Design of Oil Shale In-Situ Extraction Heater Structure and Numerical Simulation of the Fracturing Process

Líu, Hao; Sun, Tiezhi; Zhang, Yang; Wu, Baokang; Wang, Zhilei; Fan, Yacong

doi:10.1007/s10553-023-01481-0

Cited by 8 publications

(4 citation statements)

References 21 publications

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“…In prior studies, oil shale reservoirs were typically discovered at depths exceeding 50 m [8,9]. The downhole heater has emerged as the optimal choice for mitigating heat loss attributed to conductive heat from the surface.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Heat Transfer Simulation of Oil Shale Large-Size Downhole Heater

Bu,

Li,

2024

Applied Sciences

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Downhole heaters are critical for effectively achieving in situ oil shale cracking. In this study, we simulate the heat transfer performance of a large-scale helical baffle downhole heater under various operational conditions. The findings indicate that at 160 m3/h and 6 kW the outlet temperature can reach 280 °C. Controlling heating power or increasing the injected gas flow effectively mitigates heat accumulation on the heating rod’s surface. The outlet temperature curve exhibits two phases. Simultaneously, a balance in energy exchange between the injected gas and heating power occurs, mitigating high-temperature hotspots. Consequently, the outlet temperature cannot attain the theoretical maximum temperature, referred to as the actual maximum temperature. Employing h/∆p13 as the indicator to evaluate heat transfer performance, optimal performance occurs at 100 m3/h. Heat transfer performance at 200 m3/h is significantly impacted by heating power, with the former being approximately 6% superior to the latter. Additionally, heat transfer performance is most stable below 160 m3/h. The gas heating process is categorized into three stages based on temperature distribution characteristics within the heater: rapid warming, stable warming, and excessive heating. The simulation findings suggest that the large-size heater can inject a higher flow rate of heat-carrying gas into the subsurface, enabling efficient oil shale in situ cracking.

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Section: Introductionmentioning

confidence: 99%

“…Wang pioneered U-type and LU-type electric heaters. In contrast to Y-type electric heaters, U-type electric heaters are typically oriented horizontally, rendering them more suitable for the development of thin layers of oil shale [8]. Nevertheless, their construction can pose challenges.…”

Section: Introductionmentioning

confidence: 99%

Numerical Heat Transfer Simulation of Oil Shale Large-Size Downhole Heater

Bu,

Li,

2024

Applied Sciences

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“…Oil shale is an abundant unconventional oil and gas resource. , According to incomplete statistics, it is found in over 30 countries worldwide, with reserves estimated at around 419.6 billion barrels, accounting for approximately 13% of global oil reserves. Effective development of oil shale can reduce dependence on crude oil, utilize resources efficiently, reduce environmental pollution, enhance energy security, and promote economic development . With the continuous development of oil shale extraction technology, in situ heating of oil shale has emerged as a new direction in oil shale development .…”

Section: Introductionmentioning

confidence: 99%

“…Effective development of oil shale can reduce dependence on crude oil, utilize resources efficiently, reduce environmental pollution, enhance energy security, and promote economic development. 3 With the continuous development of oil shale extraction technology, in situ heating of oil shale has emerged as a new direction in oil shale development. 4 In situ heating of oil shale involves the conversion of electrical energy into heat energy, which is then used to heat the oil shale formation through conduction or the generation of high-temperature fluids.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Enhanced Heat Transfer of Downhole Slotted-Type Heaters for In Situ Oil Shale Exploitation

Sun,

Liu,

Yan

et al. 2023

ACS Omega

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In order to improve the flow state of the heater shell side and enhance the performance evaluation of the heater, this paper proposes a perforated plate-type heater model. Based on Fluent, numerical studies are conducted on the heat transfer performance and shell-side fluid flow characteristics of a perforated plate-type heater. The variations of the heat transfer factor Nu, friction factor f, and evaluation parameter Nu/f 1/3 are analyzed for different helix angles β and ratios of the long and short semiaxes of the circular holes on the heating plate under different Reynolds numbers Re. The results reveal that under the same shell-side Reynolds number Re, the heat transfer factor Nu shows an increasing trend with the increase in the proportion of the helix angle β. The heat transfer factor Nu for the heating plate with the hole shape ratio a/b = 1 does not exhibit significant improvement compared to hole shape ratios a/b = 0.8 and a/b = 0.6, but it increases by 4.87 to 7.07% compared to the hole shape ratio a/b = 0.4 in the perforated plate-type heater. On the other hand, the friction factor f decreases as the helix angle β and the ratio of hole shapes on the heating plate increase. The lowest friction factor f is observed for the helix angle β of 25°and the hole shape ratio a/b = 1 in the perforated plate-type heater. When the helix angle β is 25°and the hole shape ratio is a/b = 1, the evaluation parameter Nu/f 1/3 reaches its highest value, indicating the optimal overall performance of the perforated plate-type heater.

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