Fracking: How far from faults?

Wilson, M.P.; Worrall, F.; Davies, R.J.; Almond, S.

doi:10.1007/s40948-018-0081-y

Fracking: How far from faults?

Wilson, M.P.; Worrall, F.; Davies, R.J.; Almond, S.

Authors

Miles Wilson miles.wilson@durham.ac.uk
Academic Visitor

F. Worrall

R.J. Davies

S. Almond

Abstract

Induced earthquakes and shallow groundwater contamination are two environmental concerns associated with the interaction between hydraulic fracturing (fracking) operations and geological faults. To reduce the risks of fault reactivation and faults acting as fluid conduits to groundwater resources, fluid injection needs to be carried out at sufficient distances away from faults. Westwood et al. (Geomechanics and geophysics for geo-energy and geo-resources, pp 1–13, 2017) suggest a maximum horizontal respect distance of 433 m to faults using numerical modelling, but its usefulness is limited by the model parameters. An alternative approach is to use microseismic data to infer the extent of fracture propagation and stress changes. Using published microseismic data from 109 fracking operations and analysis of variance, we find that the empirical risk of detecting microseismicity in shale beyond a horizontal distance of 433 m is 32% and beyond 895 m is 1%. The extent of fracture propagation and stress changes is likely a result of operational parameters, borehole orientation, local geological factors, and the regional stress state. We suggest a horizontal respect distance of 895 m between horizontal boreholes orientated perpendicular to the maximum horizontal stress direction and faults optimally orientated for failure under the regional stress state.

Citation

Wilson, M., Worrall, F., Davies, R., & Almond, S. (2018). Fracking: How far from faults?. Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 4(2), 193-199. https://doi.org/10.1007/s40948-018-0081-y

Journal Article Type	Article
Acceptance Date	Jan 16, 2018
Online Publication Date	Feb 28, 2018
Publication Date	Jun 1, 2018
Deposit Date	Jan 30, 2018
Publicly Available Date	Mar 1, 2018
Journal	Geomechanics and Geophysics for Geo-Energy and Geo-Resources
Print ISSN	2363-8419
Electronic ISSN	2363-8427
Publisher	Springer
Peer Reviewed	Peer Reviewed
Volume	4
Issue	2
Pages	193-199
DOI	https://doi.org/10.1007/s40948-018-0081-y

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