Geological conditions of deep coalbed methane in the eastern margin of the Ordos Basin, China: Implications for coalbed methane development

Li, Song; Tang, Dazhen; Pan, Zhejun; Xu, Hao; Tao, Shu; Liu, Yanfei; Ren, Pengfei

doi:10.1016/j.jngse.2018.03.016

“…Currently, China has initially achieved the large‐scale commercial development of high‐rank CBM in the Qinshui Basin and the eastern edge of the Ordos Basin, compared to the low‐rank coal development area of the Junggar Basin, the Tarim Basin, the Ordos Basin, etc The research on the basic theory of CBM geology and exploration in the low‐rank coal has been left behind . The material composition, pore structure, surface chemistry, and other properties in low‐rank coals are clearly distinguished from high‐rank coals, and the former usually shows short but concentrates methane adsorption equilibrium, especially the higher initial desorption rate and desorption efficiency . However, there are also problems of lower gas content, higher water content, stronger chemical activity, and lower gas production and recovery for low‐rank coals …”

Section: Introductionmentioning

confidence: 99%

“…4 The material composition, pore structure, surface chemistry, and other properties in low-rank coals are clearly distinguished from high-rank coals, and the former usually shows short but concentrates methane adsorption equilibrium, especially the higher initial desorption rate and desorption efficiency. [5][6][7][8][9][10][11] However, there are also problems of lower gas content, higher water content, stronger chemical activity, and lower gas production and recovery for low-rank coals. [12][13][14][15] The key point of improving CBM recovery is to reasonably allocate the methane supply capacity and seepage ability.…”

mentioning

confidence: 99%

Wettability modification and its influence on methane adsorption/desorption: A case study in the Ordos Basin, China

Li

¹

,

Ma

²

,

Zhang

³

et al. 2019

Energy Science & Engineering

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Wettability modification of coal rock may cause serious change in the methane adsorption/desorption behaviors. Thus, the contact angle measurement and isothermal adsorption/desorption experiment of raw coal and samples treated with surfactants (STS) were conducted to investigate the wetting properties and methane adsorption/desorption characteristics. The results indicated that the long‐flame coal (LFC) has the good hydrophilicity itself, and there was no evident sign of saturated adsorption for different samples at relatively low‐pressure (<8 MPa) stage. The sample treated with the wettability reversal agent (G502) had the larger methane adsorption capacity than the wetted samples (LAS, JFC, and 6501), with the latter facilitating the methane desorption. Additionally, the adsorption capacity of the air‐dried samples was stronger than that of the water‐containing samples, including the moisture‐equilibrated, LAS, JFC, and 6501, reflecting that the better the hydrophilicity, the weaker the methane adsorption. Besides, the desorption hysteresis rate of the same sample was mainly controlled by pressure, i.e. the desorption hysteresis indicated a logarithmic decrease with the increasing pressure, but the STS clearly showed the desorption hysteresis to varying degree due to the wettability differences. The pressure drop in the low‐pressure stage was difficult to drive the adsorbed methane to immediately desorb from the matrix surface, whereas even caused further adsorption or re‐adsorption, meaning that the coal required a greater depressurization to enter the effective desorption stage. Finally, the positive implications of wettability modification including enhancing CBM recovery, as well as coal and methane outburst prevention and coal dust control in the mining industry were discussed.

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“…The Ordos basin is located in the middle of the North China Plate and has become the second largest coalbed methane development base after the Qinshui Basin since the 1980s [20][21][22][23]. Liulin area is located in the east of the Ordos basin.…”

Section: Introductionmentioning

confidence: 99%

In Situ Stress Distribution and Its Control on the Coalbed Methane Reservoir Permeability in Liulin Area, Eastern Ordos Basin, China

Feng

¹

,

Li

²

,

Tang

³

et al. 2021

Self Cite

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Permeability is one of the important factors that affect the production efficiency of coalbed methane, and it is mainly controlled by in situ stress. Therefore, it is very essential to study the in situ stress and permeability for the extraction of coalbed methane. Based on the injection/falloff well test and in situ stress measurement of 35 coalbed methane wells in the Liulin area in the east of the Ordos basin, the correlations between initial reservoir pressure, in situ stress, lateral stress coefficient, permeability, and burial depth were determined. Finally, the distribution characteristics of in situ stress and its influence on permeability were analyzed systematically. The results show that with the increase of burial depth, the initial reservoir pressure and in situ stress both increase, while the lateral stress coefficient decreases. The permeability variation is related to the type of stress field in different burial depths, and its essence is the deformation and destruction of coal pore structures caused by stress. The distribution characteristics of in situ stress at different depths and its effect on permeability are as follows: at depths < 800 m , the horizontal principal stress is dominant ( σ H ≥ σ v > σ h ) and the permeability is a simple decreasing process with the increase of the depth; at depths > 800 m , the vertical stress is dominant ( σ v ≥ σ H > σ h ). The permeability of most coal is very small due to the large in situ stresses in this depth zone. However, because of the stress release at the syncline axis, coal with high permeability is still possible at this depth zone. Due to the existence of high permeability data points at burial depth (>800 m) and the fitting relationship between permeability and vertical stress, the maximum and minimum horizontal principal stress is poor. However, the coal permeability and lateral stress coefficient show a good negative exponential relationship. This indicates that the lateral stress coefficient can be used to predict permeability better.

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“…These cleats provide the ﬂow pathways for methane out of coal seams and are directly affected by in situ stress and geothermal temperature (Zhao et al., 2016). Recent research converges in identifying the impacts of external stress ﬁelds, temperature ﬁelds, and hydrodynamic and tectonic conditions on the variations of coal reservoir characteristics and CBM recovery (Li et al., 2013, 2018; Mazumder et al., 2012; Tang et al., 2018; Wu et al., 2017).…”

Section: Introductionmentioning

confidence: 99%

Geological conditions of coalbed methane accumulation in the Hancheng area, southeastern Ordos Basin, China: Implications for coalbed methane high-yield potential

Guo

¹

,

Xia

²

,

Ma

³

et al. 2019

Energy Exploration & Exploitation

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The Hancheng area is a hot spot for coalbed methane exploration and exploitation in China. Structure is a key factor affecting coalbed methane accumulation and production in the Hancheng area. For a better understanding of the coalbed methane accumulation conditions and high-yield potential, this study investigates the structural patterns and evolution, the hydrogeological conditions, and the geothermal field in the coal-bearing strata in the Hancheng area. Then, the spatial distribution of the coalbed methane content and the tectonic deformation of the coal seam are evaluated. Finally, the critical depth for coalbed methane enrichment and a high-yield

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Geological conditions of deep coalbed methane in the eastern margin of the Ordos Basin, China: Implications for coalbed methane development

Cited by 98 publications

References 25 publications

Wettability modification and its influence on methane adsorption/desorption: A case study in the Ordos Basin, China

Wettability modification and its influence on methane adsorption/desorption: A case study in the Ordos Basin, China

In Situ Stress Distribution and Its Control on the Coalbed Methane Reservoir Permeability in Liulin Area, Eastern Ordos Basin, China

Geological conditions of coalbed methane accumulation in the Hancheng area, southeastern Ordos Basin, China: Implications for coalbed methane high-yield potential

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