Dual-functional surfactant system for enhanced foam drainage and anti-aggregation in gas wells

In gas well operations, efficient foam drainage and prevention of hydrate aggregation are crucial for maintaining production efficiency and preventing blockages. This study presents a novel dual-functional surfactant system (TPS) composed of cetyltrimethylammonium chloride (CTAC), alkylphenol ethoxylate (OP-10), and sodium dodecyl sulfate (SDS), designed to enhance both foam drainage and hydrate anti-aggregation. The optimized TPS formulation (0.05 % CTAC + 0.5 % OP-10 + 0.02 % SDS) demonstrated exceptional foaming ability with an initial foam volume of 540 ml and a half-life of 7.5 min at 50 °C. The system maintained high liquid-carrying capacity (72.5 %) even at elevated temperatures (65 °C) and in the presence of methanol, which is commonly used as a hydrate inhibitor. Differential scanning calorimetry (DSC) and microscopic observations revealed that TPS significantly reduced the phase transition temperature of tetrahydrofuran (THF) hydrates, thereby suppressing hydrate formation and aggregation. The compatibility of TPS with polyvinylpyrrolidone (PVP), a common kinetic hydrate inhibitor and foam stabilizer, enhanced foam stability. This dual-functional system offers a robust solution for improving gas well productivity and mitigating hydrate-related risks, with potential applications in complex oil and gas field environments.