DIAGENESIS - FLUID-ROCKS INTERACTIONS

摘要

The recovery of hydrocarbons strongly depends on the distribution of internal reservoir heterogeneities. The spatial prediction and the modelling of such heterogeneities in both carbonate and siliciclastic reservoir rocks form a significant challenge for optimizing the hydrocarbon production. Improving reservoir characterization is also critical to manage any underground storage (CO2 storage, natural gas storage, freshwater storage) and also geothermal exploitation. The reservoir heterogeneity distribution is first related to the depositional processes which controlled the main reservoir architecture. Then, during burial, diagenesis, faulting and fracturing among other processes add a huge complexity to the reservoir heterogeneity distribution. These processes being interdependent (fracture intensity depends on the bedding and the lithology, fractures can be opened or cemented...), it is then crucial to understand their genesis and their relative chronology. Whether occurring at near-surface or during progressive burial, the diagenetic processes are usually associated with fluid flow (advective flow in fractures and/or diffusive flow in matrix). The impact of fluid flow is usually expressed through considerable changes in the properties of host rocks, namely their porosity and permeability.