The image above represents separator gas gravity.

To compute for the separator gas gravity, four essential parameters are needed and these parameters are **API Gravity (°API), Actual Separator Temperature (°Rankine) (T _{sep}), Actual Separator Pressure (P_{sep})** and

**Gas Gravity at Actual Separator P**

_{sep}and T_{sep}(γ_{g}).The formula for calculating the separator gas gravity:

γ_{gs} = γ_{g}[1 + 5.912(10^{-5})(°API)(T_{sep} – 460)log(^{Psep} / _{114.7})]

Where:

γ_{gs} = Separator Gas Gravity

°API = API Gravity

T_{sep} = Actual Separator Temperature (°Rankine)

P_{sep} = Actual Separator Pressure

γ_{g} = Gas Gravity at Actual Separator P_{sep} and T_{sep}

Let’s solve an example;

Find the separator gas gravity with an API Gravity of 21, actual separator temperature of 18, actual separator pressure of 14 and gas gravity at actual separator of 32.

This implies that;

°API = API Gravity = 21

T_{sep} = Actual Separator Temperature (°Rankine) = 18

P_{sep} = Actual Separator Pressure = 14

γ_{g} = Gas Gravity at Actual Separator P_{sep} and T_{sep} = 32

γ_{gs} = γ_{g}[1 + 5.912(10^{-5})(°API)(T_{sep} – 460)log(^{Psep} / _{114.7})]

γ_{gs} = 32[1 + 5.912(10^{-5})(21)(18 – 460)log(^{14} / _{114.7})]

γ_{gs} = 32 [1 + 5.912(10^{-5})(21)(18 – 460) log(0.1220)]

γ_{gs} = 32 [1 + 5.912(10^{-5})(21)(-442) log(0.1220)]

γ_{gs} = 32 [1 + 5.912(10^{-5})(21) (-442) (-0.9134)]

γ_{gs} = 32 [1 + 0.501]

γ_{gs} = 32 [1.501]

γ_{gs} = 48.039

Therefore, the separator gas gravity is **48.039**.