Abstract: During the depletion recovery process of gas condensate reservoirs, stacks of retrograde condensed liquids in the near bore formation by the effect of phase behavior, and reverse imbibitions water blockage effect that was caused by the well bore liquid accumulation under the action of wellbore backpressure, rock wettability and micro pore capillary pressure will lead to blockage of the permeable passages. So condensate gas wells productivities will decrease, especially in low permeability condensate gas wells. On the basis of analyzing the pollution mechanism of condensate gas wells by retrograde condensate and reverse imbibitions and internal and external technical methods that reduce or remove the pollutions, a more effective method of removing these pollutions to enhance gas well productivities was put forward directing at low permissibility gas condensate reservoir. By this method, a slug of methanol (ethanol, surfactants) solution was injected before huff and puff to more effectively remove the formation damages and blockages caused by retrograde condensate, especially reverse imbibitions water blockage effect.

Key words: condensate gas well, retrograde condensate blockage, huff and puff, methanol slug, gas well productivity