To address the challenge of reusing foaming agents in foam drainage gas production processes, we developed a redox-responsive surfactant with a straightforward preparation method based on molecular electrostatic interaction assembly. The redox response mechanism of the surfactant was investigated through surface tension, absorbance, particle size, and Zeta potential analyses. Results indicate that the minimum surface tension in the oxidized state can reach 26.4 mN∙m^-1, and even after 6 repetitions, it remains at 28 mN∙m^-1. In the oxidized state, the surfactant’s particle size can reach 310 nm, effectively stabilizing foam by reducing the liquid discharge rate of the liquid film through large micelles. Moreover, oxidized surfactants exhibit excellent dispersion and stability properties, with a Zeta potential of 28.7 mV. Even after 6 repetitions, the Zeta potential remains above 27.1 mV. Foaming performance tests demonstrate that the oxidation-reduction surfactant exhibits favorable foaming, stabilizing, and reusing effects. At 90 ℃, the initial and 5-minute foaming heights reached 131 mm and 94 mm, respectively. After 6 repetitions, these heights were 124 mm and 85 mm, respectively. The successful development of this treatment agent can effectively address on-site foam drainage needs and reduce the operational costs associated with foam drainage.

A Gemini cationic surfactant was synthesized through an aldehyde-amine condensation reaction to address challenges related to bacterial corrosion and foaming during shale gas extraction. This treatment agent exhibits sterilization, corrosion mitigation, and foaming properties. The mechanism of action was characterized through tests measuring surface tension, particle size, sterilization efficacy, corrosion mitigation efficiency, and foaming behavior. Results from the surface tension test indicate that at 60 °C, surfactants with a low carbon chain structure achieve the lowest surface tension of 32.61 mN/m at the critical micelle concentration. Particle size distribution (PSD) tests reveal that within the 1–10 critical micelle concentration range, three types of surfactants can form aggregates through self-assembly, with a PSD range of 100–400 nm. Antibacterial performance tests demonstrate that a concentration of 0.12 mmol/L at 20–60 °C achieves a bactericidal rate exceeding 99%, maintained even after 24 h of contact. The bactericidal effect is enhanced under acidic and alkaline conditions. Corrosion mitigation tests show that at 50 °C, the corrosion mitigation rate reaches an optimal value of over 70%. Bubble performance evaluation results suggest that the optimal surfactant concentration is 1 mmol/L at 60 °C, exhibiting resistance to mineralization up to 200 g/L. The development of this surfactant establishes a foundation for effectively addressing issues related to bacterial corrosion and wellbore fluid encountered in shale gas wells.

Due to the low success rate in high-temperature gas well drilling or workover operations, a new type of biobased temporary sealing material was synthesized using vanillin, succinic anhydride (SA), cellulose, and acetylacetone zinc hydrate (AZH) as catalysts. Infrared analysis proved the synthesis of vanillin-derived epoxy and the formation of a vitrimer with hydroxyl ester. The results of thermodynamic properties tests show that it has excellent thermal stability with a high glass transition temperature (T_g). The dynamic mechanical test results show that the characteristic relaxation time of the material at 120 °C is 3500 s and the self-healing rate can reach 61% within 20 min. The test results of mechanical properties show that under 10 MPa pressure, it has good elastic deformation performance, the rebound rate is more than 36%, and the crushing rate is less than 17%. The degradation performance results show that the decomposition increases to 80% under 120 °C and 1.2% NaOH. The comprehensive performance evaluation results show that the new temporary plugging material has good compatibility, and its plugging performance is better than those of a gel, composite material, and shape memory polymer. The maximum fracture plugging capacity is 5 × 4 mm, with a pressure up to 10 MPa.