Oil fields. Main oil fields

Russian Federation is rightfully considered one of the world's leading oil exporters.

About 505,000,000 tons of “black gold” are mined in the country every year.

Today, the volume of proven natural oil reserves being developed has brought Russia to 7th place in the world.

The main deposits are Samatlorskoye, Romashkinskoye, Priobskoye, Lyantorskoye, Fedorovskoye, Mamontovskoye.

Samotlorskoe

The largest oil field in Russia is in 6th place in the world list. For a long time its location was considered a state secret.

At this time, this information is no longer classified. Developments on it have been going on for more than 45 years, its use will last until the end of the 21st century.

Explored in 1965. The expedition was led by V.A. Abazarov.
Start of operation: 1969
Location: Nizhnevartovsk district of Khanty-Mansky Autonomous Okrug.
Geological reserves: about 7,100,000,000 tons.
Recoverable reserves: about 2,700,000,000 tons.
Extraction method: drilling rigs on artificially created islands, cluster drilling.

Over the years of operation, more than 2,300,000,000 tons of hydrocarbons were produced. Currently, work is being carried out at the field to intensify production. It is planned to build more than 570 new wells. The main part of the development belongs to NK Rosneft.

Romashkinskoe

Belongs to the Volga-Ural oil and gas basin. It is strategically important for the country. For several decades in a row, it has served as a kind of “testing ground” for testing new oil production technologies.

Opened in 1948 by the team of S. Kuzmin and R. Khalikov.
Start of operation: 1952
Location: Leninogorsk district, Almetyevsk, Tatarstan.
Geological reserves: about 5,000,000,000 tons.
Recoverable reserves: about 3,000,000,000 tons.
Production method: intra-circuit flooding method, drilling with a turbodrill on water.

More than 2,200,000,000 tons of oil have already been extracted from the depths of the field. As of 2010, the volume of proven reserves is 320,900,000 tons. Development is carried out by Tatneft.

Priobskoe

Multilayer low-productivity field. It has great potential, but its implementation requires significant financial investments. Development is complicated by the swampy nature of the area, flooding, and the proximity of fish spawning areas.

Explored in 1982.
Start of operation: 1988.
Location: Khanty-Mansi Autonomous Okrug, Khanty-Mansiysk.
Geological reserves: 5,000,000,000 tons.
Recoverable reserves: 2,400,000,000 tons.
Extraction method: hydraulic fracturing technology, water drilling.

The field belongs to the West Siberian oil and gas basin. More than 80% of it is located in the floodplain of the Ob River. About 1,350,000,000 tons of hydrocarbons have already been extracted. The development is carried out by Rosneft and Gazprom Neft.

Lyantorskoye

It is considered one of the most difficult Russian fields to develop. Belongs to the West Siberian oil and gas province.

Explored in 1965.
Start of operation: 1978.
Location: Khanty-Mansi Autonomous Okrug, Surgut district, Lyantor.
Recoverable reserves: 380,000,000 tons.
Production method: nine-point inverted development system, flowing method of well operation.

The main operator of the field is OJSC Surgutneftegaz.

Fedorovskoe

Belongs to the Surgut arch, southeastern part of the Chernorechensky uplift. Included in the class of giant deposits.

Opening: 1971.
Start of operation: 1971
Location: Khanty-Mansi Autonomous Okrug, Surgut.
Geological reserves: 2,000,000,000 tons.
Recoverable reserves: 189,900,000 tons.
Production method: horizontal drilling, hydraulic fracturing, physical and chemical method of processing the bottomhole zone, etc.

It is the basis of the resource base of Surgutneftegaz. Since its commissioning, more than 571,000,000 tons of oil have been produced at the field.

Mamontovskoe

Belongs to the large class. Hydrocarbon deposits are located at a depth of approximately 2 – 2.5 km.

Explored in 1965. The leader of the expedition is I.G. Shapovalov.
Start of operation: 1970.
Location: Khanty-Mansi Autonomous Okrug, Pyt-Yakh.
Geological reserves: 1,400,000,000 tons.
Recoverable reserves: 93,400,000 tons.

The deposit's geological structure is complex. Since the start of operation, 561,000,000 tons of oil have been pumped out. Development is currently being carried out by Rosneft.

A large number of oil is spilled during its transportation, read the link which ecological problems arise in this regard near the Sea of Azov

Exploration continues

There are promising places in our country where production can reach large volumes.

The Velikoye deposit was discovered in 2013. According to initial estimates, its geological oil reserves are close to 300,000,000 tons. There is no exact information yet about what part of this volume of hydrocarbons is recoverable.

Velikoye is one of the largest oil fields discovered on land in recent decades. The AFB company received a license for its development. It will probably attract other operators as partners.

In 2015, it is planned to begin the development of the Bazhenov formation - this is the most large in Russia. It is very difficult to extract oil from shale; this requires the use of export equipment. But plans may change due to sanctions imposed on the Russian Federation.

In 2014, a new field called “Pobeda” was discovered in the Kara Sea - 100,000,000 tons.

Traditionally, Oilman's Day (Day of Workers in the Oil, Gas and Fuel Industry) is celebrated in September. In the Russian Federation, this day is celebrated, as in Soviet times - the first Sunday of September, in Ukraine, the holiday was moved to the second Sunday of September.

Oil is an oily, flammable natural liquid consisting of a complex mixture of hydrocarbons and some organic compounds. There is still no clear opinion of the scientific world about the origin of oil, although the main hypothesis is considered to be burial organic matter sedimentary rocks with subsequent complex transformation.

Oil is one of the main minerals on the planet, however, its reserves are not evenly distributed. And they are used differently by their states. For example, Russia, being in 7th place in the world in terms of oil reserves of 77 billion barrels, produces as much oil (505 million tons) as the USA (294 million tons) and Canada (173.4 million tons) produce. and Kazakhstan (70 million tons) combined (2010).

Oil reserves at the largest oil fields exceed 10 billion tons. Next Top 10 largest oil fields.

1 Chicontepec oil field 22.1 billion tons (Mexico)

Super-giant oil and gas field in Mexico, located in east coast Mexico. Opened in 1926.
Operator: Pemex

2 Al-Ghawar oil field 20 billion tons (Saudi Arabia)

The largest giant oil and gas field in terms of reserves in Saudi Arabia. One of the largest oil and gas fields in the world, located in the Persian Gulf basin.
Operator: Saudi Aramco

3 Greater Burgan Oil Field 13 billion tons (Kuwait)

The largest giant field, which contained more than 5% of the proven recoverable oil reserves in the world until 2004
Operator: Kuwait Petroleum Corp

4 Carioca Sugar Loaf oil field 11 billion tons (Brazil)

Group of Large Oil and Gas Fields in Brazil. Located in the Atlantic Ocean 330 km southeast of Sao Paulo
Operator: Petrobras

5 Oil field Bolivar Shelf 8.3 billion tons (Venezuela)

a group of oil fields in Venezuela (Maracaibo Oil and Gas Basin). Includes the Lagunillas, Tia Juana, Bochaquero deposits
Cinematographer: Petroleos de Venezuela

6 Upper Zakum oil field 8.2 billion tons (UAE)

Supergiant UAE Oil Field located in the Persian Gulf.
Operator: ADNOC, ExxonMobil, Japan Oil Development Co.

7 Samotlor oil field 7.1 billion tons (Russia)

The largest oil field in Russia and one of the largest in the world. Located in Khanty-Mansiysk Autonomous Okrug, near Nizhnevartovsk, in the area of Lake Samotlor. Translated from Khanty, Samotlor means “dead”, “thin water”.
Operator: TNK-BP

8 North / South Pars oil field 7 billion tons (Iran, Qatar)

Supergiant Oil and Gas Field, the largest in the world. Located in the central part of the Persian Gulf in territorial waters Qatar (North) and Iran (South Pars)
Operator: Qatar Gaz, Petropars

9 Kashagan oil field 6.4 billion tons (Kazakhstan)

A supergiant oil and gas field in Kazakhstan, located in the north of the Caspian Sea. Belongs to the Caspian oil and gas province.
Operator: ENI, KazMunayGas, Chevron, Total, Shell

10 Daqing Oil Field 6.3 billion tons (China)

Supergiant Oil Field, the largest in China.
Operator: PetroChina

Hello everyone, Vyacheslav Bulenkov is with you and in this issue, I will share the TOP 10 richest people in Russia in the Forbes world ranking for 2015. On March 2, the American Forbes published its traditional, 29th, global ranking of billionaires. This time, the list included 88 businessmen from Russia, 33 less than a year earlier, and Vladimir Potanin became the leader for the first time - he displaced Alisher Usmanov from the first “national” line. Russian participants in the rating have become noticeably “impoverished” over the year - the reason for this is the crisis in the country’s economy and Western sanctions due to the annexation of Crimea from Ukraine and the war in Donbass. In terms of the number of dollar billionaires, Russia is now inferior not only to the United States and China, but also to Germany and India. 10. Mikhail Prokhorov Net worth: $9.9 billion Change over the year: -$1 billion Position in the world ranking: 125 Athlete, banker, metallurgist, playboy, investor, media mogul, politician and owner of the NBA club - all this is Mikhail Prokhorov. In 2012, he shocked all of Russia with his unexpected candidacy for the post of president of the country - and according to the election results he collected a quite respectable 8% of the vote. But since then the businessman’s political career has faded. His most notable American project is the construction of a new arena for the Nets. In December 2013, he acquired 27% in Uralkali, the world's largest producer of potash fertilizers. 9. Gennady Timchenko Net worth: $10.7 billion Change for the year: -$4.6 billion Position in the world ranking: 118 Gennady Timchenko owns shares in many companies in the gas, transport and construction industries. Among its assets are the largest gas producer Novatek, the petrochemical holding Sibur, the railway carrier Transoil and the insurance company Sogaz. Being one of the most influential people in the country, the billionaire, who is considered a close friend of Vladimir Putin, came under US sanctions in 2014. Among Timchenko’s non-business workload is the supervision of Russian hockey: he chairs the KHL board of directors and holds the post of president of the St. Petersburg club SKA. 8. Vladimir Lisin Net worth: $11.6 billion Change over the year: -$5 billion Position in the world ranking: 107 Vladimir Lisin made his fortune in metallurgy, railway transportation and logistics. Previously, he became a partner in the Trans-World Group, which over several years has grown into a leading Russian exporter of aluminum and steel. By that time, Lisin had accumulated a wealth of experience in managing metallurgical production, so that during the division of assets in 2000, he naturally received ownership of the industry giant, the Novolipetsk Iron and Steel Works. The billionaire also controls the logistics holding UCL, which owns the First Freight Company. 7. Leonid Mikhelson Net worth: $11.7 billion Change for the year: -$3.9 billion Position in the world ranking: 105 Leonid Mikhelson is the main owner of the gas producer Novatek, the chemical group Sibur and the First United Bank. In July 2014, the United States and the European Union imposed sanctions against Novatek, putting pressure on Timchenko's business partner, who is considered a close friend of Putin in the West. The company remains the controlling shareholder of the Yamal LNG project, which is developing despite sanctions pressure. To support it, Novatek requested $2.3 billion in support from the National Welfare Fund. The total cost of the project is estimated at $27 billion, Chinese investors are ready to invest $10 billion. 6. Vagit Alekperov Net worth: $12.2 billion Change for the year: -$1.4 billion Position in the world ranking: 96 Vagit Alekperov heads Lukoil, the largest oil company in Russia, which, in particular, is developing the West Qurna 2 field in Iraq, possessing some of the richest deposits on the planet. The billionaire does not have a reputation as a businessman from the inner circle of President Vladimir Putin, which did not save Lukoil from US sanctions in September 2014. Having gone through all the career stages in the oil industry, at the end of the USSR the future billionaire even managed to work as an industry minister. In 1991 he privatized three large deposits and founded Lukoil. Alekperov is the author of the book “Russian Oil: Past, Present and Future.” 5. Alexey Mordashov Net worth: $13 billion Change over the year: +$2.5 billion Position in the world ranking: 89 In mid-January 2015, Putin received Mordashov and made the metallurgical magnate promise not to allow unreasonable investments. Against the backdrop of bad market conditions for Russia, the billionaire got rid of all American assets - his company Severstal is now focusing on the national market. At the end of 2013, the businessman, together with entrepreneur Yuri Kovalchuk, close to Putin, bought a 50% stake in the fourth largest Russian mobile operator Tele2 Russia. Also, together with Kovalchuk, Mordashov is a shareholder of Rossiya Bank, which is under US and EU sanctions due to the “pro-presidential” reputation of its main shareholder. In 2011, the owner of Severstal increased his stake in the Power Machines holding company, purchasing 25% from Siemens. 4. Viktor Vekselberg Net worth: $14.2 billion Change over the year: -$3 billion Position in the world ranking: 73 Russian authorities elected Viktor Vekselberg to the role of curator of the project of the national analogue of Silicon Valley - the Skolkovo innovation city - in 2010. Since then, three billionaire companies have already appeared among the project residents who received grants from the state. In 2013, the businessman, together with Mikhail Fridman and Leonard Blavatnik, sold a 50% stake in the oil company TNK-BP to the state-owned Rosneft for $28 billion. Vekselberg earned his first million from selling scrap metal. In the 1990s, he founded the holding company SUAL. In 2007, SUAL merged assets with the Rusal group and the mining company Glencore - this is how the world's largest aluminum producer UC Rusal was born. In addition, Vekselberg has stakes in petrochemical, consumer goods and telecommunications businesses. 3. Alisher Usmanov Net worth: $14.4 billion Change for the year: -$4.2 billion Position in the world ranking: 71 Alisher Usmanov lost his status as the richest man in Russia after three years of leadership, but continues to remain a key figure in several major sectors of the national economy. . Among his assets are the metallurgical giant Metalloinvest, the country's second largest mobile operator Megafon, the Internet holding Mail.ru Group and the Kommersant publishing house. The billionaire's most successful investments internationally are in the tech industry: He was an early investor in Facebook, but sold all of his shares in the social network in 2013 to invest in rising Chinese e-commerce giant Alibaba and Chinese budget smartphone maker Xiaomi. Usmanov also remains a shareholder of the London football club Arsenal. 2. Mikhail Fridman Net worth: $14.6 billion Change over the year: -$3 billion Position in the world ranking: 68 Together with his friends from study, Mikhail Fridman controls Alfa Group, the largest private financial and industrial group in Russia. In 2011, Alfa-controlled mobile operator VimpelCom acquired the telecommunications holding of Egyptian billionaire Naguib Sawiris and became the sixth largest player in the global market. Fridman and partners also own the second largest chain of stores in Russia – X5 Retail Group. 1. Vladimir Potanin Net worth: $15.4 billion Change over the year: +$2.8 billion Position in the world ranking: 60 Vladimir Potanin, a former employee of the USSR Ministry of Foreign Economic Relations, met his future partner Mikhail Prokhorov in 1991. In 1993, the partners created Oneximbank, which lured IBES clients to serve them. Oneximbank became a platform for the construction of the Interros holding. With the support of the state, the billionaire became the largest private investor in the Winter Olympics in Sochi - he built the Rosa Khutor ski resort. And so, this was the TOP 10 richest people in Russia in the Forbes world ranking for 2015. Subscribe to the channel to receive new inspiring and useful episodes, write your opinion in the comments, and if you liked the episode, like and share this video with your friends. This will be the biggest support for me. And Vyacheslav Bulenkov was with you and see you again!

1. Introduction……………………………………………………………

2. Origin of oil and gas…………………………………

3. Rocks containing oil and natural gases………………

4. Concepts: “deposit”, “trap”, “deposit”, “layer”….

5. Deposits and fields of oil and gas……………………….

6. World oil and gas reserves……………………………..

7. Classification of deposit reserves, promising and forecast resources of oil and combustible gases in Russia

8. Groups of oil and gas reserves………………………………

Conclusion………………………………………………………..

List of references…………………………….

Introduction

“Oil and gas have attracted attention since time immemorial. Peoples different countries used oil, asphalt and bitumen in medicine, construction, as fuel, lubricant, lighting and for military purposes. Currently, technical progress in all industries is associated with the use of oil and gas."

Oil and gas play a big role in the development of the national economy of our country. Oil and gas, as the most efficient and energy-intensive of all natural substances, have a dominant position in the energy sector.

Almost all cars and planes, as well as a significant part of ships and locomotives, run on petroleum products. An oil derivative - kerosene with liquid oxygen - is used in rocket technology, where the problem of fuel energy intensity is especially acute.

The value of oil as a fuel is determined by its energy properties, its physical condition, sufficient stability during storage and transportation, low toxicity.

But no less valuable is oil as a raw material for the chemical industry. Today, the petrochemical industry covers the production of synthetic materials and products mainly based on oil and natural gas products (synthetic rubber, products of basic organic synthesis, carbon black, rubber, asbestos and other products).

Gas is a high-calorie fuel. This is an excellent raw material for chemical production. In a certain sense, it replaces coke, being a technological component in metal smelting, used in cement production and for generating electricity, and has found wide application in everyday life.

1. Origin of oil and gas

There are different theories about the origin of oil and gas. Some of them assume inorganic, while others - organic formation of these minerals.

I will give the essence of some of them.

Water moves toward the Earth's core through cracks. Under conditions of high temperatures and pressures, water vapor reacts with heavy metal carbides, resulting in the formation of their oxides and hydrocarbons, i.e., components of oil and gas. Hydrocarbon vapors rise to the upper cold zones of the Earth, condense there and accumulate in cracks, voids and pores, forming deposits.

Another hypothesis about the cosmic origin of oil. The Earth was formed from gas and dust matter scattered in the protosolar system. The gas shell of the Earth contained hydrocarbons. As the Earth cooled and transitioned from a fiery liquid state to a liquid-solid state, hydrocarbons were absorbed by the cooling substance. In the coolest upper layers On Earth, they condensed, moved along cracks and accumulated in certain zones, forming oil and gas deposits.

This is how the supposed inorganic origin of oil and gas is explained.

The theory of organic formation of oil and gas is generally accepted. The remains of animal and plant organisms, decomposing in the bowels of the Earth without access to oxygen under the influence of high temperatures and pressures, formed hydrocarbons - components of oil and gas.

Oil formation is associated with the processes of formation and subsequent changes in sedimentary rocks in significantly subsided basins. This process is multi-stage: oil consists of components that were formed in different periods. Some of its components arose in living organisms. The next generation of oil components was formed during the transformation of loose sediments into sedimentary rocks in the upper zone earth's crust.

Oil saturates the rock, which over time is subjected to increasing rock pressure due to the increase in the thickness of sedimentary rocks. Under the influence of this pressure, oil moved into more porous rocks, resulting in the formation of deposits.

The following factors confirm the organic origin of oil. Oil deposits are almost absent in volcanic areas and those areas that are composed of rocks erupted from great depths. The vast majority of known oil and gas accumulations are associated with sedimentary rock strata.

2. Rocks containing oil and natural gases

Rocks that have the ability to hold oil, gas and water and release them when their accumulation sites are developed are called reservoirs. Most reservoir rocks are of sedimentary origin. Oil and gas reservoirs are sands, sandstones, siltstones, siltstones, some clay rocks, limestones, chalk, dolomites.

Reservoir rocks are characterized by two characteristics - porosity and permeability. Porosity characterizes the volume of voids in the rock, and permeability describes the ability of oil, water or gas to penetrate through the rock. Not all porous rocks are permeable to oil and gas. Permeability depends on the size of voids or pores, grains, relative position and packing density of particles, and rock fracturing. Supercapillary voids have dimensions >0.5 mm, capillary 0.5-0.0002 mm, subcapillary<0,0002 мм. Движение нефти в пласте возможно лишь по сообщающимся между собой поровым каналам размером >0.0002 mm.

There are total, open and effective porosity. Total porosity is the volume of all the pores in the rock. Open porosity is the volume of only those pores that communicate with each other. Effective porosity is determined by the presence of pores from which oil can be extracted when developing areas where it accumulates. The porosity value reaches 40%.

When developing oil and gas accumulation areas, artificial methods are sometimes used to increase porosity and permeability.

The reservoir properties of oil and gas bearing formations often change over short distances in the same formation.

Accumulations of oil and gas in reservoir rocks are covered by rocks impermeable to oil, gas and water. Such rocks are called tires. Their role is played by clays, salts, gypsum, anhydrites, etc.

Seal rocks vary in thickness, density, permeability, mineralogical composition and distribution pattern.

At the same time, absolutely impermeable tires for oil and gas do not exist in nature. The best rocks are those that have a high screening ability, i.e., low absolute permeability to gas.

If a reservoir rock contains oil, gas or water and is shielded by poorly permeable rocks, it is called a natural reservoir.

Natural reservoirs are stratified, massive and lithologically limited on all sides.

A reservoir reservoir is a reservoir with a significant area (hundreds and thousands of square kilometers) and small thickness (from fractions to tens of meters), often containing individual lens-shaped layers of impermeable rocks (Fig. 1).

A massive reservoir is a massive layer of reservoir strata that may contain impermeable layers. All layers of permeable rocks communicate with each other, representing a single reservoir.

A lithologically limited natural reservoir is practically surrounded on all sides by impermeable rocks (for example, a lens of sands in a layer of clayey rocks).

Oil and gas, once in a natural reservoir filled with water, begin to move (migrate) and strive to occupy the highest position in it. This occurs as a result of the different densities of oil, gas and water and

the action of gravitational forces (gravity). First, gas and oil move to the top of the natural reservoir (the top of the reservoir formation - or the bottom of the capstone formation). If the layer is inclined, then they move along its roof until they reach the surface of the earth's crust or to some obstacle (lithological screen, a change in the slope of the layer to the opposite). In the first case, oil coming to the surface is absorbed by the rocks surrounding the outcrop, and the gas evaporates into the atmosphere; in the second, an accumulation of oil and gas is formed in front of the barrier, shielded by some kind of obstacle. The part of a natural reservoir in which oil and gas can be screened and accumulated is called a trap. Once trapped, the oil and gas are in a state of relative peace. A lithologically closed natural reservoir is itself a trap.

In nature there are traps of different forms (structural, stratigraphic, lithological and reefogenic).

3. Concepts: “field”, “trap”, “deposit”, “layer”

Field oil and gas is a collection of oil and gas deposits confined to one or more natural traps in the depths of the same limited area controlled by a single structural element.

Trap – part of a natural reservoir in which an equilibrium state of water, oil and gas is established over time. Since the gas density is the lowest, it accumulates in the upper part of the trap. Below gas is oil. Water, as the heaviest liquid, accumulates at the bottom of the trap.

Trapped in any shape favorable conditions Significant amounts of oil and gas may accumulate. This trap is called deposit. The shape and size of the deposit are determined by the shape and size of the trap.

Plast - a mass of any rock, presented mainly in the form of a horizontal layer of this rock, enclosed between two layers of other rocks. The upper surface of the formation is called the roof, the lower - the bottom. The distance between the roof and the base is called the thickness of the formation. The main elements characterizing the occurrence of a formation are the direction of dip, strike and angle of inclination.

5. Oil and gas deposits and deposits

Oil and gas deposits are their natural accumulation in permeable porous or fractured reservoirs. The shape and size of the deposit are determined by the shape and size of the trap. Gas, oil and water are located in the trap according to their densities (Fig. 2). Gas is in the roof of the natural reservoir under the lid, below is oil, and even lower is water. The contact surfaces of gas and oil, oil and water are called gas-oil and water-oil contact surfaces, respectively. The line of intersection of this surface (gas-oil or water-oil contact) with the roof of the productive formation is called the outer contour of gas or oil content. The line of intersection of the surface of the oil-water (gas-oil) contact with the bottom of the formation is called the internal oil-bearing (gas-bearing) contour.

A gas cap is an accumulation of free gas above oil in a reservoir. It is formed if the pressure in the reservoir is equal to the saturation pressure of oil with gas at a given temperature in the reservoir. If the reservoir pressure is higher than the saturation pressure, then all the gas will dissolve in the oil.

If there is not enough gas and oil in the trap to fill the entire thickness of the formation, then there are no internal contours of gas or oil content (for deposits in massive natural reservoirs).

The length, width and area of the deposit are determined by its projection (image) onto a horizontal plane inside the outer contour of the oil-bearing capacity (gas-bearing capacity). The height of the deposit is the vertical distance from the base to its highest point.

Deposits are genetically related to traps, therefore they, like traps, are divided into structural, lithological, reefogenic and stratigraphic.

A set of oil and gas deposits confined to one or more natural traps in the depths of the earth’s crust of the same limited area is called an oil and gas field (a natural accumulation of oil and gas in some area of the earth’s crust in large quantities).

A single deposit is considered a field if, taking into account oil and gas reserves, it is advisable to carry out its commercial development. Several deposits are included in one field, provided that they have the same type of structure and require the same approach to their development.

Oil and gas fields are divided into two classes:

Class I - deposits formed in geosynclinal areas (for example, in Azerbaijan, Uzbekistan);

Class II - deposits formed in platform areas (for example, in Western Siberia).

A set of adjacent and similar in their geological structure oil and gas fields, confined to a specific and generally unified group of genetically interconnected local traps, represents an oil and gas accumulation zone.

Large oil and gas bearing territories include: oil and gas bearing areas and oil and gas bearing provinces.

An oil and gas bearing area is a part of an oil and gas bearing area that unites oil accumulation zones and is distinguished by geographic or geostructural characteristics.

Oil and gas bearing area is a territory confined to one of the large geostructural elements (arches, depressions, troughs, etc.), and having a common geological structure and geological history of development with it.

An oil and gas province is a single geological province that unites adjacent oil and gas areas and is characterized by the common stratigraphic position of the main oil and gas deposits in the section and the similarity of the main features of regional geology.

6. World oil and gas reserves

Energy consumption in the world is constantly growing. Naturally, the question arises: how long will they last?

Information on proven oil reserves, as well as their volumes in 1996, is given in Table 1. When compiling it, countries with the largest reserves of “black gold” were selected for each region.

Region, country	Proven reserves		Oil production in 1996		Inventory ratio,
billion tons	% from	million tons	% of	years
world	world
1	2	3	4	5	6
Asia and
Oceania, total	5,79	4,2	354,0	11,2	16,4
including:
China	3,29	2,4	156,4	4,9	21,0
Indonesia	0,68	0,5	75,8	2,4	9,0
India	0,59	0,4	32,1	1,0	18,4
Northern and
Latin
America, total	21,26	15,2	849,2	26,8	25,0
including:
Venezuela	8,88	6,4	147,8	4,7	60,1
Mexico	6,68	4,8	142,7	4,5	46,8
USA	3,06	2,2	323,8	10,2	9,5
Africa, total	9,25	6,6	334,4	10,6	27,7
including:
Libya	4,04	2,9	70,1 ,	\| 2 " 2	58,0
Nigeria	2,13	1,5	100,7	3,2	21,2
Algeria	1,26	0,9	40,8	1,3	30,9
Middle and
Average
East of everything	92,65	66,4	952,0	30,0	97,3
including:
Saudi	35,48	25,4	392,0	12,4	90,5
Arabia
Iraq	15,34	11,0	30,0	0,9	511,3
Kuwait	12,88	9,2	90,9	2,9	141,7
Iran	12,74	9,1	183,8	5,8	69,3
Abu Dhabi	12,63	9,0	92,3	2,9	136,8
1	2	3	4	5	6
Eastern
Europe, total	8,10	5,8	364,1	11,5	22,3
including
CIS	7,81	5,6	352,2	11,1	22,2
Romania	0,22	0,2	6,8	0,2	32,4
Albania	0,02	less than 0.1	0,5	less than 0.1	40,0
Western
Europe, total	2,52	1,8	315,0	9,9	8,0
including:
Norway	1,54	1,1	154,3	4,9	10,0
Great Britain	0,62	0,4	131,6	4,2	4,7
Denmark	0,13	0,1	10,3	0,3	12,6
Total in the world	139,57	100,0	3168,8	100,0	44,1

Proven reserves are only one component of oil resources. In addition to these, there are also probable and possible reserves.

Proved reserves are the part of reserves that will most likely be extracted from developed deposits under existing economic and technical conditions.

Probable reserves are part of the reserves, geological and engineering, the data on which is still insufficient for an unambiguous judgment about the possibility of development in the existing economic and technical conditions, but which can be economically effective even with a slight increase in information about the relevant deposits and the development of production technology.

Possible reserves are those portions of the reserves for which there is only sufficient geological information to provide at least an approximate estimate of the cost of extraction or an approximate indication of the optimal method of extraction, but only with a low degree of probability (such an estimate is indicative and depends on the individual point of view).

Probable and possible reserves differ from proven reserves in that either they are impractical to develop at the current price level and technologies used, or information about them is insufficient.

“About 40 thousand oil and gas fields have been discovered in various regions of the world. Oil and gas production is carried out in the territories and waters of more than 75 countries of the world."

Table 1 shows that the countries in the Near and Middle East are the richest in oil - 66.4% of its world reserves are concentrated here. If current production rates are maintained, these reserves will last for an average of 97.3 years. Saudi Arabia has the most oil (35.48 billion tons). Next in descending order are Iraq (15.34 billion tons), Kuwait (12.88), Iran (12.74), Abu Dhabi (12.63). The total oil reserves of the listed countries account for over 96% of the reserves of the region as a whole.

The second region for oil reserves is North and Latin America. 15.2% of the world's reserves of “black gold” are concentrated here. It will last for an average of 25 years. Venezuela has the largest oil reserves here (8.88 billion tons), the subsoil of Mexico (6.68) and the USA (3.06) are relatively rich.

Africa contains 9.25 billion tons of oil (6.6% of world reserves). At the current level of production, these reserves will last for an average of 27.7 years. Libya (4.04 billion tons), Nigeria (2.13) and Algeria (1.26) have the most oil in this region.

Eastern Europe ranks 4th in the world in terms of oil reserves (5.8% of the world). There is no competition here from the CIS countries (7.81 billion tons). Romania has much smaller reserves - about 220 million tons. The third country in terms of reserves of Eastern Europe- Albania has only 20 million tons of oil.

In the depths of Asia and Oceania there are about 4.2% of the world's reserves of “black gold”, of which about 57% are in China.

Western Europe has the smallest oil reserves in the world - less than 2% of the world's reserves. More than half of them are the property of Norway (1.54 billion tons), approximately a quarter is the property of Great Britain (0.62).

In general, proven oil reserves in the world in 1996 amounted to 139.6 billion tons, which at the current level of production will last for 44.1 years.

Gloomy forecasts that “oil is running out” have been heard for a long time. In 1935, scientists predicted that in 15...20 years all known oil deposits would be depleted. The prediction did not come true. In 1955, world oil production amounted to over 700 million tons. In 1951, it was expected that “oil will disappear in 25 years.” But in 1976, people managed to pump out about 3 billion tons of oil from the depths. At the same time, the deadline for depleting the planet’s oil reserves was moved to the 21st century.

Will this forecast come true? Most likely no.

Proven oil reserves in countries around the world are constantly being updated. Table 2 shows the dynamics of changes in proven reserves in a number of leading oil-producing countries in the world.

Table 2. Dynamics of changes in proven oil reserves in countries around the world, billion tons.

A country	1961 G .	1965 G .	1981 G .	1993 G .	1995 G .
Venezuela	2,0	2,4	2,5	8,6	8,8
Iraq	3,6	3,4	4,1	13,6	13,7
Iran	5,6	5,5	7,9	12,6	12,1
Kuwait	8,4	8,4	8.9	12,8	12,9
Mexico	-	-	6,0	6,9	6,8
Nigeria	0,1	0,4	2,3	2,4	2,9
Saudi	6,5	8,1	22,6	35,2	35,4
Arabia
USA	4,3	4,3	3,6	3,2	3,1

The table shows that proven oil reserves in the vast majority of countries have not only not decreased in more than 30 years, but have increased several times. We can expect this trend to continue in the future.

However, as proven reserves decline, oil prices rise. New, more advanced oil production technologies are emerging. In this regard, eventually probable and possible oil reserves will become proven.

Considering that the values of all three types of reserves are comparable, the timing of the onset of the “oil famine” can be postponed by several more decades. Even if we assume that not a single new oil field will be discovered during this time.

The widespread use of natural gas in the world began only in the 50s of our century. Since that time, scientists began to seriously study its reserves. The change in proven natural gas reserves in the world can be judged from the data in Table. 3.

Table 3. Proven reserves of natural gas in the world

It is easy to see that in all regions except Western Europe, proven natural gas reserves increased from 1975 to 1996. Accordingly, world gas reserves increased from 65 to 140 trillion. m 3. If in 1975 the countries of the Near and Middle East had the largest gas reserves, then in 1996 - the CIS countries (56 trillion m 3) and, above all, Russia.

Iran ranks 2nd in terms of proven gas reserves (21 trillion m3). This is followed by Qatar (7.1), Abu Dhabi (5.4), Saudi Arabia (5.3), USA (4.7).

The world's total natural gas resources (including probable and possible reserves) are estimated at 398 trillion. m 3. If the current level of gas production is maintained (about 2200 billion m 3 /year), these resources will last for about 200 years.

However, natural gas is not only found underground in pure gas fields. Significant quantities of it are concentrated in coal seams, in groundwater ah and in the form of gas hydrates.

Tragic accidents in coal mines are usually associated with methane contained in coal. Methane is found in the rock mass in a sorbed state. According to geologists, methane reserves in all coal-bearing regions of the world are close to 500 trillion. m 3.

Methane is also found in groundwater. The amount of dissolved gases in them exceeds all proven reserves of gas in its traditional form. for example, 736 trillion are dissolved in the formation waters of the Gulf Coast field (USA). m 3 of methane, while natural gas reserves in pure gas fields of the United States amount to only 4.7 trillion. m 3.

Another large source of methane can be gas hydrates - its compounds with water, reminiscent of appearance March snow. One cubic meter of gas hydrate contains about 200 m 3 of gas.

Deposits of gas hydrates are found in sediments of deep-sea areas and in the interior of land with thick permafrost (for example, in the polar part of the Tyumen region, off the coast of Alaska, the coast of Mexico and North America).

Scientists believe that 9/10 of the area of the World Ocean contains gas hydrates. If this assumption is confirmed, then gas hydrates can become an inexhaustible source of hydrocarbon raw materials.

7. Classification of deposit reserves, promising and forecast resources of oil and combustible gases in Russia

Accounting and control of mineral reserves, including oil and gas, is an important task. To calculate reserves, a comprehensive geological study of the field with which oil and gas deposits are associated and knowledge of the specific conditions of their occurrence are required.

Russia has always been famous for its corps of mining engineers and scientific geologists. Back in 1888, geologist A.I. Konshin carried out calculations of reserves for fields in southern Russia.

“In 1925, the first attempt was made to calculate oil reserves for the country as a whole. In 1937, on the initiative of the Energy Institute of the USSR Academy of Sciences, M. A. Zhdanov and S. V. Shumilin calculated gas reserves for the first time.” The development of the methodology for calculating oil and gas reserves was largely facilitated by the Central Commission for Reserves (CDC), created in 1935, which was later renamed the All-Union Commission for Reserves (VKZ), and then the State Commission for Reserves (GKZ) under the Council of Ministers of the USSR, now State Reserves Committee of Russia.

Field reserves and promising resources of oil and combustible gas are calculated and taken into account in the state balance of mineral reserves of Russia based on the results of geological exploration and field development. By flammable gas we mean natural gas - free gas, gas from gas caps and gas dissolved in oil.

Forecast oil and gas resources, the presence of which is assumed on the basis of general geological concepts, theoretical premises, results of geological, geophysical, geochemical studies, are estimated within large regions, oil and gas provinces, water areas, regions, districts, areas. Data on predicted oil and gas resources are used when planning prospecting and exploration work.

When determining deposit reserves, reserves of oil, gas, condensate and the components they contain (ethane, propane, butane, sulfur, helium, metals), the feasibility of extraction of which is justified by technological and technical-economic calculations, are subject to mandatory calculation and accounting. Calculation and accounting of reserves of oil, gas, condensate and the components they contain that are of industrial importance are carried out for each deposit separately and for the field as a whole.

Prospective resources are calculated and taken into account, and predicted resources are assessed separately for oil, gas and condensate.

Deposit reserves and prospective resources of oil and condensate, as well as ethane, propane, butane, sulfur and metals are calculated and taken into account, and the predicted resources of oil and condensate are estimated in mass units; deposit reserves and promising gas and helium resources are calculated and taken into account, and forecast gas resources are estimated in volume units. Counting, accounting and evaluation are carried out under conditions reduced to standard (0.1 MPa at 20° C).

The quality of oil, gas and condensate is assessed in accordance with the requirements of state, industry standards and technical specifications taking into account the technology of extraction and processing, ensuring their comprehensive use.

When receiving groundwater inflows from wells in oil and gas fields, the chemical composition groundwater, its content of iodine, bromine, boron and other useful components, temperature, water flow rates and other indicators to justify the feasibility of carrying out special geological exploration work in order to assess groundwater reserves and determine the possibility of using them for the absorption of useful components or for thermal power, balneological and other needs.

The application of this Classification to deposit reserves and promising oil and gas resources is determined by the instructions of the State Reserves Committee of Russia.

“Reserves of oil, gas, condensate and the components they contain that are of industrial importance are divided into four categories according to the degree of exploration: explored - categories A, B, C 1 and preliminary estimated - category C 2."

Oil and gas resources, according to the degree of their validity, are divided into promising - category C 3 and forecast - categories D 1 and D 2.

Category A - reserves of a deposit (its part), studied in detail, providing a complete determination of the type, shape and size of the deposit, effective oil and gas saturated thickness, type of reservoir, nature of changes in reservoir properties, oil and gas saturation of productive formations, composition and properties of oil , gas and condensate, as well as the main features of the deposit, on which the conditions of its development depend (operating mode, well productivity, reservoir pressure, oil, gas and condensate flow rates, hydraulic conductivity and piezoelectric conductivity, etc.).

Category B - reserves of a deposit (its part), the oil and gas potential of which is established on the basis of the obtained industrial inflows of oil or gas in wells at various hypsometric marks. Type, shape and size of the deposit, effective oil and gas saturated thickness, type of reservoir, nature of changes in reservoir properties, oil and gas saturation of productive formations, composition and properties of oil, gas and condensate in reservoir and standard conditions and other parameters, as well as main features the deposits that determine the conditions for its development have been studied to a degree sufficient to draw up a project for the development of the deposit.

Category B reserves are calculated based on the deposit (its part) drilled in accordance with the approved technological scheme for the development of an oil field or a pilot project for the development of a gas field.

Category C 1 - reserves of a deposit (its part), the oil and gas potential of which is established on the basis of industrial inflows of oil or gas obtained in wells (some of the wells were tested by a formation tester) and positive results of geological and geophysical studies performed in untested wells.

The type, shape and size of the deposit, the conditions of occurrence of the oil and gas reservoirs are established based on the results of drilling exploration and production wells and geological and geophysical research methods tested for the area. Lithological composition, reservoir type, reservoir properties, oil and gas saturation, oil displacement coefficient, effective oil and gas saturated thickness of productive formations were studied from core and well logging materials. The composition and properties of oil, gas and condensate under reservoir and standard conditions were studied based on well testing data. The industrial value of the oil rim has been established for gas-oil deposits. Well productivity, hydraulic conductivity and piezoelectric conductivity of the formation, reservoir pressure, temperature, oil, gas and condensate flow rates were studied based on the results of well testing and exploration. Hydrogeological and geocryological conditions were established based on the results of well drilling and by analogy with neighboring explored fields.

Category C 1 reserves are calculated based on the results of geological exploration and production drilling and must be studied to the extent that provides the initial data for drawing up a technological scheme for the development of an oil field or a pilot project for the development of a gas field.

Category C 2 - reserves of a deposit (its part), the presence of which is justified by data from geological and geophysical research: in unexplored parts of the deposit adjacent to areas with reserves of higher categories; in intermediate and overlying untested layers of explored deposits.

The shape and dimensions of the deposit, the conditions of occurrence, the thickness and reservoir properties of the formations, the composition and properties of oil, gas and condensate are determined in general outline based on the results of geological and geophysical studies, taking into account data from a more studied part of the deposit or by analogy with explored deposits.

Category C 3 reserves are used to determine the prospects of a field, plan geological exploration or geological field studies when transferring wells to higher-lying formations, and partly for designing the development of deposits.

Category C 3 - promising oil and gas resources prepared for deep drilling of areas located within the oil and gas bearing area and delineated by methods of geological and geophysical research proven for the given area, as well as reservoirs of explored deposits not exposed by drilling, if their productivity has been established in other deposits of the area .

The shape, size and conditions of occurrence of the deposit are determined in general terms based on the results of geological and geophysical studies, and the thickness and reservoir properties of the formations, the composition and properties of oil or gas are taken by analogy with explored fields.

Promising oil and gas resources are used when planning prospecting and exploration work and the increase in reserves of categories C 1 and C 2.

Quantitative assessment of predicted oil and gas resources of category D 1 is made based on the results of regional geological, geophysical and geochemical studies and by analogy with explored fields within the assessed region.

Category D 2 - predicted oil and gas resources of lithological-stratigraphic complexes, assessed within large regional structures, the industrial oil and gas potential of which has not yet been proven. The oil and gas potential of these complexes is predicted based on data from geological, geophysical and geochemical studies. A quantitative assessment of the predicted resources of this category is made according to hypothetical parameters based on general geological concepts and by analogy with other, more studied regions where there are explored oil and gas deposits.

Reserves of commercially important components contained in oil, gas and condensate are calculated in the oil and gas reserve calculation circuits in the same categories.

8. Oil and gas reserve groups

Reserves of oil, gas, condensate and components contained in them in industrial quantities, according to national economic importance, are divided into two groups that are subject to separate calculation and accounting: balance - reserves of fields (deposits), the involvement of which in development is currently economically feasible; off-balance sheet - reserves of fields (deposits), the involvement of which in development is currently economically inexpedient or technically and technologically impossible, but which can later be transferred to balance sheet.

In balance reserves of oil, dissolved gas, condensate and the components they contain that are of industrial importance, recoverable reserves are calculated and taken into account.

Recoverable reserves are part of the balance reserves that can be extracted from the subsoil with the rational use of modern technical means and production technology, taking into account permissible level costs (closing) and compliance with requirements for the protection of subsoil and the environment.

Oil and condensate recovery factors are determined on the basis of variant technological and technical-economic calculations and are approved by the State Reserves Committee of Russia, taking into account the conclusions of the relevant departments.

Oil and gas reserves located within the protective zones of large reservoirs and watercourses, settlements, buildings, agricultural facilities, nature reserves, natural, historical and cultural monuments, are classified as on-balance or off-balance sheet on the basis of technical and economic calculations, which take into account the costs of moving objects or costs associated with the use of special methods of field development.

Conclusion

Oil and gas are playing and will continue to play in the coming years main role in the country's energy balance. With increasing difficulties in providing various types energy in the world, the question arises of increasing their resources. The search and exploration of new deposits is becoming more difficult and expensive every year (primarily due to increasing drilling depths and access to the shelf). Therefore, the important tasks of oil and gas producing enterprises are to achieve high efficiency in the development of oil and gas fields, and to increase the recoverable reserves of oil and gas in developed fields. All this makes it necessary wide application methods of geological and field geophysical study of oil, gas and gas condensate fields.

The study of the geological structure of oil and gas fields, the calculation of oil and gas reserves in them, the study of processes occurring in the subsoil during the development of fields, as well as monitoring their development - all these issues constitute a section of mining and geological science, which is called oil and gas field geology.

The current stage of development of field geological research is characterized by broad complexity, which involves the use of data from geology, field geophysics, drilling, operation, economics, etc.

List of used literature:

1. Burdyn T.A., Zaks Yu.B. Chemistry of oil, gas and formation waters. – M.: Nedra, 1975.

2. Gorshkov G.P., Yakushova A.F. General geology. – M., 1973.

3. Eremenko N.A. Geology of oil and gas. - M., 1968.

4. Kabirov M.M., Razhetdinov U.Z. Basics of well oil production. – Ufa, 1994.

5. Kalinin V. G., Vagin S. B. et al. Oil and gas field geology and hydrogeology. M., 1997.

6. Korshak A.A., Shammazov A.M. Fundamentals of oil and gas business. – Ufa, 2001.

7. Maslov N.I., Kotov M.R. Engineering Geology. – M., 1971.

8. Permyakov V.G., Khairetdinov N.Sh., Shevkunov E.N. Oilfield geology and geophysics. - M., 1986.

9. Eliyashevsky I.V. Oil and gas production technology. - M., 1985.

Kabirov M.M., Razhetdinov U.Z. Basics of well oil production. – Ufa, 1994. P.3.

Bakirov A. A., Borodovskaya V. I. and others. Geology and geochemistry of oil and gas. M., 1993. P. 270.

Zhdanov M.A. Oil and gas field geology and calculation of oil and gas reserves. M., 1970. P.405.

Kalinin V.G., Vagin S.B. et al. Oil and gas field geology and hydrogeology. M., 1997. P. 153.

The natural accumulation of oil in the subsurface is called an oil reservoir. Almost every oil deposit also contains gas, i.e. is essentially an oil and gas reservoir. Pure gas deposits are also found in nature, i.e. accumulations of natural gas in porous rocks.

The main known oil and gas deposits are concentrated in sedimentary rocks. Characteristic sign sedimentary rocks - their layering. These rocks are composed mainly of almost parallel layers (layers), differing from each other in composition, structure, hardness and color. The surface limiting the formation from below is called sole, and on top - roofing

Layers of sedimentary rocks can lie not only horizontally, but also in the form folds(Fig. 1), formed during oscillatory, tectonic and mountain-building processes. The bend of the formation, directed convexly upward, is called anticline, and with the convexity down - syncline. The adjacent anticline and syncline together form full fold.

Fig.1. A fold formed by sedimentary rocks.

Fig.2. Schemes of structural traps.

a - trap in the arch of the local uplift; b – tectonically

screened trap in the near-crest part of the local uplift.

In Russia, almost 90% of the oil and gas found are in anticlines, abroad - about 70%. The average dimensions of anticlines are: length 5...10 km, width 2...3 km, height 50...70 m. However, giant anticlines are also known. Thus, the world's largest oil field, Ghawar (Saudi Arabia), has dimensions of 225x25 km and a height of 370 m, and the Urengoy gas field (Russia): 120x30 km with a height of 200 m.

By permeability Rocks are divided into permeable (reservoirs) and impermeable (tires). Collectors- these are any rocks that can contain and release liquids and gases, as well as pass them through themselves when there is a pressure difference. Porous reservoirs have the best reservoir properties.

Other types of collectors may also have good abilities to contain and release liquids and gases, as well as pass them through themselves. Thus, in some fields in Saudi Arabia, interconnected systems of fractures create channels up to 30 km long. More than 50% of discovered oil reserves are confined to fractured reservoirs abroad, and 12% in Russia.

Tires- These are practically impenetrable rocks. Usually they are rocks of chemical or mixed origin, not disturbed by cracks. Most often, clays play the role of tires: when wetted with water, they swell and close all the pores and cracks in the rock. In addition, rock salt and limestones can be used as tires.

Industrial deposits of oil and gas are found only in sedimentary rocks. Oil and gas fill the pores and voids between individual particles of these rocks.

It is known that sedimentary rocks include sands, sandstones, limestones, dolomites, clays, etc. However, industrial oil accumulations are not found in clayey rocks. Clay layers in oil fields play only the role of impermeable ceilings, between which lie more porous rocks saturated with oil, gas or water. If there were no clayey rocks underlying and overlying oil or gas accumulations, the latter would be dispersed throughout the entire thickness of the earth's crust.

For the formation of oil and gas deposits, in addition to the presence of porous rocks closed on top by impermeable layers, one more condition is required: certain structural forms of the formation. Long-term practice of exploiting oil and gas deposits has shown that oil and gas do not occur in undisturbed (horizontal) formations; all their accumulations are located in various folds.

The most common and have highest value in the structure of oil and gas deposits, structural forms of the anticlinal type and structural forms are associated with the monoclinal occurrence of layers. Most of the world's oil and gas deposits are confined to these structural forms.

In Fig. Figure 1 shows a diagram of a reservoir-type oil and gas deposit. Its main elements and parameters are the geometric dimensions and shape, as well as the position of the external and internal contours of oil and gas content.

Fig.3. Scheme of a reservoir-type oil and gas deposit

1 – internal contour of gas content; 2 – external contour of gas content;

3 – internal contour of oil content; 4 – external contour of oil content.

The line of intersection of the surface of the oil-water contact with the roof of the formation is called the external oil-bearing contour, and with the bottom of the formation - the internal oil-bearing contour.

The accumulation of free gas above the oil in a reservoir is called a gas cap.

The line of intersection of the surface of the oil and gas interface with the roof of the formation represents the outer contour of the gas content, and with the bottom of the formation - the internal contour of the gas content.

In addition to reservoir-type oil and gas deposits, there are also massive oil or gas deposits confined to large massifs or reefs, usually composed of limestone. There are also reservoir-screened and lithologically limited oil and gas deposits.

The constant satellites of oil in oil deposits are petroleum gas and produced water. Their distribution along the height of the deposit, as can be seen from the diagram in Fig. 1 corresponds to their densities: in the upper parts of the anticlinal or monoclinal fold there is gas, oil lies below the gas, and the latter is supported from below by water.

The volume of voids in rock, consisting of pores, pore channels between individual grains and rock particles, cracks, caverns, etc., is usually called porosity. The numerical value of porosity is determined by the ratio of the total volume of all voids in the rock to the entire volume of the rock with voids.

Porosity value various breeds varies over a very wide range - from fractions of a percent to several tens of percent. Thus, for igneous rocks, porosity ranges from 0.05 to 1.25% of the total volume of rock with voids, for oil sands - from 18 to 35%, for sandstones - from 13 to 28%. The permeability of the rock depends on the size of the pores and the channels connecting these pores. How larger size pores, the higher the permeability and vice versa. For example, clays may have the same porosity as sands, i.e. a unit volume of clay rock can hold the same amount of liquid as the same volume of sand. However, due to the negligible size of individual pores and channels between clay particles, the adhesive forces and internal friction in them are so great that there is almost no movement of liquid or gas in the clay formation. Clays are practically impermeable to liquids and gases.

In addition to the geometric volume of an oil or gas deposit, the porosity and permeability of the rocks that make up this deposit, its industrial value also depends on the amount of reservoir energy, on the quality of the oil contained in it and, most importantly, on oil and gas saturation.

Oil saturation (gas saturation) is the ratio of the volume of pores in a reservoir filled with oil (gas) to the total volume of pores. The fact is that the pores of oil or gas-containing rock always contain water, which remains motionless during the exploitation of the deposit. This water is “bound” to the rock due to the adhesion forces between the rock and the water. It has been established that of the total pore volume of an oil-containing rock, from 60 to 90% of the pores are filled with oil, the rest: the pore volume is filled with water.

A collection of oil and gas deposits located on one area of the earth's surface is an oil or gas field.

Figure 4 schematically shows a multi-layer oil and gas field of an anticlinal type. In this field, formation A - pure gas, layers B and C - oil. Top part reservoir B is filled with gas, and the oil is supported from below by formation water.

Fig.4. Oil and gas field diagram.