The use of natural gas

"Natural gas", also commonly known as "gas", is an indispensable fuel in human life. Gas is used in our daily life in cooking, heating, transportation, the manufacture of nitrogen fertilizer, and even electricity generation. Gas has created convenience in our lives. Between 6000 BC and 2000 BC in what is today Iran, people first discovered the leakage of "natural gas". However, the first use of "natural gas" as an energy source occurred in China. The early exploitation of natural gas was connected with early salt collection.

Salt has been mined or produced in China for about 5,000 to 6,000 years, and the time when "natural gas" was first used by the Chinese can be traced back more than 2,200 years. According to the records in the Chinese historical document “Huayang Guozhi·Shu Zhi” 《華陽國志·蜀志》 (Chronicles of Huayang), which is also the oldest extant gazetteer in China, written by the historian Qu Chang 常璩 (ca.291-361 CE) of the Eastern Jin Dynasty, at the end of the Warring States period, King Xiaowen of Qin 秦孝文王(302-250 BC) sent Bing Li 李冰, a hydraulic engineering expert, to the area of present day Chengdu, Sichuan (Guangdu as it was named in those years) to build a water conservancy project (the Dujiangyan 都江堰 project). During the water control construction, he accidentally discovered a salt spring that flowed naturally. This opened an opportunity to begin the excavation of salt wells. This is the earliest record of salt wells, dating from 255 BC. Salt was originally a very important staple asset in ancient China. A large part of the governments’ tax revenue came from the salt tax. Therefore, the discovery of brine was like the discovery of a gold mine. While excavating the salt well and digging under the ground, salt miners discovered another important natural resource-natural gas.

Yingxing Song 宋應星(1587-1666), a late Ming Dynasty scientist wrote about salt and natural gas in his book “Tiangong Kaiwu· Salt Well《天工開物·井鹽》（The Exploitation of the Works of Nature: Salt Well）” Song reported: “There are fire wells in Xichuan, which are very peculiar. The well water is cold and without hot heat at all.” This paragraph describes the reality of fire wells in the western part of Sichuan and contradicts people’s imagination, because “fire wells” seem like they should be very hot. The "fire well" that is mentioned here is the natural gas well as we know it today. The water through which the natural gas bubbled was not heated by the gas, because the gas was not hot. The gas only became fire after emerging from the water and brine and getting ignited.

To draw the "natural gas" from a well requires some knowledge of how to utilize specialized tools. Taking advantage of bamboo, abundant in Sichuan, and its characteristic flexibility and shape, bamboo became the best tool for the earliest pipelines. Bamboo is hollow in its trunk. There are diaphragms in internodes. Thus, by splitting the bamboo in half and removing the diaphragms, then putting the two halves together again and wrapping the seams tightly with varnished cloth, the result was a long open tube. The flexibility of bamboo allowed salt miners to insert one end of the bamboo pipes into the well, to draw the gas up, and connect other ends of the bamboo to the stove where miners could cook the brine to evaporate the liquid and leave the salt crystals. After being ignited, the gas turned into a powerful flame and allowed swift boiling of the brine. “Chronicles of Huayang” also mentioned "If you use a well fire to boil 20 liters of brine, you will get about ten liters of salt; if you use firewood which is commonly used for cooking at home to decoct brine, then you won't get much salt." The "well fire" is what we know today as a natural gas well. The local salt industry in Sichuan flourished, and the emergence of natural gas contributed to it. Certainly the natural gas from the fire well was not only used as a fuel for salt production. It could also be used as a torch for illuminating an area at night, allowing common people to see around them.

"The use of natural gas" was unveiled in China more than 2,000 years ago and other countries, such as the United Kingdom in 1659 and the United States in 1821, have successively developed the energy of natural gas. Although natural gas brings convenience to life, we know that natural gas is a fossil fuel, when it is completely burned it will produce carbon dioxide, and leaks will create plumes of methane. Excessive concentrations released into the air will cause the greenhouse effect and affect the earth’s climate. Therefore, when we use any of Earth’s natural resources, we should consider environmental factors, and appropriately use and protect natural resources.

Links about the use of natural gas:

1. At the 2007 world conference of the International Federation for the Promotion of Mechanism and Machine Science, B. Kopey presented this paper on drilling technology (pdf), and claims in it (citing a paper by W. D. Moor) that the Chinese knew how to drill wells by 1000 BC.
2. 2. Mike Bradner's 2004 article from Alaska Business Monthly describes the history of drilling and includes a description of Chinese drilling.
3. An article from 1999 by Lothar von Falkenhausen describes some of the ancient salt mining areas of China.
4. Paul Noll's very interesting photographs of a 1987 visit to the Zigong Salt Museum in China, where Chinese drilling technologies related to salt and natural gas mining were displayed.
5. A Chinese language web article by the Salt Association mentions (very briefly) some facts about oil wells, but mainly describes old Chinese drilling technologies.