Seminars and Events
Detrital clay distribution in a modern turbidite system and implications for reservoir quality
Porosity and permeability (pore-scale attributes) of a host rock are the two important parameters defining the quality of hydrocarbon reservoirs. These parameters are controlled by (i) depositional and (ii) diagenetic factors, which often act together to determine the final pore-scale attributes. Particularly in clastic reservoirs, early diagenesis is strongly linked to depositional properties, which includes texture, detrital composition, fabric and original pore water composition. These factors determine the fluid flow pathways and available elements in a relatively closed system.
Many reservoir quality studies focus on diagenetic controls, as they seem to be the main porosity and permeability destructive phases. However, some phases (such as early diagenetic chlorite) enhance the pore-scale attributes by inhibiting quartz cementation and hence preserving the pore space. In some cases, formation of a certain authigenic phase is mainly dependent on the presence of another detrital precursor mineral. Therefore, predicting the spatial distribution of the precursor detrital mineral can take us one step closer to predicting the diagenetic phase distribution in a subsurface reservoir.
Here, the two case studies aim to link sedimentary processes to mineralogical make up of sandstones and then to subsurface pore-space attributes. The first case study explores the links between depositional processes and sandstone texture (such as grain size, sorting and grading) on Carboniferous deltaic sediments. The second study focuses on the detrital clay distribution in a modern turbidite system. It aims to link the clay distribution to flow properties and questions the use modern analogues in such studies.