Question

Sandstone pore of 20 mm in diameter and 100 mm long with porosity of 15% is prepared for
core flood experiment. The sandstone pore is fully (100%) saturated with water by injecting
water with viscosity of 1cp at volumetric flow rate of 20 cubic mm/sec. A pressure drop of 1
atm was recorded across the pore during the injection process.
i. What is the absolute permeability of the sandstone pore sample in mD?
ii. What is the pore volume of sandstone sample?
iii. The sandstone pore sample is flooded by oil with viscosity of 2 cp until
water saturation reaching to 25%. Calculate the oil volume inside the pore
at the end of flood

Answer 1

Given

Sandstone pore dimensions :-

d= 20mm, h= 100mm, n = 0.15

V= (πd​​​​​2/4)*h

=> V​​​​​​Total = 31400 mm​​​​3 .

Void ratio e = (n/(1-n)) = V​​​​​​v/ V​​​​​​s

=> e=0.176

V​​​​​​Total = V​​​​​​v + V​​​​​​s

=> On solving using above V​​​​​​total​,e values we get

V​​​​​v​​​​​= 4700mm3 ( answer of 2nd question)

V​​​​​​s = 26700mm3 .

When further oil is injected into pore, water will be slowly descipated and let us assume it reasches 25% saturation then oil will be 75% of the total pore volume.

Hence V​​​​​​oil = 0.75 * V​​​​​​v = 3525 mm​​​​3  ( answer of 3rd question)

​​​​

​