Experimental Investigation of the Evolution
of Permeability and Porosity of Fushun Oil
Shale After High Temperature
Mengtao Cao 1,2 , Yide Geng 1,2(B) , and Pengfei Wu 1,2
1 College of Mining Engineering, Taiyuan University of Technology, No. 18 Xin Kuang-yuan
Road, Yingze West Street, Taiyuan 030024, People’s Republic of China
gengyide@tyut.edu.cn
2 Key Laboratory of In-Situ Modified Mining of Ministry of Education, Taiyuan
University of Technology, No. 18 Xin Kuang-yuan Road, Yingze West Street, Taiyuan 030024,
People’s Republic of China
Abstract. It is a key issue of how to improve the efficiency and security in the
development of oil shale, which is associated with the evolutions of permeability,
pore and fracture structures of oil shale under the condition of high temperature. To
investigate the influences of temperature and tri-axial stresses on the permeability
of oil shale, the WYF-1 high-temperature and high-pressure pyrolysis reaction
device and Smart perm III impulse-type gas permeability measuring apparatus
were used to test the oil shale samples after a temperature ranging from 20 °C to
600 °C. Moreover, the mercury intrusion porosimetry was also used to analyze
the evolution of pore and fracture structure inside the specimen. The results show
that the temperature has a significant effect on the permeability of oil shale that
can be divided into three stages: low growth stage, rapid growth stage, and steady
stage. At the low growth stage that the temperature is from 20 °C to 300 °C, the
weight loss rate and porosity change of oil shale are rare and the permeability
of oil shale gradually increases with raising the temperature, and the volumetric
stress (13 MPa, 26 MPa, 39 MPa) has little effect on the permeability; However,
for the rapid growth stage with the temperature from 300 to 400 °C, its weight
loss and porosity increased rapidly, and the permeability increased sharply by 24.3
to 92.4 times of that at the temperature of 300 °C, the volume stress showed an
obvious effect on the permeability; Lastly, for the temperature from 400 to 600 °C,
the weight loss rate and porosity further increased but the growth rate slowed
down, resulting in that the permeability nearly kept constant with temperature,
and the volumetric stress has a larger influence on the permeability. Besides, the
mercury intrusion porosimetry was used to investigate the distribution law and
connectivity characteristics of pore and fractures. The porosity sharply increased
with the temperature reaching 400 °C and further increased with the temperature
until 600 °C, which corresponds to the evolution of permeability of oil shale. This
research can provide some guidance for the selection of a reasonable pyrolysis
temperature in the process of in situ pyrolysis of oil shale.
Keywords: Oil shale · High temperature · Permeability
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
S. N. Atluri and I. Vušanovi´ c (Eds.): ICCES 2020, MMS 97, pp. 171–181, 2021.
https://doi.org/10.1007/978-3-030-64690-5_16
of Permeability and Porosity of Fushun Oil
Shale After High Temperature
Mengtao Cao 1,2 , Yide Geng 1,2(B) , and Pengfei Wu 1,2
1 College of Mining Engineering, Taiyuan University of Technology, No. 18 Xin Kuang-yuan
Road, Yingze West Street, Taiyuan 030024, People’s Republic of China
gengyide@tyut.edu.cn
2 Key Laboratory of In-Situ Modified Mining of Ministry of Education, Taiyuan
University of Technology, No. 18 Xin Kuang-yuan Road, Yingze West Street, Taiyuan 030024,
People’s Republic of China
Abstract. It is a key issue of how to improve the efficiency and security in the
development of oil shale, which is associated with the evolutions of permeability,
pore and fracture structures of oil shale under the condition of high temperature. To
investigate the influences of temperature and tri-axial stresses on the permeability
of oil shale, the WYF-1 high-temperature and high-pressure pyrolysis reaction
device and Smart perm III impulse-type gas permeability measuring apparatus
were used to test the oil shale samples after a temperature ranging from 20 °C to
600 °C. Moreover, the mercury intrusion porosimetry was also used to analyze
the evolution of pore and fracture structure inside the specimen. The results show
that the temperature has a significant effect on the permeability of oil shale that
can be divided into three stages: low growth stage, rapid growth stage, and steady
stage. At the low growth stage that the temperature is from 20 °C to 300 °C, the
weight loss rate and porosity change of oil shale are rare and the permeability
of oil shale gradually increases with raising the temperature, and the volumetric
stress (13 MPa, 26 MPa, 39 MPa) has little effect on the permeability; However,
for the rapid growth stage with the temperature from 300 to 400 °C, its weight
loss and porosity increased rapidly, and the permeability increased sharply by 24.3
to 92.4 times of that at the temperature of 300 °C, the volume stress showed an
obvious effect on the permeability; Lastly, for the temperature from 400 to 600 °C,
the weight loss rate and porosity further increased but the growth rate slowed
down, resulting in that the permeability nearly kept constant with temperature,
and the volumetric stress has a larger influence on the permeability. Besides, the
mercury intrusion porosimetry was used to investigate the distribution law and
connectivity characteristics of pore and fractures. The porosity sharply increased
with the temperature reaching 400 °C and further increased with the temperature
until 600 °C, which corresponds to the evolution of permeability of oil shale. This
research can provide some guidance for the selection of a reasonable pyrolysis
temperature in the process of in situ pyrolysis of oil shale.
Keywords: Oil shale · High temperature · Permeability
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
S. N. Atluri and I. Vušanovi´ c (Eds.): ICCES 2020, MMS 97, pp. 171–181, 2021.
https://doi.org/10.1007/978-3-030-64690-5_16