Browsing Institutt for geovitenskap og petroleum by Journals "Geophysics"
Now showing items 1-20 of 26
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A low frequency deghosting method: Analysis and numerical tests
(Journal article; Peer reviewed, 2017)The low-frequency component of seismic data can be beneficial for several reasons: improved signal penetration into the earth, enhanced resolution, and better constrained inversion results. We have developed a detailed ... -
A3Mark: Seismic attribute benchmarking
(Journal article; Peer reviewed, 2018)Seismic attribute computation is one of the most active research and engineering topics in the computational geophysics world. Although numerous algorithms for seismic attribute computation have been developed, relatively ... -
An anelliptic approximation for geometrical spreading in transversely isotropic and orthorhombic media
(Journal article; Peer reviewed, 2018)The relative geometric spreading along the raypath contributes to the amplitude decay of the seismic wave propagation that needs to be considered for amplitude variation with offset or other seismic data processing methods ... -
Approximate reflection coefficients for a thin VTI layer
(Journal article; Peer reviewed, 2018)We have developed an approximate method to derive simple expressions for the reflection coefficients of P- and SV-waves for a thin transversely isotropic layer with a vertical symmetry axis (VTI) embedded in a homogeneous ... -
Bayesian rock physics inversion using a localized ensemble-based approach - with an application to the Alvheim field
(Peer reviewed; Journal article, 2023)We describe, implement and show results of a localized ensemble-based approach for seismic AVO inversion with uncertainty quantification. Ensembles are simulated from continuous prior probability distributions for fluid ... -
Bounds of elastic parameters characterizing transversely isotropic media: Application to shales
(Journal article; Peer reviewed, 2016)Several rocks, and in particular shales, are often described as transversely isotropic (TI) materials. Geophysical data coverage does not always permit reliable determination of all five elastic parameters, neither in ... -
Detecting gas leakage using high-frequency signals generated by air-gun arrays
(Journal article; Peer reviewed, 2017)Recent field experiments have demonstrated that marine air-gun arrays create acoustic energy greater than 1 kHz. We have suggested to use the high-frequency signal as a source to look for gas leakage at, for instance, a ... -
Distributed acoustic sensing of ocean-bottom seismo-acoustics and distant storms: A case study from Svalbard, Norway
(Peer reviewed; Journal article, 2023)Distributed acoustic sensing (DAS) leverages an ocean-bottom telecommunication fiber-optic cable into a densely sampled array of strain sensors. We demonstrate DAS applications to passive acoustic monitoring (PAM) through ... -
Estimating source signatures from source-over-spread marine seismic data
(Journal article; Peer reviewed, 2018)Recent developments in marine seismic acquisition include deploying a source vessel above a towed-streamer spread. We have developed an inversion algorithm to estimate source signatures for such acquisition configurations, ... -
Estimation of rock physics properties from seismic attributes - Part 1: Strategy and sensitivity analysis
(Journal article; Peer reviewed, 2016)The quantitative estimation of rock physics properties is of great importance in any reservoir characterization. We have studied the sensitivity of such poroelastic rock physics properties to various seismic viscoelastic ... -
Estimation of rock physics properties from seismic attributes - Part 2: Applications
(Journal article; Peer reviewed, 2016)The estimation of quantitative rock physics properties is of great importance for reservoir characterization and monitoring in CO2CO2 storage or enhanced oil recovery as an example. We have combined the high-resolution ... -
How to adapt numerical simulation of wave propagation and ultrasonic laboratory experiments to be comparable — A case study for a complex topographic model
(Journal article; Peer reviewed, 2018)Numerical methods are widely used in seismic exploration to simulate wave propagation; however, the algorithms are based on various assumptions. The accuracy of numerical simulations is of particular interest in the case ... -
Low-frequency acoustic signal created by rising air-gun bubble
(Journal article; Peer reviewed, 2017)In the seismic industry, there is increasing interest in generating and recording low frequencies, which leads to better data quality and can be important for full-waveform inversion. The air gun is a seismic source with ... -
Near-surface characterization using shear-wave resonances: A case study from offshore Svalbard, Norway
(Peer reviewed; Journal article, 2024)Shear-wave (S-wave) resonances are typically observed when the surficial marine sediments over a rock substrate have relatively low S-wave velocities. We observe these phenomena using ocean-bottom fiber-optic distributed ... -
On low frequencies emitted by air guns at very shallow depths - An experimental study
(Journal article; Peer reviewed, 2019)In marine seismic acquisition, the enhancement of frequency amplitudes below 5 Hz is of special interest because it improves imaging of the subsurface. The frequency content of the air gun, the most commonly used marine ... -
A one-step Bayesian inversion framework for 3D reservoir characterization based on a Gaussian mixture model-A Norwegian Sea demonstration
(Peer reviewed; Journal article, 2021)We have developed a one-step approach for Bayesian prediction and uncertainty quantification of lithology/fluid classes, petrophysical properties, and elastic attributes conditional on prestack 3D seismic amplitude-varia ... -
Overburden 4D seismic analysis: Influence of stress and pore-pressure changes accounting for elastic contrast between a reservoir and its anisotropic surrounding rocks
(Journal article; Peer reviewed, 2023)Time-lapse (4D) seismic data analysis is widely used to monitor producing hydrocarbon or CO2 storage reservoirs and their surroundings. The influence of potentially significant undrained pore-pressure changes around depleting ... -
Quick clay monitoring using distributed acoustic sensing: A case study from Rissa, Norway
(Peer reviewed; Journal article, 2023)Quick clay avalanche is one of the most devastating landslide types worldwide. Hence, an early warning system is in demand to mitigate the fatal consequences caused by such events. To address this, distributed acoustic ... -
Reducing high-frequency ghost cavitation signals from marine air-gun arrays
(Journal article; Peer reviewed, 2016)Ghost cavitation, which is a term describing that cavitation bubbles are generated acoustically, has been hypothesized to occur when the ghost reflected signals from many individual air guns beneath the sea surface produce ... -
Seismic attribute benchmarking on instantaneous frequency
(Journal article; Peer reviewed, 2019)The complex seismic trace analysis is a widely applied and versatile method for computing seismic attributes. Instantaneous frequency is an important complex trace attribute, and it is generally used for identifying specific ...