Prediction of Potential Reservoir Bodies from 3D Palinspastic Restoration

By

 Stuart Bland¹, Delphine Roques¹, Stephen Calvert¹, Alan Gibbs¹

(1) Midland Valley Exploration Ltd, Glasgow, United Kingdom

 Structural restoration is an established method by which to validate seismic interpretations. In addition, palinspastic reconstruction can help identify potential reservoir depocentres, enable the measurement of catchment areas at the time of hydrocarbon migration and lead to an improved understanding of complex hydrocarbon systems such as those in the deepwater, offshore Nile Delta.

Accurate identification, quantification and risking of prospects set within complex channel systems are challenging tasks. Palinspastic restoration offers a means by which these challenges can be met, as well as revealing the geological evolution of the system. Restoration is achieved by the sequential backstripping of the present day depth model. Upon removal of each successive layer, the remaining surfaces within the model are adjusted to account for faulting, decompaction and isostatic adjustment. Using the complete palinspastic history gives significantly different result than simply using isopachs and palaeoisopachs alone. Lateral variations in sediment thickness will result in non-uniform changes to the surfaces furthermore local variations in sediment porosity can be accounted for by application of attribute maps. Down-dip sediment dispersal on the back-stripped surface delineates the palinspastic accommodation space for a range of spill thicknesses and reveals potential reservoir body locations. Conducting up-dip hydrocarbon migration analysis, prospects can be ranked in order of volume and risk. On correlation with proved fields, this technique can be extrapolated to frontier areas and used in risk reduction in high cost deepwater exploration.