Abstract: The Ordovician reservoirs in the Tahe oil field are typical fractured-vuggy carbonate reservoirs. As water injection efficiency becomes worse gradually, new methods for fractured-vuggy carbonate reservoirs are demanded, among which gas injection is an effective way. Spillway distance, gas injection timing, gas injection speed, and gas/water proportion were compared, putting forward a new method for improving the gas injection efficiency of carbonate reservoirs.