Variation characteristics of coal-rock mechanical properties under varying temperature conditions for Shanxi Linfen coalbed methane well in China

Abstract

In the actual exploitation process of coalbed methane (CBM), as the fluid in the wellbore continues to circulate, the surrounding rock of the CBM well will continuously exchange heat with the fluid in the wellbore, resulting in continuous changes in the temperature of the surrounding rock itself. Linfen, Shanxi is the main exploitation area for CBM in China. This paper aims further to improve the exploitation efficiency of CBM in this area and conducts experimental research on the change characteristics of coal-rock mechanical properties under varying temperature conditions. The experimental results show that under constant pressure conditions, the higher the temperature, the lower the stress value when the coal-rock breaks. In the process of reaching peak strength, the higher the temperature, the higher the proportion of coal-rock plastic deformation in its entire deformation stage. The compressive strength, elastic modulus, and main crack length of coal-rock will decrease with temperature. The Poisson's ratio and primary fracture angle will increase with the increase of experimental temperature.

Review and prospects of research on materials to prevent and extinguish mine fires

“…The metabolism and reproduction of microorganisms consume oxygen, which utilizes the main factors of the coal oxidation chain and slows down the process of coal oxidation and spontaneous combustion. [67][68][69][70][71][72] As shown in Table 5, the main microorganisms for CSC prevention and control include fungi, bacteria, and actinomycetes. These three types of microorganisms have different effects on the hydroxyl, aliphatic hydrocarbon, and active oxygen groups in coal.…”

“…65,66 In addition, research on green technology for controlling CSCs by microorganisms is gradually intensifying. [67][68][69][70][71][72][73][74][75] In summary, there are many fire prevention materials that are currently being studied, and the effects of various materials are different. 76,77 Li et al, 11,77 reviewed the research progress of coal mine firefighting materials, but mainly focused on the inhibition effect and synergistic inhibition effect of physical-based materials and chemical-based materials.…”

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“…The limit water depth of riser used in offshore drilling engineering is 3,047m [1][2][3]. However, due to the impact force of seawater, the riser will vibrate at different frequencies, which makes it impossible for the riser to be used ideally in a deepwater environment [4][5][6]. Moreover, the manufacturing cost of the riser is prohibitive.…”