Experimental Study of Water Shut-off by Wettability Alteration to Gas Wetness

Gas wells may suffer significant decline in gas production or even get killed because of the water invasion into production zones.<br>Closing off the water producing zone may not be acceptable in many cases. In this study, the feasibility of reducing the water<br>production in gas wells by changing the wettability of the gas zone from preferential water- to gas-wetness using fluorine carbon<br>surfactant has been investigated experimentally. The basic mechanism was that the entry capillary pressure has to be overcome<br>prior to water entering the gas zone.