For almost two decades, Soviet scientists have been trying to penetrate as deep as possible into the Earth's crust. The Kola Peninsula project began in 1970 with the ambition of drilling to reach 15 kilometers. In 1989, the Kola Superdeep Drilling Rig reached 12,262 meters, and the diameter of the hole was only about 23 centimeters.
This remains the deepest vertical human penetration into the Earth's crust. For comparison, if Everest were placed upside down in the drilling, there would be more than three kilometers between its top and the bottom. Scientific publications about the project confirm the depth of 12,262 meters and describe the well as a unique laboratory for studying deep Earth structures.
Water and traces of ancient life
The drilling changed the idea of what the deep layers of the continental crust look like. Large-scale cracks and fluids were found in the rocks, including water at depths where scientists did not expect to find it. Later geological studies also described the deep rocks as fractured and saturated with fluids.
A few kilometers below the surface, microfossils of single-celled organisms, whose age exceeds two billion years, were found. The rocks turned out to be more porous and less dense than expected. The samples from the borehole were later used in studies of ancient mineral systems and fluids.
Temperature stops the descent
The most serious obstacle turned out to be not only the mechanical load, but also the temperature. Calculations show that at a depth of about 12 kilometers it should be approximately 100 degrees Celsius. In reality, a temperature of about 180 degrees was measured.
Under these conditions, the rocks began to behave differently than expected, and the equipment was increasingly stressed. Scientific data on the Kola borehole indicate temperatures of about 180-190 degrees Celsius in the deepest sections, which explains why the work became technically extremely difficult.
The goal of 15 kilometers was never reached. The high temperature, deformation of the rocks and technical problems led to the suspension of work in the early 1990s. However, the data from the well show that the deep continental crust is more complex, more permeable and more dynamic than the models of the time assumed.
Later, the oil industry drilled longer wells, but they were inclined and followed a curve in the earth's layers. The Kola well retains the record for vertical depth, although it is now abandoned. Around it was born the legend of a microphone lowered into the hole, which recorded sounds resembling human screams. Hence the fearsome nickname "the well in hell".
Sources: UNIAN