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Line 37:
Line 37: − + − Equation 1+ − − + − Equation 2
→Buoyancy forces in reservoir fluids
The two forces acting on the fluids in the pore space are controlled by physical laws. The equation for the buoyancy pressure is given by
The two forces acting on the fluids in the pore space are controlled by physical laws. The equation for the buoyancy pressure is given by
:<math>P_b = (\rho_w - \rho_{nw})gh</math><br>
where P<sub>b</sub> is the buoyancy pressure; ρ<sub>w</sub> and ρ<sub>nw</sub> are the specific gravities of the wetting and nonwetting phases respectively; g is the acceleration of gravity; and h is the height above the free-water level.
where Pb is the buoyancy pressure; ρw and ρnw are the specific gravities of the wetting and nonwetting phases respectively; g is the acceleration of gravity; and h is the height above the free-water level.
The equation for capillary forces is given by
The equation for capillary forces is given by
:<math>P_c = \frac{2 \sigma \cos \theta}{r}</math><br>
where Pc is the capillary pressure, sigma is the interfacial tension, thetas is the contact angle between the wetting fluid and the solid surface, and r is the capillary (pore throat) radius (Vavra et al., 1992).
where Pc is the capillary pressure, sigma is the interfacial tension, thetas is the contact angle between the wetting fluid and the solid surface, and r is the capillary (pore throat) radius (Vavra et al., 1992).