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Investigation of the Bitumen Impact on the Petrophysical Properties in the Carbonates


The determination of petrophysical properties in carbonate rocks is strongly affected by heterogeneity at different scales. Complex depositional and diagenetic processes have led to systems with a very wide range of pore sizes involving many decades of length-scales (e.g. from sub-micron to cm) as in Carbonates. In particular, the latest invasion of bitumen takes an important role in control of reservoir quality. Reservoir bitumen precipitates in pore systems from the alteration of trapped or migrating oil in carbonate. Reservoir bitumen is not readily identified on typical log suites, where it is read as open porosity. When present as a solid, it can be as influential on reservoir quality as carbonate, silica, or authigenic clay cements and should therefore be evaluated as part of the diagenetic evolution of any pore system whenever encountered. Calculations of flow parameters such as permeability, relative permeability and capillary pressure do require the representative multiscale pore system to get accurate prediction. Therefore models of the pore space that include the full range of pore sizes and their connectivity are vital for this requirement in petrophysics and reservoir simulation. In this work we explore the extension of this multiscale pore-reconstruction and image statistical description to include diagenetic processes. We present a study of cementation and dissolution processes on the diagenesis of carbonate rock, particularly with occurrence and distribution of bitumen. Using derived information from thin section images indicating various stages of diagenesis, a modeling of the process of cementation and dissolution as well as the occurrence and distribution of will be carried out to investigate the impact of bitumen on the pretrophysical properties in Carbonate. The diagenetic processes are modeled using Pore Architecture model to explore the dissolution of grains and cementation of the inter-particle pores in the regions of the best connectivity estimated from reconstructed 3D images of carbonate samples. At last a further study of an integrated multi-scale pore-network is then generated and the petrophysical predictions would be performed on a pore-network flow simulator and petrophysical properties is investigated to better understand the bitumen controls of the pore system and transport properties.