Vol. 337 No. 9 (2026)
DOI https://doi.org/10.18799/24131830/2026/9/5326
Estimation of scale effect and elementary representative volume of a carbonate reservoir using computed tomography
Relevance. Determined by the need to improve the quality of modeling the porosity and permeability properties of complex carbonate reservoirs characterized by a high degree of scale effect. Aim. Quantitative assessment of the scale effect and establishment of an elementary representative volume of a complex carbonate reservoir based on the computed tomography method. Methods. Computed tomography of core samples, gas-volumetric method, statistical methods. Results and conclusions. Standard and full-size core samples located as closely to each other in depth (no more than 10 cm) were selected for the study. The authors measured porosity and permeability values for the selected samples using an UltraPoroPerm-500 Permeameter/Porosimeter, and tomographic studies were performed on a Nikon X TH 225 device. Based on the tomography data, the authors constructed 3D models of the void space of the samples. Based on these models, a sample of digital samples of various sizes was formed by cutting cylinders of various volumes from the obtained models for both standard and full-size samples. For each obtained volume, the authors determined digital porosity and calculated and constructed graphs of porosity versus the studied volume of the model, as well as graphs of the relative error of the digital porosity values in comparison with the actual value determined by the gas-volumetric method on a full-size sample. An elementary representative volume of rock for measuring porosity was obtained by determining the boundary value of the volume, above which the digital porosity values do not deviate from the actual value by more than 5%. To calculate the authors used the permeability values of the digital samples, the permeability-porosity relationships obtained as a result of petrotyping of all core samples studied at the Alpha field. An elementary representative volume of rock for measuring permeability was calculated in the same way as for porosity. The following results were obtained: 1) the scale effect for porosity averaged 12%, for permeability – 300%; 2) the elementary representative volume for porosity and permeability is characterized by comparable values; 3) the value of the elementary representative volume increases with the complexity of the void space (from the pore type to the cavernous-fissured-pore type).
For citation: Kozyrev N.D., Kochnev A.A., Shirinkin D.O., Krivoshchekov S.N., Ozhgibesov E.S., Savitsky Ya.V., Yuzhakov A.L. Estimation of scale effect and elementary representative volume of a carbonate reservoir using computed tomography. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 9, pp. 136–147. http://doi.org/10.18799/24131830/2026/9/5326
Keywords:
scale effect, elementary representative volume, complex carbonate reservoir, computed tomography, standard samples, full-size samples, petrotypization
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