Improved reservoir monitoring with PP & PS time-lapse imaging utilising up/down deconvolution: Edvard Grieg field

Summary Additional insight into the interaction between pressure and fluid saturation changes within the reservoir can be extracted through discrimination of time-lapse (4D) signal from both PP and PS data. Previous processing of the 4D PP data set over the Edvard Grieg field in the Norwegian North Sea from a 2016 baseline to the 2018 monitor survey yielded interpretive saturation-related 4D changes due to production and injection. The PS radial data followed, centred on a co-processed up/down deconvolution (UDD) workflow in alignment with the PP route. This PS result provided additional insight into pressure changes across the field due to the nature of converted-wave propagation. The UDD workflow involved spectral division of the radial with the downgoing wavefield in the 3D tau-p-q domain. The output was shaped to a user-defined wavelet and, thereby, 3D deghosted. Performing joint PP-PS tomography provided an uplift in depth-domain event alignment, which helped correlate structural boundaries with the extracted 4D attributes. The 4D PS result correlates well with the predicted model and the low-frequency response was observed to be significantly improved over the legacy processing route.