Prediction of petrophysical classes and reservoir beds through microfacies and pore types characterization, Tahe Ordovician naturally fractured vuggy carbonates

What is it about?

We use spectral stratigraphy and petrophysical analysis to determine the microfacies and pore-types variation to decipher the complexity of the reservoir systems. The study proposes an INPEFA log-based self-consistent approximation method to predict the rock texture types to establish a lithology-depth profile and a new total porosity variation model, which takes into account the influence of sea-level variation cycles on the distribution of rock textures and pore-structure types. New petrophysical classes (rock-fabric numbers) are defined for naturally fractured vuggy carbonates to modify Lucia’s (1995) petrophysical classes, which relate to matrix porosity-dominated reservoirs with no touching vugs.

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Why is it important?

We propose a cost-effective (affordable) technique, using well-log data largely, to determine rock texture and pore-structure types throughout the entire reservoir interval. The results show that petrophysical classes vary closely with the pore-structure types, and using the newly-defined petrophysical classes could enable better permeability prediction and reservoir quality analysis in naturally fractured vuggy carbonates.

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