% IMPORTANT: The following is UTF-8 encoded. This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.
@PHDTHESIS{Adams:764773,
author = {Adams, Markus},
othercontributors = {Ziegler, Martin and Azzam, Rafig},
title = {{E}in optimierter semi-analytischer hydromechanischer
{K}opplungsansatz für die geologische
{CO}$_{2}$-{S}peicherung : hydraulische {R}eaktivierung von
{S}törungen},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
reportid = {RWTH-2019-07007},
pages = {1 Online-Ressource (XXIV, 273 Seiten) : Illustrationen,
Diagramme},
year = {2019},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, Rheinisch-Westfälische Technische
Hochschule Aachen, 2019},
abstract = {Carbon Capture and Storage (CCS) is a promising technology
to reduce the anthropogenic impact on global warming and
climate change. It provides the possibility to inject the
CO2 immission of, i.e., coal fired power plants into the
geological subsurface and to retain it for thousands of
years. Such a storage is necessary until the worldwide
electricity industry uses renewable resources to produce
electric power. Estimating the efficiency and sustainability
of geological subsurface utilization, i.e., Carbon Capture
and Storage (CCS) requires an integrated risk assessment
approach, considering the occur-ring coupled processes,
beside others, the potential reactivation of existing
faults. In this context, hydraulic and mechanical parameter
uncertainties as well as different injection rates have to
be considered and quantified in a probabilistic manner to
elaborate reliable environmental impact assessments.
Consequently, the required sensitivity analyses consume
significant computational time due to the high number of
realizations that have to be carried out. For this purpose,
iterative and non iterative two-way coupled simulations are
state of the art. Using this type of coupling, the pore
pressure distribution induced by CO2 injection into saline
reservoirs is determined by a multiphase fluid flow
simulator and transferred afterwards to a second simulator,
which estimates the corresponding geomechanical response,
i.e., stresses and strains. Based on these results, the
porositiy and permeability of certain elements are updated.
After transferring these parameters back to the multiphase
fluid flow simulator, the next run starts. Due to the high
computational costs of two-way coupled simulations in
large-scale 3D multiphase fluid flow systems, these are not
applicable for the purpose of uncertainty and risk
assessments. Hence, an innovative semi-analytical
hydromechanical coupling approach for hydraulic fault
reactivation will be introduced in this manuscript. This
approach determines the void ratio evolution in
representative fault elements using one preliminary one-way
coupled base simulation, considering one model geometry and
one set of hydromechanical parameters. The void ratio
development is then approximated and related to one
reference pressure at the fault base to get e(pref)
functions. The parametrization of the resulting functions is
then directly implemented into a multiphase fluid flow
simulator to carry out the semi-analytical coupling for the
simulation of hydromechanical processes. Hereby, the
iterative parameter exchange between the multiphase and
mechanical simulators is omitted, since the update of
porosity and permeability is controlled by one reference
pore pressure at the fault base. The suggested procedure is
capable to reduce the computational time required by coupled
hydromechanical simulations of a multitude of injection
rates by a factor of up to 15.A multitude of
hydromechanically one- and two-way coupled single-phase
fluid flow simulations were carried out with ABAQUS, to find
a principle describing the characteristic run of e(pref)
functions. Hence, the hydromechanical behavior of geological
faults represented by the run of these curves can be
mathematically described by five semi-analytical parameters.
For that purpose, some criteria, i.e., the invariant
behavior of the semi-analytical parameters with respect to
the injection rate and the initial fault permeability are
formulated by four hypotheses. During the process of CO2
injection, one further hypothesis additionally assumes the
hydraulic behavior of faults to be influenced mainly by the
fluid properties of brine as a consequence of trapping
mechanisms retaining the CO2 plume to migrate towards
faults. Based on extensive numerical investigations executed
with ABAQUS comprising a multitude of parametric studies the
first four hypotheses could be validated for the assumption
of single-phase fluid flow. In this context, nine different
synthetic geological models, four varying injection rates
and many different initial fault permeabilities were
investigated. For the numerical implementation of the
semi-analytical coupling approach into ABAQUS a new frame
work was implemented, to describe the constitutional
behavior of certain elements by discrete analytical
approaches. Hence, intermediate results of each simulation
step can be used to update boundary conditions and material
properties by an analytical approach. Finally, hypothesis
five was validated by the execution of a case study under
consideration of multiphase fluid flow simulated by the
TOUGH2-MP/ECO2N und FLAC3D simulators. Therefore, the
injection of CO2 into a saline aquifer considering three
different injection rates was investigated. A comparison
between results of two-way and semi analytically coupled
simulations shows the validity of the new computationally
efficient approach. The results of this scientific work
point out that the semi-analytical coupling approach is
capable to investigate the hydromechanical behavior of
hydraulically reactivated geological faults induced by CO2
injection into saline aquifers. In advance, the suggested
procedure reduces the computational time required by coupled
hydromechanical simulations of a multitude of injection
rates by a factor of up to 15.As a power law
porosity-permeability relationship was used for the
numerical simulations, a high degree of non-linear
hydromechanical effects could be considered. Due to the
benefit of low computational time, the new approach is
capable to be used for probabilistic risk assessments.},
cin = {314310},
ddc = {624},
cid = {$I:(DE-82)314310_20140620$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2019-07007},
url = {https://publications.rwth-aachen.de/record/764773},
}
guest ::