The Venezuelan Orinoco Belt heavy oil reservoirs have been subject to research over recent years with respect to their possible anomalous production behavior. High recovery factors and high initial production rates are expected, which is not predicted using conventional characterization and simulation practices. Heavy Oil reservoirs with this behavior are referred to as foamy oil reservoirs.

We present laboratory experiments that can be used to obtain predictions on the production behavior of foamy oil reservoirs. These experiments were used to obtain relative permeability end-points. The effect of confinement pressure is shown, as depletion completed with an overburden stress shows a much higher recovery and critical gas saturation than the depletion without stress.

Preliminary reservoir simulations have been carried out for an area of the Orinoco belt with 7-8 years of production history, using the obtained relative permeability end-points. The match of the oil production rate and gas/oil ratio curves is presented. It is shown that an increase of gas-oil ratio (GOR) in the field could not be predicted with the laboratory-derived relative permeability end-points. This discrepancy may be the result of too coarse a simulation grid in the region of the well bore or may just highlight the difficulty in scaling laboratory measurements to the field-scale. The implications for field-scale simulation have not been fully explored.

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