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Foams are widely used to remove liquid loading at the bottom of gas wells to improve natural gas production. However, it becomes ineffective when a gas well contains a large amount of hydrocarbon condensate because oil will rupture the foams. In this work, condensate oil-tolerant foams were developed and stabilized by a mixture of cocamidopropyl hydroxyl sulfobetaine (CHSB) and sodium dodecyl sulfate (SDS). The foam properties are examined at different temperatures under atmospheric conditions and high pressures with various contents of condensate oil. It is found that the foam stability is improved when the oil content is increased; in addition, high temperature, high salinity, and high pressure are beneficial for foam stabilizing. To reveal the mechanism of stable foam in the presence of high content of oil, a confocal microscope was employed to visualize oil–foam interactions. It was observed that the high stability of the SDS–CHSB foams is ascribed to the formation of stable pseudoemulsion between oil droplets and the gas–liquid interface. Such condensate oil-tolerant foams show promising potential to be used in the foam-assisted lift process during natural gas production.

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Deliquification with chemical foamers has proved a successful and economic technique to unload the liquids from mature natural gas wells; however, no gases are available to create foams in the low-productivity gas wells. In this work, in situ generated foams (ISGF) were developed with the gas and heat produced by the reaction of ammonium chloride and sodium nitrite in the presence of acetic acid as a catalyst, with the mixture of sodium dodecyl sulfate and cocamidopropyl hydroxyl sulfobetaine as the foamer. The molar ratio of reactants to catalyst, and the specifies of ammonium salt were optimized based on the foamability and stability of the foams. The volume of gas and the amount of heat were measured from the optimized gas-and heat-generated system. The morphology of the ISGF foams was found to be more uniform than their conventional counterpart, and these foams exhibited superior foaming at high temperature and high salinity. The optimized formulation was scaled up and applied in two typical lowproductivity gas wells, and significant increment in gas production and decline in water production were found. The ISGF foams not only offer a choice to unload liquids from mature gas wells by providing gas to create foams and to offer heat to dissolve organic pollutants but also provide candidature techniques for unconventional gas wells to prolong life spans.

Multi-pulse soliton molecules are observed in passively mode-locked fiber lasers by using 2D layered metal dichalcogenides (LMDs) as a saturable absorber. LMD has attracted significant attention in photonics and optoelectronics in which tin disulfides (SnS 2 ) are implemented for energy storage, photo-catalysts, and transistor. However, the applications of SnS 2 in optoelectronics fields are quite rare. Soliton supramolecules are the self-assembly of optical solitons into highly-ordered supramolecular structures which have not been experimentally observed due to the absence of techniques for controlling the inter-soliton forces. In this article, SnS 2 LMDs are successfully applied in a passively mode-locked fiber laser. It is confirmed that the proposed fiber laser has a center wavelength of 1561.5 nm, a 3-dB spectral width of 2.45 nm, signal-to-noise ratio of 63 dB, and a radiofrequency of 7.2 MHz. The different interiors of the second-order, third-order, and ninth-order bound state of solitons in the cavity are investigated. Furthermore, it is found that numbers of optical solitons self-assembled into highly ordered supramolecular structures in a passively mode-locked fiber laser for the first time. The bound state between the six supramolecular soliton units is obtained experimentally and theoretically which have potential applications in ultrafast laser-field manipulation and optical information storage because of special interactions between pulses.