IN Lately all the media are talking about only one thing - about an agreement on Iran's nuclear program, as a result of which sanctions will be lifted from the country. And one of the most obvious consequences of such an agreement is the return of Iran to world markets, in particular to the world oil market.
Interestingly, although Iran has huge oil reserves, it is not even among the top three leaders in terms of its proven reserves. Based on data provided by Barclays analyst Michael Cohen, a ranking of 10 countries with the largest proven oil reserves was compiled.
10. Nigeria
: 37.14 billionOil has become the main source of government revenue since the 1970s. However, as a result of the fall in oil prices last year, the country found itself in a difficult economic situation.
And now, according to some experts, Nigeria will have to face tough competition when Iranian oil hits the world markets again.
Currently, more than 300 oil and oil and gas fields have been discovered. The largest deposits are Bomu, Imo River, Okan, Meren, Delta South, Ekpe, Yokri, etc.
They are engaged in oil production joint ventures National Oil Company of Nigeria (Nigerian National Petroleum Company, NNPC) and transnational corporations Shell (controls up to 52% of production), ExxonMobil, Chevron, ConocoPhillips, Eni, Total and Addax.
9. Libya
The Libyan economy is almost completely dependent on energy. Sales of oil and gas fell sharply in 2014 due to protests at oil ports.
The oil and gas industries are under state control. Oil production is managed by the Libyan National Oil Company (NOC). Issues of international investment in projects are supervised by Oilinvest.
The main foreign oil companies operating in Libya are Agip-ENI (Italy), Canadian Occidental, Lasmo (Great Britain), Lundin Oil (Sweden), Nimr Petroleum (Saudi Arabia), OMV (Austria), Pedco ( South Korea), Petronas (Malaysia), Red Sea Oil Corp. (Canada), Repsol (Spain), Total (France), Veba and Wintershall (Germany).
At the same time, the Libyan oil industry has recently been seriously affected by the activities of ISIS militants. Thus, since the beginning of February, there have been reports of a blockade by Islamists of the al-Mabrouk oil field south of Sirte.
The well is being developed jointly by the French company Total and the Libyan state-owned National Oil Corporation, but since mid-December its work has been suspended due to the civil war.
8. Russia
Despite the fact that Moscow was trying with all its might to achieve an agreement for Iran and the signing of such an agreement was a victory for it, analysts believe that Iran's entry into the world oil market may become a problem for Russia, since Iranian oil will become the main competitor of Russian oil in European markets.
Ed Morse, Director of Global Commodity Market Analysis at Citigroup, spoke about this in an interview with Bloomberg: "Iran will compete in Europe with Russia."
To date, several dozen oil and gas fields have been discovered in Russia. Most of them are concentrated in the bowels of the Arctic seas, where their development is complicated by difficult climatic conditions.
There is also the problem of delivering oil and gas to the places of their processing. Development is carried out on the Sakhalin shelf, as well as in the Russian mainland, where quite rich oil, gas and oil and gas fields are also found.
In mainland Russia, most of the oil and gas fields are concentrated in Siberia and the Far East.
7. United Arab Emirates
The UAE is another country whose economy depends on energy. Modernization of the country's economy began more than 30 years ago, after the discovery of oil. After a sharp decline in oil markets at the end of 2014, the UAE, which is one of the largest players in OPEC, began to produce a record amount of oil.
The predominant number of deposits was discovered in Abu Dhabi: 25 oil and 4 gas and oil. Dubai has 3 oil, 1 gas and oil and 1 gas condensate fields.
Sharjah has 1 oil, 1 gas and 1 gas condensate field. In Ajman - 1 gas condensate.
In the emirates of Pac al-Khaimah and Umm al-Qaiwain - one gas condensate field each. The largest deposits on land are Murban-Bab, Murban-Bu-Xaca, Asab, Sahil; on the continental shelf - Umm Shaif, Zakum.
6. Kuwait
Oil accounts for more than half of Kuwait's GDP, and the country plans to boost oil production to 4 million barrels per day by 2020.
After sanctions were imposed on Iran in 2012, Kuwait (together with Saudi Arabia) took over almost the entire share of Tehran's "Asian trade".
There are 1.6 thousand oil wells in the country. In addition to reserves located in Kuwait, there is also the so-called neutral zone between Saudi Arabia and Kuwait, containing an additional 5 billion barrels. oil, half of which belongs to Kuwait.
The largest part of oil reserves (70 billion barrels) is concentrated in the Greater Burgan region, which includes the following oil structures: Burgan, Magwa and Ahmadi.
The reserves of such large deposits of Kuwait as Raudhatein, Sabriyah and Minagish are estimated at 5.1; 4.3; 3.3 billion barrels of oil, respectively. These fields mainly produce medium-sulphurous and light oil.
The reserves of the South Magwa field, explored in 1984, according to experts, amount to about 25 billion barrels of light oil.
5. Iraq
The Iraqi economy is state-run and the main source of income is oil. Accordingly, when oil prices began to fall sharply in 2014, government revenues fell by 30%.
As of 2015, Iraq, being one of the largest oil-producing countries, demonstrates record production levels.
At the same time, the country's economy and, in particular, the oil industry are facing great problems due to the activities of ISIS militants.
Thus, in early June 2014, militants from the Islamic State of Iraq and the Levant launched an offensive against a number of cities in northern Iraq. On June 17, 2014, an oil refinery was attacked in Baiji, 40 km from the capital of Baghdad, one of the largest in Iraq.
In this regard, some foreign companies, in particular ExxonMobil, British Petroleum, announced the evacuation of personnel or plans to evacuate employees in the event of an aggravation of the situation. On June 19, government forces managed to recapture the plant.
4. Iran
Now Iranian oil has become the main issue for discussion. Analysts believe that the return of Iranian oil to the world market could lead to a further decline in oil prices. In addition, it could lead to increased tension between Iran and Saudi Arabia, and, according to analysts, between Iran and Russia.
All known industrial accumulations of oil in Iran are located in the oil and gas basin of the Persian Gulf.
Almost the entire oil sector of the Iranian economy is completely controlled by the state-owned National Iranian Oil Company (Sharkat Malli Naft Iran; National Iranian Oil Company, NIOC).
Organizationally, exploration, production and refining of oil are carried out through subsidiaries, some of which allow access to private capital, including foreign capital: National Iranian South Oil Company, Central Iranian Oil Fields Company, National Iranian Central Oil Company, National Iranian Offshore Oil Company, National Iranian Drilling Company, Khazar Oil Exploration and Production Company, North Drilling Company, Iran Petro Development Company, Pars Oil and Gas Company, Petropars, etc.
However, now, in connection with the imminent lifting of sanctions, Iran is seeking to invite as many large international oil and gas companies as possible to develop Iranian fields.
3. Canada
Canada exports oil to the US and Europe. Overall, it is the largest foreign supplier of oil to the United States.
However, recent reports suggest that oil produced from the Canadian oil sands is nearly 20% more carbon-intensive than other types of oil.
This means that "if Canada eventually exports to the US more oil, then the level of greenhouse emissions of American cars will increase even if gasoline consumption remains at the same level," notes OilPrice.com.
Oil fields in Canada (more than 95%) are located in Alberta - in tar sands, where exploration of these lands requires a large number fresh water and energy costs.
2. Saudi Arabia
Saudi Arabia was the biggest player in the oil market last year.
Last November, Saudi Arabia, along with other OPEC members, refused to cut oil production quotas after oil prices began to decline.
In addition, Iran wants to "doubling the volume of oil exports immediately after the sanctions are lifted, and is pushing other OPEC member countries to review the quota system within the organization," which could significantly affect the oil industry in Saudi Arabia.
natural conditions The location of oil reserves makes it possible to produce oil with, perhaps, the lowest unit costs in the world. In view of this, activities for the exploration and development of new oil resources are constantly ongoing in this country.
Saudi Aramco, as part of a large-scale program, is successfully conducting exploration work to search for oil reservoirs in the coastal zone of the Red Sea.
1. Venezuela
"Venezuela remains highly dependent on oil revenues, which account for approximately 96% of export earnings, about 40% state revenue and 11% of GDP" according to the CIA Factbook.
Accordingly, the decline in oil prices in 2014, as well as the recession, led to a recession in the Venezuelan economy. And now the country is looking for allies among other OPEC member countries in the hope of stabilizing oil prices.
About 20% of oil produced in Venezuela is extracted from fields in the Gulf of Maracaibo. The country's largest oil fields are Lagunillas, Bachaquero, El Furrial, Centro, Mulata, Lama.
Oil is often referred to as the black gold of modern times. Oil reserves across countries are distributed extremely unevenly. However, absolutely everyone needs this fuel today.
Oil is the No. 1 mineral
The word petroleum, which refers to oil in many languages, consists of two roots. One of them, "petra" is Latin, and translates as "stone". The second, "oleum" is Greek, and translates as "oil". Thus, literally, oil is (that is, oil extracted from the earth).
It is known that oil was actively used in ancient India (in construction), in Babylon (for embalming the bodies of the dead), in Ancient Greece(as fuel). Since the first decades of the twentieth century, it has become the main energy resource on the planet.
So what is oil? It is an oily liquid of natural origin, which consists of a combination of different hydrocarbons. The color of this substance can be different: from saturated black to yellowish and even green. The smell of oil is specific and, as a rule, unpleasant, which is explained by its chemical composition.
Oil reserves across countries are distributed very unevenly. Basically, its largest deposits are confined to zones with a thick cover of sedimentary rocks.
Countries that have largest reserves oil (per capita) is Qatar, Kuwait, Turkmenistan, UAE, Saudi Arabia, Venezuela and Libya. By the way, if you recalculate the total oil reserves of Qatar in monetary terms, it turns out that for every citizen of this country there are about 6 billion dollars!
The use of oil in the modern world
Crude oil is practically not used. To obtain technically valuable products (gasoline, solvents, etc.), it must be processed at special factories.
In addition to the fact that oil is very valuable, it is also used for the production of plastics, various plasticizers and additives, dyes, and synthetic rubber.
Oil is a resource that has a number of advantages. First, it has very high energy density. Secondly, oil is quite easily transported over long distances (this is done using pipelines or tankers - huge sea vessels). Thirdly, a wide range of different products can be produced from it. All these aspects make oil one of the most sought-after commodities on the world market.
However, the reserves of this mineral are rapidly depleted. That is why some countries with significant oil reserves (in particular the United States) began to search (oil shale, biofuels and the like).
Features of modern oil production
Until about the mid-70s, oil was produced in the world at a frantic pace. So, if in 1970 about 2 billion tons of this energy resource were extracted from the earth's interior, then in 1973 - already 2.8 billion tons. In the early 1980s, world oil production declined somewhat.
Oil production on an industrial scale began in the middle of the 19th century. During all this time, more than forty billion tons of this resource have been "pumped" out of the earth.
Leading countries of the world in terms of oil reserves
Now let's take a closer look at the geography of distribution of this valuable energy resource.
Oil reserves vary widely across countries. So, some states are completely deprived of this wealth, while others are literally bathed in black gold. The top ten countries in terms of total oil reserves are as follows (see table).
In terms of oil production, the leaders here are the following countries:
- Saudi Arabia.
- Russia.
- Iran.
- China.
Taking into account two indicators - total oil reserves and annual oil production, one can easily calculate how many years this energy resource will last for each country.
Thus, Venezuela should be least of all worried - it will have enough oil (at today's production rates) for another 235 years. But such countries as Russia, the USA, Canada, Qatar have something to think about. In particular, the United States of America will have enough oil reserves for only 11 years, Russia - for 22 years, Canada - for 26, Qatar - for 45.
Oil prices: expert forecasts
To date, the price of one barrel of Brent fixed at $64, WTI - $61.
Prices for oil (as well as for any other product on the world market) are determined based on the ratio of supply and demand for it. Today, the supply of this energy resource still exceeds demand. In addition, pricing in this case is influenced by other factors (let's call them political). We are talking about military conflicts in Libya and Yemen, as well as the deployment of US shale projects.
Many economic experts predict that in the next two months oil will rise in price to $ 70, but after that the price of this resource will begin to fall again.
In the third quarter of 2015, as analysts predict, the price of oil may find its new bottom, reaching $50 per barrel.
Finally...
Oil is the most important energy resource of our time. The leading countries in terms of oil reserves (total) are Venezuela, Saudi Arabia, Canada, Iran, Iraq, Mexico. However, scientists warn that at the current rate of oil production, this resource in most countries of the world will last only 40-80 years. That is why already now some states have begun to think about alternative energy sources.
12.05.2017Oil is an important part of our lives, used as a fuel for transportation and power generation, running factories and lighting homes. Based on data provided by analysts of the web edition " energy business review ”, a ranking of ten countries with the largest proven oil reserves was compiled.
Venezuela
Proved oil reserves: 300 billion barrels
About 20% mined th "black gold" extracted from deposits in the Gulf of Maracaibo. In 2011, Venezuela overtook Saudi Arabia to top the list of countries with the most large stocks oil.
Saudi Arabia
Proved oil reserves: 269 billion barrels
According to experts, Saudi Arabia's oil reserves make up one fifth of the world's reserves. Although Saudi Arabia has been a major player in the oil market for several decades, in November 2016 the country refused to cut oil production quotas after lowering prices.
Canada
Proved oil reserves: 171 billion barrels
Iran
Proved oil reserves: 157.8 billion barrels
International sanctions against Iran due to its nuclear activities have affected the country's energy sector and affected oil production. All industrial accumulations of "black gold" of Iran are located in the Persian Gulf basin.
Iraq
Proved oil reserves: 143 billion barrels
The country's energy sector has suffered from military occupation and civil unrest, and the unexplored region of Iraq, according to experts, has great potential. To support oil production high level, the country needs to invest 1 billion US dollars annually.
Kuwait
Proved oil reserves: 104 billion barrels
There are 1.6 thousand oil wells in the country. The largest part of oil reserves (70 billion barrels) is concentrated in the Bolshoy Burgan area . Kuwait is the third largest member of the Organization of the Petroleum Exporting Countries (OPEC).
United United Arab Emirates
Proved oil reserves: 98 billion barrels
More than 90% of the UAE's reserves are located in Abu Dhabi (25 oil and 4 gas fields), followed by Dubai (3 oil fields) and Sharjah (1 oil, 1 gas).
Russia
Proved oil reserves: 80 billion barrels
Most of the reserves are located in the Siberian plains and on Far East. To date, several dozen oil and gas fields have been discovered in Russia.
Libya
Proved oil reserves: 48.3 billion barrels
The country has the largest oil reserves in Africa. Most of the region, where there is potential to find new oil reserves, remains unexplored. The country's oil and gas industries are under state control. Oil production is managed by the Libyan National Oil Company.
Oil is a strategically important resource on the entire planet. This hydrocarbon raw material is familiar to everyone. It is used in many areas of life. It accumulates in layers of various rocks, serving as a kind of collector and protection from the harmful effects of external environment. Despite all the fame, the importance of oil in the modern world can hardly be overestimated, as it is one of the main keys to the growth of the global economy. However, for some countries this main source budget, because oil is in demand, and there are many countries that want to buy it. For this reason, raw materials became scarce. The explored oil reserves in the world are being depleted, and new deposits have to be found in order not to cause an energy crisis.
Composition of oil
What does it consist of this species mineral? Oil contains many substances. Among them, 90% are hydrocarbons, which indicates its organic origin. Atoms also contain hydrogens and carbons, and even in small quantities, almost the entire table of chemical elements.
Oil properties
"Black gold" is an oily substance that has colors from red, slightly brownish to dark black. Oil is an excellent combustible substance. Some varieties have amazing properties. For example, some may be liquid in Siberia, but in Africa they will be solid. Oil is dangerous for the environment.
Origin of oil
Scientists puzzle over many dilemmas. One of these age-old, questionable problems is the scientific justification of the origin of oil. The first to guess about its existence was the great Russian scientist Mikhail Lomonosov. But so far no one can give an exact formulation. Some come up with fabulous hypotheses. Others believe that oil is a substance of biological origin. However, even this logical point of view, recognized by all, has its opponents, who believe that it is formed by the cycle of hydrocarbons. If you stick to the popular theory, then oil originates from the remains of organic matter - these can be animals, plants that have outlived their lives. But it is worth noting that its composition is different in different parts of the world, which indicates that it was in different conditions and a kind of "traps" that prevented it from mixing with other impurities.
What is made from oil?
"Black Blood" modern civilization used in many areas of life. But oil as such is not used in its pure form. First, it is cleaned and processed. During the primary processing cycle, it is divided into fractions. The main component of oil includes various types of fuel: gas, kerosene, gasoline for automotive and aviation equipment, as well as diesel fuel. The secondary ones include fuel oil and products of its further processing: paraffin, bitumen, oil, liquid fuel for boilers.
Application
All proven oil reserves in the world have practical use, not only in the form of fuel for machinery. Also, oil is used as road surfaces, that is, by mixing bitumen with minerals, asphalt concrete or tar is obtained. No less popular is the use of petroleum products as a fuel for space heating.
Cosmetic use is known to many. Everyone knows the fact that oil is made from oil, on the basis of which ointments and creams are produced. Waxes, toxic chemicals, plant fertilizers, dyes, solvents, paints, dishwashing detergents, polymer films, plastics, rubber, rubber, synthetics, textiles are all post-processing products. Vaseline is used to make the basis for shampoos.
Take a look around, many do not even think about what a great variety of objects of oil origin surround us. Take the same toothbrush, keyboard, toys, even the exterior trim of cars, shoes. Metallurgists use such "unnecessary" elements of oil as coke residues, which are suitable for creating electrodes. Chemists produce sulfuric acid from the "black liquid" and sulfur. But, despite all the usefulness of this raw material and its applicability in many areas, Mendeleev believed that the way oil is used is stupidity. He tended to think that it had to be used correctly, because burning it was unprofitable.
Varieties
Like plants, oil also has its own classification. It is divided according to various criteria: lightness, quality, uniformity. All oil reserves in the world have a different composition, and therefore have their own names and values. The Brent brand serves as the standard for quality and value. Other firms are adjusting to it, making the price lower, because a different grade is heavier and with impurities.
Sulfur is the main enemy of cars and engines, as it disrupts their operation. Therefore, its content in oil should be less so that the fuel is not of poor quality. The more sulfur it contains, the lower the price. Unfortunately, they are not in demand for this reason. Russian reserves oil. There is no variety in the world that would not contain sulfur at all. But despite this, the requirements for fuel are becoming more stringent in this aspect. However, not everything is so hopeless for Russia. The government is taking a number of actions to create conditions for improving the quality of oil and its ability to compete. In the meantime, its cost is slightly inferior to the products of the Brent brand.
Oil reserves in the world by country
There are oil fields in various countries. Where is the largest amount of this raw material?
How long will oil last? Venezuela has almost a fifth of all world bases of this raw material. These are the largest oil reserves in the world. Also, this country is a leader in its production. But the palm in terms of consumption, and this impressive number - 20 million barrels per day, is confidently held by the United States of America.
It is quite difficult to accurately answer the question of how much oil reserves there are in the world. Although, according to statisticians, this figure is approximately equal to 3,000 billion barrels, or 400 billion tons.
Russia has very impressive reserves, and in the near future will not need to purchase this product from other states (even if we do not have the largest oil reserves in the world). How long will this raw material last? Experts answer this question with caution. The study of the territory leaves much to be desired, but this gives an advantage, because it is not known whether other large oil fields will be discovered in our native land. In addition, mining is carried out not only on land, but also in the sea.
If you imagine how many barrels of this fuel are produced, then your head will spin. But everyone understands that everything is not eternal, no matter how huge the world's oil reserves are. It is not known exactly how many years it will last, but according to the modest calculations of analysts, the raw materials will end after half a century of use. This is taking into account the fact that oil consumption will not increase every year. But recently there has been a clear trend towards increasing the use of this hydrocarbon. Unfortunately, not all countries have oil reserves in the world, which also leads to its consumption in large quantities.
Theory of self-healing
Along with the accepted explanation for the appearance of oil, there are other interpretations of this process. One of these theories was proposed by the famous chemist Mendeleev. He believed that oil reserves in the world are formed not in millions, but in several hundred and even tens of years, thanks to the regeneration of hydrocarbons in already depleted wells. This is proved by the fact that the fields that have dried up give oil again. But this theory is always hushed up, and this raises suspicions. After all, there are stakeholders in this, such as the owners of large mining companies who will control oil prices and sing praises that it will end soon.
The exact answer will be able to give us only the next generation. Perhaps the current theories are wrong, and in the near future someone will discover the mystery associated with the appearance of oil and the processes that accompany this transformation. Naturally, the statement about its inorganic origin is more favorable for mankind, it gives hope that the main resource of the planet will not be depleted at all. But this theory says that carbon and hydrogen seep into the bowels of the Earth after tens to hundreds of years. Therefore, based on these arguments, people will have to create a work schedule for oil wells, as well as calculate all the nuances associated with the timing of recovery.
Conclusion
A final decision regarding the dispute over the origin of this hydrocarbon has not yet been made. Although there is a heated debate about this, as the facts support both positions equally.
Despite the difference in opinions regarding the origin, people understand that whatever the world's oil reserves, humanity will one day have to look for alternative sources like it. And now scientists are puzzling over how to create a prototype, that is, synthesized oil, as well as substances similar to it in properties and composition.
Venezuela is the richest country in oil modern world. According to updated statistics, in 2018 its oil reserves amount to more than 297 million barrels, which is about 20% of all world oil reserves. Saudi Arabia is in 2nd place with a slight margin: its reserves make up 18% of the world's reserves. 
The top ten countries with the largest oil reserves today include 4 countries of the Persian Gulf: , and , 2 representatives - and , as well as and . Russia in this list takes the 8th position.
Oil is a very common mineral resource in nature. Over the past 50 years, geologists have identified about 600 oil and gas basins. According to various estimates, the area with promising oil and gas fields ranges from 15 to 50 million km².
The general geological estimate of the planet's oil reserves is from 250 to 500 billion tons, and if we also take into account the heavy oil contained in tar sands and oil shale, then the value jumps to 800 billion tons.
The figures are gigantic, but this does not mean at all that humanity can sleep peacefully without worrying about tomorrow's energy resources. The fact is that the development of shale is very expensive and environmentally dangerous, so few people are engaged in their production. General geological reserves imply all the oil contained in the bowels of the earth, but most of it, with the current level of technological development, people cannot yet extract. Therefore, along with the concept of a general geological reserve, the concept of a proven or reliable oil reserve is widely used, i.e. the amount that is already today at the current level technical progress can be extracted. And now 800 billion tons are gradually turning into 150 billion tons. It is this figure that is an indicator of reliable oil reserves in the world today. And when it comes to the oil reserves of a country or region, it is precisely the reliable reserves that are meant.
However, it should be noted that any indicators related to the extraction of mineral resources, especially fuel, cannot be absolute and accurate.
Exploration work on the planet does not stop even for a minute. Therefore, despite the fact that humanity is increasing oil production every year, its reliable reserves are also increasing.
Modern technologies make it possible to explore ever greater continental depths. But the real technological breakthrough was the possibility of developing offshore fields. It is thanks to offshore development that some European countries, such as Norway and Great Britain, have become leaders in oil-producing countries. And Venezuela has become the world leader in terms of reliable reserves, having overtaken the traditional leaders - the countries of the Persian Gulf.
How was OPEC formed?
The main feature of the geography of world oil resources is that its main reserves are in developing countries, and the main consumer of oil and oil products are highly developed countries.
The problem of shortage of oil resources became more acute in the 1970s. the last century. It was during these years that the first wave of the energy crisis covered the highly developed countries of the world. And this was due to the cessation of the supply of cheap fuel from the Middle East.
Until now, energy prices from the Persian Gulf have been so miserable that it never occurred to anyone to engage in large-scale exploration of new deposits anywhere else. The sheikhs of the Arab countries took advantage of this fact and united to control the world black gold market.
The agreement on joining joint efforts in this direction was signed back in 1960 in the city of Baghdad, but the participating countries gained real strength only a decade later. This is how the organization of oil-exporting countries known as OPEC was born.
The leaders in oil reserves and production at that time were Saudi Arabia, Iran, Iraq, Kuwait and, as a result, they also became the leaders of the organization. These Arab countries managed to win decisive positions in the world oil market due to the fact that 70% of all world reserves of this energy resource were concentrated on their territory, and there were the largest oil fields with an initial supply of raw materials of more than 1 billion tons.
How and why oil reserves statistics change
The heyday of the world oil era fell on the 70-80s. the last century. It was then that large oil fields were discovered in non-OPEC countries, including the Soviet Union. These include the development of Alaska, the Gulf of Mexico, the shelves of California and the North Sea, Western Siberia, Volga-Ural region.
The discovery of new deposits brought to the world oil market new players. Although the newly discovered oil fields were very large, no one still could compete with the countries of the Middle East either in terms of oil reserves or in terms of its production level.
From the end of the 80s. all the largest and most profitable oil fields were discovered. It was no longer possible to continue to increase the reserves of raw materials at the expense of new deposits. And then a new trend arose: it consisted in the fact that they began to achieve an increase in oil reserves through additional drilling at existing fields.
This method was primarily resorted to by the top five of the richest Middle Eastern oil powers, which did not want to lose the status they had won. This included Saudi Arabia, Iran, Iraq, Kuwait and the United Arab Emirates. Thanks to the new tactics, for another 20 years these countries held the palm in terms of the number of proven oil reserves, and at the same time as the largest producers and exporters. 
But other countries, both rich and not so rich, have taken advantage of the additional drilling method, such as Canada and Venezuela. The result was not long in coming, and by the second decade of the XXI century. The picture of countries leading in terms of explored reserves of black gold has changed. Having displaced Saudi Arabia to the 2nd place, Venezuela became the absolute leader in terms of reserves. And Canada confidently took the 3rd position, displacing Iran and Iraq.
Since 1990, Saudi Arabia, having reached the level of oil reserves of 260 million barrels, continues to remain at this level. Iran and Iraq at the same time reached the level of 100 million barrels. But Canada and Venezuela have made a sharp jump up in the last 1.5 decades. At the same time, until the beginning of the 20th century. Canada had meager reserves of about 10-20 million barrels.
A sharp increase occurred in 2002-2003, when the development of new fields and the use of new technical means overnight increased the country's reserves to 175 million barrels. And Venezuela, for the same reasons, increased its own from 100 million barrels in 2010 to 297 million in 2013.
Thus, we can sum up. The richest country in oil is a very conditional concept. The situation changes from decade to decade, and sometimes it can change dramatically within 1-2 years. Exhaustibility mineral resource; discovery of new deposits; additional studies of deposits discovered earlier, but at that time recognized as unprofitable; the improvement of mining technologies, allowing to penetrate to new depths - all this leads to a constant change in statistics.
The Middle Eastern countries, albeit slowly, are losing their leadership positions, and they are being replaced by new ones. characters. Today, the top five in terms of reserves in 2018-2019 looks like this: Venezuela, Saudi Arabia, Canada, Iran, Iraq. What will happen tomorrow - time will tell.