The effect of fluorocarbon surfactant on the gas-wetting alteration of reservoir

Reservoir wettability plays a vital role in the production of shale gas. In this work, two fluorocarbon surfactants were synthesized and characterized. The wettability of shale surface was evaluated by different method. The results showed that the contact angles of water and oil increased significantly after treatment. The surface free energy rapidly reduced to 10.3mN/m and 5.9mN/m, respectively. The roughness of the shale surface remarkably increased. These results confirmed that the shale wettability is altered from liquid-wetting to gas-wetting. Besides, the thermal analysis exhibited that they have good thermal stability before 173 degrees C and 201 degrees C, respectively.