Shale gas potential of the major marine shale formations in the Upper Yangtze Platform, South China, Part II: Methane sorption capacity

Tan, Jingqiang; Weniger, Philipp; Krooß, Bernhard M.; Merkel, Alexej; Horsfield, Brian; Zhang, Jinchuan; Boreham, Christopher J.; Graas, Ger van; Tocher, Bruce A.

doi:10.1016/j.fuel.2014.03.064

Cited by 306 publications

(217 citation statements)

References 46 publications

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“…2). The Lower Silurian shale, widely developed in the Upper Yangtze Platform, has recently been selected as the main target for shale gas exploration and development (Chen et al, 2011Tan et al, 2014;Ji et al, 2015Ji et al, , 2016Jiang et al, 2016;Liu et al, 2016;Tang et al, 2016;Yang et al, 2016a,b,c). The Silurian shales occur in some strongly uplifted areas as outcrops, which indicates that the shales have experienced a complicated tectonic evolution, then influencing the gas content (Hao et al, 2013).…”

Section: Geological Setting and Samplesmentioning

confidence: 99%

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Quantitative characterization of micropore structure for organic-rich Lower Silurian shale in the Upper Yangtze Platform, South China: Implications for shale gas adsorption capacity

Chen

Jiang

Liu

et al. 2017

Adv. Geo-Energ. Res.

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The pores in shales are mainly of nanometer-scale, and their pore size distribution is very important for shale gas storage and adsorption capacity, especially micropores having widths less than 2 nm, which contribute to the main occurrence space for gas adsorption. This study is focused on the organic-rich Lower Silurian black shale from four wells in the Upper Yangtze Platform, and their total organic carbon (TOC), mineralogical composition and micropore characterization were investigated. Low pressure CO2 adsorption measurement was conducted at 273.15 K in the relative pressure range of 0.0001-0.03, and the micropore structure was characterized by Dubinin-Radushkevich (DR) equation and density functional theory (DFT) method and then the relationship between micropore structure and shale gas adsorption capacity was discussed. The results indicated that (1) The Lower Silurian shale have high TOC content in the range of 0.92-4.96%, high quartz content in the range of 30.6-69.5%, and high clays content in the range of 24.1-51.2%. The TOC content shows a strong positive relationship with the quartz content which suggests that the quartz is mainly biogenic in origin. (2) The micropore volume varies from 0.12 cm 3 /100 g to 0.44 cm 3 /100 g and micropore surface area varies from 4.97 m 2 /g to 17.94 m 2 /g. Both of them increase with increasing TOC content, indicating TOC is the key factor to control the micropore structure of the Lower Silurian shale. (3) Low pressure CO2 adsorption measurement provides the most suitable detection range (0.3-1.5 nm) and has high reliability and accuracy for micropore structure characterization. (4) The TOC content is the key factor to control gas adsorption capacity of the Lower Silurian shale in the Upper Yangtze Platform.

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Section: Geological Setting and Samplesmentioning

confidence: 99%

“…The thickness generally ranges from 50 to 100 m with an EqRo of 2.5-3.0%, generating mainly dry gas and secondary gas (Tan et al, 2014;Pan et al, 2016).…”

Section: Geological Setting and Samplesmentioning

confidence: 99%

Quantitative characterization of micropore structure for organic-rich Lower Silurian shale in the Upper Yangtze Platform, South China: Implications for shale gas adsorption capacity

Chen

Jiang

Liu

et al. 2017

Adv. Geo-Energ. Res.

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“…In China, shale from both the Niutitang and Longmaxi formations are the representative organic-rich marine shale intervals, and have been considered to be the major exploration and development targets of shale gas (Figure 1). Because of the similar tectonic movement in the peripheral regions of Sichuan basin and stable marine depositional environment, these two shale intervals in the Yangtze Platform are generally characterized by high TOC content, high thermal maturity, oil-prone organic matter, and high brittle minerals content throughout the whole Yangtze Platform [9,14]. Thus, the four marine shale samples used in this study could adequately represent the marine shales developed in other area.…”

Section: Bidisperse Diffusion Modelmentioning

confidence: 99%

“…In this experiment, the main procedures can be summarized as follows: (1) the shale powder samples need to be degassed firstly by evacuation for 12 h at 100 • C; (2) leak testing should be conducted by using helium at 8 MPa for two hours, and the accepted leakage rate is less than 500 Pa/hour; (3) the void volume of the sample cell, which should be applied for the calculation of isotherms and methane adsorption amounts, was determined by helium expansion; and (4) remove the helium within the sample cell by evacuation and then perform the methane adsorption isotherm measurement. Then, the adsorption amount of methane at various pressures during the adsorption measurement was calculated through the equation [9,41]:…”

Section: Methane Adsorption Isotherms and Adsorption Rate Measurementsmentioning

confidence: 99%

“…The pore structures of shale are highly heterogeneous, with the pore size mainly ranging from nanometer to micrometer-sized [5,6]. Previous research has reported that nanometer-sized pores, which are predominantly associated with organic matter and clay minerals [6][7][8], could provide larger surface areas and higher adsorption energy for gas molecule adsorption [9][10][11][12], while micrometer-sized pores-which are generally associated with inorganic minerals [6]-are more likely to connect with induced fractures for gas flow and transport [13,14]. For gas desorption, once external conditions, such as temperature and pressure changes, for example, and artificial fractures disturb the equilibrium, the free gas molecules in fractures and macropore networks flow from high-pressure zones to low-pressure zones, and then gas that adsorbed onto the surface of organic matter and clay minerals starts to desorb, inducing a concentration gradient between the bulk particles and their surface.…”

Section: Introductionmentioning

confidence: 99%

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Methane Adsorption Rate and Diffusion Characteristics in Marine Shale Samples from Yangtze Platform, South China

et al. 2017

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Knowledge of the gas adsorption rate and diffusion characteristics in shale are very important to evaluate the gas transport properties. However, research on methane adsorption rate characteristics and diffusion behavior in shale is not well established. In this study, high-pressure methane adsorption isotherms and methane adsorption rate data from four marine shale samples were obtained by recording the pressure changes against time at 1-s intervals for 12 pressure steps. Seven pressure steps were selected for modelling, and three pressure steps of low (~0.4 MPa), medium (~4.0 MPa), and high (~7.0 MPa) were selected for display. According to the results of study, the methane adsorption under low pressure attained equilibrium much more quickly than that under medium and high pressure, and the adsorption rate behavior varied between different pressure steps. By fitting the diffusion models to the methane adsorption rate data, the unipore diffusion model based upon unimodal pore size distribution failed to describe the methane adsorption rate, while the bidisperse diffusion model could reasonably describe most of the experimental adsorption rate data, with the exception of sample YY2-1 at high pressure steps. This phenomenon may be related to the restricted assumption on pore size distribution and linear adsorption isotherm. The diffusion parameters α and β/α obtained from the bidisperse model indicated that both macro-and micropore diffusion controlled the methane adsorption rate in shale samples, as well as the relative importance and influence of micropore diffusion and adsorption to adsorption rate and total adsorption increased with increasing pressure. This made the inflection points, or two-stage process, at higher pressure steps not as evident as at low pressure steps, and the adsorption rate curves became less steep with increasing pressure. This conclusion was also supported by the decreasing difference values with increasing pressures between macro-and micropore diffusivities obtained using the bidisperse model, which is roughly from 10 −3 to 10 0 , and 10 −3 to 10 −1 , respectively. Additionally, an evident negative correlation between macropore diffusivities and pressure lower than 3-4 MPa was observed, while the micropore diffusivities only showed a gentle decreasing trend with pressure. A mirror image relationship between the variation in the value of macropore diffusivity and adsorption isotherms was observed, indicating the negative correlation between surface coverage and gas diffusivity. The negative correlation of methane diffusivity with pressure and surface coverage may be related to the increasing degree of pore blockage and the decreasing concentration gradient of methane adsorption. Finally, due to the significant deviation between the unipore model and experimental adsorption rate data, a new estimation method based upon the bidisperse model is proposed here.

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Marine redox stratification during the early Cambrian (ca. 529‐509 Ma) and its control on the development of organic‐rich shales in Yangtze Platform

Zhang

Jiang

et al. 2017

Geochem Geophys Geosyst

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High resolution geochemical data from nine sections representing shelf to basinal environments in the Yangtze Platform were analyzed to reconstruct the marine redox environment during early Cambrian. Based on Fe species and Mo/TOC ratios, we have supplemented marine redox stratification during Stage 4 (late Canglangpuian‐Longwangmiaoan, ∼514‐509 Ma) on basis of the previously studied Stage 2‐Stage 3 (Meishucunian‐Qiongzhusian, ∼529‐514 Ma). A new proposed marine stratified redox model indicates that the middepth “euxinic wedge” developed at the base of slope during ∼514‐509 Ma in contrast to that the “euxinic wedge” prevailed at the shelf margin during ∼529‐514 Ma, even though these middepth euxinic waters both occurred between the oxic surface waters and ferruginous deep waters. This marine redox stratification resulted in high production and good preservation of organic matter during early Cambrian. TOC values in euxinic waters in the middle are generally higher than in ferruginous waters due to upwelling in slope. Therefore, the lower Cambrian organic‐rich shales in the Yangtze Platform are inferred to be deposited under the anoxic‐ferruginous and euxinic bottom waters with moderate‐strong restriction.

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Shale gas potential of the major marine shale formations in the Upper Yangtze Platform, South China, Part II: Methane sorption capacity

Cited by 306 publications

References 46 publications

Quantitative characterization of micropore structure for organic-rich Lower Silurian shale in the Upper Yangtze Platform, South China: Implications for shale gas adsorption capacity

Quantitative characterization of micropore structure for organic-rich Lower Silurian shale in the Upper Yangtze Platform, South China: Implications for shale gas adsorption capacity

Methane Adsorption Rate and Diffusion Characteristics in Marine Shale Samples from Yangtze Platform, South China

Marine redox stratification during the early Cambrian (ca. 529‐509 Ma) and its control on the development of organic‐rich shales in Yangtze Platform

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