A Tale of Deepest Hole on the Earth


There have been so many instances where U.S. and Russia stood head to head, be it space exploration, dominance in the oil and gas market, control over the Middle East and the list goes on. There was another race not many people know about. It was the race to reach the earth’s mantle. And the deepest man-made hole- Kola Superdeep Borehole – is the result. Till today, it is the deepest artificial point on the earth.

A Brief about the Earth

The adjoining picture gives us a brief about the Earth’s structure. Do you see the thinnest part ‘Crust’? Yeah, that’s where we all live. All the pandemics, businesses, wars, economy, ecology, nature, technology exist on that 0-100km thick part of the earth. Also, the earth is not a sphere (whether you like it or not), it is an irregularly shaped ellipsoid. So, the thickness of the crust varies at different points on the earth. This also means that temperature and pressure conditions would be varying accordingly.

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Kola Superdeep Borehole

Location – Kola, Peninsula, Russia (click here to see on maps)
Vertical depth- 40,230 ft. (12.2 km)
Year – Drilling commenced in 1971 and terminated in 1992.

The Kola superdeep borehole site is located at Murmansk, Russia not far from the Finland border. It is now well enclosed and welded shut, but the local claim that they have heard voices from the hell. No wonder the locals call it the well to hell.

The Kola Superdeep Borehole was the Soviet Union’s attempt to explore the depths of the Earth’s crust in the 1970s. The drilling was commenced in the 1970s with ambitious goals. But due to unpredicted temperature conditions at the depth of around 12262 km, the drilling was terminated in 1992. It followed a decade of other nations, like the U.S. attempting similar projects to understand the very nature of the Earth better.

Work began on the Kola Peninsula, NW Russia, in 1971. By 1979 the project had broken all other world records for drilling depth by beating that held by the Bertha Rogers Hole in Oklahoma, the U.S. at 9,583 meters.

But they kept going. By 1983 the drill had reached an unbelievable depth of 12km. Unsurprisingly, Soviet engineers were jubilant and apparently decided to take a year off.

During the break, the scientists and politicians from around the world made visits to the site. But the site’s equipment was left to basically rot during the hiatus.

Drilling began the following year but a 5km section of the drill string completely sheared off. After failed attempts to recover it was finally abandoned, the project started a new drilling project a 7km depth down the existing hole.

It took the team another 5 years, in 1989, to reach their previous 12km mark but drilling was later ceased due to some serious technical challenges. Temperatures at the drill head were in excess of 180 degrees Celsius which, at that time, were too technically challenging to overcome. Also, the cost of continuing was rising day-by-day. Whilst the team had expected to reach 13.5 km by 1990, and 15 km by 1993, they were forced to stop operations in 1992.

Why the superdeep hole was drilled?

The reason behind drilling this borehole was purely scientific. The Soviet scientist wanted to learn more about the development of the earth’s crust. Though science was the apparent goal, everyone wanted immodest rights for winning the race to the center of the Earth.

A similar project was undertaken by the Americans. The Project Mohole site is located in the Pacific Ocean off the coast of Mexico. The aim of the project was to reach the upper boundary of the mantle. Later, the project was discontinued due to lack of funds.

It is worth noting that German (Location- Bavaria, depth- 6 miles) and Japanese (depth – 2 miles offshore) scientists also handled similar ventures at different locations but could not reach as deep as the Soviets.

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Kola Superdeep borehole’s record was broken by an oil well drilled at Al Shaheen Oil Field in Qatar in 2008. The drillers managed to reach 12,289 meters.

The Sakhalin-I Odoptu OP-11 well (an offshore field from the Russian island of Sakhalin) also managed to beat both records in 2011. The drill team was able to reach a remarkable 12,376 meters.

But, do not let the numbers fool you. The Kola Superdeep Borehole still remains the deepest manmade hole in terms of true vertical depth (TVD).

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