Influence of water invasion on methane adsorption behavior in coal

Wang, Zhaofeng; Sui, Weiwei; Tang, Xu; Wu, Jiahao

doi:10.1016/j.coal.2018.08.004

Cited by 72 publications

(42 citation statements)

References 70 publications

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“…where c is the capillary shape coefficient, r is the average capillary radius, σ is the surface tension of liquid, η is liquid viscosity, and h is the height of mercury at the different time point t. e relationship between the pore change and gas adsorption by the action of static blasting materials was determined. ere are three states of methane in coal: free, adsorbed, and absorbed methane [33]. e absorption of methane in coal body is too small to be determined.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Static Blasting Materials on Coal Structure Changes and Methane Adsorption Characteristics

Cui

Zhang

Guo

et al. 2020

Advances in Materials Science and Engineering

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Methane in coal seam is always under the dynamic process of adsorption and desorption. It has been demonstrated that the static blasting technology is an effective way to extract methane from coal. Although it is of great significance to understand the role of static blasting materials on methane extraction, the change of methane during static blasting is not well understood due to limited research studies. In this paper, we took the reaction pressure and heat from the hydration of the static blasting materials as the main factors. Microstructure changes in the static blasting materials and coal were analyzed by scanning electron microscopy, gas chromatography, infrared spectroscopy, and mercury injection. Changes of methane adsorption and adsorption rate before and after the static blasting were also measured. Our results demonstrated that the static blasting materials entered the microcracks of the coal body and the porosity of the coal was increased by heat expansion, improving methane migration. During the blasting process, methane began to desorb from the coal and its adsorption content was decreased. In contrast, the adsorption of methane was increased after the reaction. However, methane adsorption rate is higher than that of raw coal, indicating that the adsorbed methane is easier to convert into free methane, which is conducive to emission. This is of great significance to methane extraction and the safety of mines.

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Section: Methodsmentioning

confidence: 99%

The Effect of Static Blasting Materials on Coal Structure Changes and Methane Adsorption Characteristics

Cui

Zhang

Guo

et al. 2020

Advances in Materials Science and Engineering

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“…For instance, Wang et al (2018), studied the water in uence invasion on methane adsorption behaviour in coal. The authors have procured the coal samples from the Chinese coal mines and moulded it for lab-scale examination.…”

Section: Sample Preparationmentioning

confidence: 99%

Permeability Damage and Supercritical Fluid Storage in the Cauvery Basin Neyveli Lignite Bed Containing Kaolinite Deposits during Alternative Injection of Brine and CO2

Rajkumar

Antony

Mahalingam³

et al. 2020

Preprint

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A laboratory based investigation has been conducted on permeability damage and CO2 storage or retention in the lignite core during alternative injection of brine and supercritical carbon dioxide. Moreover, anthracite and bituminous coal beds were focused by the scientific community for effective production and reservoir formation damage study. But, now-a-days, lignite based coal bed methane reservoirs have attracted attention for productive exploitation and formation collapse investigation. Hence, for this purpose, a single component injection two phase (Brine + Supercritical CO2) coreflood test analysis under alternative injections were performed to investigate the occurrence of lignite structural collapse, permeability damage, injectivity decline and CO2 retention as well. The experimental study reveals that, due to gravity segregation there is a high rate of fluid saturation in lignite core and also, moderate level of heat transfer coefficient was also noted. Also, lignite core structural collapse under the brine and supercritical CO2 injection at different velocities resulted in huge volume of coal and kaolinite fines concentration. Kaolinite and coal fines migration resulted in pressure change and permeability decline in lignite core. The suspensions produced were passed to microstructural analysis and it revealed that kaolinite fine particle tends to possess a leaflet geometrical structure, which obstructed the cleats and restricted the fluid flow. Subsequently, hysteresis modelling (Pranesh 2018) was applied to this problem to quantify the amount of CO2 retention in lignite core. Additionally, statistical model, multiple linear regression was applied to this problem to validate the experimental model, which showed good agreement.

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“…The extent to which the capacity is reduced depends on coal rank. Higher rank coals are less affected by the presence of moisture than low rank coals (Day et al, 2008; Wang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

In Situ Synchrotron X‐Ray Microtomography Observations of Fracture Network Evolution of Coal Due to Waterflooding

Zhang

Ranjith

et al. 2020

Geophysical Research Letters

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Water adsorption on coal plays a significant role in the process of CO 2 sequestration and enhanced coalbed methane recovery. Direct evidence of how coal adsorbs water and swells, affecting permeability, is still limited. Here, we studied the impact of waterflooding on fracture networks in coal by means of in situ synchrotron X-ray microtomography combined with permeability measurements. We demonstrated that swelling-induced fracture closure was responsible for an order of magnitude permeability reduction after waterflooding for over 4 days. Permeability loss was found to be time dependent, following a logistic function, and about 80% permeability reduction happened in the first 24 hr. There were probably three driven forces for water uptake, including hydrodynamic forces in fractures and macropores, capillary forces in micropores, and diffusion from micropores into deeper coal matrix. Swelling of coal matrix narrowed down and even closed the fractures and as a result weakened fracture connectivity. Residual fractures were mainly mineral-supported fractures, which have strong resistance to swelling-induced stresses.Plain Language Summary CO 2 storage in coal and simultaneously enhanced coalbed methane recovery (CO 2 -ECBM) is a global-warming mitigation technique with dual benefit. Porosity and permeability of coal are critical for CO 2 -ECBM, which determine the CO 2 storage capacity and methane productivity. Although it is widely reported that coalbed water adsorption on coal causes coal matrix swelling and reduces coal permeability, there is a lack of understanding the evolution of coal fracture networks and explaining the resulting permeability changes. We thus directly characterized and quantified the fracture network changes due to waterflooding using in situ synchrotron X-ray microtomography combined with permeability measurements. We identified the direct evidence-fracture closure resulting from adsorption-induced coal swelling-responsible for the permeability reduction after waterflooding. The existing fractures were found to narrow down readily and even close, causing an order of magnitude permeability reduction after waterflooding for over 4 days. Swelling process was found to be time dependent, and approximately 80% permeability reduction occurred in the first 24 hr. We also found that some residual fractures supported by minerals, which have strong resistance to the swelling-induced stresses, still remained after waterflooding.

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Influence of water invasion on methane adsorption behavior in coal

Cited by 72 publications

References 70 publications

The Effect of Static Blasting Materials on Coal Structure Changes and Methane Adsorption Characteristics

The Effect of Static Blasting Materials on Coal Structure Changes and Methane Adsorption Characteristics

Permeability Damage and Supercritical Fluid Storage in the Cauvery Basin Neyveli Lignite Bed Containing Kaolinite Deposits during Alternative Injection of Brine and CO2

In Situ Synchrotron X‐Ray Microtomography Observations of Fracture Network Evolution of Coal Due to Waterflooding

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