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Advances in Methane Production from Coal, Shale and Other Tight Rocks

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "H3: Fossil".

Deadline for manuscript submissions: closed (31 August 2022) | Viewed by 22693

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Special Issue Editors

College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, China
Interests: coal and coalbed methane; unconventional natural gas/oil resources; sedimentology
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Guest Editor
College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
Interests: applied geophysics; ground penetrating radar method and technology; 3D seismic inversion of coalfield; basic research on transparent mine technology
Special Issues, Collections and Topics in MDPI journals
School of Emergency Management and Safety Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
Interests: coalbed methane geology; rock mechanics; multi-physics coupling; coalbed methane drainage and technology; coal mine methane drainage and technology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Global demand for energy, directives to reduce carbon dioxide emissions, and technological advancements in horizontal drilling and hydraulic fracturing have spurred a rapid increase in alternative and unconventional energy production over the past decade. The application of new technologies has enabled natural gas and shale oil to be economically produced from shale and other unconventional formations. Further, various methods have been adopted to improve gas recovery, including but not limited to high-precision characterization of coal and shale reservoirs at multiscales, fast drilling and completion of wells with long laterals as well as large-scale volume fracturing, and new technologies such as multiple well-type development, fluid injection, nano-flooding, and enhancing biogenic methane generation methods. 

The aim of this Special Issue is to report on the state of the art in fundamental discipline application to methane production and associated challenges in geoengineering activities. We are particularly interested in the three levels of methane and other hydrocarbon production issues, geological and hydrological controls on the accumulation of hydrocarbon, coupled thermal-hydromechanical–chemical processes influencing methane migration, and new technologies and related field tests applied in hydrocarbon production in coal mines and oil fields. We hope to focus both on progress in new methods and on new technique development. We welcome both original research and review articles

Dr. Yong Li
Prof. Dr. Fan Cui
Dr. Chao Xu
Guest Editors

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Keywords

  • fundamental research in geology, geomechanics, and geofluids
  • coal mine safety issues and methane extraction advances
  • real-time detection technology of mine disaster source
  • recovery mechanisms of oil and gas from heterogeneous reservoirs
  • enhanced oil/gas production using CO2, N2, and other mixed gases
  • numerical and analytical modeling in predicting production performance
  • advances in the use of artificial intelligence for the development of geofluid resources

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Published Papers (10 papers)

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Research

14 pages, 3759 KiB  
Article
Genesis of Bedding Fractures in Ordovician to Silurian Marine Shale in Sichuan Basin
by Hu Wang, Zhiliang He, Shu Jiang, Yonggui Zhang, Haikuan Nie, Hanyong Bao and Yuanping Li
Energies 2022, 15(20), 7738; https://doi.org/10.3390/en15207738 - 19 Oct 2022
Cited by 4 | Viewed by 1312
Abstract
The effective utilization of shale bedding fractures is of great significance to improve shale gas recovery efficiency. Taking the Wufeng–Longmaxi Formation shale in Sichuan Basin as the research object, the formation process and mechanism of bedding fractures in marine shale are discussed, based [...] Read more.
The effective utilization of shale bedding fractures is of great significance to improve shale gas recovery efficiency. Taking the Wufeng–Longmaxi Formation shale in Sichuan Basin as the research object, the formation process and mechanism of bedding fractures in marine shale are discussed, based on field observation and description, high-resolution electron microscope scanning, fluid inclusion detection, and structural subsidence history analysis. The results show that the formation of bedding fractures is jointly controlled by sedimentary characteristics, hydrocarbon generation, and tectonic movement: the development degree of bedding (fractures) is controlled by the content of shale organic matter and brittle minerals, and bedding fractures formed in the layers with high organic matter; tectonic movement created stress environment and space for bedding fractures and promoted the opening of bedding fractures; the time for calcite vein to capture fluid is consistent with the time of oil-gas secondary pyrolysis stage. The formation of the calcite vein is accompanied by the opening of fractures. The acid and oil-gas generated in the hydrocarbon generation process occupied the opening space and maintained the bedding fractures open. The study of the formation process of bedding fractures is helpful to select a suitable method to identify bedding fractures, and then effectively use it to form complex fracture networks in the fracturing process to improve shale oil and gas recovery. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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15 pages, 7271 KiB  
Article
Inversion Study on Parameters of Cascade Coexisting Gas-Bearing Reservoirs in Huainan Coal Measures
by Baiping Chen, Bo Liu, Yunfei Du, Guoqi Dong, Chen Wang, Zichang Wang, Ran Wang and Fan Cui
Energies 2022, 15(17), 6208; https://doi.org/10.3390/en15176208 - 26 Aug 2022
Viewed by 1516
Abstract
The prediction and development of three gases, mainly coalbed methane, shale gas, and tight sandstone gas, in the Huainan coal measures of China, has been the focus of local coal mines. However, due to the overlapping and coexisting characteristics of the three gas [...] Read more.
The prediction and development of three gases, mainly coalbed methane, shale gas, and tight sandstone gas, in the Huainan coal measures of China, has been the focus of local coal mines. However, due to the overlapping and coexisting characteristics of the three gas reservoirs in Huainan coal measure strata, it is challenging to develop the three gas. The coal mine has been creating a single pool for a long time, resulting in the severe waste of other gas resources in developing the gas-bearing resources in the coal measure strata. The gas-containing reservoir is predicted based on geological, seismic, and logging in Huainan Mining. In addition, determining the excellent area for reference for the development of three gas resources. First, using logging data, mathematical–statistical methods are used to analyze the physical parameters of gas-bearing reservoirs in multi-layered stacked coal seams. Then, based on the theory of prestack seismic inversion, parameters, such as the impedance of P-wave, the ratio of P-wave velocity and S-wave, Lamé constant, Young’s modulus, and Poisson’s ratio and lithological distribution, are obtained for the whole area. The gas-bearing information of the reservoir is received by the statistics and equation of the parameter intersection diagram and is closely related to exploration and development. Finally, the paper synthetically predicts the most favorable area of the gas-bearing reservoir in the study area. The prediction results are compared with the actual results of coalbed methane content in the existing extraction wells, proving that the method is feasible and can provide the basis for the deployment and development of the well location. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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13 pages, 3839 KiB  
Article
Differentiation and Prediction of Shale Gas Production in Horizontal Wells: A Case Study of the Weiyuan Shale Gas Field, China
by Lixia Kang, Wei Guo, Xiaowei Zhang, Yuyang Liu and Zhaoyuan Shao
Energies 2022, 15(17), 6161; https://doi.org/10.3390/en15176161 - 25 Aug 2022
Cited by 4 | Viewed by 1474
Abstract
The estimated ultimate recovery (EUR) of shale gas is an important index for evaluating the production capacity of horizontal wells. The Weiyuan shale gas field has wells with considerable EUR differentiation, which hinders the prediction of the production capacity of new wells. Accordingly, [...] Read more.
The estimated ultimate recovery (EUR) of shale gas is an important index for evaluating the production capacity of horizontal wells. The Weiyuan shale gas field has wells with considerable EUR differentiation, which hinders the prediction of the production capacity of new wells. Accordingly, 121 wells with highly differentiated production are used for analysis. First, the main control factors of well production are identified via single-factor and multi-factor analyses, with the EUR set as the production capacity index. Subsequently, the key factors are selected to perform the multiple linear regression of EUR, accompanied by the developed method for well production prediction. The thickness and drilled length of Long 111 (Substratum 1 of Long 1 submember, Lower Silurian Longmaxi Formation) are demonstrated to have the uttermost effects on the well production, while several other factors also play important roles, including the fractured horizontal wellbore length, gas saturation, brittle mineral content, fracturing stage quantity, and proppant injection intensity. The multiple linear regression method can help accurately predict EUR, with errors of no more than 10%, in wells that have smooth production curves and are free of artificial interference, such as casing deformation, frac hit, and sudden change in production schemes. The results of this study are expected to provide certain guiding significances for shale gas development. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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13 pages, 7109 KiB  
Article
Applicability Analysis of Pre-Stack Inversion in Carbonate Karst Reservoir
by Rui Wang and Bo Liu
Energies 2022, 15(15), 5598; https://doi.org/10.3390/en15155598 - 2 Aug 2022
Cited by 3 | Viewed by 1302
Abstract
Although pre-stack inversion has been carried out on reservoir prediction, few studies have focused on the application of pre-stack for seismic inversion in fractured-cavity carbonate reservoirs. In carbonate rock, complicated combinations and fluid predictions in karst caves are remain unclear. Post-stack methods are [...] Read more.
Although pre-stack inversion has been carried out on reservoir prediction, few studies have focused on the application of pre-stack for seismic inversion in fractured-cavity carbonate reservoirs. In carbonate rock, complicated combinations and fluid predictions in karst caves are remain unclear. Post-stack methods are commonly used to predict the position, size, and fillings of caves, but pre-stack inversion is seldom applied in carbonate karst reservoirs. This paper proposes a pre-stack inversion method for forward modeling data and oil survey seismic data, using both points to indicate the application of pre-stack inversion in karst caves. Considering influence of cave size, depth, and filler on prediction, three sets of models (different caves volume; different fillings velocity of caves; complicated combination of caves) are employed and inverted by pre-stack inversion. We analyze the pre-stack results to depict Ordovician oil bearing and characterize caves. Geological model parameters came from actual data of the Tahe oilfield, and seismic data were synthesized from geological models based on full-wave equation forward simulation. Moreover, a case study of pre-stack inversion from the Tahe area was employed. The study shows that, from both the forward modeling and the oil seismic data points of view, pre-stack inversion is applicable to carbonate karst reservoirs. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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24 pages, 11454 KiB  
Article
The Study on Diagenetic Characteristics of Coal Measures Sandstone Reservoir in Xishanyao Formation, Southern Margin of the Junggar Basin
by Aobo Zhang, Shida Chen, Dazhen Tang, Shuling Tang, Taiyuan Zhang, Yifan Pu and Bin Sun
Energies 2022, 15(15), 5499; https://doi.org/10.3390/en15155499 - 29 Jul 2022
Cited by 5 | Viewed by 1993
Abstract
The reservoir physical properties, pore types, diagenetic characteristics and reservoir quality controlling effect of the Xishanyao formation coal measure sandstone in the southern margin of the Junggar basin were discussed in this study based on thin section observation, high pressure mercury injection, low-temperature [...] Read more.
The reservoir physical properties, pore types, diagenetic characteristics and reservoir quality controlling effect of the Xishanyao formation coal measure sandstone in the southern margin of the Junggar basin were discussed in this study based on thin section observation, high pressure mercury injection, low-temperature nitrogen adsorption and scanning electron microscope observation. The result shows that the porosity and permeability of the sandstone are generally low with a medium-high texture maturity and low compositional maturity. The sandstone storage space is mainly composed of residual intergranular pores, secondary dissolution pores, inter-crystalline pores and micro-fractures. The diagenetic stage of coal measure sandstone is in the mesodiagenesis A1-A2 stage, and their diagenetic interaction types mainly include compaction, cementation and dissolution. The reservoir quality of the coal measure sandstone deteriorates by compaction due to high matrix content and plastic debris content. Because of the large amounts of organic acids generated during the thermal evolution of the coal measure source rock, the coal measure sandstone suffers from strong dissolution. The secondary dissolution pores formed by the massive dissolution of feldspar, lithic fragments and early carbonate cementation in the sandstone significantly improved the reservoir quality. In the coal measure sandstone, clay mineral cementation is the most developed cementation form, followed by quartz cementation and carbonate cementation. Although kaolinite cementation and dolomite cementation can generate a small number of inter-crystalline pores, cementation deteriorates the reservoir quality. The Xishanyao formation coal measure sandstone formed in a lacustrine-delta environment, and its composition and texture make it susceptible to the influence of compaction and dissolution during diagenesis. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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24 pages, 11428 KiB  
Article
Pore Structure in Shale Tested by Low Pressure N2 Adsorption Experiments: Mechanism, Geological Control and Application
by Feng Liang, Qin Zhang, Bin Lu, Peng Chen, Chi Su, Yu Zhang and Yu Liu
Energies 2022, 15(13), 4875; https://doi.org/10.3390/en15134875 - 2 Jul 2022
Cited by 4 | Viewed by 2357
Abstract
The N2 adsorption experiment is one of the most important methods for characterizing the pore structure of shale, as it covers the major pore size range present in such sediments. The goal of this work is to better understand both the mechanisms [...] Read more.
The N2 adsorption experiment is one of the most important methods for characterizing the pore structure of shale, as it covers the major pore size range present in such sediments. The goal of this work is to better understand both the mechanisms and application of low-pressure nitrogen adsorption experiments in pore structure characterization. To achieve this, the N2 adsorption molecular simulation method, low-pressure N2 adsorption experiments, total organic carbon (TOC) analysis, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and a total of 196 shale samples from the Wufeng–Longmaxi formations in the Sichuan basin have been employed in this study. Based on the analytical data and the simulations, two parameters, the connectivity index and the large pore volume index, are proposed. These parameters are defined as the connectivity of the pore system and the volume of large nanopores (>10 nm) respectively, and they are calculated based on the N2 adsorption and desorption isotherms. The experimental results showed that TOC content and clay minerals are the key factors controlling surface area and pore volume. However, in different shale wells and different substrata (divided based on graptolite zonation), the relative influences of TOC content and clay minerals on pore structure differ. In three of the six wells, TOC content is the key factor controlling surface area and pore volume. In contrast, clay minerals in samples from the W202 well are the key factors controlling pore volume, and with an increase in the clay mineral content, the pore volume increases linearly. When the carbonate content exceeds 50%, the pore volume decreases with an increase in carbonate content, and this may be because in the diagenetic process, carbonate cement fills the pores. It is also found that with increasing TOC content the connectivity index increases and SEM images also illustrate that organic pores have better connectivity. Furthermore, the connectivity index increases as quartz content increases. The large pore volume index increases with quartz content from 0 to 40% and decreases as quartz increases from 40% to 100%. By comparing the pore structure of shale in the same substrata of different shale gas wells, it was found that tectonic location significantly affects the surface area and pore volume of shale samples. The shale samples from wells that are located in broad tectonic zones, far from large-scale faults and overpressure zones, have larger pore volumes and surface areas. On the contrary, the shale samples from shale gas wells that are located in the anticline region with strong tectonic extrusion zones or near large-scale faults have relatively low pore volumes and surface areas. By employing large numbers of shale samples and analyzing N2 adsorption mechanism in shale, this study has expanded the application of N2 adsorption experiment in shale and clarifies the effects of sedimentary factors and tectonic factors on pore structure. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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20 pages, 11018 KiB  
Article
Source-to-Sink Comparative Study between Gas Reservoirs of the Ledong Submarine Channel and the Dongfang Submarine Fan in the Yinggehai Basin, South China Sea
by Yue Yao, Qiulei Guo and Hua Wang
Energies 2022, 15(12), 4298; https://doi.org/10.3390/en15124298 - 11 Jun 2022
Cited by 6 | Viewed by 2495
Abstract
The Ledong submarine channel and the Dongfang submarine fan, two remarkable sedimentary systems developed during the late Miocene, are considered promising hydrocarbon reservoirs in the Yinggehai Basin of the South China Sea. A comparative study was conducted to reveal the differences between the [...] Read more.
The Ledong submarine channel and the Dongfang submarine fan, two remarkable sedimentary systems developed during the late Miocene, are considered promising hydrocarbon reservoirs in the Yinggehai Basin of the South China Sea. A comparative study was conducted to reveal the differences between the source-to-sink characteristics of the two gas-bearing and gravity-driven depositional systems to determine their provenances, formation mechanisms and migration paths as well as their key controlling factors. The heavy mineral assemblages and detrital zircon U-Pb dating results suggest that the Ledong channel was fed by the Hainan provenance from the eastern margin, whereas the Dongfang fan was supplied by northwestern terrigenous sources. The relative sea level transgression and sufficient sediment supply triggered the delivery of deltaic loads toward the continental shelves. Seismic data show that fracture activity had a great impact on the tectono-morphologic features of the margins. During downward flow, the gravity flow along the Yingdong Slope encountered steeply falling faulted slope break belts and formed the Ledong incised channel, and the gravity flow of the Yingxi Slope moved through the gently dipping flexural break slope zone and formed the Dongfang dispersed lobe deposits. Since ca. 30 Ma, the sedimentary center has been migrating from the north to the southeast, which produced a clear control of the southeastward distribution pattern of these two sedimentary systems. Observations of cores and thin sections indicate that the rock structures and their compositions are more mature in the Dongfang channel than in the Ledong fan. This study documents significant differences and similarities by comparing the source-to-sink processes of the two gravity-driven systems that developed in the Yinggehai Basin and provides analogies for understanding similar submarine sedimentary systems that developed under similar geological contexts worldwide. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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15 pages, 5923 KiB  
Article
An NMR-Based Method for Multiphase Methane Characterization in Coals
by Sijian Zheng, Shuxun Sang, Shiqi Liu, Xin Jin, Meng Wang, Shijian Lu, Guangjun Feng, Yi Yang and Jun Hou
Energies 2022, 15(4), 1532; https://doi.org/10.3390/en15041532 - 18 Feb 2022
Cited by 2 | Viewed by 1712
Abstract
Discriminating multiphase methane (adsorbed and free phases) in coals is crucial for evaluating the optimal gas recovery strategies of coalbed methane (CBM) reservoirs. However, the existing volumetric-based adsorption isotherm method only provides the final methane adsorption result, limiting real-time dynamic characterization of multiphase [...] Read more.
Discriminating multiphase methane (adsorbed and free phases) in coals is crucial for evaluating the optimal gas recovery strategies of coalbed methane (CBM) reservoirs. However, the existing volumetric-based adsorption isotherm method only provides the final methane adsorption result, limiting real-time dynamic characterization of multiphase methane in the methane adsorption process. In this study, via self-designed nuclear magnetic resonance (NMR) isotherm adsorption experiments, we present a new method to evaluate the dynamic multiphase methane changes in coals. The results indicate that the T2 distributions of methane in coals involve three different peaks, labeled as P1 (T2 < 8 ms), P2 (T2 = 20–300 ms), and P3 (T2 > 300 ms) peaks, corresponding to the adsorbed phase methane, free phase methane between particles, and free phase methane in the sample cell, respectively. The methane adsorption Langmuir volumes calculated from the conventional volumetric-based method qualitatively agree with those obtained from the NMR method, within an allowable limit of approximately ~6.0%. Real-time dynamic characterizations of adsorbed methane show two different adsorption rates: an initial rapid adsorption of methane followed by a long stable state. It can be concluded that the NMR technique can be applied not only for methane adsorption capacity determination, but also for dynamic monitoring of multiphase methane in different experimental situations, such as methane adsorption/desorption and CO2-enhanced CBM. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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18 pages, 4587 KiB  
Article
Analysis of Available Conditions for InSAR Surface Deformation Monitoring in CCS Projects
by Tian Zhang, Wanchang Zhang, Ruizhao Yang, Huiran Gao and Dan Cao
Energies 2022, 15(2), 672; https://doi.org/10.3390/en15020672 - 17 Jan 2022
Cited by 12 | Viewed by 3535
Abstract
Carbon neutrality is a goal the world is striving to achieve in the context of global warming. Carbon capture and storage (CCS) has received extensive attention as an effective method to reduce carbon dioxide (CO2) in the atmosphere. What follows is [...] Read more.
Carbon neutrality is a goal the world is striving to achieve in the context of global warming. Carbon capture and storage (CCS) has received extensive attention as an effective method to reduce carbon dioxide (CO2) in the atmosphere. What follows is the migration pathway and leakage monitoring after CO2 injection. Interferometric synthetic aperture radar (InSAR) technology, with its advantages of extensive coverage in surface deformation monitoring and all-weather traceability of the injection processes, has become one of the promising technologies frequently adopted in worldwide CCS projects. However, there is no mature evaluation system to determine whether InSAR technology is suitable for each CO2 sequestration area. In this study, a new evaluation model is proposed based on the eight factors that are selected from the principle of the InSAR technique and the unique characteristics of the CO2 sequestration area. According to the proposed model, the feasibility of InSAR monitoring is evaluated for the existing typical sequestration areas in the world. Finally, the challenges and prospects of InSAR in the CCS project are discussed. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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15 pages, 2731 KiB  
Article
Preparation, Properties and Application of Gel Materials for Coal Gangue Control
by Xiaoqiang Zhang and Yuanyuan Pan
Energies 2022, 15(2), 557; https://doi.org/10.3390/en15020557 - 13 Jan 2022
Cited by 23 | Viewed by 2676
Abstract
In order to solve the problem of the spontaneous combustion of coal gangue, a coal gangue fire-extinguishing material of gel–foam was developed. The foaming agent was screened by the Waring blender method with varying foam amounts, and the superabsorbent foam stabilizer was synthesized [...] Read more.
In order to solve the problem of the spontaneous combustion of coal gangue, a coal gangue fire-extinguishing material of gel–foam was developed. The foaming agent was screened by the Waring blender method with varying foam amounts, and the superabsorbent foam stabilizer was synthesized by free radical polymerization. Moreover, the gel–foam was used in a spontaneous combustion of coal gangue mountain field practice. The results showed that when the mass fraction of sodium dodecyl sulfonate and coconut oil amide propyl betaine was 0.6% and 4:6, the foaming amount was as high as 1500 mL. When the mass ratio of chitosan to acrylic acid was 1:6, the neutralization degree was 80%, the cross-linking agent was 0.8%, and the initiator was 0.01%, the water absorption of the synthesized superabsorbent foam stabilizer reached 476 mL/g. The synthesized gel–foam was tested in a spontaneous combustion coal gangue hill in a certain area, and no reburning sign was found within one month. Full article
(This article belongs to the Special Issue Advances in Methane Production from Coal, Shale and Other Tight Rocks)
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