Around 2000 years ago; Chinese in Sichuan province originated deep drilling. The primary motive for deep drilling in China was the search for salt. Even as recently as 1965; 16.5% of China's salt supplies came from brine pumped out of deep boreholes; making this source of supply second only to sea salt.

The ancient percussive cable drilling system was called 'churn'. The derrick had a height of 11m and all parts of the rig were made from wood (mainly bamboo). A large wooden drum; 5m in diameter; was used to raise and lower the drill. A rocking movement of the balancing beam created the percussive impulses on the bit; which sometimes weighed as much as 140kg. By alternately lifting this tool and letting it fall; the Chinese could achieved a well depth of 600m.

The deep drilling for brine yielded natural gas (primarily methane) from time to time. The boreholes producing methane were known to the Chinese as 'fire wells'; thus drilling for natural gas followed and was developed at the same time.

Bamboo tubes were used as pipelines; carrying both brine and natural gas for many miles; sometimes passing under roads and sometimes going overhead on trestles. Among other uses; natural gas was used to heat evaporation pans of brine to make salt. Pictures From History