--> Abstract: Enhancement of Simulation Models Using Petrophysical Facies, by Mohamed S. AbouSayed; #90105 (2010)

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AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain

Enhancement of Simulation Models Using Petrophysical Facies

Mohamed S. AbouSayed1

(1) Reservoir Modeling Technology “ResModTec”, Abu Dhabi, United Arab Emirates.

If you ask a group of geoscientists and engineers “What is Facies?” you will definitely get very different answers. The strange thing, but funny, is that they are working for long period of time, at the same office, on modeling the same reservoir within the same field. One more strange (still funny) is that both of them are exchanging a lot of data and most of these data are facies data (type, properties, categories...).

The wrong definition of facies affects negatively not only on the definition of the reservoir geometry but also on the population of the reservoir properties. Geoscientists define facies from the geological point of view based mainly on the lithology, depositional environment, diagenitic history, fossil contents and other geological criteria. Based on these parameters geoscientists subdivide the facies into lithofacies, biofacies, microfacies, icnofacies, electrofacies and seismic facies. Engineers look at the facies as a different group of rocks that have different flow regime. Hence, if the flow of fluids within a body of the reservoir is consistent this can be considered as one facies. Both definition need to be fine-tuned to get the best results out of our reservoir models.

This paper suggests starting using the Petrophysical facies where the reservoir modeler uses all basic Petrophysical reservoir rock properties (porosity, permeability, wettability, capillary pressure and relative permeability) to differentiate between the different geological bodies within the reservoir rock. This way we use the factors that control the fluid flow in a rock as a base for differentiating different geological sittings. That will definitely give us a better chance to define the geometry of each facies and then help us populate its properties within the defined reservoir bodies.

Out of 21 modeling projects in the Middle East and North Africa region, 16 of them did not obtain the anticipated history matching because of the wrong definition of facies. Several case studies including both carbonate and sandstone reservoirs showed a much better history matching after correcting the definition of facies.