Specific gravity defined by the rate of gas density in a pressure and temperature sub surface by gas density in equal temperature and pressure (usually in surface). </ref><ref name=Wicaksono2015> Wicaksono. 2015. ''Reservoir Hydrocarbon''. AAPG Short Course: Brawijaya University.</ref>
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Specific [[gravity]] defined by the rate of gas density in a pressure and temperature sub surface by gas density in equal temperature and pressure (usually in surface). </ref><ref name=Wicaksono2015> Wicaksono. 2015. ''Reservoir Hydrocarbon''. AAPG Short Course: Brawijaya University.</ref>