| Title | Physical factors controlling the diverse seismogenic behavior of fluid injections in Western Canada |
| |
| Author | Wang, B; Kao, H ;
Yu, H; Visser, R; Venables, S |
| Source | Earth and Planetary Science Letters vol. 589, 117555, 2022 p. 1-9, https://doi.org/10.1016/j.epsl.2022.117555 |
| Image |  |
| Year | 2022 |
| Alt Series | Natural Resources Canada, Contribution Series 20210700 |
| Publisher | Elsevier |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | British Columbia |
| NTS | 93P/09; 93P/10; 93P/11; 93P/14; 93P/15; 93P/16; 94A/01; 94A/02; 94A/03; 94A/06; 94A/07; 94A/08 |
| Lat/Long WENS | -121.2500 -120.0000 56.5000 55.5000 |
| Subjects | stratigraphy; seismicity; hydraulic fracturing; structural analyses; Montney Formation; Western Canadian Sedimentary Basin |
| Illustrations | location maps; histograms; schematic diagrams; distribution diagrams |
| Program | Environmental Geoscience Shale Gas - induced seismicity |
| Released | 2022 05 11 |
| Abstract | Many factors, both natural and anthropogenic, can influence the seismogenic pattern of injection-induced earthquakes (IIE). With an enhanced earthquake catalog and a comprehensive fluid injection
database compiled for the southern Montney play in northeast British Columbia, we explore the relative significance of the potential controlling factors of IIE. We first show that hydraulic fracturing (HF) operations are most likely responsible for
the increased seismicity in the region. For areas with comparable HF activities, the regional structural geology could be one primary factor correlating with the distribution of IIE. Our investigations further reveal that the stratigraphic formation
for HF is the next important factor deciding the level of IIE. Specifically, the number of HF stages targeting the Upper Montney is about five times of that targeting the Lower-Middle Montney (LMM), yet the latter ones are responsible for the
majority of IIE. The elevated seismic response with LMM may be attributed to two possible mechanisms, 1) the proximity to deeper permeable formations and subvertical graben faults that facilitates the downward migration of injected fluid and stress
perturbation to reactivate pre-existing faults in the basement, and 2) the geomechanical heterogeneity of the two newly recognized geological units (Altares Member and Pocketknife Member) along the upper and lower boundaries of the LMM that enhances
the seismogenesis of IIE. Our results provide an important framework of constructively mitigating the injection-related seismic hazard. |
| Summary | (Plain Language Summary, not published)
There are many factors that can influence the spatiotemporal distribution of earthquakes caused by fluid injections. In this study, we first establish an
enhanced earthquake catalog and a comprehensive fluid injection database for the southern Montney play in northeast British Columbia. Then we explore the relative significance of the potential controlling factors of injection-induced earthquakes
(IIE). Our analysis shows that hydraulic fracturing (HF) operations are most likely responsible for the increased seismicity in the region. For areas with comparable HF activities, the regional structural geology could be the primary factor
influencing the seismic pattern. Finally for places with the same structural setting, we found that injections targeting the relatively deeper Lower-Middle Montney (LMM) formation have caused many more IIE than those targeting the shallower Upper
Montney. We propose a physical model to interpret the observed IIE distribution. The level of IIE is high if the injected fluid can migrate downward and re-activate pre-existing faults in the basement. Our results provide an important framework of
constructively mitigating the injection-related seismic hazard while maintaining efficiency of unconventional hydrocarbon resources development. |
| GEOSCAN ID | 329707 |
|
|