Hydrate Formation Research Articles

Behaviors of hydrate cap formation via CO2-H2O collaborative injection:Applying to secure marine carbon storage

Leakage prevention of carbon dioxide (CO2) determines the safety of carbon marine geological storage. Hydrate caps have been proven to be one of the most effective structures for preventing CO2 leakage, which has attracted worldwide attention. However, the structure and formation behavior of hydrate caps during CO2 storage process are still unclear. In this study, a strategy of CO2-H2O co-injection was proposed to simulate the actual flow process and accelerate the hydrate cap formation rate. A series of CO2-H2O flow rates (0.25–10 mL/min) were employed. The results show that there will be four stages for the dynamic formation process of hydrate cap: fluid migration and diffusion, local hydrate formation, local area plugging, and hydrate cap formation. What's more, the water-gas flow ratio is inversely proportional to hydrate cap formation rate and positively proportional to the carbon storage efficiency. Meanwhile, the huge sealed capacity of hydrate cap was also proved in this work. The sequestration pressure of CO2 under hydrate cap exceeds 12 MPa, and the maximum carbon storage efficiency increases from 53.12% to 93.30%. Moreover, the macrostructure of hydrate cap consists of two layers with a certain hydrate saturation: the zero-permeability layer and the low-permeability layer. The zero-permeability layer determined the sealed capacity of hydrate cap. These findings may provide a theoretical foundation for the prevention of CO2 leakage in actual project of carbon marine geological storage.

Based on PVM image gray level data to analysis the effect of N-vinyl caprolactam on hydrate growth

The usage of hydrate inhibitors is an effective method to solve the problem of flow assurance in deep-water pipelines. However, the mechanism of hydrate formation and transformation in inhibitor-containing systems is not well understood, and the research methodology needs to be innovated. In this study, a possible mechanism of wearing away during hydrate particle transformation was proposed for the first time, based on the hydrate growth process in the system containing the kinetic inhibitor N-vinyl caprolactam monomer. A method to analysed the hydrate growth and transformation dynamics through the change of gray level in the image was proposed. And the hydrate growth process was divided into three different stages based on the trend analysis of the gray level data of the images,trends in the dynamics of hydrate particle growth within the bulk phase corresponding to changes in gray level were verified. On this basis, the effects of stirring rate, subcooling and the monomer concentration of the NVCap on the growth of hydrates were discussed, and it was suggested that there might be differences in the mechanisms exhibited by the inhibitor at different growth stages of hydrates. In this study, the process of analysing the internal growth dynamics of hydrate systems through image gray levels was reported for the first time, and its trend changes corresponding to hydrate growth dynamics were verified, which proved the feasibility of this method, and this study provides an innovative research methodology and idea for the study of the dynamics of hydrate generation and transformation.

Liquid-liquid equilibrium of binary ethanol–polyisobutene and ternary ethanol–water–polyisobutene systems under low- and high-pressure conditions: An assessment using the PC-SAFT equation of state

Sugarcane bioethanol in either anhydrous or hydrous forms stands out as an economically viable bioproduct that can be used as a fuel or feedstock in various innovative applications, reducing human-generated greenhouse gas emissions. Low-molar-mass polyisobutene (PiB) is used as a lubricant in sugarcane-processing plants and is a possible contaminant of sugarcane bioethanol. Understanding the liquid–liquid equilibrium (LLE) of ethanol–PiB binary systems and ethanol–water–PiB ternary systems is essential to avoid undesired phase separation at high-pressure engine conditions and other potential innovative applications. However, the experimental investigation of these systems is significantly hampered by very low polymer solubilities in aqueous ethanol. The LLE of ethanol-PiB and ethanol–water–PiB mixtures was qualitatively investigated using the PC-SAFT equation of state through the development and implementation of extrapolation strategies allowing to estimate ethanol–PiB and water–PiB binary parameters using experimental data obtained for other systems containing lighter alkanes. Phase diagrams were calculated considering temperatures ranging from 298.15 K to 350 K and pressures ranging from 1 bar to 200 bar. It was shown that lower pressures, higher temperatures, lower PiB molar masses, and lower water contents increase the polymer solubility in the solvents. Thus, the risk of liquid–liquid separation can be mitigated by correctly managing such operational parameters. The obtained phase diagrams may present significant quantitative deviations from reality because of the model’s sensitivity to the estimated binary parameters. Thus, they should be interpreted as general qualitative guidelines to avoid and manage undesired phase separation in industrial processes and engines rather than phase equilibrium predictions.

A Molecular Dynamics Study of the Influence of Low-Dosage Methanol on Hydrate Formation in Seawater and Pure Water Metastable Solutions of Methane

The behavior of low concentrations of methanol (0.5 and 1.0 wt% of water) as a promoter for hydrate formation in seawater or pure water metastable solutions of methane was investigated using the classical molecular dynamics method at moderate temperature and pressure. The influence of methanol on the dynamics of the re-arrangement of the hydrogen bond network in seawater and pure water solutions of methane was studied by calculating order parameters of the tetrahedral environment and intermolecular torsion angles for water molecules, as well as by calculating the number of hydrogen bonds, hydrate, and hydrate-like cavities. It was found that hydrate nucleation can be considered a collective process in which the rate of hydrate growth is faster in systems with low concentrations of methanol, and confident hydrate growth begins earlier in a metastable solution without sea salt with a small amount of methanol than in systems without methanol.

Insights into the dual effect of an amphiphilic additive on hydrate formation from a water structure perspective

Chemical additives play an important role in gas hydrate formation, which involves the transformation of water structure. However, the relationship between the effects of additives on water structure and hydrate formation is inconclusive, especially for amphiphilic molecules. Here, we investigate the changes in water structure caused by rhamnolipid (Rha) biosurfactants and the resulting effect on methane hydrate formation through kinetic experiments, morphological observation, and in situ Raman spectroscopy. The Gaussian peaks of strongly hydrogen-bonded and weakly hydrogen-bonded water are identified, of which the integrated intensity and position are compared. It is found that the dual effect of Rha on hydrate formation kinetics, namely nucleation inhibition and growth promotion, is attributed to the ordered arrangement of water molecules with stronger hydrogen bonding interactions induced by the charged head groups. The strongly hydrogen-bonded water inhibits nucleation but promotes growth. In addition, the adsorption of Rha on montmorillonite (MMT) eliminates the changes in water structure and the dual effect of hydrate formation kinetics, providing further evidence for the above conclusion. These insights pave the way for a deeper understanding of hydrate formation kinetics from a water structure perspective, as well as providing a scientific basis for the commercial application of surfactants.

The effect of subcooling on hydrate generation and solid deposition with two-phase flow of pure water and natural gases

Deepwater oil and gas transportation systems play a crucial role in energy supply, but also face the challenges of hydrate generation and blockage. The study observed hydrate generation and deposition at different subcooling degrees and flow rates by using a high-pressure fully visualized recirculation pipeline. It was found that the subcooling degree has a nonlinear positive correlation with the total amount of hydrate generated. The hydrate formation at 11.7 °C subcooling was 4.5 times higher than that at 9 °C subcooling. According to the hydrate conversion rate analysis, the hydrate growth process under low subcooling conditions directly transitions from the bubble-promoting zone to the termination point of hydrate generation. Combined with the deposition state of the pipe wall and the differential pressure change curves, the risk of blockage at different subcooling levels and flow rates can be assessed.

Hydration kinetics of C3A: effect of lithium, copper and sulfur-based mineralizers

AbstractCalcium aluminate phases have a particular effect on the early heat release during setting initiation and have a substantial influence on the further workability of ordinary Portland cement. The nature of the calcium aluminate hydration products and its kinetics strongly depends on sulfate content and humidity. The effect of mineralisers on melt formation and viscosity is well described for calcium silicate systems, but information is still lacking for calcium aluminates. Therefore, the synergistic effect on the crystal structure and hydration mechanism of the tricalcium aluminate phase of the addition of mineralizers, i.e. Li2O, CuO, SO3 to the raw meal is here investigated. Co-doped calcium aluminate structures were formed during high-temperature treatment. Thermal analysis (TG–DTA and heating microscopy) was used to describe the ongoing high-temperature reaction. Resulting phase composition was dependent on the concentration of the mineralizer. While phase pure system was prepared with low mineralizer concentrations, with increasing mineralizer content the secondary phases were formed. Raman spectroscopy and XPS analysis were used to investigate the cation substitution and to help describe the cations bonding in co-doped calcium aluminate system. Prepared powders have been hydrated in a controlled manner at different temperatures (288, 298, 308 K). The resulting calorimetric data have been used to investigate the hydration kinetics and determine the rate constant of hydration reaction. First-order reaction (FOR) model was here applied for the activation energy and frequency factor calculations. The metastable and stable calcium aluminate hydrates were formed according to initial phase composition. In phase pure systems with low S content, the formation of stable and metastable hydrates was depended on the reaction temperature. Conversely, in systems with secondary phases and higher S content, the hydration mechanism resembled that which appears in calcium sulfoaluminates.

Preparation and pipeline transport of CO2 as a hydrate slurry – Modelling and techno-economic analysis

CO2 transportation as a hydrate slurry is modelled in Aspen Plus, including the slurry preparation and the pipeline transport. Due to the lack of built-in models for the hydrate formation, mass and energy balances were developed and implemented using a User-block function. NRTL-RK global property method was used, given the accuracy in predicting the CO2 solubility in water under incipient hydrate formation conditions and the dissolution heat of CO2 in water. The conventional process of transporting CO2 in a supercritical state was also modelled to benchmark the hydrate-based technology. The hydrate-based process is safer than the conventional process as it requires lower operating pressures, but the estimated costs are higher due to the need for refrigeration and larger pipeline diameters for transportation. The addition of thermodynamic promoters, that moderate the hydrate formation conditions, the integration of cold streams with other processes, and valuing the water transported with CO2, will enhance the economic attractiveness of the hydrate-based process.

Crystal structures and properties of derivatives of the alkaloid matrine: salts and hydrate forms.

We report the crystal structures of three matrine derivatives, namely, the salts (1R,2R,9S,17S)-6-oxo-7,13-diazatetracyclo[7.7.1.02,7.013,17]heptadecan-13-ium (2E)-3-(3,4-dihydroxyphenyl)prop-2-enoate (matrine caffeinate) sesquihydrate, C15H25N2O+·C9H7O4-·1.5H2O (Matrine-CA), and the 2-hydroxybenzoate (salicylate) monohydrate, C15H25N2O+·C7H5O3-·H2O (Matrine-SA), as well as the 1.75-hydrate form, (1R,2R,9S,17S)-7,13-diazatetracyclo[7.7.1.02,7.013,17]heptadecan-6-one 1.75-hydrate, C15H24N2O·1.75H2O (Matrine-H). Each derivative exhibited a consistent molecular conformation for the matrine core, which is notably distinct from that of the anhydrous form. Notably, both salts crystallized in the orthorhombic space group P212121, with an asymmetric unit featuring one cation and one anion. Within the two salt structures, intermolecular proton transfer between matrine and the acid is observed, culminating in the formation of a matrine cation protonated at the tertiary amine N site. The Matrine-CA crystal packing is manifested as a three-dimensional (3D) network arising from one-dimensional (1D) supramolecular helical chains, stabilized by N-H...O and O-H...O hydrogen bonds. In the case of Matrine-SA, the matrine cation is interconnected via hydrogen bonds with salicylate anions and water molecules, also forming a 1D helical motif. The structure of the hydrate form, Matrine-H, is reported again with the disordered solvent molecules accurately located. To further elucidate the structural attributes, Hirshfeld surface analysis and fingerprint plots are employed, offering a nuanced perspective on the intermolecular contacts and interactions within these crystalline forms.

EXPERIMENTAL STUDY OF HYDRATE FORMATION PECULIARITIES FOR CONDITIONS OF THE TURNO AND CENOMANIAN DEPOSITS: Part II

This paper is the second part of the research devoted to the study of hydrate formation features for the conditions of Turonian and Cenomanian deposits. The launch of new gas projects at the Turon and Senoman production facilities in Western Siberia provided a good opportunity to critically analyze the known methods of protecting production, gathering and transportation facilities of the gas field from the formation of solid gas hydrates. The paper presents the experience of implementing a program of laboratory studies of conditions of gas hydrate formation with their subsequent processing and in-depth analysis. The research program covered the area of thermobaric parameters typical for the conditions of Turon-Senoman deposits exploitation with localization of hydrate-hazardous areas in the conditions of Technological Regimes for full development. The description of laboratory studies is given, in which two gas compositions of Senoman and Turon objects, different variants of mineralization and ionic composition corresponding to formation and condensation water, as well as hydrate formation conditions under changing dosages of basic inhibitor on the basis of methanol were considered. The details of the experiment based on the method of swinging cells and the subsequent analysis of the results of the completed experiments to determine the thermobaric conditions of formation and decomposition of hydrates are given. The main features of the experiment are specified, estimates of the rate of change of the influencing parameters of the experiment on its quality are given. In the process of implementation of the experimental program, the optimal values of these parameters were selected, which allowed us to significantly reduce the variation of experimental results to determine the thermobaric conditions of hydrate formation. It is experimentally established that the temperature of hydrate decomposition is higher than the temperature of its formation at all investigated gas compositions and water mineralization.

Study on modification of natural hydraulic lime historical building repair mortar

Qingdao boasts a wealth of historical buildings, yet they have sustained varying degrees of damage due to environmental erosion over decades. Traditional cement-based repair materials can exacerbate the damage to these structures and often fall short of the stringent requirements for historical building restoration projects. Natural Hydraulic Lime (NHL) offers excellent compatibility and breathability, making it suitable for restorative work on historical buildings. However, its low early strength and durability pose limitations in Qingdao's complex environment. Consequently, this study investigates the enhancement of NHL mortar using Ground Granulated Blast Furnace Slag (GGBFS/BFS) powder. Nine mix formulations were developed to investigate the impact of varying BFS contents on the physical properties and microstructure of the repair mortar. The results indicate that, compared to the reference sample, the modified mortar exhibits reduced water requirement for normal consistency, shorter setting time, lower water absorption, and decreased shrinkage. Regarding mechanical properties, the incorporation of BFS significantly enhances the mechanical strength of the repair mortar. When the proportion of BFS is 60 %, the flexural and compressive strength of the mortar samples increase by 304 % and 611 % at 28 days, respectively. Upon incorporating BFS, a pozzolanic reaction occurs in the alkaline environment, leading to the formation of calcium silicate hydrate (C-S-H) gel. This gel fills the pores within the mortar, enhancing the densification of the system, which in turn improves the mechanical properties and microstructure of the repair mortar. SEM analysis corroborates these findings. XRD analysis confirms that BFS does not introduce harmful substances.

Chemical and Structural Evolution of Rb2-2xK2xTi2O5 Layered Titanates When Exposed to Ambient Air.

In this report, we combine thermogravimetric analysis, X-ray diffraction, and infrared spectroscopy to investigate the chemical and structural evolution upon exposure of alkali titanates Rb2Ti2O5 and K2Ti2O5 and mixed compound Rb2-2xK2xTi2O5, for which 0 ≤ x ≤ 1, to the ambient atmosphere. We show that a complete solid solution exists between the potassium and rubidium end-members and that mixed compounds exhibit an intermediate behavior. When exposed to the ambient atmosphere, all compounds degrade, with the progressive formation of first hydrates and then bicarbonates and a much quicker degradation of the rubidium titanate than of the potassium titanate. On the contrary, we show that upon hydration in the absence of CO2, the crystal structure of K2Ti2O5 is more quickly impacted than that of Rb2Ti2O5. These observations should be useful for understanding the evolution of the functional properties of M2Ti2O5 alkali titanates upon aging in the ambient atmosphere, as well as for the optimization of their hydration-dependent properties.

Significance of well placement and degree of hydrate reserve recovery for synergistic CH4 recovery and CO2 storage in marine heterogeneous hydrate-bearing sediments

The synergistic CH4 recovery and CO2 storage in marine natural gas hydrate reservoirs presents an emerging strategic solution for energy and environment challenges, yet the efficiency requires innovative engineering designs to enhance. In this study, a water-saturated CH4 hydrate-bearing sediment (HBS, V = 22 L, T = 284 K, and P = 11.2 MPa) was synthesized to investigate the pilot-scale combined processes of CH4 recovery by depressurization followed by CO2 storage through CO2/N2 injection. The synthesized HBS exhibited vertical heterogeneity with higher hydrate saturation observed in the upper sediment and a decreasing saturation trend in the lower sediment. The effect of well placement designs on CH4 recovery and hydrate restoration by mixed CH4/CO2/N2 hydrate (Mix-H) formation was investigated, considering two scenarios: upper well for recovery while lower well for injection (URLI), and lower well for recovery while upper well for injection (LRUI). Additionally, the impact of the degree of hydrate reserve recovery (100% and 80% hydrate dissociated) on subsequent Mix-H formation was also studied. Results indicate that the URLI setting achieves a higher CH4 recovery ratio and rate during depressurization compared to the LRUI setting which encounters low-T shielding. The T variation between upper and lower sediment highlights the influence of heterogeneity on fluid behaviors. Halting the CH4 recovery after 80% hydrate dissociation results in a halved recovery time and water production. During later CO2/N2 injection and Mix-H formation process, the LRUI setting achieves a 13–54% higher Mix-H saturation and a 33–56% higher CO2 hydrate encapsulation than the URLI setting. Moreover, 80% dissociation proves more favorable for Mix-H formation achieving nearly twice higher final amount than 100% hydrate dissociation. However, it results in a lower CO2 encapsulation. This study provides insights into the trade-off between CH4 recovery and CO2 storage efficiency, emphasizing the need for optimized well placement and controlled hydrate extraction.

Experimental study on hydrate blockage formation and decomposition in gas-dominated Fluctuating pipes

Current research pertaining to hydrate flow assurance in the transportation of deep-sea natural gas through undulating pipelines remains sparse. Employing a novel undulating pipeline equipped with multipoint-distributed sensors, we delve to the processes of hydrate generation, migration, deposition, blockage, and decomposition. Our findings reveal that the upward inclination sections of both lifting and underlying pipes are particularly vulnerable to hydrate blockage. The lifting pipe is not conducive to hydrate deposition and blockage, whereas the underlying pipe poses a heightened risk for hydrate formation. Increasing subcooling leads to a reduction in blockage duration and sloughing frequency, alongside an extension in decomposition time. Furthermore, increasing the water injection rate and pipeline curvature prolongs the blockage of the lifting pipe. However, the impact of the water injection rate on the underlying pipe is negligible. Increasing pipeline curvature promotes the blockage of the underlying pipe. We propose models that encapsulate hydrate blockage and decomposition based on varying gas–liquid distributions. This research fills the gap in the study of hydrate blockage and decomposition in undulating pipelines and provides a reference for monitoring hydrate risks in natural-gas transmission pipelines.

Interactions of clathrate hydrate promoters sodium dodecyl sulfate and tetrahydrofuran investigated using 1H diffusion nuclear magnetic resonance at hydrate-forming conditions.

Thermodynamic hydrate promoters and kinetic hydrate promoters can be used to reduce the P-T conditions for clathrate hydrate synthesis to decrease the nucleation induction time while increasing growth rates. Two commonly used promoters for hydrate research are tetrahydrofuran (THF) and sodium dodecyl sulfate (SDS), which can increase the overall hydrate promotion when used in tandem as compared to individually. There are several molecular theories regarding how SDS promotes hydrate growth. This study explores the micellular theory, for which hydrate formation depends on surfactant aggregates (micelles) at a critical micelle concentration (CMC) to increase the interfacial surface area. The micellular theory is the most investigated and criticized surfactant hydrate promotion theory. To address questions related to micellar behavior, this study investigates the intermolecular behavior between SDS and THF for the identification of micelles at hydrate-forming conditions. The systems explored contained THF at 3 and 5 wt. % with varying concentrations of SDS below and above the CMC. Several methods including a qualitative visual method, conductivity, interfacial tensiometry, 13C Liquid-state Nuclear Magnetic Resonance (NMR) spectroscopy, and 1H diffusion NMR spectroscopy were evaluated at temperatures below the Krafft point of SDS and above 0 °C. The presence of THF at low concentrations decreased the critical temperature for the formation of SDS micelles, where SDS is solubilized in THF/water solution at hydrate-forming temperatures without precipitation. The CMC of SDS was decreased significantly even at hydrate-forming conditions. Mixed surfactant-cosolvent micellular behavior of SDS in the presence of low concentrations of THF was confirmed at hydrate-forming conditions above 0 °C.

CO2 hydrate formation characteristics inside seawater residual/saturated sediments under marine CO2 storage scenes

Marine CO2 storage by hydrate method is a promising technology expected to achieve permanent CO2 storage. Here, this study focuses on the formation kinetics and morphological characteristics of CO2 hydrate under two typical scenes with seawater residual zone (50 % porewater saturation) and seawater saturated zone (100 % porewater saturation). Four kinds of porous media were selected to simulate sediments with different permeability. The results indicate that in the seawater residual zone, hydrates are mostly flaky and form granular cementation, while in the seawater saturated zone, hydrates form from the pore center and are distributed as granular filling. Poor pore connectivity and gas-liquid contact in the seawater saturated zone hinder further hydrate formation, resulting in final hydrate saturation being at least 25 % lower than that in the seawater residual zone. Additionally, the final gas consumption and water-to-hydrate conversion decreased with increasing particle size. The maximum gas consumption was 118 mmol CO2/mol H2O, with only 28 % of the water converting into hydrate. These findings are significant for marine CO2 storage under different porewater saturation and particle size conditions.

Gas hydrate technological applications: From energy recovery to carbon capture and storage

Hydrates are crystalline structures that trap small gas molecules inside hydrogen-bonded water cages. These structures form at high pressure and low temperature. In recent years, there has been a growing interest in gas hydrates for technological applications, specifically in energy recovery, as well as carbon dioxide capture and storage. In the CO2/CH4 exchange using gas hydrates, researchers have reported a large amount of natural gas trapped in the form of gas hydrates under the ocean seafloor and permafrost regions. This large amount of natural gas trapped inside hydrate cages in oceanic and permafrost deposits has driven interest in the energy sector to investigate the possibility of safely harvesting gas hydrates as one of energy resources. However, there are still unanswered fundamental questions including the mechanism of natural gas recovery from gas hydrates. Another gas hydrate-based technology that has a growing interest is the use of gas hydrates for separation including carbon dioxide capture and storage. Carbon dioxide molecules have been shown to be preferentially trapped in the hydrate phase, demonstrating the possibility of the usage for carbon capture technology. Similarly, there are still underlying concerns of these applications, such as thermodynamics and stability of gas hydrates in porous materials, and the crystallization kinetics and mechanism of hydrate formation. This paper provides an overview of laboratory investigations conducted to understand the mechanism and evaluate the feasibility of energy recovery as well as discussion on recent advances in laboratory investigations on gas hydrate-based technology.

Low-Dose Hydrate Formation Inhibitors Derived from Copolymers of Maleic Anhydride and Isopropylacrylamide Amidated by Dibutylaminopropylamine

Low-Dose Hydrate Formation Inhibitors Derived from Copolymers of Maleic Anhydride and Isopropylacrylamide Amidated by Dibutylaminopropylamine

Long-Term Distributed Temperature Sensing Monitoring for Near-Wellbore Gas Migration and Gas Hydrate Formation

Summary Well integrity monitoring has always been a critical component of subsurface oil and gas operations. Distributed fiber-optic sensing is an emerging technology that shows great promise for monitoring processes, both in boreholes and in other settings. In this study, we present a case study of using distributed temperature sensing (DTS) technology to monitor a cemented and plugged well in the Alaska North Slope (ANS). The well was drilled as part of a long-term gas hydrate study, and the downhole DTS data were recorded over a period of approximately 2 years. By applying a temporal gradient and removing instrument instability noise, we reveal subtle (<0.001°C/h) thermal anomalies, which are characterized by brief warming periods followed by longer cooling periods at discrete depths along the borehole. The observed coherent events show an upward trajectory from deeper formations into the overlying permafrost interval, with the thermal anomalies concentrated in relatively coarse-grained sandstone layers. We also observe that the upward migration rate of the DTS anomalies varies with formation lithology and that there is a spatial and temporal correlation between the subsurface events and measured wellhead annular pressures. We interpret that the observed warming events represent the exothermic process of gas hydrate formation that is occurring in association with the upward migration of gas outside the well casing, and this interpretation is confirmed by numerical simulations. These observations demonstrate the ability of suitably processed DTS data to detect subtle processes and highlight the value of DTS technologies for wellbore integrity monitoring.

Gas flow in frozen hydrate-bearing sediments exposed to compression and high-pressure gradients: Experimental modeling

Changes in temperature and pressure patterns in gas- and hydrate-saturated permafrost caused by natural geodynamic processes or human impacts can lead to the active flow of gas through unfrozen zones, and its explosive emission is often accompanied by crater formation. Gas flow and accumulation in the shallow permafrost can be explained by the conditions of gas pressure equal to or exceeding the overburden pressure and high-pressure gradients. For the first time, filtration tests were conducted on ice- and hydrate-saturated rocks under uniaxial compression at various negative temperatures using a developed methodology. The modeling of gas flow in a mixture of ice-saturated sand and 25 % montmorillonite at gas pressure gradients within 2 MPa, shows that gas flow can start at warm negative temperatures near the thaw point. Pore hydrate formation in frozen sand heated to positive temperatures and frozen back led to a linear decrease in gas permeability by up to eight times. However, the behavior of gas permeability during hydrate dissociation is nonlinear as it increased within a few hours after the onset of dissociation, but then decreased exponentially in the following 24 h.