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

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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Three-Dimensional Fluorescence Characteristics by Parallel Factor Method Coupled with Self-Organizing Map and Its Relationship with Water Quality

Acta Optica Sinica ◽

10.3788/aos201737.0730003 ◽

2017 ◽

Vol 37 (7) ◽

pp. 0730003

Author(s):

王娟 Wang Juan ◽

张飞 Zhang Fei ◽

王小平 Wang Xiaoping ◽

杨胜天 Yang Shengtian ◽

陈芸 Chen Yun

Keyword(s):

Water Quality ◽

Three Dimensional ◽

Self Organizing Map ◽

Factor Method ◽

Fluorescence Characteristics ◽

Parallel Factor ◽

Self Organizing

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Biogeochemistry and the associated redox signature of co-produced water from coalbed methane wells in the Shizhuangnan block in the southern Qinshui Basin, China

Energy Exploration & Exploitation ◽

10.1177/0144598720911107 ◽

2020 ◽

Vol 38 (4) ◽

pp. 1034-1053

Author(s):

Yang Li ◽

Shuheng Tang ◽

Songhang Zhang ◽

Zhaodong Xi ◽

Pengfei Wang

Keyword(s):

Coalbed Methane ◽

Produced Water ◽

Dissolved Inorganic Carbon ◽

Gas Production ◽

Redox Conditions ◽

Effective Parameters ◽

Production Rates ◽

Qinshui Basin ◽

Southern Qinshui Basin ◽

Biogeochemical Parameters

To meet the global energy demands, the exploitation of coalbed methane has received increasing attention. Biogeochemical parameters of co-produced water from coalbed methane wells were performed in the No. 3 coal seam in the Shizhuangnan block of the southern Qinshui Basin (China). These biogeochemical parameters were firstly utilized to assess coal reservoir environments and corresponding coalbed methane production. A high level of Na+ and HCO3– and deuterium drift were found to be accompanied by high gas production rates, but these parameters are unreliable to some extent. Dissolved inorganic carbon (DIC) isotopes δ13CDIC from water can be used to distinguish the environmental redox conditions. Positive δ13CDIC values within a reasonable range suggest reductive conditions suitable for methanogen metabolism and were accompanied by high gas production rates. SO42–, NO3– and related isotopes affected by various bacteria corresponding to various redox conditions are considered effective parameters to identify redox states and gas production rates. Importantly, the combination of δ13CDIC and SO42– can be used to evaluate gas production rates and predict potentially beneficial areas. The wells with moderate δ13CDIC and negligible SO42– represent appropriate reductive conditions, as observed in most high and intermediate production wells. Furthermore, the wells with highest δ13CDIC and negligible SO42– exhibit low production rates, as the most reductive environments were too strict to extend pressure drop funnels.

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Biogeochemistry and Water–Rock Interactions of Coalbed Methane Co-Produced Water in the Shizhuangnan Block of the Southern Qinshui Basin, China

Water ◽

10.3390/w12010130 ◽

2019 ◽

Vol 12 (1) ◽

pp. 130

Author(s):

Yang Li ◽

Shuheng Tang ◽

Songhang Zhang ◽

Zhaodong Xi ◽

Pengfei Wang

Keyword(s):

16S Rrna ◽

Water Samples ◽

Coalbed Methane ◽

Produced Water ◽

Major Ions ◽

16S Rrna Sequencing ◽

Qinshui Basin ◽

Isotopic Compositions ◽

Rrna Sequencing ◽

Southern Qinshui Basin

Coalbed methane is a major unconventional resource that has been exploited commercially for decades in the southern Qinshui Basin of China. The hydrogeochemical characteristics of coal reservoir water play a key role in the exploration and development of coalbed methane resources. In view of this, a detailed study was performed on coalbed methane co-produced water collected from the Shizhuangnan block to assess water–rock interactions and biogeochemical processes. Water samples were analyzed to establish major ions, isotopic compositions and perform 16S rRNA sequencing. Results suggest that the hydrochemistry was controlled by water–rock processes and that methane was consumed by sulfate reduction through calculation. Meanwhile, the isotopic compositions of water samples indicated that they had a predominantly meteoric origin and were influenced by microbial activity. The 16S rRNA sequencing results of bacteria and archaea provide an important foundation for understanding the activity of sulfate-reducing bacteria and methanogens at different hydraulic heads, which was consistent with isotopic analysis. Carbonates containing calcite and dolomite were found to be distributed at different hydraulic head due to the biogeochemical characteristics and associated water–rock interactions.

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Effects of Coalbed Methane Co-produced Water for Irrigation in China’s Qinshui Basin: An Experimental Field Study

Mine Water and the Environment ◽

10.1007/s10230-018-0536-y ◽

2018 ◽

Vol 37 (2) ◽

pp. 263-271 ◽

Cited By ~ 1

Author(s):

Xiangdong Li ◽

Bo Fei ◽

Qiyan Feng ◽

Lai Zhou ◽

Yue Sun

Keyword(s):

Field Study ◽

Coalbed Methane ◽

Produced Water ◽

Qinshui Basin ◽

Experimental Field

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Stable isotope and water quality analysis of coal bed methane produced water in the southern Qinshui Basin, China

Membrane Water Treatment ◽

10.12989/mwt.2013.4.4.265 ◽

2013 ◽

Vol 4 (4) ◽

pp. 265-275 ◽

Cited By ~ 3

Author(s):

Jienan Pan ◽

Xiaomin Zhang ◽

Yiwen Ju ◽

Yanqing Zhao ◽

Heling Bai

Keyword(s):

Water Quality ◽

Stable Isotope ◽

Produced Water ◽

Quality Analysis ◽

Coal Bed ◽

Coal Bed Methane ◽

Water Quality Analysis ◽

Qinshui Basin ◽

Southern Qinshui Basin

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Coupled Effects of Stress, Moisture Content and Gas Pressure on the Permeability Evolution of Coal Samples: A Case Study of the Coking Coal Resourced from Tunlan Coalmine

Water ◽

10.3390/w13121653 ◽

2021 ◽

Vol 13 (12) ◽

pp. 1653

Author(s):

Guofu Li ◽

Yi Wang ◽

Junhui Wang ◽

Hongwei Zhang ◽

Wenbin Shen ◽

...

Keyword(s):

Moisture Content ◽

Coalbed Methane ◽

Gas Permeability ◽

Axial Stress ◽

Gas Pressure ◽

Pressure Curve ◽

Permeability Evolution ◽

Confining Stress ◽

Qinshui Basin ◽

Gas Seepage

Deep coalbed methane (CBM) is widely distributed in China and is mainly commercially exploited in the Qinshui basin. The in situ stress and moisture content are key factors affecting the permeability of CH4-containing coal samples. Therefore, considering the coupled effects of compressing and infiltrating on the gas permeability of coal could be more accurate to reveal the CH4 gas seepage characteristics in CBM reservoirs. In this study, coal samples sourced from Tunlan coalmine were employed to conduct the triaxial loading and gas seepage tests. Several findings were concluded: (1) In this triaxial test, the effect of confining stress on the permeability of gas-containing coal samples is greater than that of axial stress. (2) The permeability versus gas pressure curve of coal presents a ‘V’ shape evolution trend, in which the minimum gas permeability was obtained at a gas pressure of 1.1MPa. (3) The gas permeability of coal samples decreased exponentially with increasing moisture content. Specifically, as the moisture content increasing from 0.18% to 3.15%, the gas permeability decreased by about 70%. These results are expected to provide a foundation for the efficient exploitation of CBM in Qinshui basin.

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Factors controlling high-yield coalbed methane vertical wells in the Fanzhuang Block, Southern Qinshui Basin

International Journal of Coal Geology ◽

10.1016/j.coal.2014.10.002 ◽

2014 ◽

Vol 134-135 ◽

pp. 38-45 ◽

Cited By ~ 73

Author(s):

Shu Tao ◽

Dazhen Tang ◽

Hao Xu ◽

Lijun Gao ◽

Yuan Fang

Keyword(s):

Coalbed Methane ◽

High Yield ◽

Vertical Wells ◽

Qinshui Basin ◽

Southern Qinshui Basin

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Irrigation with Coalbed Methane Co-Produced Water Reduces Forage Yield and Increase Soil Sodicity However Does Not Impact Forage Quality

Sustainability ◽

10.3390/su13063545 ◽

2021 ◽

Vol 13 (6) ◽

pp. 3545

Author(s):

Shital Poudyal ◽

Valtcho D. Zheljazkov

Keyword(s):

Fresh Water ◽

Coalbed Methane ◽

Produced Water ◽

Forage Quality ◽

Dry Weight ◽

Quality Parameters ◽

Forage Yield ◽

Neutral Detergent Fiber ◽

Forage Crops ◽

Feed Value

The extraction of coalbed methane produces a significant amount of coalbed methane co-produced water (CBMW). Coalbed methane co-produced water is often characterized by high levels of pH, total dissolved solids (TDS), sodium (Na) and bicarbonate (HCO−3) and if used for irrigation without treatment, it may be detrimental to the surrounding soil, plants and environment. CBMW ideally should be disposed of by reinjection into the ground, but because of the significant cost associated, CBMW is commonly discharged onto soil or water surfaces. This study was conducted to elucidate the effect of the CBMW (with TDS value of <1500 ppm) at various blending ratios with fresh water on the yield and quality of representative forage crops [i.e., oat (Avena sativa) and alfalfa (Medicago sativa)]. Various blends of CBMW with fresh water reduced fresh and dry weight of alfalfa by 21.5–32% and 13–30%, respectively and fresh and dry weight of oat by 0–17% and 0–14%, respectively. Irrigation with various blends of CBMW and fresh water increased soil pH and soil sodium adsorption ratio. However, forage quality parameters such as crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN) and relative feed value (RFV) of both forage crops remained unaffected.

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