Linking microearthquakes to fracture permeability change: The role of surface roughness

Abstract Despite its importance, the relation between microearthquakes (MEQs) and changes in hydraulic properties during hydraulic stimulation of a fractured reservoir has rarely been explored, and it is still not well understood. To investigate this relation, we first formulate a plausible scale de...

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Bibliographic Details
Main Authors: Takuya Ishibashi, Noriaki Watanabe, Hiroshi Asanuma, Noriyoshi Tsuchiya
Format: Article
Language:English
Published: Wiley 2016-07-01
Series:Geophysical Research Letters
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Online Access:https://doi.org/10.1002/2016GL069478
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Summary:Abstract Despite its importance, the relation between microearthquakes (MEQs) and changes in hydraulic properties during hydraulic stimulation of a fractured reservoir has rarely been explored, and it is still not well understood. To investigate this relation, we first formulate a plausible scale dependence, where fracture length and shear displacement are variables, for channeling flow through heterogeneous aperture distributions for joints and faults. By combining this formulation with the concept of the seismic moment, we derive quantitative relations between the moment magnitude (Mw) of MEQs and the fracture permeability change in the directions orthogonal to (kfault,⊥/kjoint) and parallel to (kfault,∥/kjoint) the shear displacement, in the form kfault,⊥/kjoint=116.4×100.46Mw and kfault,///kjoint=13.1×100.46Mw. Despite the simplicity of the derivation, these relations have the potential to explain the results of field experiments on hydraulic stimulation, such as the enhanced geothermal systems at Soultz‐sous‐Fôret and Basel.
ISSN:0094-8276
1944-8007