Wettability modification of rock cores by fluorinated copolymer emulsion for the enhancement of gas and oil recovery

• Published in: Applied surface science 2012-07, Vol.258 (18), p.7075-7081
• Main Authors: Feng, Chunyan, Kong, Ying, Jiang, Guancheng, Yang, Jinrong, Pu, Chunsheng, Zhang, Yuzhong
• Format: Article
• Language: English
• Subjects: Acrylates; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Contact angle; Copolymers; Cross-disciplinary physics: materials science; rheology; Emulsions; Exact sciences and technology; Fluorine-containing acrylate copolymer; Gas reservoirs rock; Gas-wetting; Liquid-wetting; Natural gas; Nuclear magnetic resonance; Physics; Rock; Wettability
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2012.03.180

► The fluorinated copolymer emulsion was successfully fabricated by emulsion polymerization. ► The fluorine side chains of the fluorinated copolymer predominantly moved to the air-polymer interface. ► The prepared copolymer emulsion could alter the wettability of reservoirs rock from strong liquid-wetting to gas-wetting. The fluorine-containing acrylate copolymer emulsion was prepared with butyl acrylate, methacrylic acid and 1H, 1H, 2H, 2H-perfluorooctyl acrylate as monomers. Moreover, the structure of the copolymer was verified by Fourier transform infrared (FTIR), nuclear magnetic resonance (1H NMR and 19F NMR) and X-ray photoelectron spectroscopy (XPS) analyses. The results showed that all the monomers had been copolymerized and the presence of fluorine moieties. The contact angle (CA) analyses, capillary rise and imbibition spontaneous tests were used to estimate the influence of the copolymer emulsion on the wettability of gas reservoirs. It was observed that the rock surface was of large contact angles of water, oilfield sewage, hexadecane and crude oil after treatment with the emulsion. The capillary rise results indicated that the contact angles of water/air and oil/air systems increased from 60° and 32° to 121° and 80°, respectively, due to the emulsion treatment. Similarly, because of wettability alteration by the fluoropolymer, the imbibition of water and oil in rock core decreased significantly. Experimental results demonstrated that the copolymer emulsion can alter the wettability of porous media from strong liquid-wetting to gas-wetting. This work provides a cost-effective method to prepare the fluoropolymer which can increase gas deliverability by altering the wettability of gas-condensate reservoirs and mitigating the water block effect.