The University of Oslo is currently closed, and disputations will therefore be streamed directly using Zoom. The host will moderate the digital issues while the defense manager moderates the defense.
Trial lectures
Since this is a defence for the degree Doctor Philosophiae (Dr. Philos) there will be two trial lectures. The trial lectures are:
Given topic: Review the state-of-the-art of machine learning methods applied to the processing of VSP data
Chosen topic: Plane-Wave Decomposition and Aliasing of Waveforms
Conferral summary (In Norwegian)
Denne doktorgradsavhandlingen omhandler seismiske avbildnlngsmetoder, og hvordan målinger av retningen av partikkelbevegelse (indusert av en akustisk bølge) kan innarbeides i analysene. For kompresjonsbølger innebærer de beskrevne metodene at den målte partikkelbevegelsen projiseres inn på - eller vinkelrett på - strålebanen som forbinder et muling refleksjons eller refraksjonspunkt til målepunktet. Avhandlingen beskriver hvordan dette tillater avbildninger av kompliserte reservoarstrukturer ved hjelp av data som er registrert av tre-komponent sensorer i en oljebrønn.
Main research findings
Popular scientific article about Haldorsen’s dissertation:
Optimal Formation Imaging Using Three-Component Borehole-Seismic Data
Borehole-seismic data acquisition allows for measuring the compressional and shear components of a wave field from within the rock volume. Having determined the polarizations and the arrival times of the different components over the aperture of the array, one can estimate their propagation direction. The propagation direction essentially points back along a ray to the point of reflection, scattering or conversion.
Haldorsen describes in his study how a ray-based migration/ deconvolution process can be used to separate the scattered compressional component from other wave-field components by projecting the full three-component wave field on to the ray connecting the receiver and image point for the compressional component, and perpendicular to this ray for the shear components. The projected components are used to give images of the scattering potential for the formation from a spread of surface source locations and an array of three-component receivers deployed in a well.
Photo and other information:
Press photo: Jakob Brandt Utne Haldorsen, portrait; 500px. Photo: Private
