▎ 摘　　要

NOVELTY - Water blocking agent comprises 5.0-6.0 wt.% W/O emulsifier, 0.5-1.0 wt.% wetting reversal agent, 0.5-1.0 wt.% synergist, and balance amount of solvent. USE - Water blocking agent for use in gas reservoir recovery (claimed). ADVANTAGE - The water blocking agent has good shutoff performance, has little influence on the gas phase permeability, can selectively and effectively shut off the water layer, and achieves the effect of water shutoff but not gas shutoff. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: i. A method for preparing water blocking agent, which involves dispersing W/O type emulsifier in a solvent, and adding wetting reversal agent and a synergist to obtain the desired water blocking agent; and ii. a water shutoff method, which involves injecting the water blocking agent into the formation to be water shutoff to recover the gas reservoir.