The accurate determination of mechanical parameters (namely, Young's modulus and hardness) of shale-constitutive minerals is crucial for predicting the macroscale mechanical parameters of shale composites. This study employed an advanced nanoindentation apparatus equipped with a high-resolution microscope (4000×) and a newly emerging nano-dynamic mechanical analysis (nano-DMA) module to conduct mineral-positioned

Activation energy distribution from kerogen kinetics study contains some integral characteristics of the host source rock thermal history over geological time scales. Extracting relevant information from pyrogram is critical for reconstruction of source rock maturation and hydrocarbon generation histories. In this study, in order to improve understanding of the Bakken shale source rock, we present

Ground surface movement shows different features during mining and post-mining period. If the mine goaf is dry, surface subsidence is observed in both periods. If the mine goaf is flooded by groundwater, however, ground surface uplift can be observed although much smaller in amplitude compared to the preceding subsidence. A numerical modeling strategy is proposed to predict uplift during the flooding

This study addresses a major gap in the understanding and control of microbially enhanced coal-bed methane (MECBM) production. A mathematical and conceptual model comprises a food-web that includes two types of bacteria and three types of archaea representing substrate-specific members of the community; the microbial community members are potentially interacting by competing for or being inhibited

The present research compares the yield of microbial methane production from different lithotypes of Miocene lignite from the Konin Basin in Poland and attempts to establish an understanding of the processes responsible for methanogenesis. A series of batch experiments were carried out with detritic and xylitic lignites inoculated with microorganisms from an external source (the anaerobic chamber of

During the Meso-Cenozoic, the eastern Ordos Basin (EOB) underwent a complex tectonothermal process influenced by the destruction of North China Craton, significantly affecting the thermal maturation of the Late Paleozoic source rocks. Tectonothermal modeling and maturation of coal-bearing shales were performed in the EOB to reveal the geological process of shale gas generation. Organic geochemical

Tremendous amount of gas can be adsorbed in shale nanopores as a result of the high surface-to-volume ratio, and capillary condensation might occur in mesopores (2–50 nm) for subcritical gases, leading to sorption hysteresis. However, the sorption (adsorption and desorption) behavior in different pore systems in shale is not very well understood. Herein we use a D3Q19 lattice Boltzmann model (LBM)

The Toarcian Oceanic Anoxic Event (TOAE) is characterised by a perturbation of the global carbon cycle and the widespread deposition of organic matter (OM)-rich strata/sediments in the northern areas of the West Tethys Shelf, in several northern European epicontinental basins. Contrariwise, in the southern areas of the West Tethys Shelf such as western and southern Iberian, and northern Gondwana margins

Calcium phosphate apatite, Ca5 (PO4)3(OH,F,Cl), is a common accessory mineral in coal seams. Although minor, its role in hosting P and F can reduce the economic viability of coking and thermal coal deposits. Apatite in coal is commonly <50 μm and may occur as several modes of occurrence. The modes of occurrence investigated as part of this study include apatite infilling small (i.e. less than 30 μm)

This paper examines changes in structural and petrographic characteristics of organic and inorganic matter developed in a cored 35 m thick Permian coal seam from the Moatize Basin (Mozambique) in proximity to an Early Jurassic intrusive igneous body. Megascopic and microscopic examinations of hand samples and polished blocks, respectively, were carried out to characterise the deformation and petrographic

The characterization of fracture structures is key for evaluating the permeability of coalbed methane (CBM) reservoirs, and an interconnected fracture network is essential for the production of CBM. Taking the Upper Permian coal in the eastern Yunnan and western Guizhou region as an example, we systemically studied the characteristics of coal deformation and fracture development through direct observation

Understanding the mechanical response of coal to CO2 injection is necessary to determine the suitability of a seam for carbon capture and underground storage (CCUS). The bulk elastic properties of a coal or shale, which determine its mechanical response, are controlled by the elastic properties of its individual components, i.e. macerals and minerals. The elastic properties of minerals are relatively

Six solid bitumen samples from Paja Formation (Cretaceous of Colombia) were optically, chemically and structurally characterized using bulk chemistry, reflectance indicating surface (RIS), micro-Raman and X-ray diffraction (XRD) parameters. The volatile matter and carbon contents and high random reflectance (Ro%) placed these solid bitumens in the category of cata-impsonites according to Jacob's classification

Understanding vapor transport of water in nanoporous shale is challenging due to the coexistence of multiple water phases within a multi-mineral aggregate with complex multiscale pore architecture. We explore this response through dynamic vapor sorption experiments and modeling on two shale samples with differing fractions of hydrophilic clays and contrasting pore architecture. Measured diffusion coefficients

The Eocene Kosd Formation forms part of the Hungarian Palaeogene Basin. The coal measure of this formation was investigated using an 18 m drill core from borehole W–1. Petrographic and organic geochemical investigations (Rock-Eval pyrolysis, biomarker analysis) were performed in order to characterize the depositional environment, to determine the source of the organic matter within, and to assess the

The Paraná Basin is a large volcano-sedimentary basin with a complex depositional history from Ordovician to the Cretaceous period. During Permian significant amounts of organic-rich beds accumulated within the Rio Bonito and Irati formations representing deposition in coastal (deltaic and barrier lagoon) and shallow marine environments, respectively. In this work, the thermal history of these beds

One of the biggest challenges in evaluating the transport and storage properties of shales is understanding how the pore structure and network evolve in the same stratigraphic shale during catagenesis. Using a combination of CO2 adsorption, mercury intrusion porosimetry, as well as scanning electron microscopy, we have described the evolution and the abrupt changes (jump) of pore characteristics in

Coalbed methane (CBM) is a form of natural gas that is extracted from coalbeds. Characterization of CBMs is very challenging mostly due to the very complex fracture system leading to ambiguous fluid and petrophysical properties. Among several important factors that control the performance of CBMs, permeability is the most crucial one, which summarizes the global fracture system, intensity, connectivity

The Dursunbey coalfield, a typical example of coalfields in the western Anatolia, hosts a mineable coal seam (about 9.0-m coal thickness) with altered tuff layers within early Miocene fluvio-lacustrine sequences. The aim of this study is to identify peat-accumulation conditions and factors controlling the mineralogy and geochemistry of this seam. The standard coal features and petrographical, mineralogical

Solid bitumen significantly influences reservoir quality in many unconventional tight and shale hydrocarbon accumulations. In the siltstone-dominated Montney Formation of northeast British Columbia and northwest Alberta organic matter is mostly in the form of solid bitumen and represents an original pore-filling oil phase that was later thermally cracked. Here, we show that the influence of solid bitumen

Petrographic and geochemical data for Late Permian coals and carbonaceous shales from the Transantarctic Mountains, Antarctica (source: Polar Rock Repository, PRR), were used to evaluate maturation levels and assess the effects of contact metamorphism. Coals were evaluated for locations in the Southern Transantarctic Mountains, the Central Transantarctic Mountains, and South Victoria Land, including

A sample set consisting of coal, overlying and intercalating siliciclastic rocks and kerogen concentrated from these rocks of nine Pennsylvanian subbituminous to bituminous coal seam intervals from the German Ruhr Basin was analysed in order to detect chemical structural differences of the organic matter. Vitrinites from the coal seams and the kerogen concentrates were isolated to study effects of

Igneous intrusions in or adjacent to coal seams impact the coal quality directly and cause hazards for both coal mining and coal seam gas extraction. Specifically, sills can be identified at borehole level by wireline logs, e.g. natural gamma-ray, density, and resistivity tools because of their unique petrophysical characteristics. The literature describes also the use of surface seismic surveys as

During methane production in CBM reservoirs, the influence of proppant embedment and permeability damage cannot be neglected – especially where the wall-rock is soft. Effective stresses are elevated during methane recovery, increasing both normal loading stress and confinement and simultaneously overprinting sorption-induced volumetric strains. Experiments and analytic modeling are conducted to define

The objective of this paper is to determine the origin and variability of methane and carbon dioxide concentrations in the near-surface zone and of coalbed methane in the SW part of the Chwałowice Trough and adjacent areas of the Main Syncline of the Upper Silesian Coal Basin (USCB). For this purpose soil-gas samples were taken at 202 measuring points, arranged along 5 profiles located in the mining

Core data play a significant role in analyses of fundamental petrophysical properties, such as porosity and pore size distribution (PSD), which can be used to estimate the storage capacity and recovery rate of hydrocarbons. However, coring is time-consuming, and it is sometimes difficult to retrieve an intact core, particularly from coal reservoirs that are characterized by low mechanical strength

Organic maturity levels of the Silurian and Carboniferous shales in the western and central Taurus regions are thermally over mature and therefore they can still contain shale gas. A total of 43 samples were determined using TOC analysis and Rock-Eval Pyrolysis to indicate the first basic hydrocarbon source rock characteristics. Average TOC values of Silurian samples range from 0.61 to 2.56% in wt

This study is mainly concerned with sulfur isotope (δ34S) values of inorganic sulfur species associated with the North Thrace Basin's coals (Saray and Pınarhisar coalfields). Sulfur isotope analyses were performed on pyritic sulfur, native sulfur, sulfate sulfur (rozenite) and the precipitated sulfate (P-BaSO4) (leached sulfate from the coal). The δ34S values of pyritic sulfur, rozenite, native sulfur

Coal combustion ash and pre-combustion coal refuse are currently under consideration as potential sources of rare earth elements. One of the early steps in recovering REEs from coal by-products is often acid leaching, which can result in low pH leachates with complex aqueous chemistry. The aim of this work was to understand the connection between REE solubility, pH, and major elemental components of

A multiproxy study based on sedimentology, mineralogy, magnetic susceptibility, organic geochemistry and fossil content allowed to establish the sedimentary evolution of palustrine basins and to study the interplay between tectonic and climatic forcings in the sedimentation and facies arrangement that can be extrapolated to other coal-bearing basins. The reinterpretation of the data from 18 cores allowed

This study focuses on variations in petrographic composition and chemistry of macerals from different coalfields in Colombia. The coal-bearing formations in Colombia occur in the age interval from the Maastrichtian in the Upper Cretaceous to the Paleogene and Neogene (Paleocene, Eocene, Oligocene, and Late Pliocene) up to Early Pleistocene. The coals range in rank from lignite to semianthracite. Petrographically

The role of residual bitumen on the pore structure of organic-rich shales is related to maturity. However, the studies about the role of the soluble and insoluble residual bitumen on the pore structure of organic-rich shales from low to over mature are deficient. In this study, non-extracted and extracted organic-lean shale, organic-rich shale and coal samples after the hydrous pyrolysis are used to

Important depositional characteristics indicative of climate change has been discovered in 50-m sedimentary succession consisting of oil shales with a marlstone and carbonate matrix of the Viséan shales from the Lower Carboniferous Emma Fiord Formation on Devon Island, Canada's Arctic Archipelago. Older Carboniferous (Tournaisian) shales, are however absent from Devon Island, but elsewhere such as

The effects of petroleum retention within and expulsion from five intervals within the Triassic Chang 7 Member in the Ordos Basin in China have been demonstrated by deciphering a large suite of petrologic, organic petrographic, and organic geochemical analyses on 106 core samples. Organic properties and lithological heterogeneities control the amount and chemical composition of retained petroleum.

The carbon and nitrogen stable isotopic compositions and elemental characteristics of Pliocene pale and dark lignites in the Jinsuo Basin, Yunnan Province, southwestern China, were investigated. These data were used to develop paleoenvironmental models and to discuss possible geological driving forces for the formation of pale and dark layers. The δ13C values of fossil wood (av. −24.79‰) and fusain

A Wenlock (Silurian) sedimentary continuous sequence was sampled in the Dornes region (Central Iberian Zone, Portugal) to characterize the organic matter type using different microscopic analyses (organic petrology and palynofacies). Total organic carbon (TOC) was also determined. Samples are part of Foz da Sertã Formation and correspond to mudstone, punctually with sandstone, rich in organic matter

We report 21 frictional sliding experiments performed on simulated fault gouges prepared from shale-coal mixtures. Our aim was to investigate the effects of local coal seam smearing on the frictional properties and induced seismogenic potential of faults cutting the Upper Carboniferous source rocks underlying the Groningen gas reservoir (Netherlands). We used shale/siltstone core recovered from beneath

In order to better understand the micropores (pore size less than 2 nm) in some medium-high rank coals, the development, distribution, and structure of micropores in five medium-high ranks coal samples (0.68% < Ro, max < 6.22%) were determined by low-pressure CO2/N2 adsorption (LP-CO2/N2 GA) experiments, and high-resolution transmission electron microscopy (HRTEM). The mathematical models and methods

Small-angle neutron scattering (SANS) measurements were performed on 32 rock samples from the southern Georgina Basin, central Australia to assess nanopore anisotropy. Anisotropy can only be determined from oriented core material, hence the samples were cut perpendicular to bedding in cores selected from three wells that intersect the base of the hydrocarbon-bearing, organic-rich middle Cambrian Arthur

Coalbed methane (CBM) has emerged as a clean energy resource in the global energy mix, especially in countries such as Australia, China, India and the USA. The economical and successful development of CBM requires a thorough evaluation and optimization of well placement prior to field-scale exploitation. This paper presents a two-stage, step-wise optimization framework to obtain the optimal placement

The methods used in allocating commingled production in conventional reservoirs are similar to those that are effective in performing the same task on unconventional reservoirs. However, the protocols to follow can vary a great deal. The presence of distinct endmembers in the former allows the use of the method of production allocation using peak height ratios and mixing curves and using linear regression

The Lower Bakken Shale is a key member of the Bakken Petroleum System, which is a prolific unconventional accumulation in North America. Unconventional accumulations have unpredictable lateral variations in hydrocarbon production due to a variety of factors including porosity, permeability, and other rock properties. Therefore, understanding the geochemical (source rock potential), petrological, and

Thick sequences of overmatured Paleozoic black shales Formation were deposited in the Western Peninsula (WP) Malaysia, which can be considered as the potential shale gas reservoir. Therefore, to study the shale gas potential of the Paleozoic (Silurian-Permian) shale Formations, 146 samples from seven Formations were collected from WP Malaysia. A combination of methane sorption capacities, geochemical

Lalmatia coal-bearing sequences belong to the Barakar Formation (Permian) of Lower Gondwana. The well-developed coal-bearing sequences (approx. 52 m) exposed along the mine section have been studied to understand the depositional environment. Along with this, a cuticle study was performed to understand the palaeoclimate with the help of the stomatal index. The distribution of n–alkanes (n–C15 to n–C31)

Various compositional, depositional and maturity related influencing factors affect the complex pore structure of coal. To study the pore structural evolution at nanoscale, a well characterized sample set of vitrinite-rich Carboniferous coals from the Ukrainian Donets Basin, covering a maturity interval from 0.69 to 1.47%Rr, was selected. Conventional bright field transmission electron microscopy (BF

Coal deposits comprise a huge proportion of carbon sequestered within the Earth's crust. Many deposits are anthropogenically altered by mining operations. The changes in local hydrogeology include, first - water removal from the seam to enable excavations, second – restoration of natural water condition by cessation of water pumping. In each of these cases, there is a substantial change in the living

The Late Permian coal measures in the Bowen Basin, Australia, are extensively mineralized with calcite as cleat infilling and veins. This study utilised strontium and samarium‑neodymium isotope analyses as well as rare earth element and yttrium (REY) composition of vein calcites, from two boreholes in a faulted and intruded area within the Jellinbah Thrust Zone, to investigate the origin and timing

This study conducts qualitative and quantitative analysis of flowback and post-flowback production data from six multi-fractured horizontal wells completed in Eagle Ford shale formation. Petrophysical analysis of samples from the target shale shows oil window with type II kerogen. We analyzed two groups of wells with different well-completion and operational parameters. Wells fractured with slickwater

Paleozoic gases in the Ordos Basin, China, are produced from upper Paleozoic tight sandstones, Ordovician weathered-crust, and ‘pre-salt’ (beneath gypsum deposits) dolomite reservoirs. Their origins have been debated, particularly as to whether Carboniferous–Permian (CP) or Ordovician source rocks contributed more gas to the lower Paleozoic gas reservoirs. The expanded exploration of lower Paleozoic

Paleoenvironmental conditions of the sediments of the Cretaceous Codó Formation in Brazil are still being debated. The main point of controversy is whether they were deposited in a strictly marine environment or under lacustrine conditions of varying salinity. In this study, organic facies and biomarker analyses were performed on samples from the Codó Formation in the São Luís Basin, northwest Brazil

Terrigenous materials from sediment-source regions are important controls on the types and concentrations of inorganic components in coal. The Kangdian Upland (dominated by the Emeishan basalts) is the dominant terrigenous supplier for most of the Late Permian coals, as well as for their associated host rocks (roof and floor strata) in southwestern China. The high volatile bituminous coals (Nos. 3

The effects of supercritical CO2 (scCO2) on coal pores play a critical role in the geological storage of CO2 and enhanced coalbed methane recovery (CO2-ECBM). To investigate the effects of scCO2 - H2O on the mesopore - macropore structure of high-rank coals, a series of experimental simulations and analyses were performed. Coal samples from the Qinshui Basin, China were exposed to scCO2 and deionized