Dependence of waterflood remaining oil saturation on relative permeability, capillary pressure, and reservoir parameters in mixed wet, turbidite sands
The dependence of waterflood oil recovery on relative permeability, capillary pressure, and reservoir parameters was investigated by numerical simulation. The relative permeability and capillary pressure curves were based on laboratory measurements on unconsolidated sands and were evaluated for water-wet and mixed wet states. The reservoir model was a prototype turbidite sand with a range of thickness and permeability values. The economic oil recovery was based on an economic limit water cut of 50%. The remaining oil saturation in the swept region for the water-wet cases was close to the residual oil saturation. The remaining oil saturation of the mixed wet cases ranged from low values near the residual oil saturation to far above the residual oil saturation. It is dependent on the reservoir parameters that govern: (1) the vertical {open_quotes}film surface drainage{close_quotes} of oil by gravity, (2) accumulation of a high oil saturation and thus a high relative permeability under the cap rock, (3) updip migration of the oil that accumulated under the cap rock. The dependence on the reservoir parameters can be summarized by dimensionless groups. There is a dimensionless time for the vertical displacement of oil by gravity. The accumulation of a high oil saturation under the cap rock is dependent on the ratio of the capillary transition zone and the sand thickness. The updip migration is dependent on a combination of the gravity number and the end point mobility ratio.
- OSTI ID:
- 199481
- Report Number(s):
- CONF-951002--
- Country of Publication:
- United States
- Language:
- English
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