Experimental evaluation of combination slug technique to get rid of water blocking damage in gas condensate wells

In the process of the production of condensate gas wells, long-term liquid loading can easily lead to reverse osmosis water lock effect near wellbore area, which will form water blocking damage, lower the reservoir percolation ability, increase production pressure difference, and seriously affect the release of gas well production capacity. By taking condensate gas Y-well as an example, with the use of the gas well productivity equation considering the reverse osmosis water locking, the effect of reverse osmosis water entrapment on gas well productivity was analyzed. The combination slug technique of "methanol + acid +water locking agent + nitrogen huff and puff" was adopted to carry out the experimental evaluation on the effect of lifting water locking in the long core of Y-well. The experimental results show that the open flow rate of the gas well decreases sharply with the increase of the penetration depth of the reverse osmosis water lock. The combination slug technique of "methanol + acid + water locking agent + nitrogen huff and puff" has a good effect to get rid of water blocking damage, which will make the permeability recover to 6.2 times.