油藏物理学一地层原油的高压物桂 5,by relative density of gas free oil: light oil:y<0.855,API gravity>34; medium density oil:y is 0.855~0.934, API gravity is 34~20; high oil:y>0.934,API gravity<20;油藏物理学——地层原油的高压物性 5﹑by relative density of gas free oil: light oil:γ<0.855,API gravity>34; medium density oil: γ is 0.855~0.934, API gravity is 34~20; high oil: γ > 0.934,API gravity< 20;