Hydraulic fracturing is a process of injecting fluids (mainly water mixed with sand and a small fraction of chemical additives) at high pressure into subsurface rock, in order to create connected fractures to enhance hydrocarbon production. It has been used routinely for over 50 years in the oil and gas industry to accelerate hydrocarbon production and increase recovery.
Now applied with horizontal wells and over large areas, this technology has enabled commercial production of oil and gas from low-permeability rock formations, such as shales, changing the energy landscape in North America. Modern surveillance technology, such as microseismic monitoring, has revealed that hydraulic fractures, particularly in unconventional reservoirs, have complex geometries that are not easily predictable in practice.
While hydraulic fracturing is designed to maximize petroleum production from the target formation, there is public concern that some fractures may penetrate non-target zones and/or generate seismic events (earthquakes). These rare possibilities have raised questions about contamination of shallow aquifers, fugitive emissions, land disturbances, well integrity and safety. The urgency to address the associated challenges will continue to grow as the technology utilization increases.