Method for increasing condensate oil recovery ratios of condensate gas reservoirs by means of gas injection vertical displacement

The invention discloses a method for increasing condensate oil recovery ratios of condensate gas reservoirs by means of gas injection vertical displacement, and belongs to the technical field of condensate gas field development. The method includes selecting proper injected gas according to a principle that a gravitational differentiation phenomenon is obvious when a density ratio of the preferable injected gas to fluid of the gas reservoirs is lower than 0.75 under a formation condition in gas injection physical model experiments and actual production; determining injection and production well locations, perforation intervals, well patterns and well spacing by the aid of a kinetic mechanical analysis process for micro-elements of the injected gas so as to effectively form artificial gas caps in gas injection procedures; determining critical gas production rates according to a critical production rate correction formula. The critical gas production rates are used for preventing increase of gas-oil ratios due to coning of the injected gas. The method has the advantages that the artificial gas caps can be formed at high structural positions by the injected gas, condensate gas can be subjected to vertical downward displacement by the aid of the injected gas, accordingly, the sweep efficiency of the injected gas is close to 100%, and the injected gas utilization rate and the final condensate oil recovery ratios can be obviously increased.