Interpretation of fluid-induced seismicity patterns
Microseismicity is a known by-product when extracting and injecting fluids into the subsurface. While most of these earthquakes are too small to be felt, their characteristics contain important information about the subsurface stress field and fracture systems.
Hovedinnhold
Using 14 years of earthquake, injection, and production data from the Coso Geothermal Field in California, US, this project aims to gain insight into the evolution of the local stress field and how it is affected by long-term injection. Several techniques will be used to examine the microseismicity, which is caused by both tectonic and anthropogenic stresses acting on the field. Spatial and temporal variations in microseismicity will be compared to operational parameters such as extraction and injection rates and volumes to examine their causality. Full waveform cross-correlation methods will be used to precisely relocate the observed microseismicity and classify and characterize individual events and clusters, highlighting faults and fracture systems within the field. Furthermore, investigation of the rupture properties, stress drops, and focal mechanisms of the microseismic events will shed light on any distinctive and unique behaviour caused by the geothermal fluid-injection setting.
