The most popular and memorable image that appears in all the movies about the extraction of "black gold" is the fountain gushing from the well under pressure. But few people know that in Russia there is only one field where oil is extracted in underground mines and can only be obtained by one method - preheating.
Not far from Ukhta in the Komi Republic 90 years ago the Yaregskoye field was discovered - one of the world's largest deposits of high-viscosity oil. The discoverers were geologists, serving time in one of the divisions of the GULAG on the case of a spy-sabotage organization in the oil industry of the USSR.
I must say that specialists were selected for the development of remote regions while still in custody. The former head of the Commission on Mineral Reserves at the Geolkom, Nikolai Tikhonovich, was asked only one question: "What is Ukhta?" and after his answer was offered to head the geological part of the Ukhta Exploration Expedition. That is, the project was drawn up in a cell of the Butyr prison. There was no such thing in world practice when an expedition was sent not by a departmental institute or the Academy of Sciences, but by punitive bodies - the OGPU NKVD.
The GOSPLAN commission, which arrived in Ukhta after the field discovery, stated that the new oil-bearing areas were of industrial importance beyond the regional level. However, there was one significant problem...
During the whole year of 1933, only 673 tons of quartz sandstones were produced. The rocks risen during drilling showed that there was oil, and further geophysical methods of exploration proved that the reserves were simply huge - the field was 36 km long and had a width of 4-6 km and layer height up to 87 m. But the miners could not achieve impressive results.
The thickness and density of heavy oil under conditions of low reservoir pressure reduced practically to zero all chances to extract it by traditional method. Viscosity is the most important technological property that determines the mobility of hydrocarbons in formation conditions for production or transportation. In Yarega's case, the viscosity was thousands of times higher than average - it looked more like a paste than an oily liquid. This meant that no fountain could be expected, much less from a depth of 165-200 m. It got to the point that they were ready to forget about hundreds of millions of tons of oil - the field was threatened with closure.
And then, literally at the last moment, geologists suggested trying to open the reservoir by mine. All the circumstances were to their advantage - shallow bedding, low pressure and absence of associated gas. It took almost 5 years to develop the idea and implement it. In Russia until then, no one had developed the hydrocarbons in this way. Around the world, such experience was insignificant - only a couple of examples in Germany, France and the United States.
Initially, the Ukhta and slope-well systems of extraction were used at Yarega. In the first case, mine workings were created in the overburden rocks, from which vertical and inclined wells were drilled directly into the productive formation. The oil flowed into the grooves of the workings, together with water entered the underground trap, and from there to the oil reservoir on the surface. The inclined-well method implied drilling of wells from the workings drilled directly in the reservoir.
During the Great Patriotic War the first oil mine in the USSR produced more than 70% of all the oil produced in Komi. However, despite continuous improvement of the technology, the production remained high-cost and the oil recovery was low (not more than 6%). The relevant ministry again started talking about shutting down the enterprise.
And then, in 1972, mining engineers again proposed a method that radically changed the extraction technology and provided a sharp increase in oil recovery. Specialists from Yarega, Ukhta, St. Petersburg and Moscow developed and implemented on an industrial scale a fundamentally new system of field operation - the "Thermal Shaft Method of Oil Production". Steam was pumped into the reservoir at a temperature of up to 200 degrees: oil viscosity decreased and it was much easier to "rise" the heated oil to the surface. Thermal impact methods were already available all over the world, when steam was pumped into the deposit from the surface. But near Ukhta, for the first time this method was applied in the conditions of underground mines. The technology made it possible to extract not 2-6% of the deposit, as with previous methods, but more than half of the reserves.
Yaregskoye oil has become the main raw material in the production of fuel for ultra-low temperatures, on which Arctic ships operate, as well as in the production of products for pharmaceuticals, the space industry, and road construction. For example, heavy oil and natural bitumen are used to make asphalt. According to the regulations it will last 10 years. In many countries bitumen is made from liquid oil, and such asphalt serves for about 3 years.
Samples of heavy oil and saturated rocks from the unique field since its discovery were regularly delivered to St. Petersburg, where they were examined by scientists.
Today the Mining Museum exhibits almost all the reservoirs accumulating "black gold": sandstone and sandstone-gravelite from the 1953 collection; asphalt, sandstones with hard bitumen and sandstones with oil from the 1973 collection, as well as the most recent version - viscous oil, produced in 2010.
LUKOIL has been developing the field since 2003, producing about 1.6 million tons per year. Residual reserves amount to 215 million tons, including recoverable reserves of 91 million tons. According to analysts' estimates, there will be enough hydrocarbons there at least till 2059. Not a bad result for a Gulag side experiment...
