Foam Lift for Gas Well Deliquification: A Literature Review of Technology Development, Operational Performance, and Future Research Directions

Abstract Foam lift is one of the most widely applied low cost techniques for mitigating liquid loading in gas wells, a phenomenon that arises as declining reservoir pressure reduces gas velocity below the threshold required to lift co produced liquids to surface. This report presents a literature review examining the technology development, operational challenges, and future research directions associated with foam lift. Drawing on peer reviewed journal articles and conference papers spanning more than five decades, the review traces the technique's theoretical foundations in critical velocity modeling, its evolution from early field applications to contemporary surfactant formulation engineering, and its comparative position relative to alternative deliquification methods such as plunger lift, velocity strings, and gas lift. The review finds that while foam lift is mechanistically well supported and has demonstrated field effectiveness since the early 1980s, its sustained long term performance is more variable than is often assumed, with recent longitudinal field evidence showing substantial multi year performance decline attributable to reservoir salinity evolution and inadequate well selection practices. The review further identifies a persisting inconsistency between foam lift design methodologies, which continue to rely on classical droplet based critical velocity criteria, and more recent research indicating that liquid loading is more accurately characterized by film flow reversal. Key research gaps are identified, including the scarcity of longitudinal field studies across diverse reservoir conditions, the limited investigation of combined rather than isolated formulation stressors, and the absence of a standardized framework for selecting foam lift over competing deliquification techniques. The review concludes that realizing foam lift's full technical and economic potential depends on active formulation management and more rigorous, quantitatively grounded well selection practices, and proposes specific directions for future research to address the identified gaps. Keywords Foam lift; gas well de liquification; liquid loading; surfactant injection; critical gas velocity; artificial lift; foam assisted lift