KEY CONTROLLING FACTORS OF SHALEGAS INDUCED SEISMICITY

Transcription

1 KEY CONTROLLING FACTORS OF SHALEGAS INDUCED SEISMICITY Brecht Wassing, Jan ter Heege, Ellen van der Veer, Loes Buijze Acknowledgements This work is part of a project that received funding by the European Union s Horizon 2020 research and innovation programme under grant agreement number and number The content of this poster reflects only the authors view. The Innovation and Networks Executive Agency (INEA) is not responsible for any use that may be made of the information it contains.

2 INDUCED SEISMICITY IN M4SHALEGAS Fault reactivation & induced seismicity

3 KEY QUESTIONS What are the key controlling factors (site-specific and operational) for induced seismicity (hazard and risk)? Can we assess the potential for inducing felt earthquakes during shale gas operations? Upfront, during operations? (How) can we mitigate induced seismicity?

4 Volume BBL BLACKPOOL INDUCED SEISMICITY Clarke et al., Felt seismicity associated with shale gas hydraulic fracturing: the first documented example in Europe. M 2.3 Key controlling factors of shalegas induced seismicity research/blackpoolearthquakes.html

5 INJECTION-INDUCED SEISMICITY WHAT CAN WE LEARN FROM ANALOGUES? Failure mechanisms Effective normal stress fault tensile shear ΔP Shear stress pressure increase Direct pressure effect expansion Volumetric deformation

6 KEY CONTROLLING FACTORS Site specific factors: Presence of large faults, natural seismicity, basin sensitivity to induced seismicity, mechanical rock properties, depth? Operational factors: Planned injection volumes, injection pressures, injection rates..?

7 KEY CONTROLLING FACTORS: GEOLOGICAL

8 KEY CONTROLLING FACTORS: OPERATIONAL Time after start injection Distance from operation

9 M0 KEY CONTROLLING FACTORS: OPERATIONAL McGarr, 2014: M0,max=μΔV Volumetric moment μδv (Nm) McGarr, Maximum magnitude earthquakes induced by fluid injection.

10 Seismic Moment (N m) Magnitude KEY CONTROLLING FACTORS: OPERATIONAL Galis et al., Two physics based models for estimation of magnitudes of fluid-injection-induced earthquakes M 0 max-arr =γ.δv 3/2 Atkinson et al., Hydraulic fracturing in the Western Canada Sedimentary Basin. M 0 max =μ.δv Injected fluid volume (m 3 )

11 Depth(m) VOLUMES, PRESSURE DISTURBANCE, RUPTURE EXTENT? Geomechanical & earthquake rupture modelling Velocity (m/s) fault ΔP ΔP shear disp (m)

12 Depth(m) VOLUMES, PRESSURE DISTURBANCE, RUPTURE EXTENT? Geomechanical & earthquake rupture modelling Velocity (m/s) shear disp (m)

13 Depth(m) VOLUMES, PRESSURE DISTURBANCE, RUPTURE EXTENT? Geomechanical & earthquake rupture modelling Velocity (m/s) shear disp (m)

14 Depth(m) VOLUMES, PRESSURE DISTURBANCE, RUPTURE EXTENT? Geomechanical & earthquake rupture modelling Velocity (m/s) Effect of initial stress? shear disp (m)

15 Depth(m) VOLUMES, PRESSURE DISTURBANCE, RUPTURE EXTENT? Geomechanical & earthquake rupture modelling Velocity (m/s) Effect of fault properties? shear disp (m)

16 Depth(m) VOLUMES, PRESSURE DISTURBANCE, RUPTURE EXTENT? Geomechanical & earthquake rupture modelling Borehole seismometers Velocity (m/s) Link to monitoring data? shear disp (m)

17 CONCLUSIONS & RECOMMENDATIONS Build further understanding of underlying mechanics of injection-induced seismicity: coupling of experiments models monitoring data Mitigation: Mapping of faults and fractures Avoid injection into or nearby critically stressed (basement) faults Assess seismicity potential from experience in same geological setting Minimize P: Reduce injection volumes, apply post-frac flowback Baseline monitoring of background seismicity Real-time monitoring of seismicity, locations & magnitudes: alignment along larger structures other than HF orientation? sudden increase of seismic magnitudes, changes in frequency-magnitudes? Establish operational protocols for injection sites advanced traffic light systems

18 THANK YOU FOR YOUR ATTENTION Take a look: TIME.TNO.NL

19 INJECTION-INDUCED SEISMICITY WORLDWIDE

20 Total particle velocity (m/s) WAVE PROPAGATION Formation V P V S Zechstein Rotliegend Carboniferous Rupture propagation Rupture arrest (just after) 0.12 s after rupture arrest #1 ZE #2 RO CA Complex reflections along formation boundaries Lower seismic velocities in Rotliegend Induced seismicity - geomechanical modelling

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