翻译:thefluidmustbeidentifiedbydirectmeasurementofcertainproperties.Thesemeasurementsinvolvesecuringsamplesofthefluidsfromthefield.Thesimplestprocedureistomakemeasurementsofthepropertiesoftheproducedfluids.TheAPIgravityofstock-tankoilandtheproducinggas-oilratioareroutinelydetermined.Thegas-oilratioisordinarilytheratioofvolume,instandardcubicfeet,ofgasfromtheseparatortothevolumeofstocktankoilbothmeasuredoverthesametimeinterval.Ifgoodfieldpracticeisfollowed,thegravityoftheseparatorgasisdetermined.Thesedata,togetherwithestimatesorobservationsofthereservoirpressureandtemperature,canbeusedtoestimatethepropertiesofthereservoirfluids.Suchestimatesmaybeoflimitedaccuracy.