Mechanism of Structural Damage in Low Permeability Coal Material of Coalbed Methane Reservoir under Cyclic Cold Loading

Li, Hewan; Zuo, Jianping; Wang, Laigui; Li, Pengfei; Xu, Xia

doi:10.3390/en13030519

Cited by 14 publications

(3 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Table shows the number of research articles on LN 2 fracturing by country according to SCI. − China, the United States, Australia, and Japan are the countries that have published the greatest number of articles. − …”

Section: Ln2 Fracturing Technology Developmentmentioning

confidence: 99%

Advances in Liquid Nitrogen Fracturing for Unconventional Oil and Gas Development: A Review

et al. 2022

View full text Add to dashboard Cite

Liquid nitrogen (LN 2 ) fracturing is an anhydrous fracturing technology that enhances coal permeability and supports unconventional oil and gas exploitation. In this Review, we provide a systematic review of five aspects of LN 2 fracturing. They are the history of the technology's development, research topics, factors influencing fracturing efficiency, fracturing mechanism, and engineering processes and systems. Liquid nitrogen fracturing transforms coal and rock pore structure through mechanisms such as low temperature, freeze−thaw damage, and gas expansion. It changes coal and rock mechanical properties and improves the pore penetration and efficiency of unconventional oil and gas extraction. However, in-depth studies are still required in many areas. They include theoretical studies of twophase nitrogen flow in coal and rock, development of technical equipment to support field operations, and plans to monitor and evaluate fracturing efficiency. On the basis of the advances in LN 2 fracturing research and the challenges, we conclude that future research should focus on multiphase flow and field equipment and technology.

show abstract

Section: Ln2 Fracturing Technology Developmentmentioning

confidence: 99%

Advances in Liquid Nitrogen Fracturing for Unconventional Oil and Gas Development: A Review

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Moreover, researchers can acquire comprehensive insights into the mechanical properties and fracture evolution of rocks by employing diverse testing methods and techniques, including rock mechanics experiments and observations using a fault microscope. These approaches enable the detailed examination of the rock's mechanical characteristics and the progression of fractures [15]. According to Kaiser's research, significant acoustic emission phenomena occur only when the metal specimen is subjected to loading again after unloading, and only when the stress reaches the maximum stress previously applied.…”

Section: Introductionmentioning

confidence: 99%

Effects of Temperature and Liquid Nitrogen (LN2) on Coal’s Mechanical and Acoustic Emission (AE) Properties

Teng,

Cai,

Wang

et al. 2024

FDMP

View full text Add to dashboard Cite

Liquid nitrogen has shown excellent performances as a good fracturing medium in the extraction of unconventional natural gas, and its application in coalbed methane extraction is currently a research hotspot. This study focuses on the acoustic emission properties of coal specimens treated utilizing liquid nitrogen with varying initial temperatures in a three-point bending environment. Through examination of the load-displacement curves of the considered coal samples, their mechanical properties are also revealed for different initial temperatures and cycling frequencies. The findings demonstrate a gradual decline in the maximum load capacity of coal rock as the temperature rises. Similarly, when subjected to the same temperature, an escalation in the cycling frequency leads to a reduction in the peak load of coal rock. This suggests that both temperature and cycling frequency exert a notable impact on the fracturing efficacy of liquid nitrogen. Freeze-thaw cycling treatments and exposure to high-temperature conditions can activate preexisting damage in the coal rock, and, accordingly, influence its mechanical properties. In particular, throughout the progressive loading of coal rock samples, the failure mechanisms are predominantly characterized by the occurrence of tensile cracks, succeeded by the development, spread, and fracture of shear fissures.

show abstract

“…Laboratory experiments have also found that the permeability of coal subjected to LN 2 cooling can be improved. The elastic modulus, compressive strength, and tensile strength of coal subjected to LN 2 cryotherapy decrease significantly, − and the fracture propagation becomes more active during the mechanical experiments due to changes in the internal structure after the LN 2 -cooling treatment. However, there is relatively little information about the effect of LN 2 cooling on tight gas sandstone rocks.…”

Section: Introductionmentioning

confidence: 99%

Influence of Various Control Factors on Fracture Toughness and Fracture Energy of Sandstone Subjected to Liquid Nitrogen Cooling

Hou

Cai

et al. 2021

Energy Fuels

View full text Add to dashboard Cite

Liquid nitrogen (LN2) cryogenic fracturing can significantly enhance the permeability of tight-sandstone gas reservoirs. In order to evaluate the control factors influencing the changes in the crack toughness and fracture energy of the sandstone in LN2 cryogenic fracturing, the influences of the LN2 cooling state, freeze–thaw cycle (FTC) times, moisture content of the sandstone, and notch inclination angle were studied using combined three-point bending experiments. At the same time, the internal structural damage and induced fracture morphology are employed to analyze the failure mechanism. The results show that the LN2 freeze–thaw treatment can decrease the crack toughness and fracture energy of the sandstone, while these values increase for the LN2 freezing treatment. The water saturation condition can enhance the LN2 cooling effect, but it has a larger influence on LN2 freezing. With the increase of the notch angle, both the crack toughness and the energy release rate (ERR) of the saturated sandstone significantly reduce, but the applied energy only has a slight increase. The crack toughness, ERR, and applied energy of the saturated sandstone gradually decrease with the increase in the LN2 FTC, and their values after 30 LN2 FTC times decrease by 52.67, 76.04, and 41.15%, respectively. The strength feature and fracture energy of the sandstone heavily depend on the internal microstructure and crack propagation mechanism of the sandstone.

show abstract

Mechanism of Structural Damage in Low Permeability Coal Material of Coalbed Methane Reservoir under Cyclic Cold Loading

Cited by 14 publications

References 17 publications

Advances in Liquid Nitrogen Fracturing for Unconventional Oil and Gas Development: A Review

Advances in Liquid Nitrogen Fracturing for Unconventional Oil and Gas Development: A Review

Effects of Temperature and Liquid Nitrogen (LN2) on Coal’s Mechanical and Acoustic Emission (AE) Properties

Influence of Various Control Factors on Fracture Toughness and Fracture Energy of Sandstone Subjected to Liquid Nitrogen Cooling

Contact Info

Product

Resources

About