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beneath the big salt pans. The introduction of natural gas and its
coexistence with brine pushed Zigong’s salt production into the
industrial scale.
Once wells were drilled down to 2,297 to 2,625 ft (700 to
800 m), they could produce both brine and gas. Annual salt
production in Zigong in the 1850s was about 150,000 tons. The
Chinese population was about 450 million at that time. The salt
industry was a huge economic driver, and many large cities in
Sichuan were established and flourished,because of the lucrative
salt trade.
A key technological advance was the introduction of the
“Kang Pen” drum at the end of the 18th century. This drum sat on
top of the wellhead, and the pressure within the drum was
controlled such that gas and brine could be produced
simultaneously, and efficiently separated. One bamboo pipeline
would take away the brine and others the gas.
The 2,000 year-old Sichuan salt industry has drilled
approximately 130,000 brine and gas wells, with 10% of those in
the immediate Zigong area. Zigong has a cumulative gas
production over this period of over 1.06 Tcf. The area continues to
be a major salt producer, and many of the historical wells are still
in production.
A decade before the birth of the petroleum industry, Samuel
Kier of Pittsburgh, Pennsylvania, sold 50-cent, half-pint bottles of
Pennsylvania “ Oil” proclaiming its “Wonderful Medical Virtues.”
When a Yale chemist, Benjamin Silliman, found that oil
could be distilled into a kerosene illuminant, the world changed
forever. Inspired entrepreneurs formed the Pennsylvania Oil
Company with the idea of using cable tool drilling to extract oil. It
worked, and the petroleum age was born.
Rotary drilling is most often associated with the spectacular
1901 Spindletop Hill discovery near Beaumont, Texas. Instead of
the repetitive lift and drop of heavy cable-tool bits, rotary drilling
introduced the hollow drill stem that enabled broken rock debris to

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