An undersaturated oil reservoir $($no gas cap and no water aquifer$)$ has a connate water saturation of $0\mathrm{.}24.$ The initial oil$-$in$-$place is estimated at $200$ MMSTB$.$ The compressibility of oil is $10{10}^{-6}{}^{-1}$ and that of water is $3{10}^{-6}{}^{-1}.$ The reservoir porosity is $0\mathrm{.}25.$ Estimate:

The pore compressibility.

The total compressibility in the oil reservoir.

The effective oil compressibility in the reservoir.