Coalbed methane characterization and modeling: review and outlook

Mohamed, Tarek A.; Mehana, Mohamed

doi:10.1080/15567036.2020.1845877

Cited by 40 publications

(16 citation statements)

References 67 publications

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“…The accurate determination of the coal seam gas content (CSGC) is significant for the safety of coal mines and CBM (coalbed methane) exploitation [1,2]. It is mainly determined by two methods: one is the direct method developed by Bertard et al [3] and Kissell et al [4]; the other is the indirect method [5].…”

Section: Introductionmentioning

confidence: 99%

Temperature Variation Law of Core Tube Wall during Coring in Different Strength Coal Seams: Experiment and Modelling

et al. 2022

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Temperature is the primary factor affecting the law of coal gas desorption. When the core method is used to measure the coal seam gas content (CSGS), the temperature of the coal core sample (CCS) will increase. The heat generated by the core bit cutting and rubbing the coal during coring is transferred to the CCS through the core tube, resulting in the temperature rising of the CCS. Because the CCS entering the core tube during coring is a dynamic process, the temperature of CCS is difficult to measure. To solve this problem, the temperatures of the core tube wall during coring in the Jiulishan coal mine (JLS), Guhanshan coal mine (GHS) and Zhaogu coal mine (ZG) at the core depth of 20 m were measured by the self-designed temperature measuring device. The thermodynamic models of the core bit and the core tube during coring were established. The reliability of the model was verified by comparing the numerical simulation results with the field measurement results. The verified model was used to predict the temperature changes of the core tube wall during coring in different strength coal seams and different core depths. The results show that the temperature change of the core tube wall was divided into a slowly temperature rising stage Ⅰ, a fast temperature rising stage Ⅱ and a slowly temperature rising and slowly temperature falling stage Ⅲ, which correspond to the process of pushing the core tube, drilling the CCS and early stage and later stage of withdrawing the core tube, respectively. The maximum temperature of the core tube wall appears in the first 3 min of withdrawing the core tube, and increases with the core depth increasing. The temperature of the measuring point at the end of drilling the CCS and the maximum temperature during coring linearly increase with the core depth. The temperature heating rate of the core tube is negatively linear, with the coal seam strength during pushing the core tube wall process. However, the temperature heating rate of the core tube wall is positively linear with the coal seam strength during drilling the CCS process. This study can provide a basis for further research on the dynamic distribution characteristics of temperature in the CCS during coring, which is of profound significance to calculate the gas loss amount and CSGC.

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Section: Introductionmentioning

confidence: 99%

Temperature Variation Law of Core Tube Wall during Coring in Different Strength Coal Seams: Experiment and Modelling

et al. 2022

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“…The differences in water drainage can affect the change in reservoir pressure propagation during CBM production, thus affecting gas production (Hu et al, 2019;Ma et al, 2021). In the initial state, the coal seam fracture was usually completely saturated with water, and the water saturation in the reservoir fracture was 100%, providing the necessary pressure for the adsorption of CBM on the coal matrix (Mohamed and Mehana, 2020).…”

Section: Water Saturationmentioning

confidence: 99%

Coalbed methane reservoir dynamic simulation comparisons using the actual steeply inclined model and ideal steeply inclined model

Qin

Peng

et al. 2022

Front. Earth Sci.

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Numerical simulation is an efficient method to quantitatively describe the reservoir dynamics of coalbed methane (CBM) reservoirs. The ideal steeply inclined model (ISIM), assumed to be a steeply inclined plate, has been widely applied in steep coalbed methane reservoir modeling, although the ISIM cannot accurately reflect the actual reservoir geological conditions. In this paper, the dynamics of CBM production and reservoirs using the ISIM and actual steeply inclined model (ASIM) were compared, taking the steep coal in the Fukang mining area located in northwestern China as an example, with the purpose of revealing the differences and applicability of the ASIM and ISIM. The ASIM and ISIM were established by Petrel software, and CBM production was matched and predicted by Eclipse software. Data reflecting reservoir dynamics, such as water saturation, reservoir pressure, and gas content, were extracted. The dynamic changes in the reservoir physical properties of the ASIM and ISIM were also compared. The results showed that: 1) multiple gas production peaks occurred in both ASIM and ISIM. The maximum daily gas production of ASIM occurred earlier than the maximum daily gas production of ISIM. The peak gas production and cumulative gas production of ASIM were both greater than the peak gas production and cumulative gas production of ISIM. 2) Due to the variations in grid shape and dip angle with each grid in the ASIM, the production effect of the ASIM was better than the production effect of the ISIM in the third stage (4–10 years) of drainage. 3) In the third stage (4–10 years) of drainage, the decrease rate of reservoir pressure of ASIM was larger than the decrease rate of reservoir pressure of ISIM because of the relatively better production performance of ASIM. 4) Differentiation of gas and water dominated the variation trend of gas content, and in the third stage (4–10 years) of drainage, the ASIM has higher recovery efficiency compared with ISIM. Compared with ISIM proposed by previous scholars, the ASIM was more helpful to monitor the dynamic behavior of coal reservoirs, and ASIM can provide a more reliable basis for guiding coalbed methane development.

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“…Coalbed methane (CBM) is the term given to natural gas of an unconventional form in the adsorption state found in coal deposits or coal seams. 1 − 3 The exploitation of CBM plays a vital role in improving the current energy structure, alleviating gas disasters, and restraining the greenhouse effect. 4 The Qinshui Basin is the most important development base of CBM in China.…”

Section: Introductionmentioning

confidence: 99%

“…Coalbed methane (CBM) is the term given to natural gas of an unconventional form in the adsorption state found in coal deposits or coal seams. − The exploitation of CBM plays a vital role in improving the current energy structure, alleviating gas disasters, and restraining the greenhouse effect . The Qinshui Basin is the most important development base of CBM in China. − Although over 4000 CBM wells have been drilled and installed in the southern Qinshui Basin, the average mean daily gas production of gas from a single well is less than 500 m 3 in China.…”

Section: Introductionmentioning

confidence: 99%

Drainage Type Classification and Key Controlling Factors of Productivity for CBM Wells in the Zheng Zhuang Area, Southern Qinshui Basin, North China

Han

Zhang

et al. 2022

ACS Omega

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The production of coalbed methane (CBM) wells varies greatly in the Qinshui Basin, North China. Analyzing the primary factors controlling the CBM well productivity is essential to improve their development efficiency. Based on the geological conditions and production data of CBM wells in the Zheng zhuang area, the principal component analysis (PCA) method was used to classify the drainage types and screen the key factors influencing the production of gas and water. The drainage types of the CBM wells in the study area can be divided into four categories. The gas production shows an increasing trend with the increase of the comprehensive score of the PCA. The key controlling factors of productivity for CBM wells can be summarized by the gas-bearing property, permeability, groundwater fluid potential, and burial depth. The impact of burial depth on CBM well productivity is manifested in its control of gas content and permeability. The groundwater flows to a low fluid potential area, which leads to a high water production and a small pressure drop. The gas production shows a positive correlation with post-fracturing permeability. The gas content is a key factor for controlling the critical desorption pressure, critical gas production pressure, and pressure drop at the gas breakthrough point. High gas content is a prerequisite for the high productivity of CBM wells.

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Coalbed methane characterization and modeling: review and outlook

Cited by 40 publications

References 67 publications

Temperature Variation Law of Core Tube Wall during Coring in Different Strength Coal Seams: Experiment and Modelling

Temperature Variation Law of Core Tube Wall during Coring in Different Strength Coal Seams: Experiment and Modelling

Coalbed methane reservoir dynamic simulation comparisons using the actual steeply inclined model and ideal steeply inclined model

Drainage Type Classification and Key Controlling Factors of Productivity for CBM Wells in the Zheng Zhuang Area, Southern Qinshui Basin, North China

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