An Experimental Study on the Interaction Law of the Pore Gas Pressure and Stress in Gassy Coals

Hu, Zuxiang; Sun, Jian; Tang, Mengqi

doi:10.17559/tv-20180805103717

Cited by 4 publications

(1 citation statement)

References 10 publications

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“…When the stress exceeds the compressive strength of the coal, gas pressure begins to decrease with that stress. Thus, an increasing stress and gas pressure are negatively correlated [21]. A new apparatus (LSTT) was developed to conduct a simulated experiment.…”

Section: Introductionmentioning

confidence: 99%

A Gas Pressure Prediction Model of the Excavation Face Based on Gas Emission

Chen

Liu

2022

IJERPH

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Gas pressure is one of the important factors related to the occurrence of coal and gas outburst disasters. The accurate gas pressure forecasting is of significance for the prevention and control of a gas disaster. In this work, a gas pressure prediction model based on the sources of gas emissions was established. The verified results show that the predicted gas pressure was roughly consistent with the actual situation. This model could meet the needs of engineering projects. Coal and gas outburst dynamic phenomenon are successfully predicted in an engineering application using the model. Overall, the prediction of coal and gas outburst using the gas pressure model achieves a continuous and dynamic effect. The model can overcome both the static and sampling shortcomings of traditional methods and solve the difficulty of coal and gas outburst prediction at the excavation face. With its broad applicability and potential prospects, the model is of great importance for guiding gas drainage, and the prevention of coal and gas outburst disasters.

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Section: Introductionmentioning

confidence: 99%

A Gas Pressure Prediction Model of the Excavation Face Based on Gas Emission

Chen

Liu

2022

IJERPH

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Study on normalization of critical values of the prediction indicator initial gas emission from boreholes

et al. 2022

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Mechanical behaviors of coal surrounding horizontal wellbore during drilling process considering the effects of loading rate, pore pressure and temperature

Zhang

Zhao

Wang

et al. 2023

Geomech. Geophys. Geo-energ. Geo-resour.

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Coal is a kind of rock with the characteristics of soft structure, developed joints, cleats, cracks, and pores, resulting in that its mechanical behaviors are highly sensitive to stress, pore coalbed methane (CBM, gas) pressure and temperature. Thus, due to the variations in stress, pore pressure and temperature caused by the drilling operation, the coal surrounding wellbore can be easily damaged, which would cause serious wellbore instability problems. In this presented work, a stress path of loading axial stress and unloading confining pressure (LAS-UCP) was first determined based on the stress redistribution of the coal surrounding horizontal wellbore in CBM reservoir during drilling process. A series of triaxial compression tests with the LAS-UCP stress path was then conducted to study the effects of axial loading rate, pore pressure and temperature on the mechanical behaviors of coal. The results show that: (1) Under the LAS-UCP stress path, the deformation of coal can be divided into elastic deformation stage, plastic deformation stage, and stress reduction stage. With the decrease in axial loading rate and the increases in pore pressure and temperature, the elastic deformation stage becomes shorter, the plastic deformation stage becomes more significant, stress reduction rate in the stress reduction stage becomes slower, and the coal shows more features of plasticity and ductility. (2) With the increasing axial loading rate, the compressive strength and apparent elastic modulus increase linearly, the absolute values of axial strain, radial strain and volumetric strain at peak stress grow gradually, but the apparent Poisson’s ratio changes irregular. (3) With the increase in pore pressure, the compressive strength, axial strain at peak stress and apparent elastic modulus decrease linearly, the radial strain and volumetric strain at peak stress have no change rule, and the apparent Poisson’s ratio increases gradually. (4) With the increasing temperature, the compressive strength, axial strain at peak stress and apparent elastic modulus reduce gradually, but the absolute values of radial strain and volumetric strain at peak stress, and the apparent Poisson’s ratio increase linearly. The results can not only provide a guidance for safety drilling operation of the horizontal wellbore in CBM reservoir, but also have important significance for other engineering constructions related to coal seam.

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An Experimental Study on the Interaction Law of the Pore Gas Pressure and Stress in Gassy Coals

Cited by 4 publications

References 10 publications

A Gas Pressure Prediction Model of the Excavation Face Based on Gas Emission

A Gas Pressure Prediction Model of the Excavation Face Based on Gas Emission

Study on normalization of critical values of the prediction indicator initial gas emission from boreholes

Mechanical behaviors of coal surrounding horizontal wellbore during drilling process considering the effects of loading rate, pore pressure and temperature

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