An undersaturated oil reservoir with a bulk volume of 20 x 10^6 bbl has an average porosity of 0.20 and a water saturation of 25%. Oil formation volume factor (B_o) = 1.23 bbl/STB. Reservoir thickness...

An undersaturated oil reservoir with a bulk volume of 20 x 10^6 bbl has an average porosity of 0.20 and a water saturation of 25%. Oil formation volume factor (B_o) = 1.23 bbl/STB. Reservoir thickness = 53 ft
Use the data given and,
What was the reservoir pore volume?
What was the reservoir of oil?
What was the volume of original oil in place?
If we expect that we will recover 12% of initial oil in place by primary recovery. How many STB of oil will we recover?