International Journal of Coal Geology最新文献

{"title":"Matrix permeability anisotropy of organic-rich marine shales and its geological implications: Experimental measurements and microscopic analyses","authors":"Yong Ma, Huiting Hu, Zhejun Pan, Ningning Zhong, Fujie Jiang, Chengyu Yang, Jianbin Ma, Binhao Feng","doi":"10.1016/j.coal.2024.104670","DOIUrl":"https://doi.org/10.1016/j.coal.2024.104670","url":null,"abstract":"Due to the presence of natural and/or preparation-related fractures, the anisotropy of the matrix permeability of shales is usually difficult to characterize. In this study, we used X-ray micro-computed tomography (XRμCT) imaging to select samples from the Lower Cambrian and Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation of the Upper Yangtze Platform, China, showing no natural or artificial fractures. From these samples, cubic specimens were prepared with a wire saw and then re-inspected for fractures. Using a specially developed sample holder, the matrix permeability of these specimens were measured in the three principal directions using the pulse decay method with N<ce:inf loc=\"post\">2</ce:inf> as the flowing fluid. To analyze the microscopic lithological and structural controls on shale matrix permeability anisotropy, we employed a combined methodology using thin sections, focused ion beam-scanning electron microscopy (FIB-SEM), and permeability simulation.","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"21 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Organic petrology and geochemistry of the late Neogene Shizigou Formation in the Qaidam Basin, China: Characteristics of a prospective microbial gas source rock","authors":"Jinqi Qiao ,&nbsp;Qingyong Luo ,&nbsp;Shouxin Guo ,&nbsp;Xianglu Tang ,&nbsp;Ludmila Kopaevich ,&nbsp;Ralf Littke","doi":"10.1016/j.coal.2024.104658","DOIUrl":"10.1016/j.coal.2024.104658","url":null,"abstract":"<div><div>The discovery of natural gas trapped in the late Neogene Shizigou Formation in the Yikeyawuru anticline indicates the potential for additional microbial gas reservoirs outside of the primary exploration targets for microbial gas in the younger, i.e., the Pleistocene sediments of the Qaidam Basin. In this study, a detailed investigation is presented on the bulk geochemistry and organic petrography of the potential microbial source rocks as well as on molecular organic geochemistry of the solvent extracts obtained from the late Neogene Shizigou Formation of the Yiliping Depression. The objectives are to elucidate i) the depositional environment, ii) biological sources of organic matter (OM), and iii) biodegradation levels in these microbial gas source rocks.</div><div>The samples from the well situated at the center of the Yiliping Depression (the H 1 well) exhibit minor variations in total organic carbon (TOC) and total sulfur contents, whereas the samples from the well located at the margin of the depression (the Y 3 well) show large variations in these values. All these samples are presently thermally immature. The kerogen of the TOC-rich Y 3 well samples is mainly composed of mixed types II–III kerogen and characterized by a complex maceral composition (i.e., a mixture of large fragments of huminite, semifusinite, fusinite, resinite/fluorinite, lamalginite, and liptodetrinite). In contrast, samples from the H 1 well contain typically type III kerogen with a less complex maceral composition consisting of huminite, lamalginite, and liptodetrinite. The molecular data illustrates that the OM is predominantly derived from bacterial and algal biomass as well as aquatic higher plants (primarily in the Y 3 well samples), while angiosperms are the primary source of the subordinate terrestrial OM in the samples. The marginal area is characterized by salinity levels akin to normal marine conditions with bottom-water paleoredox conditions ranging from dyoxic (samples with high TOC content) to oxic, whereas the central area developed a mesosaline environment with oxic bottom-water conditions prevailing. In contrast to the primary microbial gas producing layer, the Pleistocene Qigequan Formation, the late Neogene Shizigou Formation exhibits a higher contribution of emergent macrophytes but a reduced abundance of lower aquatic organisms in the OM as well as a higher salinity level in the water column. Despite the late Neogene Shizigou Formation demonstrating a lower potential for hydrocarbon generation and a lower degree of biodegradation of OM than the Qigequan Formation, it still shows generally favorable geological and geochemical conditions that are conducive to the development of microbial gas reservoirs, which is underscored by the biodegradation levels between 3 and 4 for the studied samples.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"296 ","pages":"Article 104658"},"PeriodicalIF":5.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anomalies in Vicker's microhardness of subbituminous and high volatile bituminous coals","authors":"Saeed Chehreh Chelgani ,&nbsp;James C. Hower ,&nbsp;Maria Mastalerz ,&nbsp;Susan M. Rimmer","doi":"10.1016/j.coal.2024.104659","DOIUrl":"10.1016/j.coal.2024.104659","url":null,"abstract":"<div><div>Vickers microhardness (MH) of coal is known to be strongly correlated with coal rank. To examine coal rank and other coal quality parameters, such as organic sulfur, that might influence MH, a suite of more than 300 samples from the Penn State Coal Quality database with vitrinite R_max &lt; 1.1 % were examined. The data set was narrowed down to 296 coals with moisture (as-received basis) &lt; 20 %. As MH is a parameter measured on vitrinite, vitrinite R_max was used as the rank parameter. The Eocene Big Dirty coal (Washington state) stood out as a high MH/high-moisture coal while Hanna and Green River basin coals (Wyoming) had low atomic H/C values and K Unita Basin (Utah) coals had high H/C. Organic S did not show a correlation with MH within discrete rank ranges. With respect to vitrinite R_max vs. MH, the Big Dirty coal and some Illinois and Iowa coals lie on the high-MH/low-R_max side and the Pennsylvanian Tioga (West Virginia) and the Indiana Brazil Formation coals, all dominated by dull lithotypes, lie on the low-MH/high-R_max side of the main data trend. Overall, the quadratic regression of vitrinite R_max vs. MH yields an R² of 0.55, indicating a significant correlation at the 95 % level.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"296 ","pages":"Article 104659"},"PeriodicalIF":5.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Characteristics of the low-pressure spatial and temporal distributions of oil- and gas-bearing layers in the Ordos Basin, China” [Int. J. Coal Geol. 2024 (285) 104476].","authors":"Yang Qin ,&nbsp;Chiyang Liu ,&nbsp;Lei Huang ,&nbsp;Jianqiang Wang ,&nbsp;Junfeng Zhao ,&nbsp;Deyong Shao ,&nbsp;Lihua Yang ,&nbsp;Xiaochen Zhao ,&nbsp;Ehsan Khalaf ,&nbsp;Shaohua Zhang ,&nbsp;Nan Du","doi":"10.1016/j.coal.2024.104622","DOIUrl":"10.1016/j.coal.2024.104622","url":null,"abstract":"","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104622"},"PeriodicalIF":5.6,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep syntectonic burial of the Anthracite belt, Eastern Pennsylvania","authors":"Mark A. Evans ,&nbsp;Aaron M. Jubb","doi":"10.1016/j.coal.2024.104646","DOIUrl":"10.1016/j.coal.2024.104646","url":null,"abstract":"<div><div>Fluid inclusion microthermometry and Raman spectroscopy of fluid inclusions in quartz veins from the Pennsylvanian rocks of the Anthracite belt, eastern Pennsylvania support a deep burial model of coalification in favor of focused orogenic hot fluid flow. High-temperature (250 to 255 °C) trapping of CH₄ ± CO₂ saturated aqueous fluids and CH₄ ± CO₂ inclusions indicate fluid trapping at depths of 11.5 to 13.4 km under a cover of Pennsylvanian to Permian(?) syntectonic load. In the folded rocks to the south of the Anthracite belt, CH₄ ± CO₂ fluid inclusions indicate a sediment load that was up to 16.3 km thick. <em>Re</em>-equilibrated aqueous fluid inclusions from veins in Silurian through Devonian rocks give the same range of trapping conditions but a wide range of fluid salinities suggesting that folding, fracturing, and meteoric recharge resulted in the intermixing of fluids from throughout the stratigraphic succession.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104646"},"PeriodicalIF":5.6,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of tectonic evolution processes on burial, thermal maturation and gas generation histories of the Wufeng-Longmaxi shale in the Sichuan Basin and adjacent areas","authors":"Shuyong Shi ,&nbsp;Yunpeng Wang ,&nbsp;Chengsheng Chen ,&nbsp;Jinzhong Liu ,&nbsp;Ping'an Peng","doi":"10.1016/j.coal.2024.104642","DOIUrl":"10.1016/j.coal.2024.104642","url":null,"abstract":"<div><div>The Wufeng-Longmaxi (WL) shale is widely distributed in the Sichuan Basin and adjacent areas in southwest China. The basin experienced multiple-stage complex tectonic movements, whose influences on burial, thermal maturation and gas generation histories in different areas are poorly understood. Based on a detailed study of the denudation stages, strata thickness, and thermal history of the basin, burial and thermal maturation histories of seven wells in different areas were modelled using PetroMod software. Due to the high maturity of the WL shale, a low-maturity Silurian Polish Llandovery shale was used for gold tube closed-system pyrolysis experiments to obtain kinetic parameters for evaluating methane generation history. The Polish shale was selected due to its depositional age, sedimentary environment and organic type, which are similar to the WL shale. The burial history of the WL shale can be divided into five stages: I. Early to Middle Silurian rapid burial; II. Caledonian uplift and denudation; III. Permian to Triassic sustained burial and denudation; IV. sustained burial since the Late Triassic; and V. Late Cretaceous to present sustained uplift and denudation. The thermal maturity of the WL shale in all wells increased with burial depth during stage IV. In addition, high calculated reflectance increments in wells JY1 and N201 during stage III occurred due to the relatively high basal heat flow and deep burial depth, resulting in higher current thermal maturities than in the other wells. The late Permian–Early Triassic and the Middle Jurassic–Early (or Late) Cretaceous were the key methane generation periods for wells JY1 and N201. In contrast, the other five wells had a single methane generation stage, mainly determined by burial and thermal maturation processes. The time of uplift and the amount of denudation during stage V, the current burial depth, the development of faults and fractures, high proportion of retention and the seal capacity of the overlying caprock are key factors for shale gas preservation. Hence, this study will help guide future shale gas development in the Sichuan Basin.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104642"},"PeriodicalIF":5.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Devolatilization behaviour of Kolubara and Kostolac lignite (Serbia) during the combustion process: A case study","authors":"Miodrag Životić ,&nbsp;Nenad Nikolić ,&nbsp;Dragoslava Stojiljković ,&nbsp;Danica Bajuk-Bogdanović ,&nbsp;Dragana Životić","doi":"10.1016/j.coal.2024.104641","DOIUrl":"10.1016/j.coal.2024.104641","url":null,"abstract":"<div><div>In this study the devolatization behaviour of lignite samples, of various grain sizes, on a wire mesh reactor is evaluated. Lignite samples were rapidly heated at four different temperatures (300, 500, 700 and 900 °C). The feed lignite reveals a high content of huminite, a low inertinite and liptinite contents in the Kostolac samples and a slightly higher liptinite content in the Kolubara samples. The char obtained at 300 °C and 500 °C shows slight petrographic and chemical changes. The major changes in chemical and petrographic compositions were observed in char heated at higher temperatures (700 °C and 900 °C). FTIR spectral data for both Kolubara and Kostolac lignite samples reveal a decrease in aliphatic- and oxygen­containing structures with increase in temperatures from 300 to 700 °C. The lack of aliphatic and oxygen-containing structures, the breakdown of clay minerals and negligible amount of water are detected in samples devolatilized at 900 °C where aromatic structures dominate.</div><div>Huminite reflectance of initial samples confirms the low rank (lignite) of all the samples. Char of all grain sizes obtained at 300 °C and 500 °C showed very small changes in the maceral composition and reflectance value and still corresponded to lignite rank. A significant change in maceral composition and increase reflectance is observed in char obtained at 700 °C and 900 °C of all grain sizes.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104641"},"PeriodicalIF":5.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effects of sample preparation on the interpretation of pyrolysis-based organic matter analysis in immature oil shale","authors":"Zibin Zhao ,&nbsp;Ralf Littke ,&nbsp;Christoph Hartkopf-Fröder","doi":"10.1016/j.coal.2024.104648","DOIUrl":"10.1016/j.coal.2024.104648","url":null,"abstract":"<div><div>Oil shale as well as shale oil and shale gas are significant energy resources with huge reserves present in different parts of the world. Various geochemical proxies have been applied to assess the petroleum potential of oil shales with samples pre-treated in various ways, e.g. as whole rock or demineralized sample or as solvent extracted rock/kerogen. In this respect, it is important to understand and quantify, how achieved geochemical parameters are influenced by pre-treatment. In this study, a systematic comparison is presented based on a study on i) whole rock, ii) extracted whole rock, iii) kerogen concentrate, and iv) extracted kerogen concentrate obtained after solvent extraction of demineralized shales. In total, seven immature, organic matter-rich samples from the Miocene lacustrine sediments of the Nördlinger Ries impact crater, Germany, were pretreated in this way leading to overall 28 samples. A set of elemental analysis (C, H, N), Rock-Eval pyrolysis, and Curie Point-pyrolysis–gas chromatography–mass spectrometry measurements were performed on these pretreated samples. Mineral matter removal leads to significant increase of total organic carbon, but also thermally evaporable and pyrolytically cracked organic matter (Rock-Eval S1 and S2 peaks). To some extent, labile organic matter represented in the original S2 peak can be destructed by mineral removal with hydrochloric and hydrofluoric acid, as shown by elevated values of PI [S1/(S1 + S2)] after demineralization. The organic matter type tends to be more petroleum-prone with raised hydrogen index (HI) and aliphaticity values after demineralization, while Rock-Eval T_max values commonly applied as parameters for thermal maturity tend to decrease, though not for all samples.</div><div>Reduced TOC, S1, S2 and PI values of extracted samples suggest that both thermally evaporable and additionally some non-evaporable but soluble organic matter hidden in the original S2 peak can be lost after solvent extraction. Increased values of HI, H/C and N/C of extracted samples indicate more oil-prone organic matter types than unextracted samples. Typical maturity-related parameters such as aliphaticity and Rock-Eval T_max decrease. Smectite and zeolites, which are abundant in the samples, are suggested to protect organic matter to some extent against solvent extraction, influencing a variety of geochemical proxies and the occurrence of metal cation-containing minerals. Zeolite invigorates the protection effect.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"296 ","pages":"Article 104648"},"PeriodicalIF":5.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palynofacies as sea-level-sensitive proxy in Early Cretaceous marine mudstones – A critical evaluation","authors":"Hauke Thöle ,&nbsp;Ulrich Heimhofer ,&nbsp;André Bornemann ,&nbsp;Jochen Erbacher","doi":"10.1016/j.coal.2024.104645","DOIUrl":"10.1016/j.coal.2024.104645","url":null,"abstract":"<div><div>Stratigraphic distribution patterns of particulate organic matter (POM) have been widely used for facies recognition and paleoenvironmental interpretation as well as to decipher proximal to distal trends within fine-grained sediments. The Lower Cretaceous mudstone-dominated succession in the eastern Lower Saxony Basin (LSB) offers an excellent opportunity to critically evaluate such palynofacies parameters, commonly used to identify transgressive-regressive (T-R) cycles in marine sediments. For the seemingly monotonous succession, a robust sequence stratigraphic framework has been previously established by integrating high-resolution elemental intensity data from X-Ray Fluorescence (XRF) core scanning and biostratigraphy from four drill cores. In this study, the composition and distribution of the POM has been assessed by analysis of 220 strew mounts using transmitted-light microscopy. Overall, the POM composition indicates deposition in a mud-dominated proximal to distal shelf setting. The ratio of opaque versus translucent phytoclasts (OP/TR ratio) shows a distinct long-term increase from the Berriasian onwards with maximum values during the early Hauterivian, followed by a subsequent decrease in OP/TR ratio. This trend broadly reflects the overall T-R evolution of the succession interpreted from Si/Al changes. This also applies to the size and sorting of opaque phytoclasts, with the greatest amplitude changes in opaque particle size parameters being observed in the more proximal deposits of the studied succession. On the other hand, the ratio of terrestrial versus marine palynomorphs (T/M ratio), often applied as indicator of proximal to distal trends and distances from the coastline, shows no correlation with the T-R cycles. Systematic long- and short-term trends visible in T/M ratio correspond to variations in the XRF-derived Ca/Ti stratigraphic trend, which is interpreted to reflect variations in carbonate content. This may indicate that the T/M ratio in the LSB is largely controlled by variations in marine palynomorph flux, probably related to productivity changes of the organic-walled microplankton.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104645"},"PeriodicalIF":5.6,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coke-based proppant for coalbed methane technology","authors":"Rafał Morga,&nbsp;Krzysztof Labus,&nbsp;Tomasz Suponik","doi":"10.1016/j.coal.2024.104647","DOIUrl":"10.1016/j.coal.2024.104647","url":null,"abstract":"<div><div>The production of ultra-light weight coke proppants for fracturing coal bed methane deposits is presented. The raw material is blast-furnace coke, foundry coke and a coke breeze. The method used obtains coke proppants that meet all the requirements of the ISO 13503-2:2006/Amd.1:2009 standard for proppants used in hydraulic fracturing, with the exception of crush resistance. They have porosity up to 40 % and they are mainly macroporous materials, containing predominantly cylindrical, less frequently bottle-shaped or wedge-shaped pores. The proppants with the lowest crush rate were obtained from the blast furnace coke (CSR &gt; 65 %).</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104647"},"PeriodicalIF":5.6,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}