Sequence stratigraphic-based analysis of reservoir connectivity: influence of sealing faults – a case study from a marginal marine depositional setting

Abstract

This case study of the Sunrise and Troubadour fields (offshore northwest Australia) deals with the impact of sealing faults on reservoir connectivity via a sequence stratigraphic-based, 3D reservoir modelling approach. The marginal marine, wave- and fluvial-dominated reservoir succession was subdivided into sequence stratigraphic units. The connectivity of sandbodies in each parasequence was calculated, following a palinspastic restoration of the 3D models to a depositional datum (depositional connectivity). Once the top structure and fault architecture interpreted from seismic data were incorporated into the 3D models, sandbody connectivity was again calculated on the same stratigraphic basis, with the faults being considered sealing (structural connectivity). The impact on sandbody connectivity of additional, probabilistic, sub-seismic sealing faults was also analysed. The results indicate that the depositional architecture is the controlling factor on reservoir connectivity for low sealing fault densities. However, at a critical sealing fault density, the major control becomes the structural architecture. Using the approach detailed in this paper, relationships between sealing fault density and reservoir connectivity for different development well layout scenarios can be predicted as a basis for optimizing development well patterns.