Formation pressure monitoring method for water-containing gas reservoir injected with carbon dioxide

The invention relates to a formation pressure monitoring method for a water-containing gas reservoir injected with carbon dioxide, and belongs to the field of gas reservoir engineering. The problem that a method for monitoring the formation pressure of a water-containing gas reservoir injected with carbon dioxide does not exist nowadays is solved. According to the technical scheme, carbon dioxide is injected into the water-containing gas reservoir and part of the carbon dioxide is dissolved in water, a material balance formula is established based on the constant-volume gas reservoir, the material balance formula of the water-containing gas reservoir considering carbon dioxide injection is deduced, and the material balance formula is solved by applying an iterative algorithm; and drawing a relational graph of the change of the formation pressure along with the accumulated ground carbon dioxide injection quantity, thereby realizing the formation pressure monitoring of the water-containing gas reservoir injecte