China drills deepest vertical well in Asia

The China National Petroleum Corporation (CNPC) announced on Thursday that it has completed the drilling of the deepest vertical well in Asia, with a borehole reaching a depth of 10,910 meters in China's northwestern desert.

Located in the heart of the Taklimakan Desert in the Tarim Basin, the Xinjiang Uygur Autonomous Region, the well, known as "Shenditake-1," is a scientific exploration project.

"Drilling the Shenditake 1 well is like boring through Mount Qomolangma and then descending two more kilometers underground," said Dou Lirong, the executive director and dean of the Research Institute of Petroleum Exploration and Development at CNPC. "The risks and challenges are enormous."

Before Shenditake 1, the only onshore well exceeding 10,000 meters was the Soviet Union's SG-3 well on the Kola Peninsula, drilled from 1970 to 1993 to a depth of 12,262 meters. Shenditake 1 is now the world's second-deepest vertical well, achieving breakthroughs in ultra-deep drilling, including the deepest liner cementing, deepest wireline imaging logging, and the fastest onshore drilling to exceed 10,000 meters.

The drilling began on May 30, 2023. Reaching 10,000 meters took 279 days, but the final 910 meters required 300 days due to escalating challenges.

In a written interview with CGTN, Dou explained the immense difficulties of working in the heart of the desert and drilling under extremely high temperatures and pressures. He detailed the difficulties including the harsh working conditions in the Taklimakan Desert, where the temperature difference between summer and winter can exceed 80 degrees Celsius, putting a significant strain on the workers' physical and mental endurance. 

The deeper the well, the more extreme conditions became. The temperatures and pressures at the bottom of the well, reaching up to 220 degrees Celsius and 145 megapascals respectively, make it difficult for conventional drilling tools and materials to function properly. The weight of the drilling equipment, with over 1,130 drill pipes weighing more than 350 tonnes and the heaviest casing weighing 665 tonnes, also poses a high risk of drill pipe breakage, further complicating the drilling process.

To support the project, CNPC developed the world's first 12,000-meter automated drilling rig and a suite of advanced ultra-deep well logging tools.

The well penetrated 12 geological layers in the Tarim Basin, reaching oil-and-gas-rich rocks between 10,851–10,910 meters, according to Wang Chunsheng, the chief technical expert of the Tarim oilfield branch of PetroChina.

At present, China's onshore deep and ultra-deep oil and gas resources total 67.1 billion tonnes of oil equivalent, accounting for 34 percent of the country's total oil and gas resources. However, only 3 billion tonnes of oil equivalent have been proven in China's ultra-deep formations. So far, more than 300 wells drilled in the Tarim Oilfield have reached depths exceeding 8,000 meters, delivering a total production of 19.57 million tonnes of ultra-deep oil and gas.

"Shenditake 1 demonstrates China's growing capability in deep-Earth exploration, critical for energy security," Dou said.