Here is why China is drilling another 10,000-metre hole in the Earth

China has begun drilling a 10,000-metre hole in the ground for the second time this year as it seeks natural gas reserves. PetroChina Southwest Oil and Gasfield Company began drilling the Shendi Chuanke-1 Well in Sichuan province, with a designed depth of 10,520 metres (6.5 miles), Xinhua News Agency reported on Friday.

The project comes after China National Petroleum Corp. began drilling a well in Xinjiang in May, which was described as the deepest in China at that time.

The Sichuan project aims to find ultra-deep reserves of natural gas, while the earlier well was described as experimental, with its primary purpose being to test drilling technologies and provide data on the Earth's internal structure.

 

Sichuan has some of China's largest shale gas reserves. However, due to the region's difficult terrain and complex underground geology, Chinese firms have not been able to fully explore the potential of these reserves.

State news outlet China Electric Power News reported that the exploration of Chuanke-1 constitutes the Deep Earth drilling project, which is part of a larger initiative to "provide an important foundation and support for China's future scientific research and oil and gas resource development".

Post 2021, China's supply of natural gas has surpassed its production of oil, and the country has become the world's fourth largest producer of natural gas.

What are ultra-deep wells?

Ultra-deep wells, which are more than 9,000 metres deep, are considered to be the most technically challenging drilling projects in the oil and gas engineering industry.

 In China's 13th Five-Year Plan period (2016–2020), several key tools such as high-end working fluid, automatic drilling rigs, and logging and cementing technology for deep and ultra-deep wells were developed under the aegis of national oil and gas special projects.

Advancements in technological aids, such as non-planar tooth bit, high-temperature resistance and ultra-high density oil-based drilling fluid, highly ductile cement slurry, deep-well coiled tubing operation unit, and automatic drilling rig helped in the exploration of ultra-deep wells to a new stage of 8000 m in the Tarim Basin, Sichuan Basin, southern margin of the Junggar Basin, and the Qaidam Basin.

Drilling in ultra-deep wells is replete with severe challenges such as deep burial depth, narrow pressure window, thick gravel layer and salt bed, complex multi-pressure system, and high temperature and pressure.