Developing subsurface energy exploitation strategies by considering seismic risk
Abstract
The injection or extraction of fluids in the subsurface for energy purposes (e.g. geothermal exploitation, CO2 storage or geological energy storage) requires both the operation efficiency and the associated environmental risks to be assessed and controlled. Even though scientific and technological progress allows more accurate 3D modelling of the subsurface, we still do not have a thorough understanding of coupled underground hydromechanical processes. Indeed, the injection or production of fluids interacting with existing geological features can still result in unintended and unexpected 'harmful' consequences. This review aims to propose a unified strategy ranging from an understanding of the hydromechanical factors at the origin of the induced seismicity to seismic risk evaluation expressed in terms of ground-motion effects. The challenge is to utilize mechanical modelling to anticipate the evolution of seismicity; how the population perceives this is also an important factor to be taken into account in this risk evaluation. While mechanical modelling may include some degree of uncertainty, probabilistic analysis is capable of providing a quantitative estimation of the risk incurred and feedback to the exploitation strategy.