 |
| Titel |
Small scale laboratory design investigation of leakage of gaseous CO2 through heterogeneous subsurface system |
| VerfasserIn |
F. Basirat, P. Sharma, A. Niemi, F. Fagerlund |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250066205
|
|
|
|
|
|
| Zusammenfassung |
| The technology for geological sequestration of carbon dioxide has been developed to
reduce the CO2 emissions into the atmosphere from the use of fossil fuels in power
generation and other industries. One of the main concerns associated with the geological
storage is the possible leakage of CO2 into the shallow aquifers, for which effective
detection methods are needed. The processes related to the spreading and trapping of
CO2 in the reservoir formation and in supercritical conditions have received major
attention and form the basis of understanding of CO2 trapping processes. Some of the
CO2 may, however, also leak to the upper layers of the rock and all the way to land
surface through faults and imperfections in the seal. A proper understanding and
capability to detect such leaks is essential for a safe performance of any storage
operation.
This, in turn, involves a proper understanding of the processes related to the transport of
gaseous CO2 in the near-surface conditions, a topic that has received considerably less
attention. The objective of this study is to analyze the transport and migration of gaseous CO2
in heterogeneous porous media, in controlled laboratory conditions. CO2 may reach the
unsaturated zone by different leak mechanisms which may subsequently affect how and
where it can be detected by leakage monitoring program. These mechanisms include
exsolution from CO2 supersaturated water and continuous bubbling or gas flow along a
leakage path. Below the water table, gaseous CO2 can also be trapped under capillary
barriers. However, as more CO2 is supplied by leakage from below the water table, the
pressure may at some point exceed the entry pressure of the barrier leading to a leak event.
Similarly, fluctuations in the water table may also produce leak events of temporarily trapped
CO2. In the unsaturated zone, the CO2 is heavier than air and may accumulate below
ground surface and move laterally. The presence of heterogeneity influences both the
movement and detectability of the CO2. Our laboratory experiment is designed and
implemented for measuring CO2 distribution in time and space through the heterogeneous
porous material. The CO2 concentrations through the domain are measured by using
sensitive gas sensors. To better understand the consequences of CO2 leakage and
how it can be detected, this study presents a conceptual model together with the
design and setup of an experimental system to understand the transport, trapping
and detectability of gaseous CO2 in a heterogeneous shallow geological system. |
|
|
|
|
|
|