Browsing Bergen Open Research Archive by Author "Jakobsen, Morten"
Now showing items 1-11 of 11
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3-D induction log modelling with integral equation method and domain decomposition pre-conditioning
Saputera, Durra Handri; Jakobsen, Morten; van Dongen, Koen W. A.; Jahani, Nazanin; Eikrem, Kjersti Solberg; Alyaev, Sergey (Journal article; Peer reviewed, 2024)The deployment of electromagnetic (EM) induction tools while drilling is one of the standard routines for assisting the geosteering decision-making process. The conductivity distribution obtained through the inversion of ... -
A 3D computational study of effective medium methods applied to fractured media
Sævik, Pål Næverlid; Berre, Inga; Jakobsen, Morten; Lien, Martha (Peer reviewed; Journal article, 2013-10)This work evaluates and improves upon existing effective medium methods for permeability upscaling in fractured media. Specifically, we are concerned with the asymmetric self-consistent, symmetric self-consistent, and ... -
Electrical conductivity of fractured media: A computational study of the self-consistent method
Sævik, Pål Næverlid; Berre, Inga; Jakobsen, Morten; Lien, Martha (Journal article; Peer reviewed, 2012)Effective medium theory can be used to link conductivity estimation methods with prior knowledge about the distribution of fractures in the investigated geological structure. In the literature, little work has been presented ... -
Homotopy analysis of the Lippmann-Schwinger equation for seismic wavefield modeling in strongly scattering media
Jakobsen, Morten; Huang, Xingguo; Wu, Ru-Shan (Peer reviewed; Journal article, 2020)We present an application of the homotopy analysis method for solving the integral equations of the Lippmann-Schwinger type, which occurs frequently in acoustic and seismic scattering theory. In this method, a series ... -
Homotopy method for seismic modeling in strongly scattering acoustic media with density variation
Xiang, Kui; Jakobsen, Morten; Eikrem, Kjersti Solberg; Nævdal, Geir (Journal article; Peer reviewed, 2020)The wave equation for acoustic media with variable density and velocity can be transformed into an integral equation of the Lippmann-Schwinger type; but for a 4-dimensional state vector involving the gradient of the pressure ... -
Homotopy scattering series for seismic forward modelling with variable density and velocity
Xiang, Kui; Eikrem, Kjersti Solberg; Jakobsen, Morten; Nævdal, Geir (Journal article; Peer reviewed, 2021)We have derived a convergent scattering series solution for the frequency-domain wave equation in acoustic media with variable density and velocity. The convergent scattering series solution is based on the homotopy analysis ... -
A matrix-free variant of the distorted Born iterative method for seismic full-waveform inversion
Xiang, Kui; Jakobsen, Morten; Eikrem, Kjersti Solberg; Nævdal, Geir (Journal article; Peer reviewed, 2023)The distorted Born iterative method reduces a nonlinear inverse scattering problem to a sequence of (ill-posed) linear inverse scattering problems that can be solved using a regularized least-squares formulation. This ... -
Microseismic wavefield modelling in anisotropic elastic media using integral equation method
Shekhar, Ujjwal; Jakobsen, Morten; Iversen, Einar; Berre, Inga; Radu, Florin Adrian (Journal article; Peer reviewed, 2023)In this paper, we present a frequency-domain volume integral method to model the microseismic wavefield in heterogeneous anisotropic-elastic media. The elastic wave equation is written as an integral equation of the ... -
On the applicability of a renormalized Born series for seismic wave modelling in strongly scattering media
Huang, Xingguo; Jakobsen, Morten; Wu, Ru-Shan (Peer reviewed; Journal article, 2020)Scattering theory is the basis for various seismic modeling and inversion methods. Conventionally, the Born series suffers from an assumption of a weak scattering and may face a convergence problem. We present an application ... -
On the relative importance of global and squirt flow in cracked porous media
Ali, Aamir; Jakobsen, Morten (Journal article, 2014)A unified theory of global and squirt flow in cracked porous media was developed several years ago on the basis of a combination of the dynamic T-matrix approach to rock physics. The theory has been successfully used to ... -
Seismic characterization of reservoirs with multiple fracture sets using velocity and attenuation anisotropy data
Ali, Aamir; Jakobsen, Morten (Journal article, 2011)Knowledge about the spatial distribution of the fracture density and the azimuthal fracture orientation can greatly help in optimizing production from fractured reservoirs. Frequency-dependent seismic velocity and attenuation ...