Synthetic capillary pressure modeling with dipole sonic waves for enhanced reservoir characterization
Gap Declaration
In this study, model reliability was ensured by restricting the analysis to clean, well-consolidated sandstone intervals, where the NPHI–Wyllie porosity estimation and the underlying petrophysical assumptions remain valid. It must be noted, however, that the approach has not yet been tested in mixed lithologies, carbonates, shales, or clay-rich units; thus, its sensitivity to these rock types cannot be evaluated with the current dataset. Future work should focus on extending, calibrating, and validating the methodology in more heterogeneous lithologies to assess its broader applicability and potential limitations. The methodology presented in this article has been applied exclusively to sandstones, primarily for two reasons. First, elastic measurement data from various sandstone types were available, which are essential for calibrating the elastic moduli response to seismic velocities.
Abstract
This study presents a mathematical framework for generating synthetic capillary pressure curves using dipole sonic log information and a fractal model of the pore structure. The approach estimates key petrophysical properties such as porosity and elastic constants by simulating the deformation behavior of porous media under effective stress conditions through boundary element methods. Pore geometries are modeled using a combination of Euclidean shapes and fractal distributions, which allow for realistic simulation of elastic responses and pore volume variability. A central issue addressed is the non-uniqueness problem, where different pore structures can produce similar elastic properties. To mitigate this, the model incorporates a fractal pore population constrained by scaling laws derive…
Conclusions / Discussion
Conclusion This work presents a methodology for calculating a topological model of the porous space in sedimentary rocks, emphasizing the integration of fractal and Euclidean pore distributions and their influence on the material’s elastic constants. The approach combines computational tools and field data to develop accurate representations of the porous space’s behavior under varying conditions. The effect of obtaining a unique pore distribution has a direct implication for the uniqueness of the capillary curve predicted by the model. Because the pore volume as a function of pore perimeter, which is directly related to fluid saturation, is uniquely determined by the pore distribution, the resulting capillary curve is therefore uniquely defined. In the first case study, corresponding to the Tapi–TTT Oilfield in Ecuador, the synthetic capillary pressure curve generated by the model showed a deviation of approximately 10 psi compared to the laboratory measured curve. This discrepancy is likely due to the incorporation of synthetic data to compensate for incomplete well log sections and the limited availability of hard field data. The use of synthetic inputs, although necessary, incr…
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Technique originates in genomics bioinformatics; functional analogues in epidemiology, psychology literature are absent.
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