Prediction of coal seam gas content based on the correlation between gas basic parameters and coal quality indexes

Dai, Linchao; Hong-yan, Lei; Cheng, Xinjian; Li, Rifu

doi:10.3389/fenrg.2022.1096539

Cited by 5 publications

(4 citation statements)

References 44 publications

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“…For example, a two-dimensional curve characterized by the relationship between the methane concentration and distance S at different times, as well as the methane concentration change over time at different positions, is insufficiently representative (see Figure 2 in [26]) owing to the deformation of a three-dimensional surface when it is projected onto a two-dimensional plane. This conceptual imperfection in the methodological approach does not allow for adequately Spatial analysis of heterogeneous data remains one of the most difficult tasks of predicting the distribution of the response function over the factor space [52], solved using different approaches: fuzzy logic in MATLAB fuzzy logic [53]; stochastic modeling [54][55][56]; wavelet analysis with the Morlet algorithm (CWT) [57,58]; analytical methods based on using trigonometric relationships for quadratic surfaces [59]; nearest neighbor method [60]; inverse weighted distance (IDW) method [61]; multivariate nonlinear regression in SPSS software, www.ibm.com/spss [62]; and machine learning [63], fuzzy cognitive map (FCM) [64], or artificial neural networks (ANN) [65], using GIS technologies-crunching methods [66][67][68]. At the same time, deterministic methods of three-dimensional data interpolation have not lost their relevance [69].…”

Section: Methodsmentioning

confidence: 99%

Substantiation of Drilling Parameters for Undermined Drainage Boreholes for Increasing Methane Production from Unconventional Coal-Gas Collectors

et al. 2023

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Decarbonization of the mining industry on the basis of closing the energy generation, on the basis of cogeneration of coal mine methane, and on the internal consumption of the mine is a promising direction in ensuring sustainable development. Known problems of deep underground mining do not allow for realizing the potential of man-made gas reservoirs due to the deterioration of the conditions of development of reserves of georesources. The aim of the work was to improve recommendations for the substantiation of drilling parameters for undermined drainage boreholes for increasing methane production from unconventional coal-gas collectors. The authors’ approach innovation lies in the possibility of using the established patterns of better natural stability of undermined boreholes to optimize them as spatial orientation parameters in an existing drilling passport for the improvement of methane extraction productivity. For this purpose, smoothing (LOESS) of the experimental data of two similar types of wells was used; then deterministic interpolation methods in combination with a three-dimensional representation of the response function in “gnuplot” were used. As a result, it was found that the increase in the inclination angle from 40° to 60° leads to a significant transformation of the model of the studied process, accompanied by a decline in the dynamics of methane emission and a decrease in the distance of the productive work zone of this type of well from 13 to 5 m before the roof landing, which then is replaced by a sharp increase in the productive work zone up to 35 m ahead of the longwall face. This allows under specific conditions for recommending increasing the productivity of methane capex from technogenic disturbed coal-gas reservoir replacement of wells with a smaller angle of rise to the transition to a more frequent grid of clusters from wells #4.

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Section: Methodsmentioning

confidence: 99%

Substantiation of Drilling Parameters for Undermined Drainage Boreholes for Increasing Methane Production from Unconventional Coal-Gas Collectors

et al. 2023

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“…Coal measures refer to the special rock formations composed of sedimentary rocks that contain coal seams or coal lines [1]. These rock formations are mainly formed in the interplay of land and sea or in a terrestrial environment, often appearing in residual basins with different structural properties [2].…”

Section: Introductionmentioning

confidence: 99%

“…Sam et al [11] said key factors affecting gas content variability include gas generation, coal properties, and reservoir conditions. Dai et al [1] investigated how gas basic parameters and coal quality indexes affect the sorption capacity of coalbed methane. Li et al [12] analyzed the effects of porosity and permeability on the quality of coalbed methane reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Petrophysical and Geochemical Investigation-Based Methodology for Analysis of the Multilithology of the Permian Longtan Formation in Southeastern Sichuan Basin, SW China

Zhang,

Liu,

et al. 2024

Energies

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Against the backdrop of the national strategic goals of carbon peaking and carbon neutrality, the imperative for China’s low-carbon new energy transformation is evident. Emerging as an efficient and clean new energy source, the coal-based “three gases” (coalbed methane, tight sandstone gas, and shale gas) have gained prominence. Nevertheless, the current exploration of the coal-based “three gases” is limited to individual reservoirs, posing challenges to achieving overall extraction efficiency. The primary obstacle lies in the conspicuous disparities in gas content among different reservoirs, with the causes of such disparities remaining elusive. To address this issue, this study focused on the Permian Longtan Formation (coal, shale, and tight sandstone) in the southeastern Sichuan Basin. Through a comparative analysis of the mineral composition, organic geochemical features, and pore structure characteristics, this study aimed to delineate reservoir variations and establish a foundation for the simultaneous exploration and exploitation of the coal-based “three gases”. The research findings revealed that the differences in reservoir characteristics account for the variations in gas content among coal, shale, and tight sandstone. The mineral composition of the rock formations in the study area primarily consists of quartz, feldspar, clay minerals, pyrite, calcite, and dolomite. By comparison, the coal samples from the four major coal seams in the study area exhibited relatively large pore sizes, which are favorable for gas accumulation.

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“…Coal seam gas content is a key parameter in the exploration and development of coalbed methane resources, which can effectively predict the occurrence of protrusion, examine the effectiveness of regional antisurge, and evaluate the degree of coal mine gas hazard. – The methods of coal bed gas content determination are divided into direct method – and indirect method. , The process of the indirect method to determine coal seam gas content is complicated, the measurement period is long, and the success rate is low, so the direct method is mostly used to measure coal seam gas content underground in China. The direct method of measuring coal seam gas content mainly includes three parts: determination of gas desorption in underground coal samples, determination of residual gas in a laboratory, and extrapolation of gas loss during sampling, of which the first two parts can be measured according to relevant requirements, and the results are real and reliable.…”

Section: Introductionmentioning

confidence: 99%

Low-Temperature Response Characteristics of Coalbed Methane Desorption under High and Low Destruction Degrees

Zhu,

Wang,

Liang

2023

ACS Omega

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Freeze-coring technology can effectively reduce the amount of gas loss during the sampling process and improve the accuracy of gas content measurements in underground coal seams. In this study, high-and low-damage coals were selected as test objects to investigate whether the freezecoring technique is universally applicable to inhibit gas desorption in high-and low-damage coals. In this paper, the pore structure of the test coal samples was first tested using an ASAP2020 specific surface area analyzer, and then a nonfreezing and freezing simulation test was carried out on high-and low-damage coals using a self-developed freezing coring response test platform. The results showed that the gas desorption curves of both high-and low-damage coal samples followed the pattern of rapid increase in the early stage, slow increase in the middle stage, and stability in the late stage under both conditions; freezing conditions significantly reduced the gas desorption during the sampling process, and the difference in gas desorption between high-and low-damage coals was reduced; the gas desorption inhibition rate of high-damage coals was higher at an external heating temperature of 60 °C under freezing conditions; at an external heating at an external heat temperature of 90 °C, the gas desorption inhibition rate of low-damaged coal was higher in the early stage, and the gas desorption inhibition rate of high-damaged coal was higher in the later stage; freeze coring had a significant inhibition effect on the gas desorption of both high-and low-damaged coal types, which verified that the inhibition effect of freeze coring on the gas desorption of high-and low-damaged coal samples was universal. It provides a basis for the future application of freeze-coring technology in coal mines.

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Prediction of coal seam gas content based on the correlation between gas basic parameters and coal quality indexes

Cited by 5 publications

References 44 publications

Substantiation of Drilling Parameters for Undermined Drainage Boreholes for Increasing Methane Production from Unconventional Coal-Gas Collectors

Substantiation of Drilling Parameters for Undermined Drainage Boreholes for Increasing Methane Production from Unconventional Coal-Gas Collectors

Petrophysical and Geochemical Investigation-Based Methodology for Analysis of the Multilithology of the Permian Longtan Formation in Southeastern Sichuan Basin, SW China

Low-Temperature Response Characteristics of Coalbed Methane Desorption under High and Low Destruction Degrees

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