Reservoir Flow Units: A Comparison Between Three Different Models in the　Santa Barbara and Pirital Fields North Monagas Area Eastern Venezuela Basin

摘要

The North Monagas Area presents apparently homogeneousrnthick sand bodies in the producing section. These sands, somernin the order of hundreds of feet, have been until recentlyrnconsidered as single flow units. However, different productionrnscenarios have indicated the presence of distinct flow unitsrnwith particular petrophysical characteristics within each sand.rnSeveral definitions and techniques have been applied torndetermine flow units. In this study, flow units are defined asrnsediment intervals that maintain a similar relation betweenrntheir petrophysical properties such as porosity, permeability,rnwater saturation, pore throat radius, and storage and flowrncapacity, and that differ from the petrophysical characteristicsrnof the intervals immediately above and below. Three differentrnmethodologies were analyzed and compared with the purposernof determining their similarities and divergences. The firstrnmethod is derived from the sedimentological description ofrncores, using grain size as the main factor. The second methodrnapplies empirical equations based on pore throat radius an itsrnrelation to flow capacity, and their use in the determination ofrnpetrofacies or rock types, whereas the third method is based onrna systematic model which uses the concepts of mean hydraulicrnradius and flow zone indicators to determine hydraulic units.rnThe definition of flow units allowed a better petrophysicalrncharacterization of the field and provided better judgement forrnthe selection of production and injection intervals.