

• Small events (>1 ML) required in restriction zones

2. Rate of events

• Poisson arrival time with change point detection

3. Define restriction zones

4. Magnitude of events

• Truncated Pareto distribution

• Truncated exponential distribution

Arrival time of earthquakes follows a Poisson process

• random arrival times

Magnitude follows a Power Law

• word frequency, letter frequency, page views, size of forest fires, cities, Facebook likes

Probability Distributions

Of course youdon’t have the

right data

Seismic Event Rate Change Detection

• Time windows start when fracking commences for internal monitoring and continue with real time analysis

• Poisson arrival time change point detects rate changes within restriction zone

Ross, Gordon J., Journal of Statistical Software (2015), v 66, pp. 1-20

Visualization

Seismic Event Magnitude Changes

• Changes in magnitude distributions after change points (Gutenberg-Richter relationship) 902 events

Seismic Risk Management

• Rate changes or fracking operations define data collection time periods

• Daily report based on magnitude distribution quantifies daily changes in seismic risk

Implementingthe solution

Reporting and Monitoring - Alberta

Reporting and Monitoring - BC

Risk Management Process Flow

Risk Management Process Flow Proactive

Incorporate broader play based risk factors (geologic insights* injection volume, pressure and rate).Update quarterly or yearly

Reactive

Change threshold to >2 ML,

*such as Schultz , et al. (2016)

Tools of the Trade