VoI + Geothermal + Seismic: value of seismic survey in geothermal assessment
Author: Juri Muzi
Year: 2023
Supervisors: Juliet Ann Newson, Egill Júlíusson
Abstract:
Geothermal systems are often characterized by the presence of subvertical fracturing
responsible for the large permeabilities allowing the circulation of the large quantity of
fluids. Such fracturing can be identified by standard 3d reflection seismic surveys
through the measurement of seismic anisotropy.
Active source 3d seismic acquisition is not, however, a standard technique in
geothermal exploration and assessment as it is considered expensive and of limited
value.
The Value of Information (VOI) theory can be used to determine the potential
economic value of gathering seismic data. Comparing the cost of seismic data
acquisition and the potential value of the seismic information will determine whether it
is worth investing in a survey.
A methodology is developed through adaptation of VOI assessment of resistivity
surveys on geothermal fields by Dr. Trainor-Guitton (Trainor-Guitton et al., 2014) and
it is subsequently tested on two case studies: Grado (Italy), a low enthalpy geothermal
exploration, and Rittershoffen (France), an Enhanced Geothermal System (EGS)
stimulation & production.
Results show that 3d seismic is not economical for exploration of large areas if a
single well is planned; it can still be a useful tool to de-risk a single well in depth once
the optimal location within a prospect is chosen.
Using 3d seismic also doesn’t seem to be economically justifiable as a production
decision making scenario tool; equivalent results can however be achieved through
passive seismic at a much smaller cost.