Print this pageAAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain
Quantitative Seismic Attributes for Fractured Reservoir Characterisation
(1) Geophysics, OMV, Vienna, Austria.
It is a considerable challenge to effectively produce from heterogeneous fractured reservoirs in a complex structural setting. In this Middle Eastern onshore field the production comes mainly from fractured igneous intrusive and metamorphic basement rocks and an overlying clastic formation. This partially eroded and therefore heterogeneously distributed clastic formation can also have significant fracturing. The presence of this clastic formation has a big impact on production of the drilled wells but unfortunately it is below seismic resolution and therefore cannot be conventionally mapped on seismic. The aim of this study was to detect fractured zones and to describe the distribution of the clastic formation using seismic attributes calibrated to well information. A 400km2, high fold, wide-azimuth seismic data set was acquired to provide an optimum illumination of the complex reservoir structure. Azimuthal anisotropy from the wide-azimuth seismic survey proves to be one of the main productivity indicators in this reservoir. Well production is quantitatively correlated with anisotropy intensity. In some wells additional matrix porosity contributing to production is present in the heterogeneous sandstone layer above the basement. The partially eroded sandstone layer can be detected with seismic inversion. Therefore we find that a combination of these seismic attributes provides a powerful tool to describe this complex reservoir. The attributes are used for well planning and reservoir modelling.