Multiscale Qualitative–Quantitative Characterization of the Pore Structure in Coal-Bearing Reservoirs of the Yan’an Formation in the Longdong Area, Ordos Basin DOI Open Access
Rong Wang, Baohong Shi, Tao Wang

et al.

Processes, Journal Year: 2024, Volume and Issue: 12(12), P. 2787 - 2787

Published: Dec. 6, 2024

Accurate characterization of coal reservoir micro- and nanopores is crucial in evaluating coalbed methane storage gas production capacity. In this work, 12 coal-bearing rock samples from the Jurassic Yan’an Formation, Longdong area, Ordos Basin were taken as research objects, nanopore structures characterized via scanning electron microscopy, high-pressure mercury pressure, low-temperature N2 adsorption low-pressure CO2 experiments. The main factors controlling pore structure development influence on content studied by combining reflectivity specular microscopic composition determined through industrial analyses isothermal absorption results show that strata mine are a very important source, Formation study area exhibit remarkable organic clay mineral accompanied clear microfractures interlayer joints, which together optimize conditions form efficient microseepage pathways for gas. Coalstone, carbonaceous mudstone differential distributions volume specific surface area. general trend best, second weakest. samples’ microporous properties positively correlated with sample group, whereas there no correlation inert group. An increase moisture air-dried matrix promotes development, leading to increases CH4 increasing average maximum approximately 8.13 m3/t. limit amount adsorbed samples, VL, indicating larger is, greater can be samples. PL value, not correlated, direct mathematical relationship between them.

Language: Английский

Data-Driven Approach for the Prediction of In Situ Gas Content of Deep Coalbed Methane Reservoirs Using Machine Learning: Insights from Well Logging Data DOI Creative Commons
Qian Zhang, Shuheng Tang, Songhang Zhang

et al.

ACS Omega, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 14, 2025

The in situ gas content is a critical determinant of the exploitation potential and recovery coalbed methane (CBM) resources. Deep CBM resources have enormous potential, but their intricate geological conditions hinder acquisition data. To enhance efficiency accuracy acquiring data for deep CBM, this study integrates gray relational analysis (GRA) genetic algorithm (GA) into back-propagation neural network (BPNN) model, establishing novel prediction model using well logging results show that multialgorithm joint can overcome inherent shortcomings BPNN. GRA method effectively identifies optimal input parameters BPNN GA optimizes initial weights thresholds BPNN, thereby enhancing stability model. mean square error (MSE) GRA-GA-BPNN decreases by 77.60% compared with Furthermore, taking wells Ningwu Basin North China as an example, reliability was verified (4.62% average relative only). proposed exhibits high robustness strong generalization ability. It achieve high-precision content, circumventing overreliance on experimental measurements, holding significant practical application significance.

Language: Английский

Citations

1
Fractal Characterization of a Multi-Scale Pore Structure in Ultra-Deep Coal Seams DOI Creative Commons
Yanwei Qu, Feng Chen, Lulu Ma

et al.

Fractal and Fractional, Journal Year: 2025, Volume and Issue: 9(4), P. 250 - 250

Published: April 15, 2025

The pore–fracture structure of ultra-deep coal is critical for evaluating resource potential and guiding the exploration development deep coalbed methane (CBM). In this study, a sample was obtained from Gaogu-4 well at depth 4369.4 m in Shengli Oilfield Shandong, China. A comprehensive suite characterization techniques, including Field Emission Scanning Electron Microscopy (FE-SEM), X-ray diffraction (XRD), Mercury Intrusion Porosimetry (MIP), Low-temperature Nitrogen Adsorption (LT-N2GA), Low-pressure CO2 (LP-CO2GA), were employed to investigate surface morphology, mineral composition, multi-scale characteristics coal. Based on fractal geometry theory, four dimension models established, pore parameters then used calculate dimensions sample. results show that relatively rough, with prominent fractures limited presence as observed under FE-SEM. Energy Dispersive Spectrometer (EDS) analysis identified elements such C, O, Al, Si, S, Fe, thus suggesting contains silicate iron sulfide minerals. XRD shows kaolinite, marcasite, clinochlore. indicate predominantly composed micropores, followed by mesopores. Macropores are least abundant, yet they contribute most volume (PV), accounting 70.9%. specific area (SSA) micropores occupies an absolute advantage, up 97.46%. model, 1.4372, while mesopores, macropores 2.5424, 2.5917, 2.5038, respectively. These morphology distribution non-uniform exhibit statistical characteristics. dominated seams provides numerous adsorption sites CBM, thereby controlling capacity CBM.

Language: Английский

Citations

1
Pore Structure and Heterogeneity Characteristics of Deep Coal Reservoirs: A Case Study of the Daning–Jixian Block on the Southeastern Margin of the Ordos Basin DOI Open Access
Bo Li,

Yanqin Guo,

Xiao Hu

et al.

Minerals, Journal Year: 2025, Volume and Issue: 15(2), P. 116 - 116

Published: Jan. 24, 2025

To clarify the micropore structure and fractal characteristics of Danning–Jixian block on eastern margin Ordos Basin, this study focuses deep coal rock Benxi Formation in that area. On basis an analysis quality physical properties, qualitative quantitative studies pore structures with different diameters were conducted via techniques such as field emission scanning electron microscopy (FE-SEM), low-pressure CO2 adsorption (LP-CO2A), low-temperature N2 (LT-N2A), high-pressure mercury intrusion (HPMI). By applying theory integrating results from LP-CO2A, LT-N2A, HPMI experiments, dimensions pores obtained to characterize complexity heterogeneity samples. The indicate reservoirs have abundant nanometer-scale organic matter gas pores, tissue a small number intergranular showing strong influenced by microscopic components forms distribution matter. exhibits significant cross-scale effects is predominantly composed micropores account for more than 90% total volume; affected mainly degree coalification, vitrinite group, ash yield. Fractal reveals macropores greater mesopores micropores. This may be attributed smaller sizes concentrated distributions micropores, which are less diagenesis, resulting simpler lower dimensions. In contrast, macropores, larger broader distributions, exhibit diverse origins reflecting heterogeneity. storage space self-similarity facilitate occurrence, flow, extraction coalbed methane.

Language: Английский

Citations

0
Molecular Structural Evolution During Coal Oxidation Based on in Situ Ftir and Raman Spectroscopy DOI

Guoqing Chen,

Yongsheng Guan,

Jiaxun Liu

et al.

Published: Jan. 1, 2025

Language: Английский

Citations

0
Multiscale Pore–Fracture Structure Characteristics of Deep Coal Reservoirs in the Eastern Margin of the Ordos Basin, China DOI
Guoliang Tao, Zhenzhi Wang, Yi Jin

et al.

Natural Resources Research, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 16, 2025

Language: Английский

Citations

0
Thermal Evolution of Organic Matter in Low-Maturity Shale: A Multimodal Nanoscale Investigation DOI
Yingjie Li, Tianhao Wu,

Junliang Zhao

et al.

Energy & Fuels, Journal Year: 2025, Volume and Issue: unknown

Published: April 10, 2025

Language: Английский

Citations

0
Geological Controls on Gas Content of Deep Coal Reservoir in the Jiaxian Area, Ordos Basin, China DOI Open Access

Shaobo Xu,

Qian Li, Fengrui Sun

et al.

Processes, Journal Year: 2024, Volume and Issue: 12(6), P. 1269 - 1269

Published: June 20, 2024

Deep coalbed methane (DCBM) reservoirs hold exceptional potential for diversifying energy sources. The Ordos Basin has attracted much attention due to its enormous resource reserves of DCBM. This work focuses on the Jiaxian area basin, and multi-factor quantitative evaluation method sealing cap rocks is established. abundant geologic reservoir information synthesized explore variable factors affecting gas content. Results indicate that capacity coal seam roof in area, with a mean index 3.12, surpasses floor’s by 13.87%, which averages 2.74. more positive impact enrichment (CBM). In addition, conditions preserving would be boosted as thickness increased, leading enhanced content seams. CH4 increases an average ~2.38 m3/t interval 1 m. increasing burial depth represents incremental maturity organic matter generation ability seams, contributes improving There correlation between degree fragmentation certain extent. These findings provide valuable insights targeted drilling strategies enhancing natural production Basin.

Language: Английский

Citations

2
A Physical Parameter Characterizing Heterogeneity of Pore and Fracture Structures in Coal Reservoirs DOI Open Access
Haiyang Pan,

Yinchuan Shao,

Zhizheng Liu

et al.

Processes, Journal Year: 2024, Volume and Issue: 12(8), P. 1553 - 1553

Published: July 25, 2024

Pore structure heterogeneity of coal reservoirs restricts the diffusion-seepage process coalbed methane, thereby restricting production capacity methane. Therefore, 10 samples from Linxing area are taken as an objective, and high-pressure mercury intrusion testing was used to describe pore distribution all samples. On this basis, four single multifractal models were perform fractal calculations, correlation analysis conducted on advance retreat dimension values clarify physical significance removal values. Finally, relationship between curves parameters clarified, applicability various in characterizing explored. All can be divided into type A B by using volume percentage greater than 1000 nm efficiency. The T model has universality strongest parameter based injection curve obtained, then quantitatively characterize fracture reservoirs. This is complexity gas water transport during methane production, further elucidating under constraint

Language: Английский

Citations

2
Characterisation of the Full Pore Size Distribution of and Factors Influencing Deep Coal Reservoirs: A Case Study of the Benxi Formation in the Daning–Jixian Block at the Southeastern Margin of the Ordos Basin DOI Open Access
Xiaoming Chen, Tao Wang, Song Wu

et al.

Processes, Journal Year: 2024, Volume and Issue: 12(11), P. 2364 - 2364

Published: Oct. 28, 2024

The complex geological environment in deep layers results differences the pore and fracture structures states of coalbed methane (CBM) occurrences between shallow coal reservoirs. coexistence multiphase gases endows CBM with both “conventional” “unconventional” attributes. Based on systematically collected samples from Benxi Formation Daning–Jixian area Ordos Basin, high-pressure mercury intrusion (HPMI), low-temperature N2 adsorption (LTN2A), low-pressure CO2 (LPCO2A) experiments were conducted to characterise across full size distribution coals. aim this research is gain an in-depth understanding full-size pores explore factors influencing their structure control over gas content indicate that study unimodal nanopores are present. sizes relatively small, average total volume (PV) 0.073 cm3/g specific surface (SSA) 227.87 m2/g. Among these, micropores account for 92.26% PV 99.57% SSA, making primary contributors storage space Mesopores macropores contribute little which unfavourable permeability. development coals influenced by maturity, vitrinite content, ash yield. Generally, increases when coal’s rank increases; increase promotes micropores, whereas a high yield leads decreases SSA. influence SSAs reflected mainly its effect adsorbed content. Since molecules exist state, strongly affect capacity gas.

Language: Английский

Citations

1
Occurrence, Origin, and Infill Modification Effects of Minerals in Deep Coals in the Ordos Basin, China DOI

Zhanwei Li,

Shida Chen,

Dazhen Tang

et al.

Energy & Fuels, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 14, 2024

Minerals in deep coals contribute to coal reservoir heterogeneity and influence coalbed methane enrichment by modifying the physical properties of pore-fracture system. This study has used multiple qualitative quantitative analytical techniques characterize system occurrences minerals Daji block, Ordos Basin. The with high rank medium-low ash yield show a complex dual structure obvious cross-scale effects. is genesis diverse morphology, open fractures varying scales may communicate pores form networks. Mineral phases consist mainly kaolinite, calcite, pyrite, minor other (quartz, Illite, siderite, collophanite, bauxite minerals, halite). modes mineral occurrence, including syngenetic epigenetic origins, depended on mineralogical associated coal-forming process. Different infilling modified extents. Overall, seams have reduced porosity but increased permeability some extent. Higher clay carbonate contents collectively lower porosity; however, higher sulfide permeability.

Language: Английский

Citations

0