How to compare the oil production in barrel vs production in tons
I suspect that 3.75 million tons of oil is actually tons of oil equivalent (toe). This is a unit of energy rather than mass. The US uses a barrel of oil equivalent (boe) as a measure of energy. The advantage of these energy units is that natural gas, coal, and refined petroleum products can all be measured in terms of tons or barrels of oil equivalent.

The US still measures oil production in volume. Depending on the quality of the crude oil, it takes between 6.5 and 7.9 barrels of oil to yield one ton of oil equivalent, with 7.33 barrels as an average value. That means that the 1 131 557 443 barrels produced in Texas in 2016 represents somewhere between 143 to 174 million tons of oil equivalent.