China to drill world’s deepest borehole, breaking Kola Superdeep record

China has embarked on an ambitious project to drill 15 km (9.3 miles) into the Earth’s crust, aiming to uncover the deep interior’s geological composition and access untapped energy resources. If successful, this will become the deepest borehole ever drilled in the world, surpassing the current record held by Russia’s Kola Superdeep Borehole, which reached a depth of 12.2 km (7.6 miles) in 1989.

The Kola Superdeep Borehole, located on the Kola Peninsula in northwestern Russia, was part of a Soviet scientific research project that began in 1970. The drilling effort, which lasted nearly two decades, was driven by the desire to study the Earth’s crust beyond what had ever been observed.

Despite encountering extreme temperatures of around 180 °C (356 °F) at the deepest levels—hotter than initially expected—the project provided valuable insights into the composition of the Earth’s crust, revealing unexpected layers of rock and water at depths previously thought to be dry.

China’s new drilling initiative is expected to push well beyond this limit, delving an additional 2.7 km (1.7 miles) deeper than the Kola borehole. This project is part of the country’s broader strategy to enhance energy security by exploring geothermal and other deep-Earth resources. Scientists also aim to use the borehole as a natural laboratory to study subsurface conditions, seismic activity, and the structure of the Earth’s layers, which remain largely uncharted at such depths.

However, drilling to such extreme depths poses significant engineering challenges. The Soviet team at Kola had to develop specialized drilling techniques to handle the intense heat and pressure, as standard drilling equipment failed under extreme conditions.

Similarly, China’s project will require advanced materials and cooling systems to withstand the immense stress on the drill and maintain structural integrity in a high-temperature, high-pressure environment.

Beyond technical difficulties, scientists face uncertainty about the composition and behavior of materials at these depths. The Kola Superdeep Borehole unexpectedly encountered porous rocks filled with water, which led to difficulties in maintaining stable borehole walls. China’s project may encounter similar or even greater challenges as it reaches previously unexplored depths in the Earth’s crust.

By drilling deeper than any previous scientific effort, China aims to gain unprecedented insight into the Earth’s interior while also investigating the feasibility of harnessing deep geothermal energy. If successful, the findings could have implications for geology, energy exploration, and planetary science.

The initiative is led by the Chinese Academy of Geological Sciences in collaboration with leading universities, research institutions, and industrial enterprises.

“The Deep Earth National Science and Technology Megaproject is a forward-looking strategy that aligns with global scientific frontiers while ensuring national energy and resource security,” China’s state news agency, Xinhua, stated.

The future of ultra-deep drilling and the technology driving it beyond 15 km

The success of ultra-deep drilling beyond 15 km (9.3 miles) hinges on technological advancements, robust engineering techniques, and precise scientific planning. With the growing interest in deep-Earth research, experts constantly refine drilling methods to withstand extreme heat, pressure, and geological instability. To drill deeper than any project before one needs a combination of materials science, automation, and innovative cooling technologies.

Key participant, Jilin University, outlined several technical challenges, including high-temperature drilling mud management and the automated coordination of ultra-long drill strings. The challenges are critical to ensure continuous operation in conditions where conventional drilling methods would fail.

To tackle this, scientists are developing heat-resistant drilling fluids that maintain their viscosity under extreme thermal stress exceeding 400 °C (752 °F). The fluids help in cooling the drill bit and stabilizing the borehole walls. Advancements in drill string automation aim to minimize human intervention, allowing precision-controlled adjustments to drilling speed, torque, and pressure distribution.

The extreme depths China aims to reach will also require rethinking drilling equipment durability. Standard drill bits wear down quickly under high temperatures and stress, making it necessary to use diamond-impregnated bits that can sustain continuous operations for extended periods. The structural integrity of the borehole is another concern as rocks at these depths experience stresses that could lead to unexpected fractures and collapses.

The project builds upon the “Crust-1 10k” initiative which was first proposed in 2018 to push the limits of ultra-deep exploration. Lessons from the previous effort have provided valuable data on rock mechanics, borehole stability, and high-pressure fluid processes.

“Temperatures reach 400 °C (752 °F) at a depth of 13 000 m (42 650 feet), and high stress in the crust means rocks are likely to explode and damage the drill string,” said Sun Youhong, vice-president of Jilin University and director of the drilling program.

By refining automated drilling techniques, enhancing cooling and lubrication systems, and incorporating real-time data monitoring, researchers believe they can push through barriers that once limited deep-Earth exploration. The technology developed through the project will not only contribute to China’s energy security but may also influence future planetary drilling missions where similar extreme conditions exist beneath the surface of celestial bodies.

Recent developments in deep drilling

China’s deep-Earth drilling capabilities have made rapid progress in recent years, with a major breakthrough occurring on March 5, 2024. The “Shenditake 1” borehole, located in the Taklimakan Desert of the Tarim Basin, became Asia’s deepest vertical well, reaching a depth of 10 km (6.2 miles). The project represents an important step in China’s long-term strategy to explore and utilize deep-Earth resources.

The borehole is set to extend even further, with engineers aiming for a final depth of 11.1 km (6.7 miles). The significance of the project extends beyond setting depth records; it is a testbed for extreme drilling technologies and provides valuable data on how to manage high-pressure, high-temperature conditions deep underground. The data gained will directly contribute to future ultra-deep drilling initiatives including the ambitious 15 km (9 miles) borehole China is now preparing for.

Drilling such extreme wells presents multiple challenges, ranging from unpredictable geological formations to managing equipment durability under intense heat and stress. 

“It took nearly 5 months to drill from the surface to a depth of 8 km (5 miles), while it took over 4 months to drill from 8 km to 10 km (6.2 miles),” chief expert of the Tarim Oilfield of China National Petroleum Corporation, Wang Chunsheng, said.

The slow but methodical approach ensures stability and safety as engineers push the boundaries of drilling depth.

The Taklimakan Desert is chosen for the ultra-deep borehole because the region is known for its rich oil and gas reserves, with the Tarim Basin holding some of China’s largest untapped deposits. Deep-Earth drilling in such regions is crucial for mapping hidden hydrocarbon reserves and understanding how geological formations behave under extreme conditions. 

By using the Shenditake 1 project as a foundation, China is refining its approach for future ultra-deep drilling missions that may lead to new energy discoveries.

Boreholes are essential for scientific research into the Earth’s interior including seismic activity studies, geothermal energy potential, and deep biosphere exploration. The deeper scientists can drill, the more they can learn about subterranean heat flow, tectonic movements, and even microscopic life forms that thrive in extreme underground conditions.

As China continues advancing its deep-Earth drilling initiatives, lessons from the Shenditake 1 borehole will play an important role in shaping future projects, those targeting depths beyond 15 km (9.3 miles).

China’s offshore drilling milestone

China has also expanded its deep-sea drilling capabilities with the launch of its first domestically built ocean drilling vessel, Mengxiang (“Dream”), in December 2023. The vessel is designed to penetrate the Earth’s crust beneath the seafloor, opening new possibilities for oceanic geological research and energy exploration.

Mengxiang measures 179 m (587 feet) in length and 32.8 m (108 feet) in width, with a cargo capacity of 33 000 tonnes. It can operate for up to 120 days per voyage and is capable of drilling to depths of 11 km (6.8 miles) below the seafloor. The vessel’s level of endurance allows researchers to conduct long-term studies on submarine fault zones, methane hydrate deposits, and deep-sea crustal structures.

Deep-sea drilling presents unique challenges compared to land-based drilling. Ocean currents, shifting seafloor sediments, and high-pressure environments require highly advanced stabilization technology to keep the vessel steady and ensure precision drilling. Mengxiang integrates real-time seismic imaging and automated drilling controls which help scientists study subduction zones, earthquake activity, and deep-sea mineral deposits.

By advancing its offshore drilling capabilities, China is expanding its scientific reach beyond continental exploration, unlocking resources hidden beneath the ocean floor while contributing to global geophysical studies.

Strategic energy expansion

China has been ramping up efforts to secure its energy future through extensive ultra-deep drilling initiatives, and in July 2024, a major restructuring of its national energy sector took place. The country established a new energy entity that integrates national oil producers such as China National Petroleum Corporation (CNPC) and Sinopec with other state-owned enterprises. The consolidation aims to enhance efficiency, streamline research and development efforts, and accelerate the discovery of ultra-deep oil and gas reserves.

The initiative is a direct response to China’s increasing reliance on energy imports. With 34% of China’s total oil and gas resources estimated to be in ultra-deep formations, the strategic move seeks to unlock unconventional energy reserves that were previously inaccessible because of technological constraints. 

By combining the expertise and resources of its largest energy firms, China is looking to achieve energy independence while simultaneously reducing the environmental impact of traditional fossil fuel extraction.

The restructuring also aligns with the directive of Xi Jinping, President of the People’s Republic of China, to strengthen national energy security and ensure a stable energy supply for future generations. Investments are being funneled into advanced seismic imaging, high-pressure drilling technologies, and AI-driven exploration methods to improve extraction efficiency and sustainability.

Global context and prospects

China’s ultra-deep drilling initiatives have far-reaching implications not only for its resource security but also for global energy markets and scientific exploration. The country’s efforts to tap into deep oil and gas reserves which account for approximately 34% of its total resource base could reshape energy supply chains in the coming decades.

The Tarim and Sichuan basins remain key areas of focus, with large deposits still untapped because of the extreme depths and complex geological conditions.

Deep-Earth drilling plays an important role in understanding planetary processes, tectonic activity, and subsurface resource distribution. China has extended its ambitions beyond national borders by actively engaging in international geological collaborations focusing on the Himalayan and Tibetan regions. The areas are of interest because of their complex plate tectonics and deep-crustal structures which can provide data into mountain-building processes and seismic activity.

To further its deep-Earth research capabilities, China has also proposed the Earth Crustal Tomography (Earth CT) project. The initiative aims to create a global cross-sectional imaging system of the Earth’s crust, leveraging seismic and subsurface data collected from ultra-deep boreholes. Such a system could help scientists map underground structures on a global scale and can enhance understanding of deep geothermal reservoirs, mineral resources, and earthquake-prone fault zones.

References:

¹ China’s deep drill project: a quest for deep-Earth energy resources – SCMP – January 29, 2025

Rishika Yadav

Rishika holds a Master’s in International Studies from Stella Maris College, Chennai, India, where she earned a gold medal, and an MCA from the University of Mysore, Karnataka, India. Previously, she served as a Research Assistant at the National Institute of Advanced Studies, Indian Institute of Science, Bengaluru, India. During her tenure, she contributed as a Junior Writer for Europe Monitor on the Global Politics website and as an Assistant Editor for The World This Week. Her work has also been published in The Hindu newspaper, showing her expertise in global affairs. Rishika is also a recipient of the Women Empowerment Award at the district level in Haryana, India, in 2022.

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