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

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

The characteristics of coal deposits are relatively homogeneous in general; therefore, their geometric and quality parameters have stationary distributions. However, the geological setting could change this stationarity characteristic; thus, the coal may contain spatially different data trends. These data trends should be treated to derive an accurate estimation of the available coal resources. The

Bacteria are ubiquitous in all depositional environments, especially in marine environments where anoxic/euxinic conditions prevail. In such environments, sulfate-reducing bacteria play a critical role to supply sulfur as a biogenic source for H2S through biomass degradation. In the biodegradation process, chemical and mechanical properties of the organic matter alter. In order to document these variations

Coal ash is one of the largest industrial waste streams in the United States and contains elevated concentrations of hazardous elements that could pose environmental and human health risks. Due to the relatively high strontium concentrations in coal ash and the distinctive 87Sr/86Sr ratios, Sr isotopes have been utilized to trace coal ash contaminants in impacted water resources. While previous studies

A “permeability equilibration time” is typically assumed in interpreting permeability measurements – indicating that equilibration has been reached and both sorption-induced changes in deformation and their impact on permeability evolution have ceased. However, for extremely low matrix permeability (tight) dual porosity rocks, this “permeability equilibration time” may easily exceed the time interval

Fossil wood is well known from the uppermost part of the Brassington Formation of Miocene age from two localities in Derbyshire, central England, UK, but its preservation has not been previously studied. Likewise, lignite is also present but has not been studied hitherto. This study examines preservation of selected wood samples using a combination of organic petrography and organic geochemistry. The

In-situ stress pattern and subsurface fractures control the production of Coal Seam Gas (CSG) reservoirs and, hence, comprehensive analyses are required for better development of these reservoirs. The Surat Basin is a prolific CSG province with major economic impacts in eastern Australia. Recent studies have reported significant stress variations in this basin due to local geological structures. However

The systematic understanding of organic matter chemical structure-thermal stability relationships is central to resource outcomes in sedimentary basins. This study integrates molecular spectroscopy (solid-state 13C NMR) and step-wise isothermal analysis (isoTGA) in elucidating key structure-maturity-stability relationships in shales containing type I and II kerogens (Green River and Eagle Ford Formations

To study the possible role of base-level oscillations in the formation of thick coal seams in coastal plain (paralic) environments, the Early Permian Shanxi Formation No.21 thick coal seam was investigated in 3 cores spanning a distance of 29 km in the Anhe (Anyang-Hebi) coalfield, Henan Province using sedimentology, sequence stratigraphy, and coal petrology. The accommodation condition and origin

Fluorescence spectroscopy via confocal laser scanning microscopy (CLSM) was used to analyze ancient sedimentary organic matter, including Tasmanites microfossils in Devonian shale and Gloecapsomorpha prisca (G. prisca) in Ordovician kukersite from North American basins. We examined fluorescence emission as a function of excitation laser wavelength, sample orientation, and with respect to location within

The paper reports the results of the organic petrological, palynological and geochemical characterization of lignite samples from the Kipra lignite seam (Late Miocene, Maritsa-West Basin, Bulgaria). The bulk of the organic matter (OM) is represented by highly gelified detrohuminite with locally abundant leaf-derived ulminite. Liptinite group is characterized by predominance of microsporinite and liptodetrinite

For sample mounting, organic petrology laboratories typically use cold-setting epoxy-resin (e.g., 40 °C, used by Oklahoma Geological Survey, OGS) or heat-setting thermoplastic (e.g., 180 °C, used by U.S. Geological Survey, USGS). Previous workers have suggested a systematic huminite/vitrinite reflectance (VRo) increase was associated with the thermoplastic preparation process, relative to epoxy mounting

In 1982 and 1986, Lyons and co-authors defined secretinite as one of the two types of sclerotinite (the other being funginite) and established its origin based on its occurrence inside the secretory ducts of medullosan seed ferns. However, in 2001, the International Committee for Coal and Organic Petrology implicitly classified many materials whose derivation is not clear (e.g. inertinite discrete

Coal failure has been observed in many coal seam reservoirs during gas production, which generated significant impacts to coal permeability and to the efficiency of gas recovery. In this paper we develop a flow-geomechanical-coupled numerical approach and use two genuine field examples to discuss the relevant large-scale coal failure behaviours in fields. One example is with the CBM production in Cedar

As the interest in the renewable resources has been increasing worldwide, the wood pellet sector has the potential to become a mainstream fuel of the future in the heat market. This development is especially noted in the European Union countries which consumed 50 % of global wood pellets in 2018. While only about 2 % of the United States energy consumption was derived from wood and wood waste in 2018

We carried out a detailed organic facies study on shale cutting samples from the Devonian Pimenteira Formation in the São Luís Basin, northwest Brazil, to reconstruct the depositional paleoenvironment and origin of the organic matter. Samples were collected from the stratigraphic well 2-ANP-5-MA and were analyzed for total organic carbon (TOC), total sulfur (%S), insoluble residue (RI), spore coloration

The chemical composition of ambers is highly diverse, characterized by the occurrence of a variety of terpenoids including: mono-, sesqui-, di-, and triterpenoids. The direct analyses of their chemical constituents in total extracts using polar solvents permits the elucidation of unaltered natural products, which are characteristic of the source plants or paleobiome. At this time, knowledge is limited

The geochemistry of source rock–controlled coals from the Late Triassic Daqiaodi Formation in the Dabaoding Coal Mine of the southwestern Sichuan Province was investigated. A total of 15 coal samples, 6 parting samples, and 4 roof and floor rock samples from the D15–3 and D18 coals were subjected to proximate and ultimate analyses for coal quality, by using LTA-XRD with Siroquant software for minerals

The bulk elemental concentration of selected Albert Formation oil shale deposits of Mississippian age from New Brunswick was analyzed using ICP-MS and Prompt Gamma. Results compared to that of the Big Marsh oil shale of similar age from Nova Scotia. Reflected white and fluorescence light was used to determine the characteristic organic matter, and RockEval analyses were used to determine the hydrocarbon

Self-heating of coal waste is a major problem in the leading coal-producing and consuming countries, independent of the recent or past coal exploitation history. The phenomenon of self-heating is dependent on many factors such as the properties of organic matter (maceral composition and rank), moisture and pyrite content, climate effects, and storage conditions (shape of the dump or compaction of the

The microscopic analysis of methane (CH4) adsorption in the heterogeneous pore structure of coals is vital for the success of the coalbed methane (CBM) projects. In this work, to make up for the limitations of laboratory testing conditions, grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were performed to systematically study the mechanism of CH4 adsorption on dry and moist

Much of our existing knowledge of Middle Jurassic paleoclimate is based on well-dated marine isotopic records that show fluctuations between warm (greenhouse effected) and cool climates. In contrast, much less is known from contemporaneous terrestrial deposits that are often difficult to correlate stratigraphically with marine successions, and are typically considered as showing regional rather than

Abundant in organic matter, the lower Silurian Longmaxi shale in the Upper Yangtze Platform, South China, has been demonstrated to play important roles in the petroleum system as both a good source rock and a shale gas reservoir. In order to better understand the heterogeneous organic matter accumulation of such shales in the southeastern Chongqing area, the vertical variations of total organic carbon

Ultra-low permeability, inertinite-rich, poorly cleated, dehydrated, overpressured coal seams deeper than 9000 ft (2740 m) in the Cooper Basin of central Australia represent a fundamentally different play type to shallow and “deep” coal seam gas reservoirs. Proof-of-concept gas flow was achieved in 2007. Four Patchawarra Formation coal seams were subjected to low-proppant concentration slick-water

Shale formations demonstrate distinct characteristics, such as a wide spectrum of pore size from micro-scale to nano-scale, limited pore connectivity and ultra-low permeability. Despite extensive research work over recent years to characterize flow properties of shale samples, the interplay between pore connectivity and permeability still remains to be understood. In this study, numerical methods were

Density log data is one of the key physical attributes used for reservoir characterization by quantifying and qualifying lithological attributes in a wellbore. The density log is most often acquired by geophysical wireline logging techniques after drilling. However, wireline logging can be difficult to execute in highly deviated wells and alternative data acquisition such as logging-while-drilling

Thermal maturity of source rocks indicated by vitrinite reflectance (Ro) is an important and reliable parameter to determine the petroleum potential of sedimentary basins. Originally, Ro was used to characterize the degree of coalification of coals and thus works well for coal seams, but it has limitations when used to determine the thermal maturity of black shale successions. A suite of six coal-shale

The paper presents a review of stratigraphy, lithology and metallogeny of the Paleogene and Neogene coal basins from the Primorye region of southeast Russia. The stratigraphic division of the studied sections is based on the abundant fossil plant material, represented by leaf impressions and, in lesser amounts, fruit and seed fossils, as well as detailed palynological analyses. Previously published

Late Miocene samples from the Xiaolongtan Formation in Puyang Basin were sampled systematically from bottom to top of the main coal seam. Organic petrological as well as geochemical methods have been applied, aiming at the reconstruction of the depositional environment. The studied samples contain abundant detrovitrinite and liptinite macerals with high ash but low to moderate sulfur contents. This

As a problem that has plagued geochemists, the perspective of time has long been recognized as an important factor in organic matter evolution and hydrocarbon generation. This article discusses two time series analysis methods based on econometrics, damping trend and autoregressive integrated moving average (ARIMA), to mine the potential value of data and abstract useful information from pyrolysis

Coal seam degasification and its efficiency are directly related to the safety of coal mining. Degasification activities in the Black Warrior basin started in the early 1980s by using vertical boreholes. Although the Blue Creek seam, which is part of the Mary Lee coal group, has been the main seam of interest for coal mining, vertical wellbores have also been completed in the Pratt, Mary Lee, and Black

This paper presents a study assessing potential factors and migration paths of methane emissions experienced in a room-and-pillar mine in Lower Kittanning coal, Indiana County, Pennsylvania. Methane emissions were not excessive at idle mining areas, but significant methane was measured during coal mining and loading. Although methane concentrations in the mine did not exceed 1% limit during operation