Performance Evaluation of the Regional Seismograph Network in Northeast British Columbia, Canada, for Monitoring of Induced Seismicity

2016 ◽  
Vol 87 (3) ◽  
pp. 648-660 ◽  
Author(s):  
Alireza Babaie Mahani ◽  
Honn Kao ◽  
Dan Walker ◽  
Jeff Johnson ◽  
Carlos Salas
Keyword(s):  
British Columbia ◽  
Performance Evaluation ◽  
Induced Seismicity ◽  
Seismograph Network

Well-Log-Based Velocity and Density Models for the Montney Unconventional Resource Play in Northeast British Columbia, Canada, Applicable to Induced Seismicity Monitoring and Research

2020 ◽  
Author(s):  
Alireza Babaie Mahani ◽  
Dmytro Malytskyy ◽  
Ryan Visser ◽  
Mark Hayes ◽  
Michelle Gaucher ◽  
...  
Keyword(s):  
British Columbia ◽  
Hydraulic Fracturing ◽  
Cross Sections ◽  
Induced Seismicity ◽  
Focal Depth ◽  
Depth Resolution ◽  
Velocity Model ◽  
The North ◽  
Seismicity Monitoring ◽  
Unconventional Resource

Abstract We present detailed velocity and density models for the Montney unconventional resource play in northeast British Columbia, Canada. The new models are specifically essential for robust hypocenter determination in the areas undergoing multistage hydraulic-fracturing operations and for detailed analysis of induced seismicity processes in the region. For the upper 4 km of the sedimentary structure, we review hundreds of well logs and select sonic and density logs from 19 locations to build the representative models. For depths below 4 km, we extend our models using data from the southern Alberta refraction experiment (Clowes et al., 2002). We provide one set of models for the entire Montney play along with two separated sets for the southern and northern areas. Specifically, the models for the southern and northern Montney play are based on logs located in and around the Kiskatinaw Seismic Monitoring and Mitigation Area and the North Peace Ground Motion Monitoring area, respectively. To demonstrate the usefulness of our detailed velocity model, we compare the hypocenter location of earthquakes that occurred within the Montney play as determined with our model and the simple two-layered model (CN01) routinely used by Natural Resources Canada. Locations obtained by our velocity model cluster more tightly with the majority of events having root mean square residual of <0.2  s compared with that of <0.4  s when the CN01 model is used. Cross sections of seismicity versus depth across the area also show significant improvements in the determination of focal depths. Our model results in a reasonable median focal depth of ∼2  km for events in this area, which is consistent with the completion depths of hydraulic-fracturing operations. In comparison, most solutions determined with the CN01 model have fixed focal depths (0 km) due to the lack of depth resolution.

scholarly journals Application of focal-time analysis for improved induced seismicity depth control: A case study from the Montney Formation, British Columbia, Canada

Geophysics ◽  
2020 ◽  
Vol 85 (6) ◽  
pp. KS185-KS196 ◽  
Author(s):  
Naimeh Riazi ◽  
David W. Eaton ◽  
Alemayehu Aklilu ◽  
Andrew Poulin
Keyword(s):  
British Columbia ◽  
Seismic Data ◽  
Induced Seismicity ◽  
Search Algorithm ◽  
Focal Depth ◽  
Global Search ◽  
3D Seismic ◽  
Global Search Algorithm ◽  
Montney Formation ◽  
3D Seismic Data

Characterization of induced seismicity and associated microseismicity is an important challenge for enhanced oil recovery and development of tight hydrocarbon reservoirs. In particular, accurately correlating hypocenters of induced events to stratigraphic layers plays an important role in understanding the mechanisms of fault activation. Existing methods for estimating focal depth, however, are prone to a high degree of uncertainty. A comprehensive analysis of inferred focal depths is applied to induced events that occurred during completions of horizontal wells targeting the Montney Formation in British Columbia, Canada. Our workflow includes a probabilistic, nonlinear global-search algorithm (NonLinLoc), a hierarchical clustering algorithm for relative relocation (GrowClust), and depth refinement using the recently developed focal-time method. The focal-time method leverages stratigraphic correlations between P-P and P-S reflections to eliminate the need for an explicit velocity model developed specifically for hypocenter depth estimation. We find that this approach is robust in the presence of noisy picks and location errors from epicenters obtained using a global-search algorithm, but it is limited to areas where multicomponent 3D seismic data are available. We have developed a novel method to determine statics corrections to ensure that the passive seismic observations and 3D seismic data share a common datum in areas of moderate to high topography. Our results highlight the importance of transverse faults, which appear to provide permeable pathways for activation of other faults at distances of up to 2 km from hydraulic fracturing operations.

Seismic b-value within the Montney Play of Northeast British Columbia, Canada

2021 ◽  
Author(s):  
Alireza Babaie Mahani
Keyword(s):  
British Columbia ◽  
Hydraulic Fracturing ◽  
Induced Seismicity ◽  
B Value ◽  
Systematic Difference ◽  
Magnitude Distribution ◽  
Seismicity Rate ◽  
Northern Area ◽  
Seismicity Rates ◽  
Frequency Magnitude Distribution

Critical analysis of induced earthquake occurrences requires comprehensive datasets obtained by dense seismographic networks. In this study, using such datasets, I take a detailed investigation into induced seismicity that occurred in the Montney play of northeast British Columbia, mostly caused by hydraulic fracturing. The frequency-magnitude distribution (FMD) of earthquakes in several temporal and spatial clusters, show fundamental discrepancies between seismicity in the southern Montney play (2014-2018) and the northern area (2014-2016). In both regions, FMDs follow the linear Gutenberg-Richter (G-R) relationship for magnitudes up to 2-3. While in the southern Montney, within the Fort St. John graben complex, the number of earthquakes at larger magnitudes falls off rapidly below the G-R line, within the northern area with a dominant compressional regime, the number of events increases above the G-R line. This systematic difference may have important implications with regard to seismic hazard assessments from induced seismicity in the two regions, although caution in the interpretation is warranted due to local variabilities. While for most clusters within the southern Montney area, the linear or truncated G-R relationship provide reliable seismicity rates for events below magnitude 4, the G-R relationship underestimates the seismicity rate for magnitudes above 3 in northern Montney. Using a well-located dataset of earthquakes in southern Montney, one can observe generally that 1) seismic productivity correlates well with the injected volume during hydraulic fracturing and 2) there is a clear depth dependence for the G-R b-value; clusters with deeper median depths show lower b-values than those with shallower depths.

Interferometric time-lapse velocity analysis: application to a salt-water disposal well in British Columbia, Canada

2019 ◽  
Vol 219 (2) ◽  
pp. 834-852
Author(s):  
Yoones Vaezi ◽  
Mirko Van der Baan
Keyword(s):  
British Columbia ◽  
Induced Seismicity ◽  
Relative Velocity ◽  
Seismic Velocity ◽  
Salt Water ◽  
Broad Band ◽  
Injection Pressure ◽  
Time Lapse ◽  
Water Disposal ◽  
Velocity Variations

SUMMARY We investigate the possibility of passive monitoring of a salt-water disposal well in British Columbia, Canada, using continuously recorded ambient seismic noise. We find seismic velocity variations induced by a reduction of injection pressure in an effort to mitigate an elevated level of seismicity, most likely associated with the disposal of salt water. The relative velocity variations are derived from time-shifts measured between consecutive cross-correlation functions for each station pair in a surface array composed of five broad-band seismometers. The probable driving mechanisms responsible for the velocity changes are reduced pore pressures and/or lowered poroelastic stresses beyond the injection wellbore, respectively. Hydrologic data (e.g. snow and rainfall), noise energy trends and fluctuations in the incident direction of dominant noise sources do not correlate with the estimated relative velocity variations. Velocity variations are detected ahead of the zone of induced seismicity, thus indicating that seismic interferometry may aid in mitigation efforts to reduce the risk of induced seismicity by (1) providing verifiable and repeatable measurements of physical changes within the surrounding area and (2) providing hard constraints for modelling efforts to constrain how and where pore-pressure fronts change.

scholarly journals Performance evaluation of harvest control rules for Pacific herring management in British Columbia, Canada

2010 ◽  
Vol 67 (9) ◽  
pp. 2005-2011 ◽  
Author(s):  
J. S. Cleary ◽  
S. P. Cox ◽  
J. F. Schweigert
Keyword(s):  
British Columbia ◽  
Performance Evaluation ◽  
Reference Point ◽  
Fishery Management ◽  
Reference Points ◽  
Management Policy ◽  
Pacific Herring ◽  
High Productivity ◽  
Control Rules ◽  
Harvest Control Rules

Abstract Cleary, J. S., Cox, S. P., and Schweigert, J. F. 2010. Performance evaluation of harvest control rules for Pacific herring management in British Columbia, Canada. – ICES Journal of Marine Science, 67: 2005–2011. Despite application of a harvest control rule (HCR) since 1986, abundance of several Pacific herring (Clupea pallasi) stocks in British Columbia, Canada, are currently below levels considered adequate for exploitation. An alternative HCR, based on default limit and upper stock reference (USR) points at 0.4 BMSY and 0.8 BMSY, was recently developed under Canada's precautionary fisheries management policy. We simulated the Pacific herring fishery management system to examine whether (i) realized fishery performance over the past 10 years is an expected consequence of applying the existing herring HCR (with a single lower reference point) and (ii) performance could be improved by adopting the Department of Fisheries and Oceans new HCR with limit and USR points. Both HCRs successfully rebuilt stocks to sustainable levels under a high-productivity scenario, but performed poorly when stock productivity was low. The two HCRs were sensitive to stock productivity, because the effect of a target harvest rate (20%) that is independent of productivity was much larger than the effects of biomass reference-point choices. We therefore recommend further research on estimating reference points and sustainable harvest rates for Pacific herring, so that HCRs may be made more responsive to changes in productivity.

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