Browsing Institutt for elektroniske systemer by Journals "Geophysics"

Now showing items 1-7 of 7

    • An adapted eigenvalue-based filter for ocean ambient noise processing 

      Wu, Guoli; Dong, Hefeng; Ke, Ganpan; Song, Junqiang (Peer reviewed; Journal article, 2020)
      Accurate approximations of Green’s functions retrieved from the correlations of ambient noise require a homogeneous distribution of random and uncorrelated noise sources. In the real world, the existence of highly coherent, ...

    • Comparing the broadband acoustic frequency response of single, clustered and arrays of marine air guns 

      Landrø, Martin; Langhammer, Jan (Peer reviewed; Journal article, 2020)
      Field data acquired from a seismic vessel by a seabed hydrophone is used to analyze the broadband response (10 Hz to 62.5 kHz) for various source configurations: single air guns, clustered air guns, and a full array ...

    • Estimating source signatures from source-over-spread marine seismic data 

      Helgebostad, Kristian; Landrø, Martin; Vinje, Vetle; Nilsen, Carl-Inge Colombo (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, ...

    • Numerical study of the effect of cement defects on flexural-wave logging 

      Song, Ruolong; Dong, Hefeng; Bao, Xueshan (Journal article; Peer reviewed, 2019)
      Cement-bond evaluation is needed for new wells and plug and abandonment activities. The ultrasonic leaky Lamb-wave (also called the flexural-wave) technique, in combination with the pulse-echo technique, has been widely ...

    • On low frequencies emitted by air guns at very shallow depths - An experimental study 

      Wehner, Daniel; Landrø, Martin; Amundsen, Lasse (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 ...

    • Repeatability of high-resolution 3D seismic data 

      Waage, Malin; Bünz, Stefan; Landrø, Martin; Plaza-Faverola, Andreia; Waghorn, Kate Alyse (Journal article; Peer reviewed, 2018)
      High-resolution 4D (HR4D) seismic data have the potential for improving the current state-of-the-art in detecting shallow (≤ 500 − 1000 m below seafloor) subsurface changes on a very fine scale (approximately 3–6 m). ...

    • Tube-wave monitoring as a method to detect shear modulus changes around boreholes: A case study 

      Wehner, Daniel; Borges, Filipe; Landrø, Martin (Peer reviewed; Journal article, 2021)
      Monitoring the shear modulus of formations around boreholes is of interest for various applications, ranging from near-surface investigation to reservoir monitoring. Downhole logging tools and borehole seismic are common ...