The PhD defence and trial lecture are fully digital and streamed using Zoom. The host of the session will moderate the technicalities while the chair of the defence will moderate the disputation.
Trial lecture
Integration of state-of-art techniques for landslide/quick clay hazard assessment
Conferral summary (in Norwegian)
Usedvanlig lavt poretrykk i undergrunnen i nordlige deler av Barentsokkelen byr på utfordringer for boring etter olje/gass og CO2 lagring. Nylig, i geologisk tid, har Barentsokkelen blitt hevet slik at gass og væske ikke lenger er i likevekt. Resultatet av dette er at det dannes undertrykk og påvirker eller har påvirket vandring av fluider i undergrunnen. På Svalbard, især Spitsbergen, har hevingen også store volumer av gass blitt fanget under permafrosten somutgjør en risiko for klimagassutslipp eller en framtidig lokal energikilde.
Main research findings
Popular scientific article about Birchhall’s dissertation:
Pore Pressure Regimes of the Northern Barents Shelf - Implications for Fluid Flow
The ground beneath our feet is anything but dry; there is more water held in Earth’s rocks than all the world’s oceans combined. Fluids in the subsurface are always on the move and understanding this is important in the fields of hydrocarbon exploration, CO2 storage and hydrogeology. Pore pressure is the pressure of fluids found within rock pore spaces and is the principal driver of subsurface fluid movement. Abnormally high pore pressures are a well-documented phenomenon throughout the world, whereas abnormally low pore pressures are rare and poorly understood. The northern Barents shelf provides a globally unique example of the latter, where extremely low pore pressures are observed offshore and onshore.
The candidate’s PhD research shows that all cases of abnormally low pressure have undergone geologically recent uplift and typically occur at relatively shallow depths. In the Barents shelf, including the High Arctic Svalbard archipelago, low pressures must have developed in the last few thousand years and are in a present state of disequilibrium. Indeed, this disequilibrium has probably driven geologically recent fluid migration and is almost certainly still happening today. In Svalbard, large volumes of gas trapped beneath the permafrost are a widespread occurrence.
Photo and other information:
Press photo: Thomas Birchall, portrait; 500px. Photo: Private
