Construction of multi-mineral digital rocks for upscaling the numerical simulation of tight rock physical properties

Abstract

Tight sandstone reservoirs are characterized by multi-scale pore space and high clay content, resulting in intricate rock physical responses. In this work, multi-scale imaging techniques, including computed tomography and stitched scanning electron microscopy, are applied to identify the large intergranular pores and micropores within major minerals. The pore structure of tight sandstones is quantitatively investigated using multi-scale images. Besides, multi-mineral digital rocks are constructed by performing registration and segmentation processing on the images obtained from microcomputed tomography and energy-dispersive scanning electron microscopy. These digital rocks are treated as composite materials consisting of different mineral types and micro-porosities, which enables the upscaling of the numerical simulation of rock physics properties. The results reveal that residual intergranular pores are interconnected through micropores within clay minerals, which significantly influences the electrical conductivities and permeabilities of tight sandstones. The proposed upscaling method can effectively couple the contribution of formation brine in multi-scale pores and clay minerals to bulk rock physics properties. This approach is suitable for the numerical simulation of diverse rock physical properties and can be applied to various tight reservoirs.

Document Type: Perspective

Cited as: Hu, J., Xiao, Z., Ni, H., Liu, X. Construction of multi-mineral digital rocks for upscaling the numerical simulation of tight rock physical properties. Advances in Geo-Energy Research, 2023, 9(1): 68-70. https://doi.org/10.46690/ager.2023.07.07

References

Archie, G. E. The electrical resistivity log as an aid in determining some reservoir characteristics. Transactions of the AIME, 1942, 146(1): 54-62.

Liu, X., Wang, J., Ge, L., et al. Pore-scale characterization of tight sandstone in Yanchang Formation Ordos Basin China using micro-CT and SEM imaging from nm- to cm-scale. Fuel, 2017, 209: 254-264.

Liu, X., Yan, J., Zhang, X., et al. Numerical upscaling of multi-mineral digital rocks: Electrical conductivities of tight sandstones. Journal of Petroleum Science and Engineering, 2021, 201: 108530.

Waxman, M. H., Smits, L. J. M. Electrical conductivities in oil-bearing shaly sands. Society of Petroleum Engineers Journal, 1968, 8(2): 107-122.