| dc.description.abstract | Geothermal energy is expected to produce 23% of the total heat demand in the
Netherlands by 2050. As geothermal energy production is known to induce seismicity,
risk assessment is crucial for a safe transition to new energy sources. The
exact mechanisms inducing seismicity in geothermal reservoirs are, however, very
complex and poorly understood.
In this thesis, a fully coupled seismo-hydro-mechanical numerical code by Petrini
(2019) is adapted to work for a geothermal setting with a set-up that represents the
Dutch subsurface. The main goal is to investigate whether this code is suited for
studying such a setting and to debug any potential mistakes in the code. Furthermore,
the aim is to investigate how stress and strain build-up due to geothermal
energy production in the Dutch subsurface. Lastly, a parameter study is executed
to examine the effect of operational parameters (injection and production rates) and
fault material parameters.
The adapted code successfully triggers multiple (seismic) events, giving insight
into the relationship between fluid flow and solid deformation during multiple phases:
1) inter-seismic, 2) nucleation, 3) propagation, and 4) post-seismic. The seismicity
that was triggered, however, was very mild (ML<2.0), meaning that it would not be
felt at the surface.
While the code is very efficient in examining the short-term effects (i.e. less than
a year) of geothermal energy production, it requires too much computational time
to see what happens if geothermal energy were to be produced long-term (i.e. for
decades of production). Insights are offered into why the computational time is so
long and solutions are offered for future work. | |
