Integrated Reaction Transport Modelling of Dolomite Evolution

  • Whitaker, Fiona F (Principal Investigator)
  • Gabellone, Tatyana (Researcher)
  • Griffiths, Graham L (Researcher)
  • Palmer, Thomas (Researcher)
  • Yapparova, Alina (Student)

Project Details


Two basic styles of replacement dolomitisation occur; diffuse dolomites formed at relatively cool temperature and high-temperature dolomites generally related to fractures. The former (which may also be fracture guided) are relatively well understood, volumetrically significant and may be important precursors for later dolomites. Work on high-temperature dolomites has described dolomite geometries and their relationship with fractures, petrography and geochemistry, and inferred mechanisms of formation, eg the HTD model of Davies & Smith (2006). Significant questions remain about Mg2+ mass balance requirements, both in terms of plumbing and fluid chemistry, and the extent to which hydrothermal fluids can form large volumes of matrix dolomite.
This project integrates process-based numerical modelling with existing observational data to generate predictive concepts of diagenetic modification of reservoir-quality in fractured carbonates. 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.
RTMs also offer considerable potential to address uncertainties in fracture dolomitisation and to predict the geometry, spacing and poro-perm of dolomite bodies. Here, correct modelling of matrix-fracture exchanges is key. By comparing dolomitisation predicted by EPM models with simple fracture zones, dual permeability and discrete fracture models we can evaluate trade-offs between increasing model complexity and predictive power
Effective start/end date1/04/1231/07/14