Methane Sorption Research Articles

Evaluation of Matrix Swelling Behavior in Shale Induced by Methane Sorption under Triaxial Stress and Strain Conditions

Gas sorption can lead to the volumetric swelling of the shale matrix and reduction of the effective pore volume, which further impacts the gas transportation in micro- and nanopores in shale. At pr...

Comparative study on sorption characteristics of coal seams from Barakar and Raniganj formations of Damodar Valley Basin, India

The methane retention mechanism in coal seams is markedly different from those of conventional gas reservoirs. Methane remains mainly as physically adsorbed molecules on micropore surface. Chemical and petrographic compositions of coal are the measures of maturity and type of organic matter that control the methane sorption characteristics of the coal. 99% of Indian coal occurrences are contributed by lower Gondwana sequences housed in two major geologic formations, younger Raniganj and older Barakar. The Raniganj Formation is best exposed in Raniganj Sub-basin and Barakar Formation is best exposed in Jharia Sub-basin of Damodar Valley. Present work attempts a systematic investigation on comparative account of methane sorption characteristics of coals from Raniganj Formation of Raniganj Sub-basin and Barakar Formations of Jharia Sub-basin in relation to their chemical composition and petrographic makeup. Chemical analyses shows that moisture, ash, volatile matter and fixed carbon varies between 2.5 and 4.6%, 10.0–27.2%, 38.8–40.2% (dmmf) and 59.8–61.2% (dmmf), respectively for Raniganj coals and, 0.5–1.1%, 16.7–32.9%, 20.7–22.0% (dmmf) and 78.0–79.3% (dmmf), respectively for Barakar coals. Carbon content is distinct for the suites of coal, 79.2–85.4% and 85.6–92.0% for Raniganj and Barakar coals, respectively. The vitrinite reflectance for the Raniganj coals ranges 0.53–0.72% and the Barakar coals ranges 1.09–1.23%. Based on the chemical composition and vitrinite reflectance value Raniganj coals belongs to high volatile bituminous type, whereas Barakar coals belongs to high to medium volatile bituminous type. Such variation in composition and maturity is mainly attributed to the variation in precursor organic matter as well as the basinal and thermal history of the sub-basins under consideration.H/C atomic ratio of the Raniganj and Barakar coals varies between 0.65 and 0.80 and 0.51–0.72 and O/C atomic ratio varies between 0.05 and 0.13 and 0.01–0.07, respectively. Coals of both the Raniganj and Barakar formations are mostly of kerogen Type-III with Raniganj coals falling in wet gas maturity stage approaching early-thermogenic methane generation whereas Barakar coals falling in condensate gas stage approaching peak-thermogenic methane generation. The Langmuir volume ranges from 9.3–21.8 cc/g (daf) for Raniganj coals and 21.1–29.1 cc/g (daf) for Barakar coals. Sorption capacity for the set of coals shows a strong rank dependency and increase with corresponding increase in rank down the stratigraphic column. Methane sorption capacity shows positive relationship with carbon content and vitrinite reflectance, and negative relationship with moisture content, ash and volatile matter. Moisture effect is more prominent in low rank Raniganj coals. The adsorption capacity shows a strong positive relation with vitrinite content and a moderate negative relation with inertinite content for both the Raniganj and Barakar coals, which may be attributed to dominancy of micropores in vitrinites with rank enhancement. The multiple regression analysis shows that the moisture is the main predictor of the VL, and the interaction of moisture with ash and reflectance mainly control the sorption capacity. A predictive model equation is developed for determination of sorption for Damodar basin coals from carbon, ash and moisture data.

The carbon dioxide, methane and nitrogen high-pressure sorption properties of South African bituminous coals

In this paper, we report the CO2, CH4 and N2 sorption isotherms of four dry South African bituminous coals at pressures up to 16 MPa at 55 °C. The sorption capacities of the samples with respect to the adsorbate gases decreased in the order: CO2 > CH4 ≈ N2 by weight, and CO2 > CH4 > N2 by volume. A new model, based on a hybrid Dubinin-Radushkevich and Henry law approach (DR-HH) provided substantially better fits to the sorption isotherm data than the previously used modified DR (M-DR) model. Obtained uncertainty metrics show that the DR-HH model generally returned lower error sum of squares (ESS) and root mean square (RMS) residuals, and higher quality of fit (QOF) compared to the M-DR model. The net heat of sorption, βEs, of the samples for the three adsorbate gases were generally low (8.5–12.8 kJ/mol), but comparable to previous determinations of other coals, indicating that physisorption was the dominating sorption mechanism. The sorption capacities of the samples were found to be rank-dependent as they decreased with increasing vitrinite reflectance and elemental carbon content. The micropore properties of the samples as measured by both CO2 low-pressure gas adsorption (LPGA) and small angle X-ray scattering (SAXS), impacted the sorption properties of the sample more than both the mesopore and macropore properties determined from N2 LPGA, SAXS, and mercury intrusion porosimetry. The sorption capacities of the samples were found to increase with increasing lithotypes abundance, suggesting that lithotype bandings enhances either the fluid transport processes or the micropore properties of the coal matrix. In addition, it has been demonstrated that critical properties of the adsorbate gases influenced their sorption properties.

Solvent‐Induced Control over Breathing Behavior in Flexible Metal–Organic Frameworks for Natural‐Gas Delivery

AbstractFinding appropriate stimuli for controlling the breathing behavior of flexible metal–organic frameworks (MOFs) is highly challenging. Herein, we report the solvent‐induced changes in the particle size and stability of different breathing phases of the MIL‐53 series, a group of flexible MOFs. A water/dimethylformamide (DMF) ratio is tuned to synthesize members of the MIL‐53 series which have different behaviors. The breathing is explored by high‐pressure methane sorption tests. Increasing DMF concentration decreases MOF particle size and increases the stability of the porous phases, boosting the 5.8–65 bar sorption difference of methane, which is required for natural‐gas delivery.

Solvent-Induced Control over Breathing Behavior in Flexible Metal-Organic Frameworks for Natural-Gas Delivery.

Finding appropriate stimuli for controlling the breathing behavior of flexible metal-organic frameworks (MOFs) is highly challenging. Herein, we report the solvent-induced changes in the particle size and stability of different breathing phases of the MIL-53 series, a group of flexible MOFs. A water/dimethylformamide (DMF) ratio is tuned to synthesize members of the MIL-53 series which have different behaviors. The breathing is explored by high-pressure methane sorption tests. Increasing DMF concentration decreases MOF particle size and increases the stability of the porous phases, boosting the 5.8-65 bar sorption difference of methane, which is required for natural-gas delivery.

Thermodynamic evidence of a transition in ZIF-8 upon CH4 sorption.

We present the results of an experimental study of methane sorption in ZIF-8. We measured isotherms at five different temperatures between 87 K and 107 K. We have observed three sub-steps in each of the isotherms. The intermediate sub-step had not been observed experimentally in previous studies of this system. This newly determined experimental feature suggests that a transition is taking place in the sorbed system (this newly observed sub-step occurs over a loading interval where published computer simulation results for CH4 in ZIF-8 had identified a structural transition occurring in the sorbent). We have studied the kinetics of adsorption for this system (we measure the time required for the system to reach equilibrium after gas is added to the experimental cell as a function of sorbent loading). We observed a sharp peak in the equilibration time at high loadings, below saturation. We have explored the isosteric heat of adsorption, and its dependence on sorbent loading, for this system. We found a broad peak in the isosteric heat at loadings corresponding to the intermediate isotherm sub-step. Previously reported computer simulations for the isosteric heat dependence on loading for CH4 in ZIF-8 are in good agreement with our experimental results for this quantity.

Computational Tuning of the Paddlewheel tcb-MOF Family for Advanced Methane Sorption

A series of metal–organic frameworks (MOFs) with tcb net topology and linkers of increasing size (combining triple bonds and benzene rings) is computationally designed using molecular mechanics and density functional theory. By grand canonical Monte Carlo simulations, we identify MOFs with outstanding methane total uptakes and working capacities, satisfying the targets of the U.S. Department of Energy for automobile applications in cold weather regions (50 wt %, 263 cm3(STP)cm–3). For example, the 5B MOF achieves at 298 K working capacities of 52.2 wt % at 5–65 bar and 61.9 wt % at 5–80 bar. The 3B MOF exhibits at 298 K the most balanced (gravimetric versus volumetric) total uptake and working capacity in the family of tcb-MOFs: 28.4 wt %, 160.9 cm3(STP)cm–3 at 35 bar and 23.0 wt %, 130.3 cm3(STP)cm–3 at 5–35 bar (exceeding the benchmarks of IRMOF-6, PCN-14, Ni-MOF-74, Al-soc-MOF-1, MOF-5, MOF-205), 38.4 wt %, 218.0 cm3(STP)cm–3 at 65 bar and 33.0 wt %, 187.5 cm3(STP)cm–3 at 5–65 bar (exceeding the benchm...

A study on the effect of gas shale composition and pore structure on methane sorption

Ten moist, powdered European shale samples were analyzed for their sorption properties by volumetric method. The adsorption capacities were correlated to the shale organic types and maturity. The pore-size distribution obtained from low-pressure CO2 micropore adsorption was also correlated with the porosity and shale organic types. Furthermore, pore volume and average pore width were taken into consideration to determine the dominant parameters controlling adsorption. To identify the discrepancy between available and actual pore space for adsorption, helium and krypton gases were used for void volume estimation. Methane adsorption isotherms follow Langmuir Type I behavior and, in general, showed a positive trend with Total Organic Content (TOC) and Hg-porosity although some deviations were also observed. Low to moderate level of hysteresis between adsorption and desorption isotherms for some samples was visible, which may be attributed to the experimental uncertainty and existence of heterogeneous pores for shale-methane interaction. The low-pressure micropore adsorption analysis indicated dominance of nanopore and very fine micropores in the shale matrix structure along with associated microporosity of the clay materials. The observed “negative” adsortion or “decline” in adsorption isotherm are related to the mismatch of the available pore spaces for helium and methane. In general, He-calibrated isotherms showed higher levels of adsorption than the corresponding Kr-calibrated isotherms although the unit void volume for all samples follow a negative trend with the maximum methane capacity.

Experimental measurement and analytical estimation of methane absorption in shale kerogen

Gas storage in shale (organic-rich mudstone) consists of three different states: free gas in pores and natural fractures; adsorbed gas on organic and inorganic pore walls; and absorbed gas into organic matter (kerogen). Since it is difficult to differentiate absorbed gas from adsorbed gas, most current studies combine the adsorbed gas with absorbed gas and call the combination as gas sorption. In this study, a conceptual model of gas sorption is proposed to account for the contributions from adsorption and absorption to gas storage in shale, respectively. Methane sorption capacity of Barnett and Eagle Ford shale core samples is measured by magnetic suspension sorption system. Regression analysis is performed on the measured data by Simplified Local-Density model coupled with modified Peng-Robinson Equation of State (SLD-PR). Absolute sorption capacity of these two shale core samples is estimated based on the density profile of SLD-PR model. Additionally, the absorbed gas, which is regarded as the gas molecules dissolving/diffusing into the bulk of solid kerogen, is distinguished from the adsorbed gas through interpreting the results of gas expansion measurements using Fick’s law of diffusion. Moreover, methane diffusion coefficients for the two shale core samples are determined, which range from 10−22 m2/s to 10−21 m2/s. The percentage of absorbed gas accounting for total sorbed gas increases with pore pressure. When the pore pressure increases, more gas molecules attempt to adsorb on the surface of kerogen and create a larger gas concentration gradient for gas diffusing into the kerogen. The gas molecules, which adsorb on the pore walls of kerogen and then diffuse into the solid lattice of kerogen, may lead to the swelling of kerogen and thus reduce the pore width for free gas transportation. Therefore, the accurate prediction of the gas absorption capacity of kerogen is significant to understand gas storage mechanism and characterize original gas in place (OGIP) in shale gas reservoirs.

Comparative analysis of shale reservoir characteristics in the Wufeng-Longmaxi (O3w-S1l) and Niutitang (Є1n) Formations: A case study of wells JY1 and TX1 in the southeastern Sichuan Basin and its neighboring areas, southwestern China

A systematic comparative analysis of shale reservoir characteristics of the Wufeng-Longmaxi (O3 w-S1 l) and Niutitang (Є1 n) Formations in southeastern Sichuan Basin and its neighboring areas was conducted with respect to mineralogy, organic geochemistry, pore structure, methane sorption, brittleness, and fractures. Results indicate that (1) organic matter (OM)-hosted pores that are hundreds of nanometers to micrometers in size in the Longmaxi shale are well-developed in migrated OM rather than in the in situ OM, and they are the dominant reservoir spaces. Furthermore, the total organic carbon (TOC), brittleness, organic pores, and bedding fractures have good synergistic development relationships. However, there are fewer OM-hosted pores in the Niutitang shale; they are smaller in size, usually less than 30 nm, and have a more complicated pore structure. The intergranular pores in cataclastic organic-inorganic mineral fragments are the dominant reservoir spaces in the Niutitang shale and are coupled with stronger methane sorption and desorption capacities. (2) The piecewise correlation between TOC and brittleness indicates the significant differences in pore and fracture characteristics. When the TOC [Formula: see text], the TOC, brittleness, organic/inorganic pores, and fractures synergistically develop; when the TOC [Formula: see text], even though the increase in ductility reduces the number of fractures, the lower cohesive strength, internal friction angle, and weaker surfaces of interlayer fractures and cataclastic minerals promote the development of slip fractures, which significantly improves the fracture effectiveness and reservoir spaces for free and absorbed shale gas. (3) The Longmaxi, Wufeng, and Niutitang shales formed and evolved in different evolutionary stages. With the evolution of hydrocarbon generation, diagenesis, tectonic deformation, and pressure, the size and proportion of OM-hosted pores gradually decrease. At the same time, the complexity of the pore-fracture structure, the methane adsorption/desorption capacity, and the proportion of inorganic pores and fractures increase.

Development of temperature-induced strains in coal–CH4 and coal–CO2 systems

Expansion/contraction of coal, induced by the sorption of carbon dioxide and methane in isothermal and non-isothermal conditions, was measured. The investigation is of great importance in the context of validating the potential CO2 sequestration in unmined coal seams. Changes in temperature in underground coal beds can influence the sorption balance, resulting in strains in coal strata, which could lead to the desorption of gas and leaks to the ground surface. The research shows that the strains induced by CO2 sorption are about twice the size of those resulting from the sorption of CH4. The linear strains are anisotropic and greater in the direction perpendicular to the bedding plane. The results of the non-isothermal experiments show that a temperature increase gives rise to the sample swelling in the presence of methane, but a different pattern is observed for coal–CO2 systems, where sample contraction occurs. This behaviour is explained by the different mechanism of CH4 and CO2 deposition and by the diversity in the maceral composition of the samples.

Experimental Testing of a Bi-Functional Material Cu-Cao Composite within the Ca/Cu H2 Production Process

A novel CaO/CuO based composite material (53 wt% CuO/ 22 wt% CaO/ 25 wt% Ca12Al14O33), developed for combined CO2 capture and heat transfer for the Ca/Cu hydrogen production process, showed a maximum CO2 capture rate of 1.53*10-2 kmol CO2/h.kg material, at a linear gas velocity of 0.55 m/s when operating in a fixed bed reactor in presence of a commercial reforming catalyst during methane Sorption Enhanced Reforming (SER). The system was able to convert up to 2.4 kg CH4/h.kg catalyst, producing a gas stream with over 93 % vol. hydrogen (dry basis) at 10 bars for a steam to carbon molar ratio of 3.2.

Controls on methane sorption capacity of Mesoproterozoic gas shales from the Beetaloo Sub-basin, Australia and global shales

Exploration in the Beetaloo Sub-basin in Australia's Northern Territory has indicated gas-saturated, quartz-rich source rocks that are gas mature and laterally continuous over large areas. In the Sub-basin shale targets have been identified within the Velkerri Formation and the Kyalla Formation. These shales are of Mesoproterozoic age and thus significantly older than any of the North American shale plays and most other shales currently under investigation for their gas production potential.In this work, we characterise two sets of drill cutting samples from the Beetaloo Sub-basin for their composition, pore structure, and CH4 adsorption capacity. The objective of this study is to assess the adsorption potential of these shales and investigate the properties controlling this. Measurements from other researchers are included in the analysis to determine to what degree commonly characterised properties such as bulk clay and total organic carbon (TOC) content control gas adsorption capacity on a larger scale and thus provide an indication of the range of adsorption behaviours that may be expected.The adsorption measurements are carried out at reservoir conditions - that is high pressures (up to 30 MPa) and high temperatures (up to 110 °C). The results show that the organic-rich (TOC: 3.7–6.2%) middle Velkerri shale samples have a significantly higher adsorption capacity (expressed by the Langmuir volume) than the clay-rich, organic-lean (TOC: 0.85–1.8%) lower Kyalla shale samples: 2.89–3.38 m3/t compared to 1.88–2.81 m3/t. This is in agreement with the higher average micropore volume of the middle Velkerri shale samples.Results of our analysis demonstrate that, depending on a shale's composition, different properties control gas adsorption in shale, though in the organic-rich middle Velkerri B shale samples the controlling paramters cannot be clearly determined. A positive correlation between TOC and CH4 adsorption capacity is observed, but only up to a TOC of 4.5%. Above this point the adsorption capacity appears to decrease again. The lack of a strictly positive correlation between TOC and adsorption capacity is likely caused by other parameters affecting sorption behaviour, in particular variations in organic matter type and thermal maturity. However, analysis of a global adsorption data set of marine shales of non-differentiated maturity nevertheless indicates that, on a larger scale, the TOC content can provide a reasonable first estimate of a shale's CH4 adsorption capacity.In the organic-lean lower Kyalla shale samples clay minerals control microporosity and CH4 adsorption. It is the high illite/muscovite content (30–40%) in particular that is indicated to be the main contributor to microporosity and gas adsorption capacity. Results from the analysis of the global shale adsorption data set are in agreement with these findings, showing that for organic-lean shales with a TOC < 2% clay may be the primary control on CH4 adsorption.

Thermodynamic Characteristic of Methane Sorption on Shales from Oil, Gas, and Condensate Windows

High-pressure methane sorption isotherms at 40–101 °C and pressures up to 25 MPa were measured on Jurassic lacustrine and Silurian marine shales from China. Shale samples span a thermal maturity range from low mature (oil window) to overmature (dry gas window). Low-pressure CO2 and N2 adsorption techniques were used to quantify specific surface area, pore volume, and pore size distributions. The thermodynamic characteristic of methane sorption on shales was assessed based on the experimental multitemperature isotherms. The effects of physical and chemical properties of shales on thermodynamic properties were analyzed and discussed. Finally, standard enthalpy of sorption was first introduced to evaluate the sorption affinity of methane on shales, and a general pattern describing the evolution of methane sorption as a function of thermal maturity was proposed. The Langmuir sorption capacity of these shales varies from 0.09 to 0.16 mmol/g. The low total organic matter carbon, clay-rich lacustrine shales have...

Experimental Study of the Relationship Between Particle Size and Methane Sorption Capacity in Shale.

The amount of adsorbed shale gas is a key parameter used in shale gas resource evaluation and target area selection, and it is also an important standard for evaluating the mining value of shale gas. Currently, studies on the correlation between particle size and methane adsorption are controversial. In this study, an isothermal adsorption apparatus, the gravimetric sorption analyzer, is used to test the adsorption capacity of different particle sizes in shale to determine the relationship between the particle size and the adsorption capacity of shale. Thegravimetric method requires fewer parameters and produces better results in terms of accuracy and consistency than methods like the volumetric method. Gravimetric measurements are performed in four steps: a blank measurement, preprocessing, a buoyancy measurement, and adsorption and desorption measurements. Gravimetric measurement is presently considered to be a more scientific and accurate method of measuring the amount of adsorption; however, it is time-consuming and requires a strict measuring technique. A Magnetic Suspension Balance (MSB) is the key to verify the accuracy and consistency of this method. Our results show that adsorption capacity and particle size are correlated, but not a linear correlation, and the adsorptions in particles sieved into 40 - 60 and 60 - 80 meshes tend to be larger. We propose that the maximum adsorption corresponding to the particle size is approximately 250 µm (60 mesh) in the shale gas fracturing.

Experimental Study of the Relationship Between Particle Size and Methane Sorption Capacity in Shale

Experimental Study of the Relationship Between Particle Size and Methane Sorption Capacity in Shale

Pore structure, gas storage and matrix transport characteristics of lacustrine Newark shale

Abstract Shale gas production in the U.S. fuelled research activities in unconventional reservoir rock characterization. Most studies focused on organic-rich shales of marine origin, while disregarding lacustrine sequences. In this study, thirteen lacustrine shale samples from the Newark Basin, NJ, USA are comprehensively characterised in terms of pore structure, gas storage and matrix transport characteristics. These thermally overmature (VRr 1.4–2.7%) shales have a Na-rich, heterogeneous mineralogy with TOC contents of up to 3.6%. Methane sorption capacity and pore structure parameters as identified with low-pressure N2 physisorption (microporosity, BET surface area) are neither interrelated with each other nor with any shale components (e.g. clay content, TOC). In contrast, porosity shows a positive correlation with TOC content, which is also typical for many thermally overmature marine shale sequences. Correspondingly, porosity and TOC positively correlate to bedding parallel matrix permeability coefficients (between 2 and 80 nD at 40 MPa effective stress). In contrast, permeability coefficients perpendicular to bedding are two to three orders of magnitude lower. Compared to previous studies on marine lithotypes, Newark shales have rather poor gas storage properties with average He-porosities of 2.3% and average methane sorption capacities of 0.047 mmol g−1.

Three stages of methane adsorption capacity affected by moisture content

Methane adsorption capacity is a key factor in determining shale gas in place (GIP) – requiring that it is determined under in situ moisture conditions. Current methods may be insufficient to investigate these exact characteristics when applied to actual reservoirs with high or variable moisture contents. We propose a heating and cooling (HC) method to prepare shale samples to arbitrary moisture contents (Mc up to 10%). A series of CH4 adsorption experiments on two different types of shale are conducted as a function of Mc at 35 °C, 45 °C, and 55 °C, and at a CH4 pressure of up to 10 MPa. Experimental results indicate that the methane sorption capacity versus moisture content curves exhibit a linear decreasing stage, a flat stage and a convex decreasing stage, separated by two threshold moisture contents. The lower moisture content threshold (Mfc) represents coverage of the entire hydrophilic surface by a monolayer of water. The upper moisture content threshold (Msc) is the point at which no methane is adsorbed on the surface of the clay pores and adsorption capacity is further reduced as moisture content is increased. The linear stage with Mc up to the Mfc is mainly dominated by the competition between water and methane for adsorption sites on the surface of clay pores. Slope value of this stage are affected by pressure, temperature and shale compositions. The flat stage represents that the moisture content has negligible effect on shale adsorption capacity for Mc in the range Mfc to Msc. Methane adsorption capacity decreases in a convex manner above Msc, suggesting water condensation in organic pores as the surface area for methane adsorption is reduced by water blocking. A conceptual Bi-Langmuir model is presented to represent the crucial effects of moisture content on methane adsorption capacity including accurate estimations of original GIP under different reservoir conditions.

Upper Paleozoic Marine Shale Characteristics and Exploration Prospects in the Northwestern Guizhong Depression, South China

Multiple sets of organic-rich shales developed in the Upper Paleozoic of the northwestern Guizhong Depression in South China. However, the exploration of these shales is presently at a relatively immature stage. The Upper Paleozoic shales in the northwestern Guizhong Depression, including the Middle Devonian Luofu shale, the Nabiao shale, and the Lower Carboniferous Yanguan shale, were investigated in this study. Mineral composition analysis, organic matter analysis (including total organic carbon (TOC) content, maceral of kerogen and the vitrinite reflection (Ro)), pore characteristic analysis (including porosity and permeability, pore type identification by SEM, and pore size distribution by nitrogen sorption), methane isothermal sorption test were conducted, and the distribution and thickness of the shales were determined, Then the characteristics of the two target shales were illustrated and compared. The results show that the Upper Paleozoic shales have favorable organic matter conditions (mainly moderate to high TOC content, type I and II1 kerogen and high to over maturity), good fracability potential (brittleness index (BI) > 40%), multiple pore types, stable distribution and effective thickness, and good methane sorption capacity. Therefore, the Upper Paleozoic shales in the northern Guizhong Depression have good shale gas potential and exploration prospects. Moreover, the average TOC content, average BI, thickness of the organic-rich shale (TOC > 2.0 wt%) and the shale gas resources of the Middle Devonian shales are better than those of the Lower Carboniferous shale. The Middle Devonian shales have better shale gas potential and exploration prospects than the Lower Carboniferous shales.

Methane Hydrate Uptake of MCM-41 Mesoporous Molecular Sieves with Preadsorbed Water

Ordered meosoporous molecular sieves of MCM-41 were prepared by adjusting the pH with acetic acid. The synthesized samples were evaluated by 77 K nitrogen-adsorption data. The sample synthesized by a one-time pH adjustment has the same good characters as that synthesized by a three-times pH adjustment. The morphology and crystal structure of the calcined MCM-41 materials were examined with XRD and TEM, in which the ordered channel structure was confirmed. The sorption equilibrium isotherms of wet samples showed a sharp rise, because the large amount methane hydrate had been formed in the MCM-41 samples’ porous space. The methane sorption amount of the mesoporous MCM-41 sample with preadsorbed water reached 10.87 mmol at Rw = 2.0, which was 2.97 times that of the dry mesoporous MCM-41 sample. The comparative methane sorption capacities of the three ordered mesoporous materials (MCM-41, SBA-15, and large-pore MCM-41) by preadsorbtion of the same water mass (Rw = 2.0) are almost identical, and no previous articles have reported similar results for the mesoporous materials. However, the methane hydrate formation pressures of the three samples are different due to the pore diameter effect.