Which countries have oil stockpiles?

Question

I was looking at data on the Energy Information Administration's website on global production and consumption of crude oil and noticed that in many years consumption exceeds production -- from 1980 to 2019, there's a total difference of 2.4 billion barrels. Does this mean there are already reserves of oil that have been extracted in previous years and stored?

But, when I look up what "oil reserves" are on Investopedia, it says:

Oil reserves are an estimate of the amount of crude oil located in a particular economic region. To qualify, oil reserves must have the potential of being extracted under current technological constraints. Reserves are calculated based on a proven/probable basis, meaning oil pools situated in unattainable depths, for example, would not be considered part of a nation's reserves.

So, my questions are:

1. What are barrels of oil that are already extracted and sitting around waiting to be used called?
2. Which countries have these already-extracted oil reserves, and how big are they?
3. Does this storage account for the difference between production and consumption?

Answer 1

The discrepancy between production and consumption is due to stock changes, additives, substitutions, and differences in accounting

I took a look at Our World in Data's reports on total oil production and consumption to track this down. They source their data from BP's energy charting tool which allows you to plot them both on the same graph:

In the notes for production, Our World in Data provides this explanation of the discrepancy:

Differences between the world consumption figures and world production statistics are accounted for by stock changes, consumption of non-petroleum additives and substitute fuels and unavoidable disparities in the definition, measurement or conversion of oil supply and demand data.

Already-extracted oil in storage is called strategic petroleum reserves or oil stocks

From Wikipedia:

Global strategic petroleum reserves (GSPR) refer to crude oil inventories (or stockpiles) held by the government of a particular country, as well as private industry, to safeguard the economy and help maintain national security during an energy crisis. Strategic reserves are intended to be used to cover short-term supply disruptions.

Interestingly, historic production exceeded consumption in every year until the 1980s oil glut, "a serious surplus of crude oil caused by falling demand following the 1970s energy crisis."

Given that the U.S. and many other nations started their reserves in response to the 1970s energy crisis, you'd expect the opposite to be true if stock changes were the biggest source of discrepancy; if every nation was slowly increasing their reserves, production should exceed consumption.

Thus, it would seem that the other factors (additives, substitutions, and accounting differences) must be more significant when accounting for the discrepancy.

At least 40 nations maintain strategic petroleum reserves

The International Energy Agency keeps up to date information on stocks held by member nations. Countries marked "net exporter" are not required by IEA to maintain stocks as they have their own production, but many still do (such as the U.S., which has the world's largest).

The IEA total is available here:

In addition to IEA members, Wikipedia lists at least 14 others including China, India, Iran, and Russia.

I've compiled some of the numbers in the table below.

Country or region	Million barrels	Days of consumption
China	684	90
IEA Europe	1 319	146
India	132	49
Iran	14	8
Russia	15	4
U.S.	727	60

Answer 2

what are barrels of oil that are already extracted and sitting around waiting to be used called

These barrels of oil can also be called "oil reserves". You might need context to differentiate between the two. Example headline.

Which countries have these already-extracted oil reserves, and how big are they?

Many countries do. See Wikipedia.