Abstract

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), which cannot be captured by a single-resolution x-ray CT image. 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. Recently a multiscale pore-networks generated from statistical models extracted from images at different resolutions have shown as an important tool for multiscale pore description (Wu et al, 2011). 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 the impact of diagenetic processes on the evolution of carbonate rock by quantification of pore size and connectivity, modelling the process of cementation and dissolution using derived information from catholuminescent thin section images indicating various stages of diagenesis. The diagenetic processes includes cementation and dissolution in both the meteoric and burial diagenetic environments and are modelled using Pore Architecture model to dissolve grains in the regions of the best connectivity estimated from reconstructed 3D images of carbonate samples. An integrated multi-scale pore-network is then generated and the petrophysical predictions would be performed on a pore-network flow simulator. At last a further study of comprehensive rock typing combining diagenetic processes on pore connectivity and petrophysical properties is investigated to better understand the diagenetic controls of the pore system and transport properties.

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