If Texas were a country it would be the fourth largest oil producer after the USA, Saudi Arabia and Russia. Texas passed Iraq and Iran in oil production.
There has been some talk about the US stopping oil and gas production. If such an energy policy were attempted, it is clear that Texas would secede from the USA to continue producing oil and gas.
The second largest producer of oil in 2018 was North Dakota (443 million bbl), followed by New Mexico (226 million bbl), Oklahoma (187 million bbl), and Alaska (175 million bbl). Total natural gas production in Texas was 8.8 trillion cubic feet (Tcf) in 2018, compared to 8 Tcf produced in the previous year. The second largest producer of natural gas last year was Pennsylvania (6.1 Tcf), followed by Alaska (3.2 Tcf), Louisiana (2.7 Tcf) and Oklahoma (2.3 Tcf).