Dependence of waterflood remaining oil saturation on relative permeability, capillary pressure, and reservoir parameters in mixed-wet turbidite sands
- Rice Univ., Houston, TX (United States)
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. The water-wet case is based on the assumption that the system is water-wet and measurements were made with refined oil. The mixed-wet case assumed that the system is mixed-wet and restored-state measurements were made with crude oil. 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 (ROS) in the swept region for the water-wet cases was close to the residual oil saturation. The ROS 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 film surface drainage of oil by gravity, (2) accumulation of a high oil saturation and thus a high relative permeability under the caprock, and (3) up-dip migration of the oil that accumulated under the caprock. 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 caprock 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 endpoint mobility ratio.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 227837
- Journal Information:
- SPE Reservoir Engineering, Vol. 11, Issue 2; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Dilute Surfactant Methods for Carbonate Formations
Evaluating the Influence of Pore Architecture and Initial Saturation on Wettability and Relative Permeability in Heterogeneous, Shallow-Shelf Carbonates