The US Energy Information Administration on June 12 looked at the 
decline in proved oil and liquid reserves of publicly traded oil 
companies.
"Annual reports of 68 publicly traded oil companies indicated that 
their aggregate proved liquids reserves declined in 2016 for the second 
consecutive year,” the EIA said in a press release.
"The decline in proved reserves was heavily concentrated in a few 
companies that reduced their estimated reserves from Canadian oil sands 
projects. Downward revisions of existing resources, relatively low 
extensions and discoveries, and relatively high production also 
contributed to a decline in proved reserves,” the EIA said, adding that 
the 68 oil companies included in this analysis are listed on US stock 
exchanges and consequently are required to report their proved reserves 
annually to the US Securities and Exchange Commission.
Collectively, their global crude oil and other liquids production 
averaged 24 million barrels per day during 2016, or about 25% of the 
global total, the EIA said.
https://www.neweurope.eu/article/eia-oil-companies-proved-oil-liquid-reserves-drop-2016/