佳文速递2025年第1期

Innovative role of Benzalkonium chloride as a quaternary ammonium salt for natural gas hydrate formation and storage

苯扎氯铵作为季铵盐在天然气水合物形成和储存中的创新作用

发表时间：2025年5月9日

发表期刊：《Scientific Reports》

Mohamed S.Gad1*, Abeer M. Shoaib3, MustafaAwad3, Hussien A. Elmawgoud1, S. A. Khalil1 & A. M.Alsabagh2

Abstract: This study assessed the kinetics of natural gas hydrate (NGH) formation using N-benzyl-N, N-dimethyldodecan-1-aminium chloride (Benzalkonium chloride, Bzc) at concentrations ranging from 500 to 3000 ppm. It investigated its effects on the hydrate formation. These experiments were compared with pure water and sodium dodecyl sulfate (SDS) solutions at 298.15 K and 6.5 MPa. The findings indicate that the Bzc significantly enhances the formation kinetics and gas consumption of NGH. The 2500 ppm of Bzc notably reduced the induction time for hydrate nucleation up to 9.9 min. In contrast, it was 41.3 min with the SDS. The hydrate formation began at the gas/liquid interface and spread upward into the gas phase and downward into the liquid phase. The NGH dissociation and recovery were slower by the SDS among the Bzc solutions (smooth and fast). This observation indicates that the Bzc improves the formation and dissociation kinetics, making it a promising NGH formation and storage reagent. The results show that the Bzc significantly boosts the kinetics of NGH formation and dissociation at a small time and pressure. Providing valuable insights for optimizing hydrate technology.

Keywords: Natural gas hydrate, Benzalkonium chloride (Bzc), Phase equilibrium, Induction time, Rate of hydrate formation, NG storage

Fig.5 Phase equilibrium of natural gas hydrates in the presence of a Pure Water—SDS Concentration 600 ppm b Different Bzc concentrations.

阅读原文：https://doi.org/10.1038/s41598-025-97520-3

Methane hydrate formation kinetics in bottom seawater and cold-seep fluids

海底海水和冷渗流体中的甲烷水合物形成动力学

发表时间：2025年5月8日

发表期刊：《Chemical Engineering Journal》

Yitong Zhang, Kuan Zhao, Liang Ma, Wanying He, Shichuan Xi, Zhendong Luan, Xin Zhang, Zengfeng Du

Abstract: Methane hydrate is a widely distributed energy resource in nature, mostly in marine continental margins. Understanding methane hydrate formation kinetics in natural fluids is essential for practical applications of hydrates, such as fluid selection for gas storage and separation. The effect of fluid environment on hydrate formation has been identified. However, laboratory experiments typically employ pure water and artificial seawater, leading to unclear hydrate formation kinetics in natural fluids. Therefore, further exploration of methane hydrate formation kinetics in complex environments is required for hydrate utilization and development. This study explored the microscopic methane hydrate formation process in pure water, bottom seawater, and cold-seep fluids from both temporal and spatial morphology perspectives using Raman spectroscopy. Detailed variations in methane hydrate nucleation kinetics were observed at ten-second intervals, and the evolution of dissolved and hydrated methane was analyzed for various fluids. Results showed that high salinity bottom seawater (salt ion concentrations 1.5 times that of cold-seep fluids) significantly decreased dissolved methane solubility (30%), prolonged induction time (24%), reduced the overall conversion ratio (5%) and rate of hydrated methane (20%), and inhibited the relative occupancy rate of small cages (25%). Although low salinity cold-seep fluids with tiny particles slightly decreased dissolved methane solubility and prolonged induction time, it promoted stable sI hydrate formation. Spatial morphology observations indicated that fluids affected hydrate formation morphology without significantly affecting spatial distribution characteristics. This work provides fundamental kinetic characteristics of methane hydrate formation in natural environments and sheds light on fluid selection for gas storage and separation.

Keywords: Hydrate formation kinetics, Methane hydrate, Time-series Raman spectroscopy, Bottom seawater, Cold-seep fluids

Fig. 7. Dissolved methane concentration as a function of subcooling for three different fluids before hydrate nucleation.

Fig. 8. Methane consumption with time for three fluids after the nucleation point. tnuc is the time elapsed from the nucleation point

阅读原文：https://doi.org/10.1016/j.cej.2025.163547.

Can gas hydrates be transported at atmospheric pressure? A review of the 

self-preservation phenomenon in gas hydrates

气体水合物能否在常压下运输？气体水合物自保现象的综述

发表时间：2025年5月8日

发表期刊：《Applied Energy》

Xuezhi Zhu, Wenxu Zhang, Yong Tang, Yu Zhang, Zhongbin Zhang, Xiaolin Wang

Abstract: Gas hydrates are a promising medium for natural gas storage and transportation due to their safety, high storage density, and cost-effectiveness. Traditional gas transportation often faces challenges such as leakage, leading to fugitive emissions. Gas hydrates can mitigate these issues by securely trapping gas molecules under phase equilibrium conditions. However, they release gas immediately when pressure or temperature deviates from the equilibrium zone, necessitating continuous, energy-intensive pressurization throughout the transportation pro cess. The self-preservation phenomenon reduces the pressure requirements for gas hydrate operations, allowing gas to be stored and transported at reduced or even atmospheric pressure. Despite the large number of studies on the self-preservation effect in gas hydrates, there has been no comprehensive review of its research status. This paper presents the first comprehensive review of the research progress on the self-preservation phenomenon in gas hydrates. It provides an in-depth discussion of the fundamental characteristics of this effect, a thorough analysis of methods used to enhance it, and the mechanisms that lead to its absence. Additionally, the review summarizes current understanding of the microscopic mechanisms underlying the self-preservation phenomenon and explores the different dissociation models of hydrates in this state. By systematically reviewing related studies, this paper offers theoretical support for a deeper understanding and practical utilization of the self- preservation effect in gas hydrates, while providing valuable insights into future research directions and tech nological applications.

Keywords: Gas hydrates, Natural gas, Self-preservation effect, Gas storage and transport, Hydrate dissociation

Fig. 11. Structural factors of the self-preservation effect

阅读原文：https://doi.org/10.1016/j.apenergy.2025.126034

Numerical Simulations of strata subsidence induced by marine hydrates exploitation via depressurization

通过减压开采海洋水合物诱发地层下陷的数值模拟

发表时间：2025年5月15日

发表期刊：《Energy》

Zhicong Shen, Dong Wang, Dengfeng Fu, Tianyuan Zheng

Abstract: Large-scale exploitation of methane hydrates in deep waters may result in severe strata subsidence, jeopardizing operations of foundations or pipelines laid on the seabed. The exploration of hydrate is essentially a process with coupled thermal-hydrodynamic-chemical-mechanical fields. A new scheme is developed, with the former three fields reproduced using the finite difference approach and the force balances solved using the finite element approach. Data are mapped between the two approaches at each time step, and mapping accuracy is verified by comparisons with the previous numerical results. Based on geological data from the Shenhu area in the South China Sea, exploitations of a multilayer hydrate reservoir are simulated to elucidate the triggering mechanisms of subsidence and its effects on the gas productivity. Compared to the depressurization through the single well, greater strata subsidence is caused given that a dual-horizontal well system is employed, although the secondary hydrate is prevented. After three-year depressurization, the strata subsidence occurs predominantly in the clayey soils overlying the hydrate layer, which is contributed to soil consolidation. The vertical displacements are minimal in the hydrate-bearing layers due to the existence of residual hydrates. The strata subsidence within the first year takes over half of the total value over three years. Subsidence around the wellbore resulted in compression of pore volumes, causing more reduction on gas productivity in the upper wellbore.

Keywords: Numerical simulation, Multiphysics coupling, Strata subsidence, Dual horizontal well, Depressurization

Fig. 10. Subsidence under various production pressures after 3-year production of NGH

阅读原文：https://doi.org/10.1016/j.energy.2025.136569

Rheological and dissociation characteristics of cyclopentane hydrate in the presence of amide-based surfactants and Span 80: From slurry to particle

环戊烷水合物在酰胺基表面活性剂和司盘80存在下的流变和解离特性：从浆液到颗粒

发表时间：2025年5月15日

发表期刊：《Energy》

Yang Liu, Yan Zhang, Yi Zhang, Peilong Li, Xiaofang Lv, Yisong Yu, Weichao Yu, Qianli Ma, Chuanshuo Wang, Shidong Zhou, Xiaoxuan Xu

Abstract: This study first investigates the flow modification effects of a mixture of Span 80 and amide-based surfactants (DPLA and DPCA) on hydrate slurries using a rheometer. The results show that, although the mixed system shortens the critical time for hydrate formation compared to the pure Span 80 system, the peak and stable viscosities of the hydrate slurry decrease significantly when the concentrations of DPLA or DPCA reach medium to high levels (with reductions of 68.8%-78.6% for peak viscosity and 87.4%-91.7% for stable viscosity). The combination of 0.6 wt% Span 80 with DPLA and 0.8 wt% Span 80 with DPCA demonstrated the best hydrate inhibition performance. Subsequently, hydrate decomposition experiments were conducted on three systems containing Span 80, Span 80+DPCA, and Span 80+DPLA. The viscosity variations during the hydrate slurry decomposition process and the hydrate particle decomposition time were obtained. The results indicate that the viscosity of the slurry decreases almost linearly with temperature rise before decomposition. The addition of DPCA and DPLA reduced the decomposition temperature of cyclopentane hydrate in water-in-oil systems to approximately 0 °C. Additionally, for the first time, this study employed a micromechanical force measurement device combined with a micro-infrared thermography camera to capture morphological and thermal imaging features during the decomposition of hydrate particles. This research not only offers new perspectives for understanding the thermal stability of hydrates and the decomposition mechanism of hydrate plugs, but also provides potential control strategies for field applications in managing hydrate blockages.

Keywords: Flow Assurance, Hydrates, Rheology, Hydrate decomposition

Fig.11. Three-dimensional temperature distribution and temperature histogram of hydrate particles during hydrate dissociation (Span 80)

阅读原文：https://doi.org/10.1016/j.energy.2025.136601

Kinetic study of CO2 storage via hydrate method in non-permafrost sites with various depths and water contents

通过水合物法在不同深度和含水量的非永久冻土区封存二氧化碳的动力学研究

发表时间：2025年5月13日

发表期刊：《Fuel》

Yaqin Tian, Qiang Gao, ,Chi Zhang, Bin Hou, Jianzhong Zhao

Abstract:CO2 is injected into non-permafrost sites to synthesize CO2 hydrate under certain temperature and pressure conditions to achieve long-term stable storage. The thermodynamic characterization and kinetics of CO2 storage using the hydrate method in the non-permafrost region have attracted widespread attention in the scientific fields. CO2 storage in non-permafrost sites can be an effective solution but is less understood systemically. We designed a series of CO2 storage experiments by employing on-site geological exploration data, including reservoir temperatures (0.0 ~ 8.7℃) corresponding to different non-permafrost depths (110 ~ 350 m) and initial effective water contents (30 %~50 %). We examined the evolution of the pressure and temperature, fluid storage behavior, and heat transfer and evaluated the storage efficiency. A higher storage temperature led to a decrease in CO2 storage ratio, and the final CO2 storage ratio decreased rapidly when the storage temperature was above 

2.72℃, with a reduction magnitude reaching 12.88 %~73.63 %. CO2 was almost not stored in the non- permafrost sites when the storage temperature was 8.70℃. Furthermore, shallow non-permafrost sites (e.g., 110–200 m) demonstrate superior CO2 hydrate storage potential in non-permafrost sites. A higher initial effective water content was not conducive to CO2 storage based on the analysis of the rapid growth of CO2 hydrates, CO2 gas consumption, duration of CO2storage, and final water conversion ratio. The CO2 storage efficiency hardly increases with the increase of initial effective water content in Caseφe =40 % and 50 %, but it is the lowest in Case φe =30 %. Our findings could facilitate choosing the storage depth and water content and designing optimal storage strategies for future field production tests.

Keywords:CO2 storage, Hydrates, Non-permafrost, Kinetics, Reservoir characterization

Fig. 6. Measured Pout-Tavg trajectory with relationship to the CO2 + H2O phase equilibrium curve during CO2 storage process in all Cases.

阅读原文：https://doi.org/10.1016/j.fuel.2025.135642

The layout optimization of the dual-horizontal depressurization wells for gas hydrate exploitation considering the interwell interferences

考虑井间干扰的天然气水合物开采双水平减压井布局优化

发表时间：2025年5月13日

发表期刊：《Energy Fuels》

Xiao YanLi, Huan WeiWei, YiWang, Xiao SenLi, Shi DongZhou, Xiao FangLv, YangLiu, Yong ChaoRao

ABSTRACT：Gas hydrate is viewed as a potential energy, and the multihorizontal depressurization wells are expected to achieve its commercial production. However, how to optimize the multi-horizontal wells layout in hydrate reservoirs is controversial. In this research, the numerical study on the hydrate exploitation from the Shenhu Area of the South China Sea by the dual-horizontal depressurization wells (DHDW)was conducted, and the optimal spatial position of DHDW was first studied. It is realized that the optimal spatial position of DHDW for gas hydrate production should be in the center of the hydrate layer. Based on this conclusion, the influences of the well spacing between DHDW (ranging from 22 to 582m)on hydrate exploitation were then investigated. It is found that there was a strong interference between DHDW when the well spacing was smaller, leading to the lower total produced gas volume. When the well spacing increased to a certain value, the interference disappeared, and the total produced gas volume reached the maximum. On this basis, a new method to calculate the optimal well spacing (do) between DHDW was proposed. According to the calculation, when the exploitation period was 10 years, the do between the DHDW values was 73.06m. Finally, the influences of the permeability (k) in the hydrate layer (2.9−145mD) and the exploitation period (t) of gas hydrate (5− 30years) on the do were further studied. The function relations of do and k, and do and t were obtained, respectively.Furthermore, the implications for the optimal layout of multihorizontal depressurization wells in hydrate reservoirs were discussed.This study could provide guidance for the exploitation of gas hydrate.

Figure 6. (a) Time dependences of the hydrate dissociation volume (Vh) for Cases 1−5; (b) the hydrate saturation contour for Cases 1−5 at the 3650th day of hydrate exploitation.

阅读原文：https://doi.org/10.1021/acs.energyfuels.5c01128