A method for liquefying production gas from a gas source containing a fluid having C1-C12 entrained gases includes passing the gas through a first stage of cryogenic liquefaction to cool the gas to a temperature between −50 degrees Celsius and −87 degrees Celsius to create a fluid containing a liquefied C3-C12 petroleum gas and a gaseous C1-C2 natural gas. The liquefied C3-C12 petroleum gas and gaseous C1-C2 natural gas are passed through a second phase separator to separate the liquefied C3-C12 petroleum gas from the gaseous C1-C2 natural gas. The liquefied C3-C12 petroleum gas is collected into liquefied petroleum gas storage vessels.