. (2013) 'Methane adsorption on shale under simulated geological temperature and pressure conditions.', Energy fuels., 27 (6). pp. 3099-3109.Further information on publisher's website:Publisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Energy fuels, copyright c American Chemical Society after peer review and technical editing by the publisher.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

. (2014) 'High-pressure methane adsorption and characterization of pores in Posidonia shales and isolated kerogens.', Energy fuels., 28 (5). pp. 2886-2901. Further information on publisher's website:http://dx.doi.org/10.1021/ef402466mPublisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Energy Fuels, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://dx.doi.org/10.1021/ef402466m. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractSorption capacities and pore characteristics of bulk shales and isolated kerogens have been determined for immature, oil-window and gas-window mature samples from the Lower Toarcian Posidonia Shale formation. Dubinin-Radushkevich (DR) micropore volumes, sorption pore volumes and surface areas of shales and kerogens were determined from CO 2 adsorption isotherms at -78°C and 0°C, and N 2 adsorption isotherms at -196°C. Mercury injection capillary pressure porosimetry, grain density measurements and helium pycnometry were used to determine shale and kerogen densities and total pore volumes.Total porosities decrease through the oil-window and then increase into the gas-window.High-pressure methane isotherms up to 14 MPa were determined at 45, 65 and 85°C on dry shale and at 45 and 65°C on kerogen. Methane excess uptakes at 65°C and 11.5 MPa were in the range 0.056-0.110 mmol g -1 (40-78 scf t -1 ) for dry Posidonia shales and 0.36-0.70 mmol g -1 (253-499 scf t -1 ) for the corresponding dry kerogens. Absolute methane isotherms were calculated by correcting for the gas at bulk gas phase density in the sorption pore volume. The enthalpies of CH 4 adsorption for shales and kerogens at zero surface coverage showed no significant variation with maturity, indicating that the sorption pore volume is the primary control on sorption uptake. The sum of pore volumes measured by a) CO 2 sorption at -78°C and b) mercury injection, are similar to the total porosity for shales. Since mercury in our experiments occupies pores with constrictions larger than ca. 6 nm, we infer that porosity measured by CO 2 adsorption at -78°C in the samples used in this study is largely within pores with effective diameters smaller than 6 nm. The linear correlation between maximum CH 4 surface excess sorption and CO 2 sorption pore volume at -78°C is very strong for both shales and kerogens, and goes through the origin, suggestin...

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[1] We present permeability and other petrophysical data (including pore size distribution, porosity, particle size distribution, grain density, specific surface area, total carbon content, organic carbon content, and sulphur content) for 30 deeply buried mudstones. Permeabilities were measured at different effective consolidation stresses ranging from 2.5 to 60 MPa with a 30,000 mg L À1 NaCl solution. Samples represent a wide spectrum of mudstone types with clay size particle contents ranging from 13 to 66%. Porosities range from 6 to 27%; pore size data show that porosity loss is driven primarily by collapse of the largest pores. Our results confirm and considerably extend previously reported results indicating the influence of clay content on pore size distributions and the way they evolve as a result of compaction. Vertical permeabilities, measured using the transient pulse decay technique, range from 2.4 Â 10 À22 m 2 to 1.6 Â 10 À19 m 2 . Horizontal permeabilities range from 3.9 Â 10 À21 m 2 to 9.5 Â 10 À19 m 2 , overlapping with but generally higher than vertical permeabilities. In general, permeability decreases logarithmically with porosity. The relationship between permeability and porosity is strongly influenced by clay content, especially at higher porosities. Ratios of horizontal to vertical permeability measured on four samples range from 1.7 to 11.8, implying the influence of both particle alignment and sedimentological heterogeneity. We have used the data to calibrate two permeability models. For the Kozeny-Carman model, values of 200 and 1000 for the product of shape and tortuosity factors provide the best fit for the vertical and horizontal permeabilities, respectively. The calibrated Yang-Aplin model predicts the permeability of almost all the samples to within a factor of ±3 over a 4 orders of magnitude range of permeability.

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractAn inter-laboratory study of high-pressure gas sorption measurements on two carbonaceous shales has been conducted in order to assess the reproducibility of the sorption isotherms and identify possible sources of error. The measurements were carried out by seven international research laboratories on either in-house or commercial sorption equipment using manometric as well as gravimetric methods. Excess sorption isotherms for methane, carbon dioxide and ethane were measured at 65°C and at pressures up to 25 MPa on two organic-rich shales in the dry state. The samples were taken from the immature Posidonia shale (Germany) and from the over-mature Upper Chokier formation (Belgium). Their total organic carbon (TOC) and vitrinite reflectance (VRr) values were 15.1% and 4.4% and 0.5% and 2.0%, respectively. The objective of the study was to assess the inter-laboratory reproducibility of sorption isotherms as would be expected with each laboratory following its own measurement and data reduction procedures. All labs were asked to follow a predefined sample drying procedure prior to measurement in order to minimize any effects related to moisture. The reproducibility of the methane excess sorption isotherms was better for the high-maturity shale (within 0.02 -0.03 mmol/g) than for the low-maturity sample (up to 0.1 mmol/g), similar to observations in earlier inter-laboratory studies on coals. The reproducibility for CO2 and C2H6 sorption isotherms was satisfactory at pressures below 5 MPa, however,the results deviate considerably at higher pressures. Artefacts in the shape of the excess sorption isotherms were observed for CO2 and C2H6 and these are explained as being due to a high sensitivity of gas density to temperature and pressure close to the critical point as well as from a limited measurement accuracy and possibly uncertainty in the equation of state (EoS).The low sorption capacity of carbonaceous shales (as compared to coals and activated carbons) sets very high demands on the accuracy of pressure and temperature measurement and precise temperature control. Furthermore, the sample treatment, measurement and data reduction procedures must be optimized in order to achieve satisfactory inter-laboratory consistency and accuracy. Unknown systematic errors must be minimized first by calibrating the pressure and temperature measurement sensors to high-quality standards. Blank sorption measurements with a non-sorbing sample (e.g. steel cylinders) can be used to identify and...