The time of light oil is drawing to a close, and substandard hydrocarbons, including sulphurous oil and bituminous rocks, have earned more attention. The total world reserves of heavy oil and bitumen amount to 790-900 billion tons, which is almost twice as much as light oil. In Russia, they make up from 10 to 35 billion tons, and 14% of them are in the Komi Republic.
The republic’s oil is concentrated mainly in the Devonian sediments, and one fifth of it belongs to the Yarega field. On Russian territory, this is one of the oldest heavy oil deposits, whose production is carried out both underground and surface methods.
Characteristics of the Yaregskoye field
Yarega oil was discovered in the Ukhta region of the Komi Republic on the northeastern slope of South Timan, not far from its transition to the Pechora depression.
The area is represented by a gently sloping swampy plain, lowering to the northeast. Its relief was formed as a result of water-glacial and mountain destructive processes, as evidenced by some elements inherited from ancient tectonic structures. The oil reservoir of the stratum-vault type is hidden at a depth of 140-200 m and is contained in sandstones of the Middle and Upper Devonian. The raw material of the field is represented by heavy oil, which has almost no paraffins. But it has an increased resin content and significant viscosity.
The Yaregskoye field is confined to the Vezhavozhskaya, Lyaelskaya and Yaregskaya structures, in which the oil content is a single circuit, and the total area is 127 square meters. kilometers. Total reserves are estimated at approximately 132 million tons of oil.
Discovery of the field
The first mention of the oil-bearing object dates back to 1890, when the expedition of F.N. Chernyshev worked on Timan, exploring the rivers of its southern and northern parts. In 1907, a group of geologists, led by P. Polev, conducted research on sites in the Yarega and Slight rivers, but their research did not lead to any serious results. In 1931, oilman I.N. Strizhov proposed resuming exploration work in the 1907 well region. He outlined his line for the construction of subsequent exploratory wells and moved according to it. In the spring of 1932, well No. 57 produced the first oil. A little later, another 2 tons of viscous thick oil was produced from well No. 62 on the Strizhov line. Drilling of the remaining wells confirmed the presence of heavy oil with high density.
The main stages of development
The history of the development of the Yarega oil field is conventionally divided into several important stages. At first, there were attempts to exploit it with wells from the surface, but this method did not allow to achieve significant indicators. From 1939 to 1954 began to develop mine fields according to the "Ukhta system". The essence of the work was that from a supra-layer horizon, located 20-30 meters above the roof, a formation was drilled along a grid of wells. Development was carried out in the natural mode of dissolved gas.
Development of the deviation-well system was carried out in 1954-1974. Its essence was that from a mine in the roof, the formation was drilled by gently sloping wells. This system made it possible to reduce the volume of penetration by several times, but oil recovery was as in the case of Ukhta - 5.9%. Practice has shown that the productivity of mine development in the natural mode is small, but at the same time it is several times greater than the results of development by wells from the surface. During the period of field development, mine development using two systems produced a total of 7.4 million tons of oil.
In 1968–1971, research began at the Yaregskoye field, in which some systems of steam-thermal influence on the formation were tested. Researches led to the creation of a thermal mine development method, which already in 1972 began to be used on an industrial scale, showing high technological efficiency.
Currently, deposits like Yaregsky are operated by single-horizon, two-horizon and underground-surface thermal mine systems.
Lyaelskaya Square
On the Lyaelskaya area of the Yaregsky deposit from 1973 to 1990 surface development work was carried out with the application of steam and thermal effects on the oil reservoir. From the outer surface, 90 vertical wells were drilled through a five-point system. The extraction of raw materials was carried out by means of a steam cycle effect on the formation and the displacement mode. The indicators of this development were significantly inferior to the results of thermal mine development.
In 2013, steam gravity drainage (TPGD) technology was first used on Liael Square. The basis of this technology is the thermal effect on the working formation by oncoming horizontal directional drilling: the steam saturated with the formation is heated, its fluidity increases to normal mobility and is pumped to the surface.
It is interesting to note that the TPGD technology was developed in Canada and remained unchanged for a long time, while domestic experts did not modernize it, using in practice counter-long drilling from different sites.
Not only oil
A feature of the Yarenga deposit is that, in addition to oil reserves, it also has huge reserves of titanium ore. Half of Russian titanium is concentrated here (about 49%). The deposit was considered to be oil until 1941, when the geologist V.A. Kalyuzhny, a prisoner from Ukhtizhemlag, discovered ore concentrations of leucoxene in sand oil reservoirs. A more detailed study of the titanium placer began to be carried out only in 1958.
Yareg ore is characterized by a peculiar mineral composition, in which leucoxene is the main industrial mineral. The uniqueness of titanium deposits lies in the genetic and spatial conjugation with heavy oil deposits. The contours of their industrial stocks partially overlap. The study of the Yarega titanium deposit proved the universality of silicon-titanium concentrates for the production of white inorganic and colored titanium pigments.
Field prospects
In January 2018, the construction of steam generating units at the Yaregskoye oil and titanium field was completed, which allows to increase oil production by 73%. The powerful complex is designed to produce steam of about 400 tons per hour, which is supplied to production wells. By the next stage of development, it is planned to reach production already in the range of 3.5 million tons per year.
Yareg not only expects an increase in oil production, in the near future its mines will have a significant functional expansion. LUKOIL-Komi, having a license to develop a titanium deposit, intends to mine annually up to 25 thousand tons of titanium ore, which will be processed locally.