By calculating the phenomena of the gas lift, the theoretical results are obtained as follows: (1) The characteristic curve of the gas lift indicates the most efficient method for the field work. (2) The maximum lifting capacity increases as the rate of submergence increases. (3) The minimum gas liquid ratio is on the point of 75 per cent of., the subme- rgence. (4) The tapered tubing method is not profitable because of the reduction of Reynolds number of the liquid.
