Geoscience Reference
In-Depth Information
5.
Independent capability exists for geomechanical modeling of pore pressure, temper-
ature, and rock stress changes induced by injection and extraction and for modeling
of earthquake sequences given knowledge of stress changes, pore pressure changes,
and fault characteristics.
6.
The range of scales over which significant responses arise in the Earth with respect
to induced seismic events is very wide and challenges the ability of models to simu-
late and eventually predict observations from the field.
Gaps
1.
The basic data on fault locations and properties, in situ stresses, pore pressures, and
rock properties are insufficient to implement existing models with accuracy on a
site-specific basis.
2.
Current predictive models cannot properly quantify or estimate the seismic effi-
ciency and mode of failure; geomechanical deformation can be modeled, but a
challenge exists to relate this to number and size of seismic events.
Proposed Actions
The actions proposed to advance understanding of the types and causes of induced
seismicity involve research recommendations outlined in Box 7.1. These recommendations
also have relevance for specific energy technologies and address gaps in understanding
induced seismicity.
ENERGY TECHNOLOGIES: HOW THEY WORK
Overarching Findings for All Technologies
1.
Injection pressures and net fluid volumes in energy technologies, such as geothermal
energy and oil and gas production, are generally controlled to avoid increasing pore
pressure in the reservoir above the initial reservoir pore pressure. These technologies
thus appear less problematic in terms of inducing felt seismic events than technolo-
gies that result in a significant net increase or decrease in fluid volume.
2.
The basic data needed to fully evaluate the potential for induced seismicity—
including fault locations and properties, in situ stresses, fluid pressures, and rock
properties—are very difficult and expensive to obtain.
3.
Existing regional seismic arrays may not be capable of precisely locating small
induced seismic events to determine causality and better establish the characteristics
of induced seismicity.
Search WWH ::
Custom Search