Earthquakes associated with various oil and gas activities such as waste-water disposal and hydraulic fracturing have become a topic of focus in the central eastern US and western Canada. Events as large as M5.6 have occurred due to the long-term injection of fluid into geological layers, triggering pre-existing critically stressed faults. Assessment of seismic hazard from potentially damaging earthquakes prior to the initiation of injection projects helps mitigate the seismic risks to the oil and gas facilities and public structures. Probabilistic seismic hazard assessment is a critical tool in understanding the likelihood of exceeding specific levels of ground motion in a time window, usually the life span of the structures in question. Currently seismic hazard models from natural earthquakes are routinely provided for the national building codes. With increasing number of injection operations across US and western Canada, these models need to be revisited to capture the true picture of seismic hazard in North America.
We offer detailed seismicity studies for injection operations according to regulations by Alberta Energy Regulator and BC Oil and Gas commission. These analyses include:
- Baseline studies for background seismicity prior to start of operations,
- Seismic hazard maps for different ground motion levels,
- Design of seismic monitoring network suitable for identification of earthquakes with magnitudes as low as 2 according to the requirements of Alberta Energy Regulator’s subsurface order No. 2 and BC Oil and Gas commission.
- Hypocenter and magnitude determination of seismic events,
- Fault activation analysis during operations and after flowback to include the delay in the response of the affected area to injection.