The impact of depositional environment and tectonic evolution on coalbed methane occurrence in West Henan, China

Cao, Zhaodan; Lin, Baiquan; Liu, Ting

doi:10.1016/j.ijmst.2019.01.006

Cited by 31 publications

(17 citation statements)

References 18 publications

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“…In recent years, with the huge demand for energy and resources promoted by global economic and social development, the associated deep geoengineering (e.g., enhanced geothermal system [1], deep mining of coal and tight oil and gas [2,3], in-situ liquefaction and gasification of coal [4], nuclear waste geological disposal [5], etc.) is becoming the frontier and hotspot of engineering worldwide.…”

Section: Introductionmentioning

confidence: 99%

Mineral Composition, Pore Structure, and Mechanical Characteristics of Pyroxene Granite Exposed to Heat Treatments

et al. 2019

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In deep geoengineering, including geothermal development, deep mining, and nuclear waste geological disposal, high temperature significantly affects the mineral properties of rocks, thereby changing their porous and mechanical characteristics. This paper experimentally studied the changes in mineral composition, pore structure, and mechanical characteristics of pyroxene granite heated to high temperature (from 25 °C to 1200 °C). The results concluded that (1) the high-temperature effect can be roughly identified as three stages: 25–500 °C, 500–800 °C, 800–1200 °C. (2) Below 500 °C, the maximum diffracted intensities of the essential minerals are comparatively stable and the porous and mechanical characteristics of granite samples change slightly, mainly due to mineral dehydration and uncoordinated thermal expansion; additionally, the failure mechanism of granite is brittle. (3) In 500–800 °C, the diffraction angles of the minerals become wider, pyroxene and quartz undergo phase transitions, and the difference in thermal expansion among minerals reaches a peak; the rock porosity increases rapidly by 1.95 times, and the newly created pores caused by high heat treatment are mainly medium ones with radii between 1 μm and 10 μm; the P-wave velocity and the elastic modulus decrease by 62.5% and 34.6%, respectively, and the peak strain increases greatly by 105.7%, indicating the failure mode changes from brittle to quasi-brittle. (4) In 800–1200 °C, illite and quartz react chemically to produce mullite and the crystal state of the minerals deteriorate dramatically; the porous and mechanical parameters of granite samples all change significantly and the P-wave, the uniaxial compressive strength (UCS), and the elastic modulus decrease by 81.30%, 81.20%, and 92.52%, while the rock porosity and the shear-slip strain increase by 4.10 times and 11.37 times, respectively; the failure mechanism of granite samples transforms from quasi-brittle to plastic, which also was confirmed with scanning electron microscopy (SEM).

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Section: Introductionmentioning

confidence: 99%

Mineral Composition, Pore Structure, and Mechanical Characteristics of Pyroxene Granite Exposed to Heat Treatments

et al. 2019

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“…After low-temperature liquid nitrogen comes in contact with the coal seam, the water in coal seam cleats and the free water in the pores freeze, and the water–ice phase transition can produce 9% volume expansion. Liquid nitrogen fracturing technology utilizes the low-temperature characteristics of liquid nitrogen to freeze coal and cause damage, increase coal fractures, change coal mechanical strength, increase permeability, and improve the CBM extraction rate. − …”

Section: Introductionmentioning

confidence: 99%

Liquid Nitrogen’s Effect on the Mechanical Properties of Dried and Water-Saturated Frozen Coal

Qin

et al. 2022

Energy Fuels

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When liquid nitrogen (LN 2 ) comes in contact with the coal seam, the mechanical properties of the coal body will be changed, which can fracture the coal seam and improve the efficiency of coalbed methane extraction. To explore the influence of liquid nitrogen on the mechanical properties of dry and saturated coal, this paper adopts different LN 2 treatment methods (freezing 0, 50 min, F-T 10 cycles) to determine the mechanical strength of the coal sample and the ultrasonic longitudinal wave velocity. After a single freezing of LN 2 for 50 min, the mechanical properties of the dry and saturated frozen coal samples have been improved. The mechanical strength of the saturated frozen coal samples has increased more than that of the dry state; the freeze−thaw cycle reduces the mechanical strength. The compressive strength has the largest decrease, which is reduced by 45.2%; the wave velocity of the dry coal sample shows a trend of first increasing and then decreasing after different LN 2 treatments, but the overall change is small. The water-saturated coal sample increases during a single freezing and decreases during the freeze−thaw cycles, and the lowest wave speed is only 0.821 km/s. By analyzing the changes in mechanical properties, it is concluded that water-saturation treatment can damage its own strength. Short-term freezing can help increase the mechanical strength of coal. Freeze−thaw cycles cause serious deterioration and damage to coal. The increase in the pore volume of coal in the freezing stage is much greater than that in the melting stage.

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“…In contrast, mesopore and macropore volume and specific surface area positively correlate with ash yield and static content (Wei et al, 2019). Cao believes that the sedimentary environment increases the ash and mineral content of coal, fills the interlayer system, reduces the porosity, and reduces methane storage capacity (Cao et al, 2019). Wang and Menthe believe that ash yield affects pore structure and coal permeability (Mendhe et al, 2017;Wang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Study on key influencing factors of competitive adsorption of coalbed methane by carbon dioxide displacement

et al. 2022

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The extraction of coal bed methane (CBM) by injecting CO2 into deeply buried unmined coal seams in competition with CH4 adsorption to provide a clean fuel is known as enhanced coal bed methane recovery (ECBM) and has proven to be an effective technological strategy to address global warming. The study of the interaction of coal with CO2 and CH4 under multi-physical field conditions is particularly necessary. In this work, a series of experiments were conducted on a home-made test system to investigate the competing sorption patterns of high and medium ash coal samples subjected to variables such as gas pressure, temperature, nodulation and lateral limit constraints. The results show that there is a sorption isotherm relationship between coal samples and exposure time. The adsorption capacity sorption of CH4/CO2 varied considerably for different ash coal samples. As the CO2 pressure increased from 2.3 to 5.5 MPa, the strain on the coal samples increased from 0.082 to 0.4%. The deformation in the vertical laminae direction is always greater than that in the parallel laminae direction. A correlation coefficient K exists between 1 and 2, and there is an internal expansion pattern in the adsorption deformation of coal. This paper can contribute to the improvement of ECBM efficiency.

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The impact of depositional environment and tectonic evolution on coalbed methane occurrence in West Henan, China

Cited by 31 publications

References 18 publications

Mineral Composition, Pore Structure, and Mechanical Characteristics of Pyroxene Granite Exposed to Heat Treatments

Mineral Composition, Pore Structure, and Mechanical Characteristics of Pyroxene Granite Exposed to Heat Treatments

Liquid Nitrogen’s Effect on the Mechanical Properties of Dried and Water-Saturated Frozen Coal

Study on key influencing factors of competitive adsorption of coalbed methane by carbon dioxide displacement

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