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gh tRe sample is maintained in the direction of the fractures, calculate: a. Per

ID: 293094 • Letter: G

Question

gh tRe sample is maintained in the direction of the fractures, calculate: a. Permeability of the fractures. b. Total permeability of the rock c. Flow rate through fractures and matrix if pressure gradient through sample is 7.5 psia and the viscosity of the fluid is 0.85 cP (2) Oil is flowing through a 10 cm core sample prepared for reservoir rock properties evaluation at a rate of 20 cm3/s. The pump pressure is 18 atm and the pressure at the end of the core chamber is 1 atm. If the diameter of the core is 5 cm and oil viscosity is 0.45 cP, calculate: a. Oil permeability of the core. b. Pressure drop through the entire core if the pump rate is changed to a new value of 13 cm/s using permeability from (a).

Explanation / Answer

a. Oil permeability at the core can be calculated as

k = - (Q. u. L) / (A. dP)

Following are the given quantities:

Flow rate, Q = 20 cm3/s

Oil viscosity, u = 0.45 cP

Length of core, L = 10 cm

Area of cross section, A = 3.14 x (5 x 5) / 4 = 19.625 cm

Pressure drop, dP = 18 -1 = 17 atm

Thus, permeability k = -(20 x 0.45 x 10) / (19.625 x 17) = -0.269 D

b. If Q = 13 cm3/s, then the pressure drop, dP, can be calculated as:

-0.269 =  -(13 x 0.45 x 10) / (19.625 x dP)

dP = 11.08 atm