Study on the Cutter–Granite Interaction Mechanism in High-Temperature Geothermal Wells

In high-temperature geothermal wells, the formation usually has extremely high abrasiveness, hardness, and temperature, which pose severe challenges to drilling tools. Among them, the interaction between the cutter of the drill bit and the rock is the key factor determining the rock-breaking efficie...

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Main Authors: Yan Yang, Dongdong Song, Kuilin Huang, Haitao Ren, Yingxin Yang, Shunzuo Qiu, Zequan Huang
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/3/719
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author Yan Yang
Dongdong Song
Kuilin Huang
Haitao Ren
Yingxin Yang
Shunzuo Qiu
Zequan Huang
author_facet Yan Yang
Dongdong Song
Kuilin Huang
Haitao Ren
Yingxin Yang
Shunzuo Qiu
Zequan Huang
author_sort Yan Yang
collection DOAJ
description In high-temperature geothermal wells, the formation usually has extremely high abrasiveness, hardness, and temperature, which pose severe challenges to drilling tools. Among them, the interaction between the cutter of the drill bit and the rock is the key factor determining the rock-breaking efficiency of PDC (Polycrystalline Diamond Composite) drill bits. To further explore the rock-breaking mechanism of cutters on granite, this study adopts a combination of experimental and simulation methods to conduct systematic research. The results indicate that the specific crushing work increases and then decreases with rising temperature, reaching a minimum of 0.388 J/mm<sup>3</sup> at 200 °C. In the temperature range of 300 °C to 500 °C, the specific crushing work is 15% lower than at room temperature. The specific crushing work during instant cooling is 12–25% lower than that during self-cooling, with instant cooling showing higher rock-breaking efficiency. As the rake angle increases, the specific crushing work initially decreases and then increases. The smallest specific crushing work, 0.383 J/mm<sup>3</sup>, occurs at a rake angle of 10°, where the number of debris and particle size are maximized. With deeper cutting depths, the specific crushing work gradually decreases, resulting in more debris, larger particle sizes, and higher cutter surface temperatures. These findings clarify the variation laws of rock load, cutting tooth distribution, and rock fragmentation state when the PDC bit breaks rocks. A rake angle of 10° can be used as the selection of cutting tooth inclination angle for PDC bit design, providing a theoretical basis for the design and application of PDC bits in high-temperature geothermal drilling and holding significant guiding importance. Considering that increasing the depth of penetration can cause uneven wear of the cutter, the drilling parameters can be controlled under certain conditions to achieve a penetration depth of 2 mm, thereby improving the rock-breaking efficiency and working life of the PDC bit.
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spelling doaj-art-dd3fd82825d141b2a15ba0be00252d072025-08-20T02:48:09ZengMDPI AGEnergies1996-10732025-02-0118371910.3390/en18030719Study on the Cutter–Granite Interaction Mechanism in High-Temperature Geothermal WellsYan Yang0Dongdong Song1Kuilin Huang2Haitao Ren3Yingxin Yang4Shunzuo Qiu5Zequan Huang6School of Mechanical and Electrical Engineering, Yibin University, Yibin 644000, ChinaCNPC Chuanqing Drilling Engineering Co., Ltd., Chuanxi Drilling Company, Chengdu 610051, ChinaCollege of Mechanical and Electrical Engineering, Southwest Petroleum University, Chengdu 610500, ChinaCollege of Mechanical and Electrical Engineering, Southwest Petroleum University, Chengdu 610500, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, ChinaSchool of Mechanical and Electrical Engineering, Yibin University, Yibin 644000, ChinaSchool of Electronic Information Engineering, Yibin University, Yibin 644000, ChinaIn high-temperature geothermal wells, the formation usually has extremely high abrasiveness, hardness, and temperature, which pose severe challenges to drilling tools. Among them, the interaction between the cutter of the drill bit and the rock is the key factor determining the rock-breaking efficiency of PDC (Polycrystalline Diamond Composite) drill bits. To further explore the rock-breaking mechanism of cutters on granite, this study adopts a combination of experimental and simulation methods to conduct systematic research. The results indicate that the specific crushing work increases and then decreases with rising temperature, reaching a minimum of 0.388 J/mm<sup>3</sup> at 200 °C. In the temperature range of 300 °C to 500 °C, the specific crushing work is 15% lower than at room temperature. The specific crushing work during instant cooling is 12–25% lower than that during self-cooling, with instant cooling showing higher rock-breaking efficiency. As the rake angle increases, the specific crushing work initially decreases and then increases. The smallest specific crushing work, 0.383 J/mm<sup>3</sup>, occurs at a rake angle of 10°, where the number of debris and particle size are maximized. With deeper cutting depths, the specific crushing work gradually decreases, resulting in more debris, larger particle sizes, and higher cutter surface temperatures. These findings clarify the variation laws of rock load, cutting tooth distribution, and rock fragmentation state when the PDC bit breaks rocks. A rake angle of 10° can be used as the selection of cutting tooth inclination angle for PDC bit design, providing a theoretical basis for the design and application of PDC bits in high-temperature geothermal drilling and holding significant guiding importance. Considering that increasing the depth of penetration can cause uneven wear of the cutter, the drilling parameters can be controlled under certain conditions to achieve a penetration depth of 2 mm, thereby improving the rock-breaking efficiency and working life of the PDC bit.https://www.mdpi.com/1996-1073/18/3/719high-temperature geothermal wellgranitecutterPDC bitrock-breaking mechanismspecific crushing work
spellingShingle Yan Yang
Dongdong Song
Kuilin Huang
Haitao Ren
Yingxin Yang
Shunzuo Qiu
Zequan Huang
Study on the Cutter–Granite Interaction Mechanism in High-Temperature Geothermal Wells
Energies
high-temperature geothermal well
granite
cutter
PDC bit
rock-breaking mechanism
specific crushing work
title Study on the Cutter–Granite Interaction Mechanism in High-Temperature Geothermal Wells
title_full Study on the Cutter–Granite Interaction Mechanism in High-Temperature Geothermal Wells
title_fullStr Study on the Cutter–Granite Interaction Mechanism in High-Temperature Geothermal Wells
title_full_unstemmed Study on the Cutter–Granite Interaction Mechanism in High-Temperature Geothermal Wells
title_short Study on the Cutter–Granite Interaction Mechanism in High-Temperature Geothermal Wells
title_sort study on the cutter granite interaction mechanism in high temperature geothermal wells
topic high-temperature geothermal well
granite
cutter
PDC bit
rock-breaking mechanism
specific crushing work
url https://www.mdpi.com/1996-1073/18/3/719
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