After space, China is now turning its gaze to the center of the Earth and its unexplored abyss. Last week, scientists began one of the deepest boreholes in the world, more than 10,000 m below our feet, to study the Earth's internal structure. The well will cross more than ten continental strata within the Earth's crust and reach rocks 66 to 145 million years old, corresponding to the geological period of the Cretaceous.
Since Tuesday, May 30, in a desert in the Tarim Basin belonging to the Xinjiang autonomous region (northwest China), an 82 m high drill rig has begun its work. The equipment, which weighs more than 10,000 tonnes, is designed to withstand 200-degree underground temperatures and atmospheric pressure 1,300 times higher than at the surface, the Guardian reports.
"The rock exerts enormous pressure on the drilling machine and the walls of the hole, the machine can very quickly get stuck and therefore cause considerable financial losses," warns Christophe Vigny, geophysicist and research director at the CNRS.
Beyond these extreme underground conditions, the natural features of the Tarim Basin – China's hottest and driest desert – complicate the project. "The difficulty of constructing the drilling project can be compared to a big truck running on two thin steel cables," Sun Jinsheng, a scientist at the Chinese Academy of Engineering, told Xinhua news agency. A job that requires colossal resources: "an armada of engineers, important processes to cool the machine and a huge amount of energy to dig," says Christophe Vigny.
The drilling of China's first borehole over 10,000 meters deep for scientific #exploration began on Tuesday in the Tarim Basin, NW China's Xinjiang Uygur Autonomous Region, a great feat in China's deep-Earth exploration. The project is expected to be completed in 457 days. pic.twitter.com/lElBcltMvu
— China News 中国新闻网 (@Echinanews) May 30, 2023
Identification of mineral resources and assessment of the risks of natural disasters (earthquakes, volcanic eruptions...): studying these unexplored depths will collect "valuable and rare information on the evolution of the earth, in order to better understand the transformations of this region and even of the whole of China," reports Hao Fang, one of the scientists leading the project, with Bloomberg. "The scientific interest is quite low," points out Christophe Vigny. Earthquakes often occur at a depth greater than 10 km below the surface and, in this area, both seismicity and volcanic activity are quite low."
With this operation, led by the China National Petroleum Corporation, the main state-owned oil and gas producer, China has another interest in mind. Beijing wants to identify the energy resources, including hydrocarbons such as gas and oil, that make up its soils - the Xinjiang region being known to be rich in this area - and this while the intensive exploitation of fossil fuels is increasingly called into question by the gradual decrease in deposits and the awareness of global warming.
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"Usually, the oil industries look at much smaller depths," says Christophe Vigny. If there is a deposit, it must then be exploited, so dig new holes, which would be expensive and unrealistic. Today, there is no technology to exploit oil at a depth of ten kilometres."
Potential geopolitical asset
The project is part of China's strategy to explore new frontiers, both in space and below the earth's surface. In 2021, Chinese President Xi Jinping called on scientists to cross new limits, especially in the exploration of the Earth's depths. Knowing that China, a country dependent on crude oil imports, has a potentially exploitable deposit would be an important asset.
This artificial hole will become the deepest in Chinese territory, but will not exceed the SG-3 drilling, located in Russia in the Kola Peninsula, which reached a depth of 1989,12 m in 262, after two decades of drilling.