Macro and Meso Characteristics of In-Situ Oil Shale Pyrolysis Using Superheated Steam

Wang, Lei; Yang, Dinglong; Li, Xiang; Zhao, Jing; Wang, Guoying; Zhao, Yangsheng

doi:10.3390/en11092297

Cited by 26 publications

(15 citation statements)

References 43 publications

(41 reference statements)

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“…In the mercury injection test, porosity is the ratio of total pore volume to total medium volume (Table 5) [12]. Permeability is an important parameter reflecting the permeability characteristics of rock mass and can be determined by simulating the flow of fluid through a cylindrical channel [13]. Variations in the porosity and permeability of oil shale with temperature during pyrolysis under different heating modes are shown in Figure 5.…”

Section: Changes In the Porosity And Permeability Of Oil Shalementioning

confidence: 99%

Evolution of pore characteristics in oil shale during pyrolysis under convection and conduction heating modes

Wang¹,

Wang²,

Yang³

et al. 2020

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The pores in oil shale, which act as channels for the migration of products of cracking of organic matter and the place for heat transfer in the rock mass, directly influence pyrolysis efficiency. In this paper, the pore characteristics of oil shale during pyrolysis under the convection and conduction modes of heating were determined by mercury intrusion porosimetry (MIP). Results show that in case of both the heating modes, the threshold temperatures for transformation of pore structure from simple to complex are 382 °C and 452 °C, respectively. The porosity of oil shale subjected to convection heating is generally higher than that subjected to conduction heating. By the convection heating mode, the high-temperature fluid can extract the shale oil attached to the pore wall and increase the porosity. As the pyrolysis temperature increases from 314 °C to 555 °C, the average pore size of oil shale increases from 23.70 to 218.15 nm in convection heating and from 21.68 to 145.60 nm in conduction heating. During the pyrolysis of organic matter and extraction of oil and gas, high-temperature steam continuously widens the pores. Finally, when the pyrolysis temperature is above 314 °C, pores with a smaller size gradually change into mesopores and macropores with a larger size. It is proved that under the convection heating mode, oil shale changes from a dense rock to a porous medium with an obviously higher amount of pores.

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Section: Changes In the Porosity And Permeability Of Oil Shalementioning

confidence: 99%

Evolution of pore characteristics in oil shale during pyrolysis under convection and conduction heating modes

Wang¹,

Wang²,

Yang³

et al. 2020

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“…With the continuous exploitation of conventional oil reservoirs, easy-to-exploit light oil is dramatically reduced. Unconventional oil reservoirs, such as heavy oil and oil shale, are the main driving forces for future oilfield production [1][2][3]. Heavy oil and super-heavy oil can be utilized after reducing their viscosity.…”

Section: Introductionmentioning

confidence: 99%

“…Heavy oil and super-heavy oil can be utilized after reducing their viscosity. Moreover, oil shale is an immature source rock that needs to be heat treated to convert kerogen into oil and gas [2][3][4]. At present, oil shale in situ pyrolysis is the mainstream technology used for oil shale exploitation [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Effects of Packer Locations on Downhole Electric Heater Performance: Experimental Test and Economic Analysis

et al. 2020

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A downhole electric heater, which reduces heat loss along a heat insulation pipe, is a key apparatus used to ignite oil shale underground. Downhole heaters working together with packers can improve the heating efficiency of high-temperature gases, while different packer locations will directly affect the external air temperature of the heater shell and, subsequently, the performance and total cost of the downhole heaters. A device was developed to simulate the external conditions of heater shells at different packer locations. Then, the effects of external air temperature on the performance of a downhole heater with pitches of 50, 160, and 210 mm were experimentally studied. In the test, results indicated that the heater with a packer at its outlet had an accelerated heating rate in the initial stage and decreased temperature in the final stage. Additionally, the lowest heating rod surface temperature and highest comprehensive performance were achieved with minimal irreversible loss and lower total cost when using a downhole electric heater with a packer set at its outlet. In addition, the downhole electric heater with a helical pitch of 50 mm and a packer at its outlet was more effective than other schemes in the high Reynolds number region. These findings are beneficial for shortening the oil production time in oil shale in situ pyrolysis and heavy oil thermal recovery.

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“…During the extraction of geothermal energy from hightemperature rock masses, the degree of thermal rupture of granite or other rock foundation directly affects the permeability of rock mass, which in turn affects the extraction efficiency of geothermal energy [7][8][9][10][11][12]. It is also necessary to initiate extensive research on the deformation behavior of rocks under high temperature and pressure in other fields like oil extracting and underground gasification of coal resources [13,14]. In the 1980s, Ramana had demonstrated that the thermal expansion coefficient of granite increases with increasing temperature when granite was heated in free state [15].…”

Section: Introductionmentioning

confidence: 99%

Thermal Deformation of Granite under Different Temperature and Pressure Pathways

Zhao

Feng

2019

Advances in Materials Science and Engineering

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The thermal cracking of rocks is the phenomenon of expansion and deformation of mineral particles inside the rocks. The thermal deformation of the same granite sample under different heating pathways was meticulously analyzed, and the effect of the variation of external stress on the thermal expansion was carefully studied. The thermal deformation threshold temperature was low under triaxial stress, and a larger expansion was produced under uniaxial stress. The thermal deformation of the rock mass was found to be irreversible. Upon heating to the same temperature, the expansion was found to decrease with the increase in the number of thermal cycles. Besides, for each thermal cycle, the amount of deformation caused by cooling was always greater than the amount of deformation caused by temperature rise; this difference in deformation was especially obvious under a change from triaxial stress to uniaxial stress. In the process of elevated temperature which has the same heating rate, the thermal expansion coefficient was greater under uniaxial stress than it was under triaxial stress; under same external stress, the thermal expansion coefficient with a high heating rate was generally greater than the thermal expansion coefficient with a low heating rate.

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Macro and Meso Characteristics of In-Situ Oil Shale Pyrolysis Using Superheated Steam

Cited by 26 publications

References 43 publications

Evolution of pore characteristics in oil shale during pyrolysis under convection and conduction heating modes

Evolution of pore characteristics in oil shale during pyrolysis under convection and conduction heating modes

Effects of Packer Locations on Downhole Electric Heater Performance: Experimental Test and Economic Analysis

Thermal Deformation of Granite under Different Temperature and Pressure Pathways

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