There was a time when the term "Big Oil" meant something. One hundred years ago, "Big Oil" was Standard Oil. In the 1950s, the Seven Sisters would have qualified for that name. Today, most people in the U.S. think of "Big Oil" as the companies they can name based on the logos they see at the gas station of the so-called "supermajor" international oil companies which are publicly traded and/or privately owned, such as ExxonMobil, Chevron, BP, ConocoPhillips and Shell.
But are any of these companies truly "big" in the oil business in 2016? That depends entirely on how you measure big: by revenue, amount of oil produced, or the amount of proven oil reserves a company controls. I would argue that the last is the most important measure, but let's see how companies stack up on each of these metrics.
Oil Companies by Revenue
In October of 2015, Rig Source published an infographic of "10 Largest Oil Companies*", with the asterisk denoted their metric as gross revenue (not their actual profit) for 2014 in US dollars. Here is the breakdown:
1) Sinopec (China) - $455.06 billion
2) China National Petroleum - $432 billion
3) Royal Dutch Shell - $422.11 billion
4) ExxonMobil - $394.11 billion
5) Saudi Aramco - $378 billion
6) BP - $358.7 billion
7) Total, S.A. (France) - $266.02 billion
8) Kuwait Petroleum Corporation - $251.94 billion
9) Chevron - $192.31 billion
10) Lukoil (Russia) - $114.17 billion
4 of the companies on this list (Sinopec, CNPC, Saudi Aramco, and Kuwait PC) are NOCs, or nationalized oil companies, which the government either owns a majority stake in or controls outright.
Oil Companies by Production
If we look instead at the amount of oil produced by companies in 2013 according to Forbes, the story is slightly different:
1. Saudi Aramco - 12.7 million BOE (barrels of oil + natural gas equivalents) per day
2. Gazprom (Russia) - 8.1 million BOE per day
3. National Iranian Oil Company - 6.1 million BOE per day
4. ExxonMobil - 5.3 million BOE per day
5. Rosneft (Russia) - 4.6 million BOE per day
6. Royal Dutch Shell - 4 million BOE per day
7. PetroChina - 3.9 million BOE per day
8. Pemex (Mexico) - 3.6 million BOE per day
9. Chevron - 3.5 million BOE per day
10. Kuwait Petroleum Company - 3.4 million BOE per day
11. BP - 3.1 million BOE per day
12. Total - 2.6 million BOE per day
13. PetroBRAS (Brazil) - 2.5 million BOE per day
14. Qatar Petroleum - 2.4 million BOE per day
15. Abu Dhabi National Oil Company (UAE) - 2.4 million BOE per day
16. Lukoil (Russia) - 2.3 million BOE per day
17. Iraqi Oil Ministry - 2.22 million BOE per day
18. Sonatrach (Algeria) - 2.19 million BOE per day
19. PDVSA (Venezuela) - 2.1 million BOE per day
20. Statoil (Norway) - 2 million BOE per day
By this metric, 7 of the top 10 are NOCs, and 13 of the top 20 are NOCs.
Things start to get a bit complicated here when we start comparing production by individual companies versus production by countries as a whole. The United States, for example, is a country that allows individuals and companies to own mineral rights, whereas most countries nationalized such resources such that they are owned by the government. So if we compare the output of countries as a whole for 2014, we see there is some nuance to this story:
1. U.S.A - 14,021 thousands of barrels of oil equivalent per day ( or MBOEBPD)
2. Saudi Arabia - 11,624 MBOEPD
3. Russia - 10,847 MBOEPD
4. China - 4,598 MBOEPD
5. Canada - 4,383 MBOEPD
6. United Arab Emirates - 3,474 MBOEPD
7. Iran - 3,337 MBOEPD
8. Iraq - 3,364 MBOEPD
9. Brazil - 2,966 MBOEPD
10. Mexico - 2,812 MBOEPD
11. Kuwait - 2,767 MBOEPD
12. Venezuela - 2,685 MBOEPD
13. Nigeria - 2,428 MBOEPD
14. Qatar - 2,055 MBOEPD
15. Norway - 1,904 MBOEPD
16. Angola - 1,756 MBOEPD
17. Algeria -1,721 MBOEPD
18. Khazakhstan - 1,719 MBOEPD
19. Colombia - 1,016 MBOEPD
20. India - 1,011 MBOEPD
Countries such as Saudi Arabia, Iran, Iraq, Algeria, Norway, and Kuwait have only a single nationalized oil company, so it's quite easy to compare the financials of their NOCs to the total output of the country. Countries such as Brazil and Mexico have a few smaller players but the NOCs are by far the largest players in those countries. In Russia, there NOCs (Rosneft and Gazprom), private companies (Lukoil), and up until recent sanctions, international supermajors . Others, such as the U.S.A, have literally thousands of exploration companies operating there. An additional complexity is trying to separate the finances (revenue and profit) from the source of production for the international supermajors. Companies like Chevron produce oil in West Texas, but they also have contracts in many other countries and partnership deals to produced nationalized resources in other locales, so the relationship between production, reserves and ownership becomes a bit murky.
Oil Companies by Reserves
Another metric (and arguably the most important) is the total reserves a company controls. How much an oil company produces on a daily basis can clearly affect the market price of oil, but this strategy is useful only when put into the context of how much a company (or country) could put on the market. But getting a complete picture of simply what the reserves are is a complex and and even murkier situation than production numbers, which are quite reliable by comparison because the vast majority of oil is bought and sold in highly regulated financial markets.
For example, according to the most recent Wikipedia entry on the topic, the top 10 would break down like this:
1) Saudi Aramco (~303 billion BOE)
2) National Iranian Oil Company (~300 billion BOE)
3) Qatar Petroleum (NOC) (~170 billion BOE)
4) Iraq National Oil Company (~134 billion BOE)
5) PDVSA (Venezuela NOC) (~129 billion BOE)
6) Adu Dhabi NOC (~126 billion BOE)
7) Pemex (Mexico NOC) (~111 billion BOE)
8) Nigerian NOC (~68 billion BOE)
9) NOC Libya (~50 billion BOE)
10) Sonatrach (Algeria NOC) (~39 billion BOE)
It has been argued that since the technology exists to extract oil directly from oil shales, heavy oil bitumen reserves and other "unconventional" reservoirs, the total reserves of the US now exceed that of Saudi Arabia. But this depends on how reliably one can estimate:
1) How much oil is in the ground
2) How much of it can be recovered
3) How much of the reserve numbers are validated facts and how much is political brinksmanship.
For publicly traded companies that require complete transparency for their shareholders, #3 is not a legitimate concern. But for NOC for countries like Saudia Arabia, it's a different story. The entire economy of the nation, as well as all of the government services and infrastructure for their society, are paid for by the sale of their single valuable asset: oil. Because of the political implications, NOCs tend to keep their actual reserve estimates as very closely-guarded secrets. From the their public statements, as well as their activities with global contractors, we can make some estimates of their reserves.
Reserve numbers are also a moving target, driven largely by both technology and cost. The aforementioned shale reservoirs and unconventional plays in the US were not even considered part of our reserve estimates 20 years ago, but the enabling technologies (such as hydrofracking) changed this. Similarly, as we improve techniques to remove more oil from existing fields and reservoirs (a practice known as enhanced oil recovery, or EOR) allows us to extract a greater percentage of oil from a field. A "good" reservoir is one that you might be able to extract 30% of the oil from using conventional pumping techniques, but you might be able to bump that to 40% using steam or CO2 injection. These EOR techniques are more expensive, so the relationship between cost, technology and recoverable reserves.
Conclusion
So, who is Big Oil? The answer is, "That depends". But it's quite clear that when the average man on the street thinks or hears the words, "Big Oil", he's probably thinking of a logo for a company that he knows rather than the flag of a country he probably can't identify.