Gas-Oil Ratio

The gas-oil ratio compares how much gas comes out with a given amount of produced oil, so it tells you how “gassy” a well or reservoir fluid is. It is calculated by dividing the produced gas volume by the produced oil volume, using consistent production units; the result is usually reported as standard cubic feet of gas per stock tank barrel of oil (scf/STB). This works because it is a direct volume ratio that links the two phases measured at standard conditions, making wells and reservoirs easier to compare.

Use this in petroleum production and reservoir engineering when evaluating well performance, fluid characteristics, or separation and facility design. It is also useful for comparing production trends over time or screening wells for changes in reservoir behavior.

• Using gas and oil volumes measured at different conditions without converting to standard units
• Dividing by the gas volume instead of the oil volume
• Mixing units such as m3 and barrels without converting them first