 |
| Titel |
Investigations on the risk of brine displacement during CO2 injection into saline aquifers |
| VerfasserIn |
Lena Walter, Holger Class, Rainer Helmig |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054351
|
|
|
|
|
|
| Zusammenfassung |
| Carbon Capture and Storage (CCS) is one promising technology to reduce greenhouse gas
emissions. A challenging task is to assess the risks, which could occur during CO2
storage for the different storage sites. We focus on risk assessment for CO2 storage in
saline aquifers since throughout all possible geological formations, saline aquifers
are considered to have the largest storage potential worldwide. The assessment of
the possible risks is already important during the characterization and selection
of suitable storage sites. Numerical simulations are essential for addressing this
purpose.
The main risks, which have to be considered for CO2 storage in saline aquifers, are CO2
leakage through e.g. abandoned wells, fractures, or faults, brine displacement far away from
the injection site and geomechanical failure of the caprock. The risk of brine displacement
and infiltration into shallower water aquifers, far away from the actual injection site has not
yet been systematically investigated. The injected CO2 will be stored in pores,
which are initially filled with water or in the case of saline aquifers with brine.
The pore space required by the injected CO2 is formed through the displacement
of the brine and additionally through compression of the brine and the rock. The
displaced brine could move through fractures and faults into shallower aquifers and
could thus infiltrate into drinking water aquifers. For brine displacement, fractures,
faults or seal weaknesses, which are far away from injection and will not be reached
by the CO2 have to be investigated. Accordingly, very large model domains are
required.
This work is focused on investigations of the risk of brine displacement far away from the
injection site. For this purpose, different scenarios are set up to evaluate the risk of brine
infiltration into a water aquifer. To determine the risk of brine displacement, the amount of
infiltrated brine into the shallower water aquifer is calculated. The influence of
different geological features as for example fractures, faults or seal weaknesses on the
amount of infiltrated brine into a shallower water aquifer is investigated. It is also
important to determine how the distance of these geological features influences
the risk of brine displacement in order to define the extent of the required model
domain.
Additionally, the effect of reservoir parameters or parameters of the shallower layers
between reservoir and water aquifer as the permeability or the caprock thickness is tested.
The aim is to get a deeper understanding, which geological features and parameters are most
relevant for assessing the risk of brine displacement in order to adapt the method to data from
real storage sites. |
|
|
|
|
|
|