Source, Age, and Evolution of Coal Measures Water in Central-South Qinshui Basin, China

Wang, Haichao; Fu, Xuehai; Zhang, Xiaoyang; Cao, Liwen; Ge, Yingzi; Tian, Jijun; Cheng, Xiaoqian; Chen, Ning; Hou, Xiaolin; Du, Hua

doi:10.1021/acs.energyfuels.8b00701

Cited by 8 publications

(7 citation statements)

References 55 publications

(106 reference statements)

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“…The older age defined by 40 Ar * again supports the contention that He has been most efficiently lost from SQB coals. The 40 Ar * age overlaps the 14 C age of the production water from other regions in SQB (5×10 3 -4×10 4 yr) (Wang et al, 2018).…”

Section: 3helium Loss During Cenozoic Exhumationmentioning

confidence: 78%

“…Further, the solubility of Ar in water is higher than He (Crovetto et al, 1982;Smith and Kennedy, 1983). Thus the preservation of old formation waters in the SQB (Wang et al, 2018) will tend to have further reduced the 4 He/ 40 Ar * . The loss of He after magmatic events explains that absence of mantle He in the SQB methane.…”

Section: 3helium Loss During Cenozoic Exhumationmentioning

confidence: 99%

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Evolution of coal-bed methane in Southeast Qinshui Basin, China: Insights from stable and noble gas isotopes

Chen

Stuart

et al. 2019

Chemical Geology

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The late Carboniferous-early Permian coal seams of the Qinshui Basin in Shanxi Province are the most prolific producer of coalbed methane (CBM) in China. Methane formed in the late Triassic during deep burial and reheating in late Jurassic-early Cretaceous driven by magmatic underplating. Basin inversion brought the coal seams to 400-700 m from the surface in the mid-late Cenozoic. Here we present results of a study aimed at understanding the origin of the methane, and how it was affected by Cenozoic exhumation of the basin. Methane from a 12 km traverse perpendicular to the basin margin in the southeast part of the basin have stable isotope compositions (δ 13 C =-30.2 to-35.2‰, and δD =-155 to-194‰) indicating a thermogenic origin with limited biogenic input. They are, however, lighter than expected based on coal maturity, and C1/(C2+C3) (>1000) are significantly higher than typical thermogenic methane (<50). This is due to diffusive fractionation during commercial gas extraction. He-NeAr isotopes are a mixture of crustal-radiogenic gas with air-derived noble gases. 4 He concentrations (0.52 to 33.25 ppmv) and 4 He/ 40 Ar * ratios (0.06-1.74) are unusually low. He-NeAr concentrations are consistent with the open system Rayleigh fractionation of noble gases derived from air-saturated water with 4 He/ 40 Ar * = 1 during gas extraction. The low 4 He/ 40 Ar * , compared with average crust (5) or local production (13) values, implies that more than 90% of the radiogenic 4 He produced in the coals has been lost prior to equilibrium between gas and water phase in the reservoir. This likely occurred in response to gas loss process during rapid exhumation in Cenozoic, showing that the He and Ar content of natural gases is a sensitive indicator of gas loss event caused by recent basin inversion. The event may have led to the loss of up to 44% of the methane from the coal seams. This study demonstrates the importance of basin inversion on gas preservation in shallow CBM, and shows that, in contrast to δ 13 CCH4, the light noble gases are essential for tracing such a process. Keywords Coalbed methane (CBM), Southeast Qinshui basin, noble gas isotopes, gas loss, high coal rank Highlights  Gas compositions and stable isotopes indicate diffusive fractionation during commercial gas extraction.  There is no indication of mantle volatiles in gas samples, no evidence of mantle heating during the Yanshanian Orogeny.  The low radiogenic He and He/Ar ratio indicate loss of free gas during basin exhumation.

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Section: 3helium Loss During Cenozoic Exhumationmentioning

confidence: 78%

Section: 3helium Loss During Cenozoic Exhumationmentioning

confidence: 99%

Evolution of coal-bed methane in Southeast Qinshui Basin, China: Insights from stable and noble gas isotopes

Chen

Stuart

et al. 2019

Chemical Geology

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“…This aligns with the research conclusions made by Zhang [ 41 ] on the chemical characteristics, types, and genetic mechanisms of coalbed methane-produced water in the Qinshui Basin. The Na-HCO 3 type water results from the long-term internal circulation of stratum water and the long-term rock-water interaction, which reflects that the CBM produced water in the study area originates from a semi-closed and open hydrogeological environment with free alternate water [ 42 ].…”

Section: Resultsmentioning

confidence: 99%

Fluorescence Characteristics of Coalbed Methane Produced Water and Its Influence on Freshwater Bacteria in the South Qinshui Basin, China

Jin

Meng

et al. 2021

IJERPH

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Production of coalbed methane (CBM) resources commonly requires using hydraulic fracturing and chemical production well additives. Concern exists for the existence of chemical compounds in CBM produced water, due to the risk of environmental receptor contamination. In this study, parallel factor method analysis (PARAFAC), fluorescence index, and the fluorescence area integral methods were used to analyse the properties of CBM produced water sampled from Shizhuang Block (one of the most active CBM-producing regions in the Qinshui Basin). A culture experiment was designed to determine the effect of discharged CBM produced water on microorganisms in freshwater. Water quality analysis shows the hydrochemistry of most water samples as Na-HCO3 type produced water of CBM appears as a generally weak alkaline (pH 8.69 ± 0.185) with high salinity, high alkalinity, and a high chemical oxygen demand (COD) value. Three individual components were identified by using parallel factor method analysis as humic-like components (C1), fulvic-like components (C2), and amino acid-like substances (C3). The fluorescence characteristic index comprehensively explains that the fluorescent substances in CBM produced water has the characteristics of a low degree of humification and a high recent self-generating source. The region integration results of characteristic peaks show that tyrosine-like and tryptophan-like materials account for more than 67% of fluorescent substances in CBM produced water. The addition of produced water from coalbed methane promotes the growth of freshwater bacteria, and this process is accompanied by the decrease of the proportion of fulvic acid, humic acid, and the increase of the proportion of soluble microbial metabolites. This paper proposes a convenient method for organic matter identification of CBM produced water and provides some theoretical support and reference for the improvement of CBM water treatment and utilization.

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“…Synthetical stratum histogram of coal measures strata in Central-South Qinshui Basin (Adapted with permission from the work of Wang et al. (2018).…”

Section: Samples and Experimentsmentioning

confidence: 99%

Permeability experiments with overburden pressure of coal measure reservoirs and numerical analysis of its stress sensitivity: A case study of Qinshui Basin, China

Zhou

Li²,

Wang

et al. 2020

Energy Exploration & Exploitation

Self Cite

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The commingled exploitation of coal measure reservoirs has become the main trend in the development of coalbed methane (CBM) in the central and southern Qinshui Basin. In fact, the porosity and permeability (P&P) of coal measure reservoirs and the evolution of their stress sensitivity are a focus of the basic theory of commingling exploitation. In this study, the coal measure reservoirs in this area are taken as the research object, and the P&P characteristics and stress sensitivity of coal measure reservoirs under different overburden pressure conditions were investigated by P&P experiments on coal, sandstone, and mudstone. The results show that the P&P decreases as a negative exponential function with the increase in effective stress, and the initial porosity and initial permeability of coal are both significantly higher than those of mudstone and sandstone. Besides, the permeability stress sensitivity coefficients of coal, mudstone, and sandstone all decline with a wavy trend with the increase in effective stress. Coal is more sensitive to stress than mudstone and sandstone in the medium and low pressure stages (Pc<5 MPa), while their stress sensitivities tend to become equal in the medium and high pressure stages (Pc>5 MPa). Since the type of coal rich in organic matter is soft rock, it is more susceptible to damage and deformation in the medium and low pressure state (Pc<5 MPa). In contrast, sandstone and mudstone contain more brittle minerals such as cuttings, quartz, and clay minerals, which are, in general, more resistant to deformation, and are less sensitive than coal at the medium and low pressure stages. Finally, a stress sensitivity model based on the Langmuir equation was proposed in this study. With the aid of the model, the stress sensitivities of porosity and permeability of coal, sandstone, and mudstone were analyzed accurately.

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Source, Age, and Evolution of Coal Measures Water in Central-South Qinshui Basin, China

Cited by 8 publications

References 55 publications

Evolution of coal-bed methane in Southeast Qinshui Basin, China: Insights from stable and noble gas isotopes

Evolution of coal-bed methane in Southeast Qinshui Basin, China: Insights from stable and noble gas isotopes

Fluorescence Characteristics of Coalbed Methane Produced Water and Its Influence on Freshwater Bacteria in the South Qinshui Basin, China

Permeability experiments with overburden pressure of coal measure reservoirs and numerical analysis of its stress sensitivity: A case study of Qinshui Basin, China

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