Experimental study of the impact on methane adsorption capacity of continental shales with thermal evolution

Zhong, Jiaai; Chen, Guojun; Lv, Chengfu; Yang, Wei; Yong, Xu; Yang, Shuang; Xue, Lixin

doi:10.1016/j.jnggs.2015.12.001

Cited by 22 publications

(21 citation statements)

References 12 publications

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“…Literature data have shown that gas absorption capacity is influenced by many factors, including geochemical parameters, such as the total organic matter content (TOC), kerogen types, as well as thermal maturity [1,2,5,6], pore volume and pore size distribution [1,7], petrological and mineralogical factors [8,9], and environmental factors such as the buried temperature and pressure. Although some researchers observed that absorption capacity decreases with the increase of the TOC [10], it is generally accepted that organic matter is the primary control factor in the adsorbed gas volume and is positively correlated with the TOC [11][12][13][14]. In addition, the adsorbed gas volume increases with the confining pressure, whereas it decreases inversely to the temperature [9,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

“…The main reason for this is that the internal surface area and the adsorption energy of the small pores is higher than the large pores [1,6,7,18]. Nevertheless, recent reports revealed that the mesopores and macropores are also good places for methane adsorption [10,14,19], and some observed a negative correlation between the adsorbed gas volume and the porosity [13].…”

Section: Introductionmentioning

confidence: 99%

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Investigating Influential Factors of the Gas Absorption Capacity in Shale Reservoirs Using Integrated Petrophysical, Mineralogical and Geochemical Experiments: A Case Study

Fan

Zhao

et al. 2018

Energies

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Estimating in situ gas content is very important for the effective exploration of shale gas reservoirs. However, it is difficult to choose the sensitive geological and geophysical parameters during the modeling process, since the controlling factors for the abundance of gas volumes are often unknown and hard to determine. Integrated interdisciplinary experiments (involving petrophysical, mineralogical, geochemical and petrological aspects) were conducted to search for the influential factors of the adsorbed gas volume in marine gas shale reservoirs. The results showed that in shale reservoirs with high maturity and high organic content that the adsorbed gas volume increases, with an increase in the contents of organic matter and quartz, but with a decrease in clay volume. The relationship between the adsorbed gas content and the total porosity is unclear, but a strong relationship between the proportions of different pores is observed. In general, the larger the percentage of micropores, the higher the adsorbed gas content. The result is illuminating, since it may help us to choose suitable parameters for the estimation of shale gas content.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigating Influential Factors of the Gas Absorption Capacity in Shale Reservoirs Using Integrated Petrophysical, Mineralogical and Geochemical Experiments: A Case Study

Fan

Zhao

et al. 2018

Energies

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“…In experiment, there are two commonly used methods to study gas adsorption: gravimetric and volumetric method. Gravimetric method uses magnetic suspension balance to obtain adsorption isotherms 15 . It measures the excess adsorption capacity based on the difference between gravity and buoyancy 16 .…”

Section: Introductionmentioning

confidence: 99%

Characterization of Methane Excess and Absolute Adsorption in Various Clay Nanopores from Molecular Simulation

Tian

Yan

Jin

2017

Sci Rep

155

162

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In this work, we use grand canonical Monte Carlo (GCMC) simulation to study methane adsorption in various clay nanopores and analyze different approaches to characterize the absolute adsorption. As an important constituent of shale, clay minerals can have significant amount of nanopores, which greatly contribute to the gas-in-place in shale. In previous works, absolute adsorption is often calculated from the excess adsorption and bulk liquid phase density of absorbate. We find that methane adsorbed phase density keeps increasing with pressure up to 80 MPa. Even with updated adsorbed phase density from GCMC, there is a significant error in absolute adsorption calculation. Thus, we propose to use the excess adsorption and adsorbed phase volume to calculate absolute adsorption and reduce the discrepancy to less than 3% at high pressure conditions. We also find that the supercritical Dubinin-Radushkevich (SDR) fitting method which is commonly used in experiments to convert the excess adsorption to absolute adsorption may not have a solid physical foundation for methane adsorption. The methane excess and absolute adsorptions per specific surface area are similar for different clay minerals in line with previous experimental data. In mesopores, the excess and absolute adsorptions per specific surface area become insensitive to pore size. Our work should provide important fundamental understandings and insights into accurate estimation of gas-in-place in shale reservoirs.

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“…The simulations were performed at standard temperature and the pressure was calculated based on Ping Robinson equation of state (EOS) (Peng and Robinson, 1976) by inserting specific number of gas molecules to satisfy the required density. One hundred molecules of CH 4 were inserted in the system free of water to match a pressure of about 125 bar which was studied experimentally to represent the shale pressure (Zhong et al, 2016;Xing et al, 2018). Number of CO 2 molecules was chosen as an equimolar of methane for comparison purposes.…”

Section: Simulation Details and Algorithmmentioning

confidence: 99%

The Effect of Hydration on the Structure and Transport Properties of Confined Carbon Dioxide and Methane in Calcite Nanopores

Mohammed

Gadikota

2018

Front. Energy Res.

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With increasing interest in using or displacing confined water for CH 4 recovery or CO 2 storage in nanoporous environments, understanding the organization and diffusion of gases is confined water environments is essential. In this study, the effect of hydration on the structure and diffusivity of confined carbon dioxide (CO 2) and methane (CH 4) in 2 nm slit-shaped calcite nanopore was studied using classical molecular dynamics simulations. The absence of confined water and the effect of different water concentrations including one layer of confined water composed of 150 water molecules, 500 water molecules, and 1,296 water molecules that correspond to the density of bulk water of 1 g/cm 3 on the structural arrangement and diffusivity of confined CO 2 and CH 4 were investigated. Water molecules were found to influence the anisotropic distribution and mobility of confined CO 2 and CH 4 significantly by altering the structures of the adsorbed gas layers onto the calcite surfaces. The preferential adsorption of water on calcite surface over CO 2 and CH 4 resulted in the displacement of the adsorbed gas molecules toward the center of the pore. This water-induced displacement impacts the diffusivity of the confined gases by enabling transport through the center of the pore where there are fewer intermolecular collisions and less steric hindrance for transporting the molecules. Therefore, the diffusivity of CO 2 and CH 4 is higher in the presence of a single water layer as opposed to in pores without water. Energetic calculations showed that van der Waals and electrostatic interactions contributed to the affinity of CO 2 for calcite surfaces, while van der Waals interactions dominate CH 4 interactions with calcite and the surrounding water molecules. The anisotropic variations in the diffusivities of confined fluids emerge from changes in the organization of confined fluids and potential differences in the free energy distributions as a function of the orientation of the calcite surface. These findings suggest that any efforts to potentially engineer the nano-scale pore environment in calcite for enhanced gas recovery or storage will require us to consider the organization and anisotropic transport behaviors of confined fluids.

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Experimental study of the impact on methane adsorption capacity of continental shales with thermal evolution

Cited by 22 publications

References 12 publications

Investigating Influential Factors of the Gas Absorption Capacity in Shale Reservoirs Using Integrated Petrophysical, Mineralogical and Geochemical Experiments: A Case Study

Investigating Influential Factors of the Gas Absorption Capacity in Shale Reservoirs Using Integrated Petrophysical, Mineralogical and Geochemical Experiments: A Case Study

Characterization of Methane Excess and Absolute Adsorption in Various Clay Nanopores from Molecular Simulation

The Effect of Hydration on the Structure and Transport Properties of Confined Carbon Dioxide and Methane in Calcite Nanopores

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