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Disputas: Hossein Fazeli

Ph.d.-kandidat Hossein Fazeli ved Institutt for geofag, Det matematisk-naturvitenskapelige fakultet, vil forsvare avhandlingen Modeling of CO2-Water-Rock Interactions in Fractured Seals for graden Philosophiae Doctor.

Hossein Fazeli. Photo: Private

Hossein Fazeli. Photo: Private

Prøveforelesning - tid og sted

Fredag 7 februar, 10:15-11:00, Auditorium 1, Geologibygningen:

Impact of geochemical processes on geomechanics of carbonate rocks during CO2 injection

 

Kreeringssammendrag

I CCS er CO2 først fanget fra CO2-rike kilder, før den lagres i reservoarbergarter i undergrunnen. Det vil alltid være en liten mulighet for at lagret CO2 kan lekke opp mot overflaten gjennom lekkasjeveier i det som kalles takbergarten til reservoaret. I slike tilfeller er det viktig å forutsi hvordan CO2 vil oppføre seg, og det er behov for å lage prediktive matematiske modeller. I denne avhandlingen har Hossein utviklet nye numeriske verktøy for å modellere kjemiske reaksjoner mellom CO2, vann, og bergarter. Han bruker disse modellene til å vise hvordan reaksjoner påvirker lekkasje. I tillegg til matematiske modeller har mikro-skala laboratorieeksperimenter blitt brukt til å se på de aktuelle reaksjonene på mikro-skala.

Hovedfunn

Populærvitenskapelig artikkel om Fazelis avhandling:

Modeling of CO2-Water-Rock Interactions in Fractured Seals

Carbon capture and Storage (CCS) is a reliable mitigation strategy that can reduce the anthropogenic emissions of CO2 to the atmosphere that is a cause for global warming. In CCS, CO2 is captured from producing sources and then transported to a storage site where it is injected into underground reservoirs. Presence of a tight rock, called caprock, overlying the reservoir rock is necessary to prevent CO2 leakage. Presence of fractures in the caprock, however, might cause CO2 leakage. The ability to effectively assess the risk of leakage is related to our understanding of complex processes affecting physical and chemical properties of the fractured caprocks.

The thesis presents newly developed numerical (based on Lattice Boltzmann method) and experimental (based on microfluidic techniques) tools to investigate how CO2-water-rock chemical interactions can influence the leakage through fractures in the caprock, which can eventually affect the caprock integrity in the large scale. The chemical interactions are studied under three different research topics:

(1) CO2-induced salt precipitation in the fractures: results showed that salt crystals can clog the fractures.

(2) Fracture dissolution triggered by flow of CO2-acidified brine: results indicated that mineral heterogeneity can reduce the permeability enhancement.

(3) Probabilistic nucleation of minerals in the porous media: results showed that mineral nucleation should be modelled using probabilistic approach to better predict the hydrodynamic properties of porous media.      

Publisert 24. jan. 2020 11:22 - Sist endret 3. mars 2020 12:54