Methane adsorption effected by pore structure of overmature continental shale: Lower Cretaceous Shahezi Formation, Xujiaweizi Fault, Songliao Basin

Abstract

Overmature continental shale is commonly developed, but few studies have given insight into its pore structure and sorption capacity. Various techniques, including SEM, helium porosity and permeability, N₂/CO₂ adsorption, MICP, and NMR, were used to detect the pore structure of shale from the Shahezi Formation, Xujiaweizi Fault, Songliao Basin. The excess methane adsorption volumes were measured by the volumetric method and modeled by the Langmuir model. Based on the findings, the most developed pores are intraparticle pores in clay minerals, followed by the dissolution pores in feldspar, but organic pores are uncommon. The selected shales have low helium porosity (mean 1.66%) and ultralow permeability (mean 0.0498 × 10⁻³μm²). The pore throats are at the nanoscale, and the pore-throat size distributions are unimodal, with most less than 50 nm. The studied shales are characterized by the lower specific surface area (SSA) and pore volume (PV) but the larger average pore diameter. The total SSA is contributed by the micro- and mesopores, while the PV is dominated by meso- and macropores. The pore structures are more complex and controlled by multiple factors, such as mineral compositions and diagenesis, but organic matter is not critical. The maximum absolute adsorption methane volume (V_L) is 0.97−3.58 cm³/g (mean 1.90 cm³/g), correlating well with the total SSA, SSA, and pore volume of micropores, which indicates that methane is mainly adsorbed and stored in micropores, followed by mesopores.

Graphical abstract

Keywords

continental shale / pore structure / methane adsorption / Shahezi Formation / Songliao Basin

References

[1] Ambrose R, Hartman R, Diaz-Campos M, Akkutlu I, Sondergeld C (2012). Shale gas in-place calculations part I: new pore-scale considerations.SPE J, 17(1): 219–229

[2] Bai L, Liu B, Du Y, Wang B, Tian S, Wang L, Xue Z (2022). Distribution characteristics and oil mobility thresholds in lacustrine shale reservoir: insights from N₂ adsorption experiments on samples prior to and following hydrocarbon extraction.Petrol Sci, 19(2): 486–497

[3] Bi H, Jiang Z, Li J, Xiong F, Li P, Chen L, Pan Q, Wu Y (2017). The Ono–Kondo model and an experimental study on supercritical adsorption of shale gas: a case study on Longmaxi shale in southeastern Chongqing, China.J Nat Sci Eng, 31: 2755–2764

[4] Chen Q, Zhang J, Tang X, Li W, Li Z (2016). Relationship between pore type and pore size of marine shale: an example from the Sinian–Cambrian formation, upper Yangtze region, south China.Int J Coal Geol, 158: 13–28

[5] Curtis J (2002). Fractured shale-gas systems.AAPG Bull, 86: 1921–1938

[6] Feng G, Zhu Y, Chen S, Wang Y, Ju W, Hu Y, You Z, Wang G (2020). Supercritical methane adsorption on shale over wide pressure and temperature ranges: implications for gas-in-place estimation.Energy Fuels, 34(3): 3121–3134

[7] Feng G, Zhu Y, Wang G, Chen S, Wang Y, Ju W (2019). Supercritical methane adsorption on overmature shale: effect of pore structure and fractal characteristics.Energy Fuels, 33(9): 8323–8337

[8] Gasparik M, Ghanizadeh A, Bertier P, Gensterblum Y, Bouw S, Krooss B (2012). High-pressure methane sorption isotherms of black shales from the Netherlands.Energy Fuels, 26(8): 4995–5004

[9] GreggS, SingK (1982). Adsorption, Surface Area and Porosity (2nd ed). New York: Academic Press

[10] Hu K, Mischo H (2020). High-pressure methane adsorption and desorption in shales from the Sichuan Basin, southwestern China.Energy Fuels, 34(3): 2945–2957

[11] Hu Q, Zhang Y, Meng X, Li Z, Xie Z, Li M (2017). Characterization of micro-nano pore networks in shale oil reservoirs of Paleogene Shahejie Formation in Dongying Sag of Bohai Bay, east China.Pet Explor Dev, 44(5): 720–730

[12] Jarvie D M (2012). Shale resource systems for oil and gas: part 1-Shale-gas resource systems.AAPG Mem, 97: 69–87

[13] Jarvie D, Hill R, Ruble T, Pollastro R (2007). Unconventional shale-gas systems: the Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment.AAPG Bull, 91(4): 475–499

[14] Kelly S, El-Sobky H, Torres-Verdín C, Balhoff M T (2016). Assessing the utility of FIB-SEM images for shale digital rock physics.Adv Water Resour, 95: 302–316

[15] Klaver J, Desbois G, Littke R, Urai J (2016). BIB-SEM pore characterization of mature and post mature Posidonia Shale samples from the Hils area, Germany.Int J Coal Geol, 158: 78–89

[16] Kuila U, McCarty D, Derkowski A, Fischer T, Prasad M (2014). Total porosity measurement in gas shales by the water immersion porosimetry (WIP) method.Fuel, 117: 1115–1129

[17] Li A, Ding W, Zhou X, Cao X, Zhang M, Fu F, Chen E (2017b). Investigation of the methane adsorption characteristics of marine shale: a case study of Lower Cambrian Qiongzhusi Shale in eastern Yunnan Province, south China.Energy Fuels, 31(3): 2625–2635

[18] Li J, Li B, Gao Z, Zhang Y, Wang B (2021). Adsorption behavior, including the thermodynamic characteristics of wet shales under different temperatures and pressures.Chem Eng Sci, 230: 116228

[19] Li J, Lu S, Zhang P, Cai J, Li W, Wang S, Feng W (2020a). Estimation of gas-in-place content in coal and shale reservoirs: a process analysis method and its preliminary application.Fuel, 259: 116266

[20] Li W, Li J, Lu S, Chen G, Pang X, Zhang P, He T (2022). Evaluation of gas-in-place content and gas-adsorbed ratio using carbon isotope fractionation model: a case study from Longmaxi shales in Sichuan Basin, China.Int J Coal Geol, 249: 103881

[21] Li W, Lu S, Li J, Zhang P, Chen C, Wang S (2019). The coupling relationship between material composition and pore microstructure of southern China marine shale.Nat Gas Geosci, 30: 27–38

[22] Li W, Lu S, Li J, Zhang P, Wang S, Feng W, Wei Y (2020b). Carbon isotope fractionation during shale gas transport: mechanism, characterization and significance.Sci China Earth Sci, 63(5): 674–689

[23] Li Z, Liu D, Cai Y, Ranjith P, Yao Y (2017a). Multi-scale quantitative characterization of 3-D pore-fracture networks in bituminous and anthracite coals using FIB-SEM tomography and X-ray μ-CT.Fuel, 209: 43–53

[24] Loucks R, Reed R, Ruppel S, Hammes U (2012). Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores.AAPG Bull, 96(6): 1071–1098

[25] Lu S, Gu M, Zhang F, Zhang L, Xiao D (2017). Hydrocarbon accumulation stages and type division of Shahezi Fm tight glutenite gas reservoirs in the Xujiaweizi Fault Depression, Songliao Basin.Nat Gas Ind, 37: 12–21

[26] LuoX, WangS, WangZ, Jing Z, LvM, ZhaiZ, HanT (2015). Adsorption of methane, carbon dioxide and their binary mixtures on Jurassic shale from the Qaidam Basin in China. Int J Coal Geol, 150–151: 210–223

[27] MosherK, HeJ, LiuY, RuppE, WilcoxJ (2013). Molecular simulation of methane adsorption in micro- and mesoporous carbons with applications to coal and gas shale systems. Int J Coal Geol, 109–110: 36–44

[28] Rexer T, Benham M, Aplin A, Thomas K (2013). Methane adsorption on shale under simulated geological temperature and pressure conditions.Energy Fuels, 27(6): 3099–3109

[29] Sakurovs R, Day S, Weir S, Duffy G (2007). Application of a modified Dubinin-Radushkevich equation to adsorption of gases by coals under supercritical conditions.Energy Fuels, 21(2): 992–997

[30] Tian H, Li T, Zhang T, Xiao X (2016). Characterization of methane adsorption on overmature Lower Silurian–Upper Ordovician shales in Sichuan Basin, southwest China: experimental results and geological implications.Int J Coal Geol, 156: 36–49

[31] Wang M, Song Y, Wang W, Wang Y, Shi L (2014). Gas generation characteristics and resource potential of the deep source rock in Xujiaweizi Fault depression, northern Songliao Basin.Nat Gas Geosci, 25: 1011–1018

[32] Wang P, Jiang Z, Ji W, Zhang C, Yuan Y, Chen L, Yin L (2016b). Heterogeneity of intergranular, intraparticle and organic pores in Longmaxi shale in Sichuan Basin, south China: evidence from SEM digital images and fractal and multifractal geometries.Mar Pet Geol, 72: 122–138

[33] Wang S, Li J, Lu S, Zhang P, Zhang J, Li W (2019). Development characteristics of organic matter of marine shale in the southeastern Chongqing, China.J Earth Sci Environ, 4: 721–733

[34] Wang Y, Zhu Y, Liu S, Zhang R (2016a). Pore characterization and its impact on methane adsorption capacity for organic-rich marine shales.Fuel, 181: 227–237

[35] Wang Z, Li Y, Guo P, Meng W (2016c). Analyzing the adaption of different adsorption models for describing the shale gas adsorption law.Chem Eng Technol, 39(10): 1921–1932

[36] Xiao D, Jiang S, Thul D, Lu S, Zhang L, Li B (2018). Impacts of clay on pore structure, storage and percolation of tight sandstones from the Songliao Basin, China: implications for genetic classification of tight sandstone reservoirs.Fuel, 211: 390–404

[37] Xu Q, Lin H, Zhao Y, Wang B, Ma B, Ding R, Wang H, Hou T (2021). Evolution of pore structure in organic shale with type III kerogen and high kaolinite content in Ningwu Basin.Front Earth Sci, 15(4): 831–848

[38] Zargari S, Canter K, Prasad M (2015). Porosity evolution in oil-prone source rocks.Fuel, 153: 110–117

[39] Zhang D (2017). Characterization of microscopic pore structure of tight sandstone reservoirs through nitrogen adsorption experiment: case study of Shahezi Formation in Xujiaweizi Fault Depression, Songliao Basin, China.Nat Gas Geosci, 28: 898–908

[40] Zhang J, Chu X, Wei C, Zhang P, Zou M, Wang B, Quan F, Ju W (2022). Review on the application of low-field nuclear magnetic resonance (LF-NMR) technology in coalbed methane production simulation.ACS Omega, 7(30): 26298–26307

[41] Zhang P, Lu S, Li J (2019). Characterization of pore size distributions of shale oil reservoirs: a case study from Dongying sag, Bohai Bay basin, China.Mar Pet Geol, 100: 297–308

[42] Zhang P, Lu S, Li J, Chang X (2020b). 1D and 2D Nuclear magnetic resonance (NMR) relaxation behaviors of protons in clay, kerogen and oil-bearing shale rocks.Mar Pet Geol, 114: 104210

[43] Zhang P, Lu S, Li J, Chang X, Li J, Li W, Chen C, Wang S, Feng W (2020a). Broad ion beam-scanning electron microscopy pore microstructure and multifractal characterization of shale oil reservoir: a case sample from Dongying Sag, Bohai Bay Basin, China.Energ Explor Exploit, 38(3): 613–628

[44] Zhang P, Lu S, Li J, Chen C, Xue H, Zhang J (2018). Petrophysical characterization of oil-bearing shales by low-field nuclear magnetic resonance (NMR).Mar Pet Geol, 89: 775–785

[45] Zhao P, Han C, Sun Y, Danesh N, Liu T, Gao Y (2021a). Nano- to micro-pore characterization by synchrotron radiation SAXS and nano-CT for bituminous coals.Front Earth Sci, 15(2): 189–201

[46] Zhao P, He B, Zhang B, Liu J (2022). Porosity of gas shale: is the NMR-based measurement reliable?.Petrol Sci, 19(2): 509–517

[47] Zhao W, Li X, Wang T, Fu X (2021b). Pore size distribution of high volatile bituminous coal of the southern Junggar Basin: a full-scale characterization applying multiple methods.Front Earth Sci, 15(2): 237–255

[48] Zhou S, Xue H, Ning Y, Guo W, Zhang Q (2018). Experimental study of supercritical methane adsorption in Longmaxi shale: insights into the density of adsorbed methane.Fuel, 211: 140–148

[49] Zou C, Pan S, Jing Z, Gao J, Yang Z, Wu S, Zhao Q (2020). Shale oil and gas revolution and its impact.Acta Petrol Sin, 41: 1–12

[50] Zou C, Zhao Q, Cong L, Wang H, Shi Z, Wu J, Pan S (2021). Development progress, potential and prospect of shale gas in China.Nat Gas Ind, 41: 1–14

Acknowledgments

This work was financially supported by the Natural Science Foundation of Shandong Province (Nos. ZR2020QD036, ZR2020QD037, and ZR2021QD072).

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2023 Higher Education Press

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