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Natural resins extracted from crude oil in the South China Sea have a significant inhibition effect on hydrate nucleation and growth due to the polar functional group of resins. [Display omitted] • Resins were extracted from the crude oil from the SCS. • The resins contained many polar heteroatomic functional groups. • Hydrate grew along gas flow in the microfluidic channels. • The resins could retard the hydrate formation kinetics. • The more polar resins showed a stronger inhibitory effect. Hydrate plugging in oil and gas transport pipelines is a crucial challenge to the safety of flow and maintenance of pipelines. Specifically, the resins, the strongest polar component in crude oil would significantly affect hydrate kinetics but the mechanism of the interaction remains unclear. Here, a microfluidic chip was used to monitor the hydrate formation under gas flow in-situ , with and without resins extracted from the crude oil. FTIR–ATR and NMR results indicate the presence of a large number of polar components in the resins. High-resolution mass spectrometry showed that two resins contain a variety of heteroatom compounds and sulfur-containing heteroatom. The results indicated that these resins played a surprisingly inhibitory role in the hydrate formation kinetics; this was ascribed to the presence of the polar functional groups. The results also showed that the hydrate grew along the direction of gas flow. Notably, the presence of resins could prolong the induction time and lower the growth rate; this effect could be enhanced with the addition of resins containing more heteroatoms. This study filled the gap in the effect of natural resins on the hydrate formation kinetics and provided guidance on preventing hydrate plugging in oil and gas transport pipelines. [ABSTRACT FROM AUTHOR]

Several trial productions have been conducted on marine natural gas hydrate reservoirs, demonstrating its enormous potential as an alternative energy source. Nonetheless, sustained and efficient production still remains challenging, with crucial issues on low gas production efficiency and blockages. The large amount of hydrate decomposition and resulting heat absorption can lead to prolonged subzero conditions close to the well; this can readily induce ice formation and blockage. This study aims to investigate the issue of ice blockages caused by insufficient energy supply during the recovery process. A systematic analysis of the energy consumption and ice blockage quantification at each stage of the traditional multi-stage direct depressurization and constant speed depressurization methods is conducted. A hybrid optimized scheme is proposed, which enhances energy utilization efficiency by appropriately utilizing reservoir sensible heat during the initial stage of production. Additionally, a multi-stage constant speed depressurization method is introduced in the later stages to mitigate production fluctuations and reduce blockage duration. Results showed a 69.5 % increase in energy efficiency and an average 67.1 % decline in gas blockage duration with comparable gas productivity. The proposed method could be a viable solution to mitigate challenges of icing blockages and fluctuating production during trial tests of marine hydrate reservoirs, achieving improved energy efficiency and sustainable production. • Ice blockage in hydrate reservoirs reduced production efficiency during direct and constant-speed depressurization methods. • Proposed a hybrid method to address gas production fluctuations caused by ice blockage through energy consumption analysis. • Multi-stage analysis revealed 70% energy efficiency improvement and 67% reduced ice blockage duration with the hybrid method. [ABSTRACT FROM AUTHOR]

The utilization and transportation of clean energy require efficient energy storage solutions. Gas hydrate represents a promising way for high-density storage under mild conditions. In particular, hydrate induced by confined space has the advantage of being environmentally friendly with rapid nucleation and high mass transfer efficiency. However, the cost of artificial pore-construction methods has hindered its widespread application. In this study, we report a novel approach of hydrate storage in the -SO 3 − modified flexible balsa wood as a naturally porous material. The surface sulfonate groups were successfully grafted by coupling agents which was verified by various techniques. The material's natural porous hierarchical structure allows for efficient fluid flow in porous media, enabling a reduction in induction time by ∼88% and a storage capacity of up to 150.6 v/v by adjusting the load water amount. The 100 wt% water-loaded wood materials exhibited the highest water conversion efficiency. Moreover, the recoverable mechanical properties make it reusable without performance degradation. The inner pore structure and hydrate morphologies were further investigated by X-ray microscopy to clarify the hydrate growth mechanism. The interconnected pores and channels make the hydrate grow in layers inside. In addition, the performance could be adjusted by simply changing the hydrophobicity to regulate the gas flow which may contribute to the large storage systems. The use of natural biomass porous materials provides an environmentally friendly and economically feasible strategy for gas storage. [Display omitted] • The modified flexible balsa wood was synthesized and applied in energy storage. • Methane hydrate induction time was reduced by ∼88% and the storage capacity was enhanced to 150.6 v /v. • The 400 wt% water loaded case exhibited the best storage performance. • The hydrate started to form in axial parenchyma structures verified by X-ray microscopy. • Tunable storage performance based on hydrophobic and hydrophilic modification. [ABSTRACT FROM AUTHOR]