There are many ways for scientists to figure out what’s happening beneath the Earth’s surface, but none are as exciting as a giant hole in the ground. China has begun digging a borehole that will tunnel up to 10,000 meters (3,280 feet) deep into the planet’s crust, nearly as far down as the bottom of the Mariana Trench—the deepest ocean trench.
Work began on Tuesday in the Taklamakan Desert, part of the oil-rich Xinjiang Uyghur Autonomous Region in northwestern China. An 82-meter-high custom-made drilling rig will burrow through up to 10 layers of continental strata before reaching the Cretaceous System, a layer of rock that contains material dating back as far as 145 million years.
The well is being built by the state-owned China National Petroleum Corp., a company that has already tapped into ultra-deep natural gas reserves in Xinjiang. This new venture will seek “the occurrence of unconventional natural gas,” CNPC said.
But if the project succeeds, it won’t just be an energy find: Researchers will also use the hole to understand the planet’s structure and evolution better. According to a scientist involved in the project, which was first announced in May, the well will allow scientists to “expand and improve the understanding of the deep structures of the Earth.”
And while this borehole won’t be as deep as the 12,262-meter (40,230-foot) Kola Superdeep Borehole in Russia or the BD-04A oil well in Qatar, it will be much closer than any other hole dug by humans. That should help the world’s second-largest economy better identify mineral and energy resources and mitigate risks of environmental disasters like earthquakes and volcanic eruptions.
To reach the depths of the upcoming borehole, workers must pass through extremely high temperatures and pressures. Temperatures below 10,000 meters can make metal tools as soft as noodles, and the 138 megaPascal pressure at these depths is as high as the water pressure in the Mariana Trench. The scientists behind the project hope to finish their work by 2023.
The project comes just months after a similar drill by CNPC in the same area was described as the deepest ever undertaken in China. And while that previous well was experimental in focus, this new project is more geared towards discovering the nation’s massive reserves of unconventional natural gas.
While the well’s construction is underway in Sichuan, a southwestern province known for spicy cuisine, beautiful mountain scenery, and home to plenty of pandas, it won’t be finished until 2023. By then, the Earth will have sucked up a staggering amount of energy from the massive hole and could begin to melt down. That’s why the scientists working on this project are taking it slow and steady. They’re going to have to, given the challenges they face underground.