Interaction of structure, sedimentary architecture and mechanical stratigraphy in the diagenetic alteration of rift-related carbonates

In carbonate-dominated rifts, deep-seated faults and elevated heat provide ideal conditions for fluid migration and associated diagenetic alteration of the original carbonate rocks, due to dissolution (karst formation) or cementation (dolomitization). Faults location, growth and geometry strongly control growth and diagenetic modification of carbonate platforms. First, fault growth may exert strong control on the location and distribution of carbonate platforms (footwall growth of shelf carbonates). Second, fault-controlled fluid flow can largely affect the distribution of diagenetically altered bodies within carbonate rocks in rifts. Additionally, in carbonate-dominated rifts there is a stratigraphic control on fluid-rock interaction because of different mechanical and petrophysical properties of lithofacies.

Few studies have linked how the interaction of structural, sedimentological and diagenetic processes controls rock properties in rift basins. This work aims at understanding of the localization of fluid-rock-interactive focal points and constraining how fluids migrate within and away from faults during rift evolution.

Fig.1. Fault-related dolomitization within the footwall of Hammam Faraun Fault (Suez Rift, Egypt).

The objective of this project is to build workflows that demonstrate the processes governing interaction of depositional architecture and deformation in controlling fluid flux in carbonate rocks in rift basins. This will be achieved through analysis of outcrop and subsurface data in combination with laboratory analyses and numerical modelling of fluid flux and fluid-rock reactions. The following datasets will be utilized: i) existing field data from Eocene carbonates in the Gulf of Suez, Egypt, ii) outcrop data to be collected from Permo-Carboniferous carbonates of the Carboniferous of northern England and Wales and Svalbard, and iii) a subsurface dataset of partially dolomitized Devonian carbonates in the Western Canadian Sedimentary Basin.

This study will allow us to better constrain how fluids migrate within and away from faults during rift evolution and therefore, gives us ability to better predict the distribution of porosity and permeability in carbonate reservoirs.

Publications:
Hirani, J., Bastesen, E., Boyce, A., Corlett, H., Eker, A., Gawthorpe, R., Hollis, C. & Rotevatn, A. 2018: Structural controls on non-fabric-selective dolomitization within rift-related basin-bounding normal fault systems: insights from the Hammam Faraun Fault, Gulf of Suez, Egypt. Basin Research, doi: 10.1111/bre.12290.

Korneva, I., Bastesen, E., Corlett, H., Eker, A., Hirani, J., Hollis, C., Gawthorpe, R.L., Rotevatn, A. & Taylor R. 2018: The effects of dolomitization on petrophysical properties and fracture distribution within rift-related carbonates (Hammam Faraun Fault Block, Suez Rift, Egypt). Journal of Structural Geology, doi:10.1016/j.jsg.2017.06.005

Korneva, I., Rotevatn, A., Manifold, L., Hollis, C., Gawthorpe, R. 2017: Controls of pre-existing structural pattern on carbonate platform evolution: the Derbyshire platform (East Midlands, UK). EGU General Assembly Conference Abstracts 19, 5541

Peacock, D.C.P, Korneva, I., Nixon, C.W. & Rotevatn, A. 2017: Changes of scaling relationships in an evolving population: the example of 'sedimentary' stylolites. Journal of Structural Geology 96, 118-133.