The Kola Superdeep Borehole is a landmark scientific drilling project from the Soviet era. It is located 10 kilometers west of the city of Zapolyarny in Russia’s Murmansk Oblast, on the Kola Peninsula, near the border between Russia and Norway. This project set a world record for deep drilling at the time, with its deepest well reaching 12,262 meters, holding the title of the world’s deepest well for a long time.
The Kola Superdeep Borehole began drilling in 1970, during the Cold War, and the project was seen as a special manifestation of the technological competition between the United States and the Soviet Union. In the early stages of drilling, the process from the surface to a depth of 7,000 meters was relatively smooth. However, when the drill bit entered the more fragile rock formations, problems ensued. Frequent rock collapses occurred, and broken rocks often got stuck in the drill bit and drill pipe, causing the drill bit to drop multiple times.
The drilling team at that time faced two severe challenges. Firstly, there was the issue of drill pipe weight. Despite using lightweight aluminum alloy materials, the total weight of the 10-kilometer-long drill pipe plus the drill bit still reached 200 tons. Due to the relatively thin drill pipe and limited strength, the friction between the drill pipe and the surrounding rocks during drilling made it overwhelmed, leading to multiple fractures.
Secondly, there was the temperature problem. For every 100 meters the drill bit drilled down, the temperature rose by 3°C. When drilling to a depth of 10 kilometers, the temperature reached 300 degrees Celsius. The drill bit and the part of the drill pipe close to the drill bit could not withstand such high temperatures, easily deforming or even breaking off directly. To overcome these difficulties, the Soviet Union continued to invest a lot of manpower and material resources in the following decade, with the number of staff at the Kola well reaching as many as 300 at its peak.
With significant investment, the drilling work made continuous progress. In 1983, the drilling depth exceeded 12,066 meters, surpassing the Mariana Trench’s depth of 11,034 meters. However, due to the limitations of technical conditions at that time, further drilling became extremely difficult. By 1989, the drilling depth only reached 12,262 meters.
When the drilling depth reached 9.5 kilometers, the drill bit entered a stratum containing gold and diamonds. Analysis of the extracted core samples showed that the gold content was as high as 80 grams per ton. It is worth noting that a gold ore layer with a gold content of 4 grams per ton is usually considered commercially exploitable. This shows that the gold reserves in this stratum are extremely rich, deserving the title of a gold treasure.
Regarding the reason for the suspension of the Kola Superdeep Borehole project, there is a claim that it was due to insufficient funds, but some internal staff revealed that it was because some phenomena that cannot be explained by current science were encountered during the drilling process.
The Kola Superdeep Borehole held the record for the world’s deepest well for 20 years. However, this record was broken by Qatar’s Al Shaheen Oil Well (12,289 meters) in 2008 and then by Russia’s Odoptu OP-11 Well (12,345 meters) on Sakhalin Island in 2011. As of 2016, the Kola Superdeep Borehole ranked third among the world’s deepest wells.
The drilling history of the Kola Superdeep Borehole not only demonstrates humanity’s determination and courage to explore the depths of the Earth but also provides valuable data for geological scientific research. It also shows the challenges and opportunities faced in the development of deep drilling technology. The problems encountered in the drilling at that time, such as drill pipe load-bearing and high-temperature resistance, have now become important directions for drilling equipment research and development.
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