The specifications of the permanent OBC (LoFS) array at Valhall were designed to produce time-lapse images of the reservoir at 2.5km depth. Advances in processing technology have been leveraged to reprocess the data from several legacy LoFS surveys in order to produce high resolution images of the overburden, beyond the original specification of the array. Inclusion of the down-going arrivals into the workflow improves shallow coverage to provide a near-continuous image of the sea bed. Processing of the down-going arrivals in a 4D sense provides high resolution time-lapse images much shallower than was previously achievable. Analysis of LoFS recordings of an ultra-high resolution site survey demonstrate that the array can be reliably used to record frequencies up to 500Hz.


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  1. Mathewson, J.C., Ibram, M., Zimmerman, N., Underwood, D., Dawson, A., Alexander, G.
    [2012] Improved Imaging at Clair Field with Mirror Migration of OBC data. 74th EAGE Conference and Exhibition, Expanded Abstracts.
    [Google Scholar]
  2. Wang, L., Davies, D. and Ibram, M.
    [2014] Improved Multiples and Noise attenuation by Applying the Wavelet tau-p Deconvolution. 76th EAGE Conference and Exhibition, Expanded Abstracts.
    [Google Scholar]
  3. Barkved, O.I., Sirgue, L., Heavey, P.,Kommedal, J.H., van Gestel, J., Pettersen, R.S. and Kent, C.
    [2010] Beyond Velocities – Impact of Full Waveform Inversion at Valhall. NPF conference, Kristiansand.
    [Google Scholar]
  4. Sirgue, L., Barkved, O. I., Dellinger, J., Etgen, J., Albertin, U. and Kommedal, J.H.
    [2010] Full waveform inversion: the next leap forward in imaging at Valhall. First Break, 28(4), 65–70.
    [Google Scholar]

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