Back front of seismicity induced after termination of borehole fluid injection

[1] We study a phenomenon occurring by hydraulic fracturing stimulations, where events are triggered during injection and also after the end of injection, sometimes over hours or even days. We assume that pore-pressure diffusion is the main triggering mechanism. Based on the theory of linear poroelasticity, an equation is derived, that describes the distance from injection point at which seismicity is terminated at a given time after the end of fluid injection. We call this distance the back front of induced seismicity. Using numerical modeling and data from three case studies we show that the back front is observed in reality. The existence of the back front is an important phenomenon supporting the idea of the pore-pressure diffusion nature of fluid injection triggered seismicity. Moreover, it provides an additional means of rock characterization allowing the estimation of the scalar hydraulic diffusivity of the seismically active area.

[1]  M. Biot.  MECHANICS OF DEFORMATION AND ACOUSTIC PROPAGATION IN POROUS MEDIA , 1962 .

[2]  J. C. Jaeger,et al.  Conduction of Heat in Solids , 1952 .

[3]  Serge A. Shapiro,et al.  Characterization of fluid transport properties of reservoirs using induced microseismicity , 2002 .

[4]  J. K. Costain,et al.  Correlations between streamflow and intraplate seismicity in the central Virginia, U.S.A., seismic zone: evidence for possible climatic controls , 1991 .

[5]  A. Nur,et al.  Aftershocks and Pore Fluid Diffusion Following the 1992 Landers Earthquake , 2002 .

[6]  S. Shapiro,et al.  Estimating the crust permeability from fluid-injection-induced seismic emission at the KTB site , 1997 .

[7]  N. Courcoux,et al.  The impact of temperature errors on perceived humidity supersaturation , 2003 .

[8]  Leigh House,et al.  A method to allow temporal variation of velocity in travel-time tomography using microearthquakes induced during hydraulic fracturing , 1998 .

[9]  Ming-Kuo Lee,et al.  Analysis of fluid pressure propagation in heterogeneous rocks: Implications for hydrologically‐induced earthquakes , 1998 .

[10]  James T. Rutledge,et al.  Hydraulic stimulation of natural fractures as revealed by induced microearthquakes, Carthage Cotton Valley gas field, east Texas , 2003 .

[11]  P. Talwani,et al.  Pore pressure diffusion and the mechanism of reservoir-induced seismicity , 1984 .

[12]  D. Howells.  The time for a significant change of pore pressure , 1974 .

[13]  H. Kümpel.  Poroelasticity: parameters reviewed , 1991 .

[14]  S. Shapiro,et al.  Triggering of Seismicity by Pore-pressure Perturbations: Permeability-related Signatures of the Phenomenon , 2003, Pure and Applied Geophysics.

[15]  Francis Albarède,et al.  Upwelling of deep mantle material through a plate window: Evidence from the geochemistry of Italian basaltic volcanics , 2002 .

[16]  Pradeep Talwani,et al.  Seismogenic properties of the crust inferred from recent studies of reservoir-induced seismicity - Application to Koyna , 2000 .

[17]  E. Rothert,et al.  Pore‐pressure diffusion: A possible triggering mechanism for the earthquake swarms 2000 in Vogtland/NW‐Bohemia, central Europe , 2003 .

[18]  Leigh House,et al.  Locating microearthquakes induced by hydraulic fracturing in crystalline rock , 1987 .

[19]  J R Booker,et al.  Aftershocks Caused by Pore Fluid Flow? , 1972, Science.

[20]  Serge A. Shapiro,et al.  Microseismic monitoring of borehole fluid injections: Data modeling and inversion for hydraulic properties of rocks , 2003 .

[21]  C. Scholz.  The Mechanics of Earthquakes and Faulting , 1990 .

[22]  Pascal Audigane,et al.  Large-scale in situ permeability tensor of rocks from induced microseismicity , 1999 .