| Title | Well proximity governing stress drop variation and seismic attenuation associated with hydraulic fracturing induced earthquakes |
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| Author | Yu, H ;
Harrington, R M; Kao, H; Liu, Y; Abercrombie, R; Wang,
B |
| Source | Journal of Geophysical Research, Solid Earth 2020 p. 1-17, https://doi.org/10.1029/2020JB020103 |
| Image |  |
| Year | 2020 |
| Alt Series | Natural Resources Canada, Contribution Series 20200095 |
| Publisher | American Geophysical Union |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | British Columbia |
| NTS | 94G/07 |
| Area | Montney Play |
| Lat/Long WENS | -123.0000 -122.7500 57.5833 57.2500 |
| Subjects | hydrogeology; mathematical and computational geology; Science and Technology; tectonics; hydraulic fracturing; earthquakes; earthquake studies; tectonic environments; seismic data; stress analyses;
wells |
| Illustrations | location maps; schematic diagrams; variation diagrams; spectra; plots |
| Program | Environmental Geoscience Shale Gas - induced seismicity |
| Released | 2020 08 02 |
| Abstract | We use broadband seismic data collected within 3 km of a hydraulic fracturing (HF) well in northeast British Columbia, Canada, to estimate the stress drop values of HF-induced earthquakes and their
spatial variation. Applying both spectral ratio and clustered single-spectra fitting methods to 484 induced earthquakes (M-1.0 to 3.0), we find that earthquakes close to the injection well have lower stress drop values than those at greater distance.
Stress drop values are generally invariant within clusters either proximal (~0.1-1 MPa) or distal (~1-10 MPa) to the well, suggesting that dynamic ruptures in rocks with similar rheological properties tend to have relatively constant stress drop
values. Clustered single spectrum fitting also suggests that the seismic quality factor (Q) is lower proximal to the well. We interpret the lower stress drop values and higher seismic attenuation proximal to the well as a result of higher fracture
density and/or elevated pore pressure in the rock matrix due to hydraulic stimulation. |
| Summary | (Plain Language Summary, not published)
Seismic stress drop is the amount of tectonic force released by a seismic event. It can be calculated from ground motions recorded on seismograms. In
this study, we study 484 local earthquakes with magnitude ranging from -1.0 to 3.0 in northeastern British Columbia that occurred near an injection well during hydraulic fracturing (HF). We find that events closer to the injection well consistently
have lower stress drop values than those located farther away. We also find that the seismic wave amplitude attenuates faster in places closer to the injection well. We interpret the lower stress drop values and higher seismic attenuation proximal to
the well as a result of higher fracture density and/or elevated pore pressure in the rock matrix due to HF-fluid injection. |
| GEOSCAN ID | 326284 |
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