Experimental study on the thermal characteristics of rock at low temperatures

Park, Chong-Lyuck; Synn, Joong-Ho; Shin, Hee-Soon; Cheon, Dae‐Sung; Lim, Hyun-Soo; Jeon, Seokwon

doi:10.1016/j.ijrmms.2004.03.023

Cited by 48 publications

(12 citation statements)

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“…Scholars have conducted extensive research on the temperature field evolution of coal rock under low-temperature freezing conditions. Park et al 9 experimentally studied factors influencing the thermophysical parameters of rock and their relationship with the temperature field. The results showed that as temperature decreased from 40 to −160 °C, the specific heat and thermal expansion coefficient of rock fell while the thermal conductivity did not change much.…”

Section: Introductionmentioning

confidence: 99%

Study on Temperature Variation and Pore Structure Evolution within Coal under the Effect of Liquid Nitrogen Mass Transfer

Huang

et al. 2021

ACS Omega

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Liquid nitrogen freezing, which is an effective permeability enhancement technology, has been applied to the extraction of oil, shale gas, and coalbed methane (CBM). This study is aimed at revealing the effect of liquid nitrogen mass transfer on the temperature variation and pore structure evolution within coal. To achieve this aim, first, temperature measurement tests under the action of liquid nitrogen freezing were conducted on saturated and dried coal samples, respectively. Next, the coal samples were subjected to nuclear magnetic resonance and computer tomography tests before and after liquid nitrogen cold soaking to further explore the mechanism of coal temperature variation from a microscopic perspective. The results show that the action of liquid nitrogen mass transfer can accelerate coal temperature variation through coal pore structure and pore water phase change. The thermal stress and frost heave force generated by liquid nitrogen cold soaking exceed the tensile strength of the coal sample, which directly causes crack initiation, expansion, and connection. The mass transfer of liquid nitrogen has a significant promoting effect on pore development. This study provides the technical support necessary for the efficient exploitation of CBM resources and the improvement of CBM extraction rate.

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Section: Introductionmentioning

confidence: 99%

Study on Temperature Variation and Pore Structure Evolution within Coal under the Effect of Liquid Nitrogen Mass Transfer

Huang

et al. 2021

ACS Omega

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“…It is assumed that the parameters, including density, specific heat, thermal conductivity, and viscosity of LN, are [37]. Regarding the thermalphysical properties of granite, the fitting equations of specific heat, thermal conductivity, and thermal expansion with temperature are adopted in the calculation based on previous studies [37,38]. e specific heat of granite:…”

Section: Materials Parametersmentioning

confidence: 99%

Numerical Investigation into the Distributions of Temperature and Stress around Wellbore during the Injection of Cryogenic Liquid Nitrogen into Hot Dry Rock Reservoir

Ren

Cai

2021

Mathematical Problems in Engineering

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Cryogenic liquid nitrogen fracturing is expected to provide an effective stimulation method for hot dry rock reservoirs to increase heat production. This paper establishes a three-dimensional model to calculate the distributions of temperature and stress of the reservoir rock when liquid nitrogen is injected into the wellbore. The sensitivity of different parameters and water fracturing to the stress state is studied. The results indicate that when liquid nitrogen is injected into the bottom of well, a huge heat exchange occurs on the rock surface, which generates great thermal stress on the fluid-solid interface, and the value of thermal stress exceeds the tensile strength of rock. For the effect of parameters, the primitive temperature of the rock has a significant impact on the value of maximum principal stress. The pressure drop and ambient pressure affect the thermal stress slightly. At the same time, a series of experiments are conducted to validate the effect of thermal stress induced by liquid nitrogen injection on the rock fracture. As the temperature rises, the shale samples are broken more severely at the action of thermal stress. Thus, the study of liquid nitrogen fracturing provides a scientific and effective method for geothermal exploitation.

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“…In recent years, both domestic and international scholars have carried out experimental and numerical simulations of the evolution of rock temperature fields under low-temperature freezing conditions. For instance, Park et al [1] experimentally studied the thermophysical parameters of rocks in relation to temperature; when the temperature was varied between 40 and 160 • C, the specific heat and thermal expansion coefficient of the rock decreased with the decrease in temperature, whereas the thermal conductivity did not change substantially. To investigate the heat transfer pattern of rocks during freeze-thawing, Kenji et al [2] tested and calibrated five different sensors on the market.…”

Section: Introductionmentioning

confidence: 99%

The Temperature Field Evolution and Water Migration Law of Coal under Low-Temperature Freezing Conditions

Huang

et al. 2021

IJERPH

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This study examines the evolution law of the coal temperature field under low-temperature freezing conditions. The temperature inside coal samples with different water contents was measured in real-time at several measurement points in different locations inside the sample under the condition of low-temperature medium (liquid nitrogen) freezing. The temperature change curve was then used to analyse the laws of temperature propagation and the movement of the freezing front of the coal, which revealed the mechanism of internal water migration in the coal under low-temperature freezing conditions. The results indicate that the greater the water content of the coal sample, the greater the temperature propagation rate. The reasons for this are the phase change of ice and water inside the coal during the freezing process; the increase in the contact area of the ice and coal matrix caused by the volume expansion; and the joint action of the two. The process of the movement of the freezing front is due to the greater adsorption force of the ice lens than that of the coal matrix. Thus, the water molecules adsorbed in the unfrozen area of the coal matrix migrate towards the freezing front and form a new ice lens. Considering the temperature gradient and water content of the coal samples, Darcy’s permeation equation and water migration equation for the inside of the coal under freezing conditions were derived, and the segregation potential and matrix potential were analysed. The obtained theoretical and experimental results were found to be consistent. The higher the water content of the coal samples, the smaller the matrix potential for the hindrance of water migration. Furthermore, the larger the temperature gradient, the larger the segregation potential, and the faster the water migration rate.

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Experimental study on the thermal characteristics of rock at low temperatures

Cited by 48 publications

References 0 publications

Study on Temperature Variation and Pore Structure Evolution within Coal under the Effect of Liquid Nitrogen Mass Transfer

Study on Temperature Variation and Pore Structure Evolution within Coal under the Effect of Liquid Nitrogen Mass Transfer

Numerical Investigation into the Distributions of Temperature and Stress around Wellbore during the Injection of Cryogenic Liquid Nitrogen into Hot Dry Rock Reservoir

The Temperature Field Evolution and Water Migration Law of Coal under Low-Temperature Freezing Conditions

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