GSA Critical Issue: Induced Seismicity
Posted April 2016
The increase in oil and gas production from unconventional reservoirs has led to a concomitant increase in the need for wastewater disposal. Scientific evidence currently suggests that high-volume fluid injection in disposal wells in areas with hydraulic connection to sensitive geologic faults may induce seismicity. These faults may be unmapped, or previously unknown.
This Critical Issues paper will cover the current state of science related to the cause, occurrence, and potential impacts of induced seismicity (earthquakes likely triggered by human activities) so that policy makers, journalists, and the public can more accurately understand the issue for better decision making related to safety, protection of property, and for developing energy and related regulatory policy.
Society has depended on hydrocarbons for energy and chemical feedstock for over 100 years. The extraction of hydrocarbons, as well as their refining and processing into thousands of chemicals, creates large volumes of liquid waste that require disposal. In addition, conventional reservoir oil and gas production, supplemented by a large increase in unconventional reservoir development, has led to an increased volume of formation brines (i.e., production water) and waste water from hydraulic fracturing (i.e., flowback water) being produced with the oil and gas, thereby necessitating disposal. With advances in drilling technology and engineering, these wastes have been successfully injected into deep rock formations capable of accepting the wastes for permanent storage. However, there have been occasions when unforeseen conditions encountered in the target rock formations have resulted in earthquakes that, in some areas, are correlated spatially and temporally to the waste injection process.