LAUSR

Abstract Wettability alteration of condensate gas reservoirs is very important for improving the productivity of condensate wells. In this work, a novel gas-wetting alteration agent was synthesized by emulsion polymerization. The synthesis process conditions were optimized by the response surface methodology based on the yield of the product. Wettability alteration effect of the polymer was evaluated by the contact angle method and the Owens two-liquid method. Experimental data showed that the effect of temperature on yield is significantly greater than the other two factors. The most preferred synthesis parameters were as follows: a reaction temperature of 80 °C, a molar ratio of acrylic acid to perfluorooctylethyl acrylate of 2.5:1 and 0.06 g of potassium persulfate. Under such optimal specifications, the test yield (84.36%) was almost close to the predicted yield (83.66%). Furthermore, the contact angle of water and n-hexadecane on the core surface increased from 34° and 0° to 126° and 102° after treated by 1.5 wt.% polymer solution. The surface free energy reduced from 73 mN/m to 8.2 mN/m at equal mass fractions. These values were verified by spontaneous imbibition. The results proved that the core has been rendered hydrophobic and oleophobic properties after being treated with the synthesized gas-wetting alteration agent.