Gas injection oil displacement method and system

The invention discloses a gas injection oil displacement method and system. The gas injection oil displacement method comprises the following steps of setting the working positions of a gas injection well, a production well and a plurality of control wells, wherein the control wells are used for assisting gas injection, and the multiple control wells are arranged between the gas injection well and the production well at intervals; setting the working well depths of the gas injection well, the production well and the plurality of control wells respectively; closing the control wells, and injecting preset gas into the gas injection well; and closing the injection well and the production well within the preset time, and injecting preset gas into the multiple control wells in sequence. The control wells and the gas injection well are the same in structure; the production well comprises an oil pipe, a casing pipe and a packer arranged between the oil pipe and the casing pipe; each of the gas injection well and the