Methane adsorption on shale under in situ conditions: Gas-in-place estimation considering in situ stress

Feng, Miao; Wu, Di; Liu, Xueying; Xiao, Xiaochun; Zhai, Wenbo; Geng, Yanyan

doi:10.1016/j.fuel.2021.121991

Cited by 25 publications

(19 citation statements)

References 36 publications

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“…Based on lowpressure adsorption data, predicting the high-pressure adsorption isotherms is a very practical method. 19 Therefore, the adsorption data of samples 1−3 with a pressure less than 12 MPa are selected as the modeling data, and the adsorption data with a pressure greater than 12 MPa are used as the comparison data to compare the accuracy of the predicted data. The initial value and upper and lower limits of each parameter are set according to the value range of each parameter in Section 4.1, and the initial values of ε s /k, α p /k, and α m /k are −1000, −280, and 970 K, respectively; the upper and lower limits are −900 and −1100 K, −270 and −290 K, and 980 and 960 K, respectively.…”

Section: Excess Adsorption Isotherm Prediction Of the Monolayer And M...mentioning

confidence: 99%

“…The buried depth of the shale reservoir is generally 2000–4000 m, and the reservoir pressure can reach 30–60 MPa. , The high-pressure adsorption test requires more precise experimental equipment and longer experimental period. Based on low-pressure adsorption data, predicting the high-pressure adsorption isotherms is a very practical method . Therefore, the adsorption data of samples 1–3 with a pressure less than 12 MPa are selected as the modeling data, and the adsorption data with a pressure greater than 12 MPa are used as the comparison data to compare the accuracy of the predicted data.…”

Section: Ch4 Adsorption Mechanism Based On the Ono–kondo Lattice Mode...mentioning

confidence: 99%

“…The OK model and SLD model were used to fit the adsorption data, such as the study byPang et al 26 and Miao et al19 …”

mentioning

confidence: 99%

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Absolute Adsorption Calculation of Shale Gas Based on the Ono–Kondo Lattice Model

Chen

Feng

et al. 2022

Energy Fuels

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Adsorbed gas is the main occurrence state in shale gas, and its adsorption mechanism is of great significance for accurate evaluation of shale gas reserves. The adsorbed phase density is the key to accurately evaluate the adsorbed gas content. At present, there is no consensus on the adsorption mechanism of shale gas, resulting in different calculation results of adsorbed phase density, which further affects the calculation of absolute adsorption. Therefore, based on previous experimental studies on CH4 adsorption in shale at high pressure, the Ono–Kondo lattice (OK) model is used to investigate the influence of different adsorption mechanisms on the calculation of adsorbed phase density and the calculation of absolute adsorption, and the parameter range of the OK model suitable for describing the CH4 adsorption behavior in shale is determined. It is found that the modified two-layer OK model is suitable to describe the CH4 adsorption behavior in shale, and the adsorbed phase density varying with temperature and pressure can more accurately predict the CH4 absolute adsorption in shale. The CH4 adsorption mechanism in shale is two-layer adsorption. The mainstream monolayer adsorption overestimates the adsorbed phase density and underestimates the adsorbed phase volume, which leads to an underestimation of the adsorbed gas content and an overestimation of the free gas content. These conclusions are of great significance for accurate evaluation of shale gas reservoirs.

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Section: Excess Adsorption Isotherm Prediction Of the Monolayer And M...mentioning

confidence: 99%

Section: Ch4 Adsorption Mechanism Based On the Ono–kondo Lattice Mode...mentioning

confidence: 99%

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Absolute Adsorption Calculation of Shale Gas Based on the Ono–Kondo Lattice Model

Chen

Feng

et al. 2022

Energy Fuels

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“…After a comprehensive comparison of the advantages and disadvantages of the Langmuir model, Langmuir−Freundlich model, and Dubinin−Astakhov (D−A) model, a new adsorption model is derived by Li et al to describe the methane adsorption feature under various moisture. 38 Miao et al proposed a gas-reserve estimation method utilizing the SLD method, 39 in which the in situ stress condition was considered. From the above brief review, it can be demonstrated that the theoretical model derived from the rigorous microscopic physics can capture the methane adsorption feature in specific conditions, while key parameters required for the proposed model are generally unavailable and hard to determine.…”

Section: Introductionmentioning

confidence: 99%

Wettability Impact on Nanoconfined Methane Adsorption Behavior: A Simplified Local Density Investigation

Luo

Fang³

et al. 2022

Energy Fuels

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The key to unlock huge economic benefits from shale gas reservoirs is to reveal the methane adsorption behavior in nanopores. A clear understanding of nanoconfined methane adsorption behavior will dramatically mitigate the imbalance between energy supply and demand over the world, which remains a challenge and entails in-depth investigation. To the current knowledge, specific materials, like graphene layers, quartz, and feldspar, are utilized to mimic an organic or inorganic solid phase in shale, while the shale physical composition is complex and evidently cannot be represented by one or several identified compositions. In this paper, to bridge the knowledge gap, the wettability effect, embodied by the surface contact angle, is correlated to the nanoconfined methane adsorption behavior for the first time. Because the solid-phase composition variation will result in alteration of the contact angle regarding the solid−methane system, the incorporation of the surface contact angle enables this research to cover a wide range of solid composition variations. First, the relationship between solid−fluid interactions and the surface contact angle is revealed. Then, the simplified local density method is proposed by coupling the relationship upon the surface contact angle, and also the shift of methane critical properties induced by the nanoconfinement effect is considered. Results show that (a) the ratio of bulk methane to nanoconfined average density ranges from 0.55 to 0.71 with increasing pressure, (b) adsorption peak density can enhance up to 3 times by manipulating the solid-phase wettability effect, and (c) the adsorption capacity in organic-rich shale is 1.72 times that in inorganic-rich shale. The research provides a profound theoretical framework to elucidate the methane adsorption mechanism in nanopores and serves as a robust tool to reproduce and predict the methane adsorption behavior.

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“…The mathematical model of shale gas adsorption is usually established based on isothermal adsorption experiment by using classical adsorption models to fit the experimental results, − mainly including the mono molecule layer adsorption model, the multimolecular layers adsorption model, the microporous filling model, the simplified local density (SLD) adsorption model, the Ono-Kondo adsorption model, and the modified models based on classical adsorption theories. − Although a large amount of research on experiments, simulation, and models of shale gas adsorption has been reported, these rich achievements are mainly for shallow and middle shale, so they cannot directly describe the more complex adsorption characteristics, such as deep shale gas reservoirs with higher temperature and higher pressure. Therefore, it is important to review the existing research methods and adsorption models of shale gas and clarify their features, and then put forward the next research direction.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Models for Shale Gas: A Mini-Review

et al. 2022

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Clarifying shale gas adsorption mechanism and establishing a reliable shale gas adsorption model are the basis of evaluating shale gas geological reserve and studying flow theory, so rich research on shale gas adsorption has been reported recently. However, with the development of shale gas reservoirs, the reservoir depth is deeper, and the environment is more complicated, especially the characteristic of high temperature and high pressure. These bring a new challenge to reveal the deep shale gas adsorption characteristics by using existing shale gas adsorption theoretical models established based on the middle and shallow shale gas reservoirs. Therefore, the popular methods of experiments, simulation, and models on shale gas adsorption are summarized in detail, and their advantages and disadvantages are clarified. The results show that the isothermal adsorption experiment of shale gas is still the basis method to study shale gas adsorption, but the experimental pressure should be further increased to meet the conditions of deep shale gas reservoir. Molecular simulation can reveal the shale gas adsorption microcosmic mechanisms, but the simulation results have multiple solutions, and the simulation scale is small, difficult to truly reflect the adsorption characteristics of shale gas in a larger scale. Shale gas adsorption models are established mostly based on classical adsorption models or their modifications, and hence they are difficult to reflect shale reservoir characteristics, such as total organic carbon (TOC), primary water, and desorption hysteresis. Therefore, it is important to establish a set of shale gas adsorption−desorption model which can fully consider the shale reservoir characteristics in the future.

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Methane adsorption on shale under in situ conditions: Gas-in-place estimation considering in situ stress

Cited by 25 publications

References 36 publications

Absolute Adsorption Calculation of Shale Gas Based on the Ono–Kondo Lattice Model

Absolute Adsorption Calculation of Shale Gas Based on the Ono–Kondo Lattice Model

Wettability Impact on Nanoconfined Methane Adsorption Behavior: A Simplified Local Density Investigation

Adsorption Models for Shale Gas: A Mini-Review

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