This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Quiz 2 PGE 424 20 minutes; 10 points
1. State Darcy’s law. qx = -(k/µ) dp/dx 2. Name two conditions under which Darcy’s law is not valid. -High flow rate or Reynolds No. -Non-Newtonian fluid flow -Low pressure gas, where mean free path ~ pore size
3. How does the density of a slightly compressible liquid typically depend on pressure?
ρ = ρ 0 exp (cP); c: compressibility, P: pressure 4. What is the ideal gas law? PV = nRT
5. What is the difference between permeability heterogeneity and permeability anisotropy? Heterogeneity: Permeability is a function of location. Anisotropy: Permeability is a function of direction at the same location.
6. Two porous rocks are similar except that the pore size of the first rock is twice that of the second rock. If the permeability of the first rock is k1, what is permeability of the second rock? Because k ∝ r2, k2=k1/4. 7. What is Klinkenberg effect? At low pressure, gas molecules slip in porous media. kg = kL (1+b/Pm) 8. What is the Young-Dupre equation? Cosθ =(σ os-σ ws)/σ ow
9. The largest pore throat size in a core is rmax. What is the entry capillary pressure? With oil/water, Pce = 2 σ ow Cosθ / rmax
10. What is mixed-wettability? Some of the pores are water-wet and the others are oil-wet. The rock imbibes both oil and water spontaneously in Amott tests. ...
View Full Document
- Spring '09
- Fluid Dynamics, Darcy, pore size, permeability heterogeneity