Geochemical Characteristics and Productivity Evaluation of Water Produced from Coalbed Methane Wells in the Laochang Block, Eastern Yunnan.

The water produced from coalbed methane (CBM) wells contains abundant hydrogeochemical information, which is of great significance for the productivity evaluation of CBM wells. Based on the analysis of the conventional ions, hydrogen and oxygen isotopes, and trace elements in the water produced from three CBM wells in the Laochang Block, eastern Yunnan, the geochemical characteristics of the water produced from three CBM wells and their impacts on productivity are analyzed. The results show that the conventional ions in the water produced from all the three CBM wells in the study area exhibit similar characteristics, with low concentrations of Ca2+, Mg2+, SO42-, and F-, medium concentrations of K+, and high concentrations of Na+, Cl-, and HCO3-. As the drainage time increased, the water produced from wells S-2 and S-3 changed from the Na-Cl-HCO3 type to the Na-HCO3 type, while the water produced from well S-1 remained the Na-Cl-HCO3 type. The concentrations of HCO3- and F- are roughly positively correlated with the gas production, with higher gas production at concentrations of approximately 2000 and 2 mg/L, respectively. The gas production from well S-1 is relatively low, and it is speculated that this situation is caused by reservoir damage. The gas production from well S-2 is the lowest among the three wells in the study area, and it is speculated that the cause of this phenomenon is roughly due to breakage of the sandstone at the top of the coal seam or collapse of the wellbore, which communicates with the aquifer. Based on the characteristics of the water production from well S-3 with a good gas production, a quantitative characterization range of trace element changes in the water production from CBM wells is proposed. σY values of around 1500 µg/L and σM values of 0.4-0.5 µg/L are beneficial for the long-term gas production.

Melatonin Promotes Iron Reactivation and Reutilization in Peach Plants under Iron Deficiency.

The yellowing of leaves due to iron deficiency is a prevalent issue in peach production. Although the capacity of exogenous melatonin (MT) to promote iron uptake in peach plants has been demonstrated, its underlying mechanism remains ambiguous. This investigation was carried out to further study the effects of exogenous MT on the iron absorption and transport mechanisms of peach (Prunus persica) plants under iron-deficient conditions through transcriptome sequencing. Under both iron-deficient and iron-supplied conditions, MT increased the content of photosynthetic pigments in peach leaves and decreased the concentrations of pectin, hemicellulose, cell wall iron, pectin iron, and hemicellulose iron in peach plants to a certain extent. These effects stemmed from the inhibitory effect of MT on the polygalacturonase (PG), cellulase (Cx), phenylalanine ammonia-lyase (PAL), and cinnamoyl-coenzyme A reductase (CCR) activities, as well as the promotional effect of MT on the cinnamic acid-4-hydroxylase (C4H) activity, facilitating the reactivation of cell wall component iron. Additionally, MT increased the ferric-chelate reductase (FCR) activity and the contents of total and active iron in various organs of peach plants under iron-deficient and iron-supplied conditions. Transcriptome analysis revealed that the differentially expressed genes (DEGs) linked to iron metabolism in MT-treated peach plants were primarily enriched in the aminoacyl-tRNA biosynthesis pathway under iron-deficient conditions. Furthermore, MT influenced the expression levels of these DEGs, regulating cell wall metabolism, lignin metabolism, and iron translocation within peach plants. Overall, the application of exogenous MT promotes the reactivation and reutilization of iron in peach plants.

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

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.

Numerical Simulation of the Temperature Distribution and Evolution Law of Underground Lignite Gasification.

To study the temperature distribution characteristics and evolution law of underground lignite gasifiers, a three-dimensional heat conduction model of underground lignite gasification was constructed. Moreover, the effects of different coal thicknesses, advance speeds of the flame working face, and surrounding rock types on the gasifier were analyzed. The results show that with the increase in the coal thickness, the transfer range and distance of temperature in the roof, floor, and coal seam gradually increase, as does the coal quantity in the three zones. The heat loss rate of the gasifier decreased gradually with the coal seam thickness. When the advance speed of the flame working face is 0.5 m/d, the ideal gasification coal thickness range of lignite is 2.5-17.5 m. With the increase in the gasification rate, the maximum transfer distance of temperature to the roof and floor, the average temperature of the gasifier, and the coal quantity of the three zones gradually increase. Conversely, the coal thickness corresponding to the intersection of the coal quantity of the oxidation and reduction zones and the heat loss rate of the gasifier gradually decrease. When the coal seam below 2.5 m is gasified, the gasification rate can be increased appropriately. When the coal seam is above 13 m, increasing the gasification rate will make the coal quantity in the oxidation zone close to or even higher than that in the reduction zone. Regarding the surrounding rock types comprising a combination of siltstone, mudstone, sandy mudstone, and fine sandstone, the most favorable roof and floor type for underground coal gasification is the combination of fine sandstone and sandy mudstone (without considering the sealing and mechanical properties). These results provide important theoretical support for the industrialization of underground coal gasification.

Multi-Angle Investigation of the Fractal Characteristics of Nanoscale Pores in the Lower Cambrian Niutitang Shale and Their Implications for CH4 Adsorption.

Shale gas has received widespread interest due to its successful commercial development in China. Pore structures in shale can directly control its gas storage and migration properties. In this study, field emission scanning electron microscopy (FE-SEM), low-pressure N2/CO2 adsorption and highpressure methane adsorption were used to investigate the nanoscale pore structures of the Lower Cambrian Niutitang Formation in the southeastern Upper Yangtze platform. The fractal parameters of the pore structures were also calculated using the Frenkel-Halsey-Hill (FHH) model. The relationships between the fractal dimensions and TOC content, mineral composition and pore structure parameters were also discussed. The results show that organic matter and clay minerals are primary factors affecting the nanoscale pore development. Slit-shaped pores and ink-bottle-shaped pores are the predominant pore types in the Niutitang shale. The Brunauer-Emmett-Teller (BET) surface areas vary from 4.91 m²/g to 34.33 m²/g, and the pore volumes range from 0.689 m³/100 g to 2.964 m³/100 g. Two fractal dimensions (D1 and D2) of the Niutitang shale were obtained using the FHH model, with D1 ranging from 2.605 to 2.684, and D2 ranging from 2.681 to 2.865. D1 adequately characterizes the surface roughness of the pore structures, while D2 represents the complexity of the pore types. Inter-particle (InterP) pores commonly have greater shape complexities than OM pores and intra-particle (IntraP) pores, based on analyses using Image-Pro Plus software. In addition, the TOC content and clay minerals have great effects on the fractal dimension D1. Meanwhile, the fractal dimension D1 increases with increasing BET surface area, but there is no definite relationship between the fractal dimensions and pore volumes. Both the fractal dimensions D1 and D2 are negatively correlated with pore sizes. Further investigation indicates that the fractal dimension D1 exhibits a strong positive relationship with the methane adsorption capacity indicating that Niutitang shales with greater values of the fractal dimension D1 have higher methane adsorption capacities.

Evaluation of the Geochemical Characteristics and Exploitation Potential of Produced Water from Coalbed Methane Wells in Eastern Yunnan, China.

Based on the analysis of the geochemical characteristics of the produced water from coalbed methane wells in eastern Yunnan, the effects of the water-rock interactions on the produced water were discussed, and the mining potential of each of the four wells was evaluated. The results show that with the increase in drainage time, the Na+ and Cl- concentrations decrease while the HCO-3 concentration increases. The produced water from the two wells in the Enhong Block shows D drift characteristics, while that of the two wells in the Laochang Block shows O drift characteristics. The order of the produced water affected by the surrounding rock is D-1 well > M-1 well > D-2 well > M-2 well, and the order of the produced water influenced by the coal seam is D-1 well > D-2 well > M-1 well > M-2 well. According to the variation in the As trace element concentration, it is inferred that in the four coalbed methane wells, the D-1 and D-2 wells have a greater exploitation potential than that of the M-1 and M-2 wells. On this basis, the influencing characterization parameters of the water-rock interactions on the produced water are established.

Selenium accumulation characteristics of Cyphomandra betacea (Solanum betaceum) seedlings.

A pot experiment was conducted to study the selenium (Se) accumulation characteristics and the tolerance of Cyphomandra betacea (Solanum betaceum) seedlings under different soil Se concentrations. The 5 mg/kg soil Se concentration increased the C. betacea seedling biomass and photosynthetic pigment contents (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid), whereas the other soil Se concentrations (10, 25, and 50 mg/kg) inhibited seedling growth. Increases in the soil Se concentrations tended to decrease the superoxide dismutase activity and soluble protein content, but had the opposite effect on the peroxidase and catalase activities. The 5, 10, and 25 mg/kg soil Se concentrations decreased the DNA methylation levels of C. betacea seedlings because of an increase in demethylation patterns (versus 0 mg/kg), whereas the 50 mg/kg soil Se concentration increased the DNA methylation levels because of an increase in hypermethylation patterns (versus 0 mg/kg). Increases in the soil Se concentrations were accompanied by an increasing trend in the Se content of C. betacea seedlings. Moreover, the amount of Se extracted by the shoots was highest for the 25 mg/kg soil Se concentration. Therefore, C. betacea may be able to accumulate relatively large amounts of Se and its growth may be promoted in 5 mg/kg soil Se.

Effects of intercropping with two Solanum species on the growth and cadmium accumulation of Cyphomandra betacea seedlings.

The contamination of orchard by cadmium (Cd) has recently increased in severity. To decrease the Cd content in fruit tree, a pot-based experiment was conducted to study the effects of intercropping with two Solanum species (Solanum alatum and Solanum diphyllum) on the growth and Cd accumulation of Cyphomandra betacea seedlings. The data revealed that intercropping with two Solanum species significantly increased the biomass, photosynthetic pigment contents, antioxidant enzyme activities, and soluble protein contents of C. betacea seedlings under Cd stress condition. The intercropping significantly decreased the Cd content in C. betacea seedlings. However, the intercropping significantly decreased the S. alatum and S. diphyllum biomasses, while increased the Cd content and accumulation in the roots and shoots of two Solanum species, and the Cd uptake by S. alatum was lower than that of S. diphyllum. Therefore, intercropping with these two Solanum species, especially S. diphyllum, may promote the growth and decrease the Cd content in C. betacea.

Effects of reciprocal hybridization on cadmium accumulation in F1 hybrids of two Solanum photeinocarpum ecotypes.

In this study, farmland and mining ecotypes of Solanum photeinocarpum (a potential cadmium (Cd) hyperaccumulator plant) were reciprocally hybridized each other, and the Cd accumulation characteristics of the F1 hybrids were studied. In pot experiments, higher biomasses and Cd extraction abilities were found for two S. photeinocarpum F1 hybrids than for the parents, but the Cd contents in various organs were lower in the hybrids than the parents. However, the differences between the Cd contents in the two hybrids were not significant. The antioxidant enzyme (superoxide dismutase and peroxidase) activities were higher for the S. photeinocarpum F1 hybrids than the parents. Less DNA methylation was found in the hybrids than the parents because more demethylation occurred in the hybrids than the parents. The biomass, Cd content, and Cd extraction ability effects in field experiments were similar to the effects in the pot experiments. It was concluded that reciprocally hybridizing different S. photeinocarpum ecotypes improved the ability of S. photeinocarpum to be used to phytoremediate contaminated land.

Effect of micronutrient pack on micronutrient status and antioxidant capacities among institutional older adults in Shanghai, China.

BACKGROUND AND OBJECTIVES: Older adults are at increased risk of micronutrient deficiency, disrupting the balance of oxidation/antioxidation system and leading to serious health burdens. This study aimed to investigate the effect of micronutrient pack on micronutrient status and oxidative/antioxidative biomarkers in institutional older adults. METHODS AND STUDY DESIGN: Subjects aged 65-100 years were randomly assigned to either intervention group or control group (n=49 each), providing a package of micronutrient pack or placebo daily for three months. The concentrations of micronutrients, malondialdehyde (MDA), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were detected both at baseline and at the end of the study. RESULTS: The changes in concentrations of serum folate (21.1±1.6 vs 0.6±0.5 nmol/L), vitamin B-1 (3.4±0.4 vs -0.2±0.3 nmol/L), vitamin B-2 (11.5±3.3 vs 2.3±1.4 nmol/L), vitamin B-12 (128.8±34.8 vs 13.3±16.0 pmol/L), 25-hydroxyvitamin D (17.8±1.3 vs -0.8±0.5 ng/mL) and plasma zinc (0.6±1.8 vs -9.6±1.9 µmol/L) over 3-months were significantly increased in the intervention group compared with the control group (all p<0.05). While the prevalence of folate, vitamin B-12 and vitamin D deficiencies were significantly decreased after 3-months intervention (all p<0.05). Moreover, changes in serum MDA level (-1.5±0.2 vs 0.2±0.3 nmol/mL) were remarkably reduced, and the activities of serum GSH-Px (1.3±0.3 vs 0.3±0.2 ng/mL) and plasma SOD (14.3±2.4 vs -2.1±2.4 U/mL) were increased in the intervention group than those of in the control group (all p<0.01). CONCLUSIONS: The micronutrient pack among institutional older adults was well-accepted with good compliance and tolerance. The 3-month intervention may improve micronutrient status and enhance antioxidative capacities.