The aim of the project was to show that geologically realistic models are of great importance in order to forecast realistic CO2 migration.

In the project we have studied how top surface morphology influences the CO2 storage capacity. Alternative top-surface morphologies are created stochastically by combining different stratigraphic scenarios with different structural scenarios.

Geological scenarios

For depositional features, two scenarios were chosen for which it was considered likely that a depositional/erosional topography could be preserved under a thick regional seal; the latter commonly formed by marine shale. The two scenarios reflect situations where sand deposition is suceeded by deposition of fines as a result of marine transgression:

• Offshore sand ridges covered by thick marine shale
• Preserved beach ridges under marine shale

The left figure shows a realization from the flooded marginal marine top surface model, and the right figure shows a realization of offshore sand ridges top surface. The realizations are created by Cohiba.

For comparison, we also look at a flat model. These three stratigraphic models, were combined with four different structural scenarios. Different fault patterns were generated by using Havana.

These figures show the different fault models applied to a flat top surface.

A set of 15 conceptually models is created, and several realizations of each model are generated in order to investigate the uncertainty.

Dataset

Data are available at

• Surface
• Eclipse grids
• OneOfEachSurface

Surfaces contains 100 realizations for each of the 15 models, except for the flat case. Details can be found in this document.

Flow simulation and estimation of structural trapping

The CO2 storage capacity is computed by alternative methods for the different models. By looking at several realizations from the same model, we are able to quantify uncertainty. We have computed structurally trapped volumes by a simple spill point approach and by a vertically integrated flow simulation approach.

Workshop

A workshop was held in Bergen November 22-24, 2011. Follow the link to see the presentations.