Synthesis and Characterization of a Novel Foaming Agent for Water-Bearing Gas Reservoirs with Combined Resistance to High-Temperature, High-Salinity, and Condensate

Foam-assisted deliquification is one of the key and widely adopted techniques for enhancing natural gas recovery from low-pressure, low-productivity, and water-bearing gas reservoirs. However, conventional foaming agents often exhibit poor adaptability and limited drainage efficiency under harsh conditions such as elevated temperature, high salinity, and significant condensate content. To address this challenge, a novel foaming agent, dodecylsulfonamidopropylcarboxybetaine (DSB), was synthesized in this study via a two-step procedure involving amidation and quaternization, using dodecylsulfonyl chloride, N,N-dimethyl-1,3-propanediamine, and sodium chloroacetate as starting materials. The molecular structure of DSB, particularly the introduction of S = O bonds, was confirmed by Fourier-transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H-NMR). Comparative performance evaluations between DSB and a commercial cocamidopropyl betaine (CAB) demonstrated that DSB possesses superior properties in terms of surface activity, thermal stability, salt tolerance, and resistance to condensate interference. The successful development of DSB offers a promising strategy for designing high-performance foaming agents capable of functioning in demanding reservoir environments.