engleski

Petrophysical modelling of the Upper Pannonian reservoirs in Sava Depression

Deterministic methods are still widely used for reservoir characterization and modelling although it is clear that our knowledge about underground cannot be completely known, i.e. without any uncertainty. This is why sometimes stochastic methods can give better solution, since they include uncertainty in their calculations. This paper shows testing of the deterministic (Ordinary Kriging) and stochastic (Sequential Gaussian Simulations) methods for porosity distribution in Lower Pontian hydrocarbon reservoirs in the Sava Depression. Ten realizations were obtained by Sequential Gaussian Simulation. Although 10 realizations is enough only for the rough insight into geological underground uncertainty, the obtained results were satisfied. Areas with the highest uncertainties were well observed in the maps. Many problems in numerical simulation appeared due to high differences in values between neighbour cells. For that reason Ordinary Kriging as a deterministic method was used for the modelling of the same reservoirs. Smooth transitions between neighbour cells eliminated all the numerical modelling problems and Ordinary Kriging maps showed channel sandstone with transitional lithofacies in some reservoirs.

Geostatistics; Ordinary Kriging; Sequential Gaussian Simulations; hydrocarbon

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