China starts drilling 11,100 m borehole into Earth: A look at some of the deepest artificial holes

China has begun drilling an 11,100-meter-deep well in the Tarim Basin, located deep in the Taklimakan Desert, which is China's largest desert, Xinhua reported. The purpose of the borehole is for scientific exploration, with researchers intending to find out what is deep below the Earth's surface. The interior of the planet is difficult for scientists to study because it is remote and inaccessible.

If successful, the effort will be China's deepest well and the first to exceed 10,000 meters. The hole is widened to pass through 10 layers of continental strata, going back to the Cretaceous period. However, it will not be the deepest man-made borehole, a record held by the Kola Superdeep Borehole in Russia, which reached a depth of 12,262 meters. The Al Shaheen oil well actually had a longer well in clear distance, although it did not reach the same depth, measuring 12,289 meters in length.

Some of the deepest man-made sinkholes are embedded below, along with the Challenger Deep, the deepest natural point on the planet, located in the Mariana Trench. All depths are in meters. Layers of rock in the Earth's crust preserve Earth's history, similar to speleothems, ice cores, and tree rings. Simply put, the deeper we dig, the more we understand the history of the planet and its geological past. Reaching these depths isn't always easy, however, as researchers may encounter unforeseen difficulties, including rocks that are wetter than expected, temperatures too extreme for the equipment to work, or an initiative that has run out of funds.

Most scientific efforts to drill exceptionally deep wells lead not to a single well, but to several. Project Mohole was a scientific effort launched in the 1960s to dig into the boundary layer between the crust and the mantle, the region inside the planet where melting of rock occurs. This effort occurred during the space race between Russia and the US, which diverted funds from the expedition. Five holes were drilled, an effort notable for the use of an untethered subsea drilling rig.

Kola Superdeep Borehole began in 1970 in Russia, with the express intention of digging as deep as possible into the earth. The drill bits used were recycled from old oil wells. A total of five boreholes were dug as part of the initiative, with the deepest hole reaching a depth of 12,262 in 1989. It remains the record holder for the deepest artificial hole on Earth. The device was destroyed in each of the attempts, mud saturated with hydrogen gas bubbled up, and microfossils were discovered six kilometers below the surface.

Core samples contain evidence of past life and natural disasters. The remains of primitive organisms are buried deep in the Earth, which can provide scientists with valuable insights into the origin and development of life on the planet. However, despite many attempts, no well has yet actually succeeded in reaching the casing.