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Articles that state the difficulty of establishing an accurate and reliable relationship between porosity and permeability, in order to create a continuous permeability profile in wells, abound in the Petrophysical literature devoted to carbonate reservoirs. To try and alleviate this difficulty, new numerical methods or data mining techniques are often proposed. However, despite the necessity of interpreting data in terms of causation, those papers hardly discuss and explore, and even less so, explain, the origins of this difficulty. Therefore, questioning the ways in which these techniques are used is as legitimate as examining if they are really effective.

PDVSA INTEVEP undertook a study in a carbonate area located in a gas and condensate reservoir offshore Venezuela, where the main challenge was related to the high heterogeneity of the rock fabric. The geoscientists needed to understand how the pore system pattern reflects good porosities throughout the limestone while having significant permeability variations.  The data was collected from wells with cores, as variations in the petrophysical properties are much harder to predict in wells without core data.  The main objective was to apply a clustering approach in order to build electrofacies models and integrate them with sedimentological interpretations by extrapolating those models to wells without core data.