The distribution and reservoir quality of dolomites is difficult to predict. This is particularly true of fault-related dolomites, which are characteristically sub-seismic in scale, but can be responsible for extremely high permeability (‘super-k’) zones. These are important pay zones, but can also challenge drilling and water flood, providing strong economic drivers for this project. This work offers quantitative new insights into i) interactions between different phases of dolomitisation, ii) processes operating within and between fractures & matrix, iii) links between diagenetic facies & petrophysical properties, iv) prediction of dolomite composition, temperature & isotopic composition. Simulation of a specific case study of complex fault-controlled dolomitisation will yield generic learnings with broad application.

This project integrates process-based numerical modelling with existing observational data to generate predictive concepts of digenetic modification of reservoir-quality in fractured carbonates.s.

Hydrogeological modelling enables quantitative study of fluid flow systems, whilst reactive transport modelling (RTM) simulates reactions within the flow field. RTMs can thus address questions about drives for fluid flow and reaction patterns for different fluid types. They have already provided new insights into formation of matrix dolomites, but there is a need to resolve uncertainties about key properties (poro-perm and reactive surface area), to develop methods to appropriately condition RTMs and to enhance applicability of model results.

Reactive Transport Models offer considerable potential to generate improved process-based predictions of carbonate reservoir quality. In combination with available petrographic and geochemical data and paleoenvironmental reconstructions, this approach has important implications for reservoir exploitation in augmenting and developing scenarios for predicting dolomite geobodies.

The project commenced in 2011.