Institutt for geovitenskap
Masterprosjekt - Ressurser/Energi

Monitoring of CO2 Using Stochastic Inversion - Oda Kleveland


Storage of CO2 in depleted hydrocarbon reservoirs has been proposed to decrease the amount of CO2 released by human activity in the atmosphere. This underground storage has to be monitored regularly in order to make sure that there is no unwanted leakage into the
cap rock. This monitoring is done using a variety of techniques with seismic imaging being one of the most important ones. An example of CO2 storage where seismics has been used is Sleipner. Seismic imaging at Sleipner shows that considerable improvement in the seismic monitoring techniques would be desirable. For example, reliable uncertainty estimates in the concentration of stored CO2 would be very beneficial.

Various statistical techniques, called Ensemble filtering, which all one way or the other are based on Bayesian inversion, have been used with success in weather prediction and physical oceanography to estimate uncertainty. In seismics relatively few studies have been
done that use these techniques. Given the success of these methods in determining uncertainties of inverted quantities this is quite surprising. An obvious application would be to quantify uncertainty in subsurface properties such as CO2 saturation using time-lapse
seismic data.

In this project Ensemble Kalman filtering techniques will be used to better quantify uncertainties in CO2 properties with emphasis on AVO inversion. AVO is a useful starting point for such inversion techniques as, in principle, it is relatively efficient. Indeed, Bayesian
inversion of AVO exist. Moreover, because of all this, AVO is particularly useful in time-lapse studies. However, there are several aspects of AVO and Bayesian inversion that can be improved. For example, most Bayesian inversion assumes Gaussian statistics. Also,
anisotropy and attenuation as well as uncertainty in various rock physics parameters are not commonly considered in AVO inversion. Finally, AVO inversion itself suffers from a number of limitations. The aim of this project is to address these issues related, with special
emphasis on theoretical development.

Krav for opptak: Bachelor Geophysics from UiB

Foreslåtte emner i spesialiseringen (60 sp):
GEOV274 (10 sp)
GEOV277 (10 sp)
GEOV272 (10 sp)
GEOV375 (10sp)
Kiel course (5 sp)
GEOV352 (5 sp)
GEOV300(5 sp)
spesial pensum (5sp)