PARASCHIVOIU, EVELINA, University of Adelaide, National Centre for Petroleum Geology and Geophysics, Adelaide, South Australia

ABSTRACT: The Use of Forward Stratigraphic Modelling for Reservoir Characterisation

The project investigates the possibility of using forward stratigraphic modelling (specifically Sedsim) to build a reservoir model for an oil field which exhibits stratigraphically controlled lateral and vertical facies variations. The Stag Field (Dampier Sub-basin, Northwest Shelf of Australia) has been chosen as a case study for simulating a shallow marine siliciclastic reservoir.

The Sedsim computer package can simulate 3D distribution of uncompacted sediments of four different grain sizes on a bathymetric surface, by modelling forward in time sediment transport, deposition and erosion. Different factors influencing sedimentation, as well as different scenarios of depositional evolution can be assessed to better understand the causes of significant rock heterogeneity.

The first stage of this study consists of running a depositional simulation over an 80x50 km area on the Enderby Terrace, surrounding the Stag field, for a time interval of 10 million years in the Early Cretaceous. The palaeoreconstruction is based on 2D and 3D seismic and well data from around 20 exploration wells. Once the overall grain size distribution in this regional model is achievedand thus the main depositional controls identifieda more detailed model will be built for the Stag field (approximately 10x15km), simulating the deposition of the sands included in the M. australis palynozone. The reservoir scale model will predict and quantify facies variations and stratal architecture for the inter-well space, below the seismic resolution. The Sedsim model will form the base for a reservoir simulation model, which in turn will be history matched with production data.

AAPG Search and Discovery Article #90909©2000 AAPG Foundation Grants-in-Aid