The Volga-Ural oil and gas province is extremely important for Russia. Geographically, this is a rather large zone, which stretches from the great Volga to the Ural Range. It includes Bashkortostan and covers Tatarstan. VUNGP includes Udmurtia and several regions - under Volgograd, Saratov, Samara, Astrakhan, Perm. VUNGP covers the southern zones of the region at Orenburg. The significance of this province is that natural gas, deposits of which are discovered in the Urals, is still available in very large volumes.
Relevance of the field
Geologists, specialists in the use of natural resources, politicians and public figures agree on one opinion: the oil and gas regions of the Volga-Ural province are incredibly significant and valuable for the country. It is impossible to overestimate how significant local reserves are and their role in the economy and social life of the state. According to experts, throughout the country these deposits are the second most important. Mostly natural gas is found in the center and in the west of the zone. In the region near Orenburg, gas condensate is estimated at 1.8 trillion cubic meters. More than two trillion cubic meters were found in Astrakhan. The position of these deposits is considered quite favorable, since large industrial centers are very close. The Urals and the Volga region are rich in such. All this became the reason for the formation of a large industrial complex VUNGP.
As geologists, geographers have calculated, the Volga-Ural oil and gas province of Russia will total 670,000 sq.m. The first deposits of this area were discovered in 1929. Location area - Ural region, Verkhnechusovskiye Gorodki. After a very short time, in the 32nd, it was possible to discover another source of minerals, this time in Ishimbay. Two years later, they began to develop deposits of Perm deposits, coal. The discovery of deposits took about a decade. In the 44th year, for the first time in history, the region became a source of oil. The first field was discovered at Tuimazy site. This is the Tatar arch, its upper southern part. Over the next couple of decades, the Devonian was primarily the source of "liquid gold." Promneft was discovered in the 29th, in the 40s they began to develop fields. Thanks to this, VUNGP has long been developing as a state oil and gas base. Today it is one of the largest centers for the extraction and processing of natural raw materials.
Important Features
Oil enrichment of most of the VUNGP territory is noted. Initial resources are comprehensively estimated as 74% oil, 20% free gas, and about 5% dissolved. Condensate is estimated at approximately one percent. A study of the tectonics of the Volga-Ural oil and gas province showed the location on the edge of the East European platform. The eastern, northern borders of the zone pass along the folds of the Ural Mountains, Timan. The south of the site is limited by syneclise near the Caspian Sea. The western border is formed by the anteclise named after Voronezh, as well as the vault, which was given the name in honor of Syktyvkar. Here, tectonic features are defined by Tokmovsky, Kotelnichesky vaults.
Studies have shown that the crystalline foundation is located at a depth of one to two kilometers in the area of the so-called Tatar arch. This allows us to evaluate the age as Archean-Early Proterozoic. In other places, the level runs much deeper - up to five kilometers inland. These are exactly the indicators in the Birsk saddle. The study of the section showed halo, terrigenous, carbonate elements. Age is estimated by Riphean-Mesozoic periods.
Sedimentary cover
Studying the lithological section of the Volga-Ural oil and gas province, evaluating the age-related features of the zones, we studied the specific features of the composition of the rocks in different areas. It was established that there are Riphean-Lower Vendian deposits. Such, in their bulk, fill negative relief foundation forms. These are sandy, clay zones. The composition in the main percentage is large debris. Such a zone is characterized by a strong deployment. Some scientists suggest classifying this complex as transitional. Its depth is about 1.5 km.
The Ordovician-Lower Devonian is a sedimentary cover that reaches a depth of 2.9 km. This is the Ordovician, which is characterized by sand, clay. There is a silurium formed by dolomite, limestone. The Lower Devonian, as shown by geological studies of the zone, is red in color, characterized as terrigenous. Such a cover is especially strongly developed along the edges of the considered zone.
Exploring the natural conditions of the Volga-Ural oil and gas province, scientists have identified a cover, which was called the Middle Devonian Triassic. It is created by carbonates, belongs to the category of terrigenous. It has the weakest dislocation. Depth varies between three kilometers to a kilometer more. Such a cover is more common than others.
Sedimentary cover: more details
VUNGP is characterized by Kungur salts. These are characteristic of the upper Permian block. Local inclusions of the clay and sand complex, characterized as Mesozoic-Cenozoic, are revealed. By their structural features, such zones stand out quite strongly against the Paleozoic.
The sedimentary cover of the considered zone is distinguished by pronounced division. There are arches, deflections are present, cavities are found. To some extent, they reflect the fundamental structural plan, but only partially.
Structural elements
The geological structure of the Volga-Ural oil and gas province has been an object of research for scientists for more than a decade. It has been established that the key features of the platform cover are the arches to which the bulk of the zone belongs. These are arches in the eastern part of the region near Orenburg, arches named after Kama and Tatarstan, Perm and Bashkiria. The arches are no less important for research: Sol-Iletsky, Zhigulevsk-Pugachevsky. It is not difficult to identify them in the Carboniferous horizon, in the Devonian. The study of Perm shows that the arches become much more gentle. They are separated from each other by large depressions. Mostly such are inherited. Modern geologists call the large basins of the Buzuluks, Melekess, Verkhnekamsk. In addition to these three, there are several cavities smaller in size. The most significant is Visim. In some areas, the arches are separated by saddles. Three main ones - named after Birsk, as well as Saraylinskaya, Sokskaya.
The study of the tectonic structure of the Volga-Ural oil and gas province, specific geological features, structure and forms showed that many arches have several peaks at the same time. They are characterized by the presence of protrusions, shafts. A complicated structure due to elevation is possible. The most significant arch is Tatar. Its perimeter is estimated as 600 * 250 km. Here are several peaks that are noticeable in the sediment cover. For example, the Romashkinskoye field is located near the peak, which was given the name Almetyevskaya. Two other important peaks of the arch are Kukmorskaya, Belebeyevsko-Shkapovskaya.
About the vaults in more detail
The characteristics of the Volga-Ural oil and gas province must pay attention to the Perm arch. Its approximate parameters are 200 * 90 km. The amplitude reaches hundreds of meters. It is characterized by prostrations, the shape of the box, the slope. The Kosvinsko-Chusovskaya saddle, which is located on this arch, is divided by a cliff with the deflection of the Forward Urals.
The Bashkir arch is characterized by dimensions of the order of 170 * 130 km. It extends to the northwest. A distinctive characteristic is the pronounced asymmetry of the structure. The top of this vault is somewhat shifted towards the southeast. A typical feature is local uplifts. Their nuclei are formed by biological hermes (geologists have established: Famennian). Such herms form isometric domes.
The Sol-Iletsky arch is another element that must be described when they give a characterization of the Volga-Ural oil and gas province. Its dimensions reach 150 km in length and about 90 km in width. The amplitude exceeds half a kilometer. A distinctive feature of the arch is a triangular shape. The structure of this element of the province is horstiform. A complication was revealed in the center - a shaft named after Orenburg. It is characterized by supravlacogenic structure.
Zhigulevsko-Pugachevsky in length reaches 350 km. The width of this arch is estimated at 200 km. The inherent amplitude of the zone is about 400 m. This is a clearly asymmetric section. The linear dislocation Vyatka system passes along the foundation surface and the Dokyn layers. Geologists called this site the Kazan-Kazhim aulacogen. Where the zone is relatively young, the Vyatka Val System stands out.
About area items
The Volga-Ural oil and gas province includes the Buzuluk depression. Its dimensions are measured by geologists and are 260 * 240 km. This zone includes two arches and one ledge. A distinctive feature is the complicated internal structure of the cavity. There are descent zones, there are elevated areas, shafts are revealed. From the south aboard the geological formation developed linear systems. They were identified near the compound with syneclise in the Caspian Sea. Organogenic buildings. Their age is rated as average Devon. Such systems are associated with uplifts found on microscopic grabens (on their sides). These blocks, according to scientists, appeared before the Devonian.
Another major depression, which is present in the Volga-Ural oil and gas province, is called Verkhnekamsk. Its dimensions are estimated at 350 * 150 km. The characteristic zone extends to the northwest. The hollow is adjacent to several arches, the borders pass along the slopes. The eastern part is limestone layers dated to the Middle Devonian. Of these, reef formations appeared. Height reaches 60 m.
The Melekess depression is another large formation of the area under consideration. Dimensions are 280 * 140 km. Sokskaya saddle separates this section and the depression called Buzulukskaya. In the southwestern part, a gradual transition to the deflection can be seen. Its name is in honor of Stavropol. The depression is characterized by the presence of a number of zones in the form of shafts.
Not everything is so clear
The Volga-Ural oil and gas province is characterized by the presence of relatively small elements that provide structural individuality. Deflections are established that do not have compensating elements, as well as complexes of micro-grabens. A specific feature has been revealed - structural plans do not correspond to those formations that are higher. The most typical example is the uncompensated deflection system, called Kamsko-Kinelskaya. She appeared in the Late Devonian or Early Carboniferous. The length reaches thousands of kilometers. The system begins at the Buzuluk depression, extends towards the Vychegodsky trough. Geologists believe that this system is revealed in the southern regions into the depression at the Caspian Sea. In total, the site is formed by 12 deflections of small width. All of them do not have compensation elements. Length - up to 250 km. Depth in some areas reaches 400 m. Formations mainly from silicon, clay, carbonates. They are characterized as bituminous. The terrigenous deposits that overlap them have practically no areas reflecting the described system of deflections.
Oil and gas
The Volga-Ural oil and gas province is so valuable for the state, since it is rich in natural resources - this follows from the name of the zone. Today, about two thousand deposits are known. Currently 115 serve as sources of gas and condensate, another 650 are designed to produce "black gold". A general pattern has been established that indicates the uneven distribution of hydrocarbon accumulations in the crust of the planet. Mostly reserves are located in a few particularly important deposits. A smaller part is accounted for by small deposits. Among the richest and largest is the previously mentioned Romashkinskoye. No less significant for the country and people are those that received the names: Tuymazinsky, Mukhanovsky. The site that received the name in honor of Orenburg is very important. The deposits of the Volga-Ural oil and gas province, classified as rich and large, are those that are known to modern man as Korobkovskoye, Arlan, Kuleshovskoye. Many valuable natural gifts are obtained from the sites of Shkapovskoye and Bavlinskoye.
As specific studies have shown, the fields of the Volga-Ural oil and gas province are mainly distributed in the Vendian-Jura area. Resources are concentrated in the Paleozoic. The largest reserves are in carbon, Devon. The enrichment of the Permian era is somewhat less. Certain sources are identified in the Riphean elements characteristic of the depression of the upper part of the Kama. According to geologists, this may signal the prospects of the lower part of the section - probably productive.
Complexes
Geologists, analyzing the core of the production of the Volga-Ural oil and gas province, determined that there are about seven dozen formations that are productive for development. It was decided to single out nine key complexes from them. The first was called Riphean-Vendian. It reaches a kilometer, characterized by local prevalence. Oil deposits have been identified in the hollow of the top of the Kama. It is believed that in the general reserves the significance of this block is relatively small, but so far it has not been studied enough and is considered promising.
Modern production methods in the Volga-Ural oil and gas province are mainly implemented in the first key oil and gas complex. It is characterized as middle, upper Devonian, terrigenous in its main part. The thickness varies from 30 m to 530 m. The most promising is the development of sandstone formations, between which there are mudstones. This zone is called the Middle Devonian-Nizhnefran, it is called the terrigenous Devonian. Oil sources are identified in different parts of the territory. According to geologists, of the initial total resources, this block accounts for 41% of oil. It is here that the largest deposits are located - Romashkinskoye and neighboring ones. In particular, Shkapovskoye and Tuymazinskoye deposits are located on this site.
About sources in more detail
Verkhnefransko-Turneysky - this is such a block VUNGP, which is mainly reef, formed by carbonates. Its thickness varies between 275-1850 m. A specific feature is the widespread prevalence. The deposits in its bulk are “black gold”. Deposits were found in areas associated with powerful arches. There are quite large deposits. Among them, Kudinovskoe and Mukhanovskoe deserve special attention.
The second key OGC is the lower and middle Visean terrigenous, whose highest thickness is estimated to be higher than 0.4 km. As established by geologists, mainly sandstones and siltstones act as reservoirs. The horizon with mudstones, clay is the cover of the region. About 21% of gas resources, about 27% of oil resources are associated with this zone. The largest sources of natural wealth are the Arlan and Nurlat deposits.
Important Features
A key specific feature of VUNGP is a large group of oil sources on arches. Gas is mainly observed in the east, south of the zone. About 75% of all its reserves are in the deposit relatively close to Orenburg. Since the fourth decade of the last century, 23 of the most powerful deposits have been actively developed. Efficiency level is estimated as exceeding average. In recent years, it has been possible from time to time to identify new deposits, often insignificant, but sometimes medium.