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The Effect of Shale Activation on 4D Seismic Interpretation of a UKCS Field
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 78th EAGE Conference and Exhibition 2016, May 2016, Volume 2016, p.1 - 5
Abstract
Shale typically has a low but non-negligible permeability of the order of nanodarcys that could affect magnitude and pattern of pressure diffusion over the lifetime of a producing field. The implications of this phenomenon for reservoir monitoring by 4D seismic can be significant, but depend on the geology of the field, the time-lines for production and recovery, and the timing of the seismic surveys. This study assesses pressure diffusion effects for an offshore Paleocene turbidite reservoir in the UKCS. First, we evaluate the petrophysical characteristics of the overburden, intra-reservoir and underburden shales. Next, we adjust the simulation model to activate the shale-related contributions, and then perform 3D and 4D seismic modelling. In our reservoir of interest, fluid flow simulation results indicate that gas dominates the 4D seismic signature. It is found that activation of the shale improves the overall reservoir connectivity, which in turn impacts strongly on the breakout and distribution of gas liberated from solution and improves the fit to the observed seismic data.