Effective Foaming Agents to Rejuvenate Gas Wells with Downhole Liquid Buildup Issues in High Temperature and Salinity Reservoirs

Abstract This study aims to develop effective foaming agents that can be applied for liquid unloading of gas wells under high temperature and high salinity (HTHS) conditions. Up to nine commercial products from the local market in China were evaluated. Among them, the formulated foaming agent AFA-F was selected due to its good compatibility with HTHS condition (up to 150°C and salinity of 15,6000 ppm), along with strong foaming ability and great stability even after incubation at 150°C for up to 16 hours. The chemical stability was confirmed through TGA with no degradation below 220°C. Moreover, the liquid carrying capacity was more than 90% using the selected foaming agent AFA-F at a relatively low concentration. Even in the presence of condensate oil up to 80%, the liquid carrying capacity could still be maintained up to 75%. The high performance of this foaming agent indicated great potential for liquid unloading applications for gas wells with HTHS conditions.