Conversation so far:
where do we get petroleum as a resource
Today, petroleum is found in vast underground reservoirs where ancient seas were located. Petroleum reservoirs can be found beneath land or the ocean floor.
what is petroleum used for
Petroleum is used to make gasoline. It is also processed and part of thousands of different items, including tires, refrigerators, life jackets, and anesthetics
is petroleum renewable
Petroleum, like coal and natural gas, is a non renewable source of energy.

Question: where is the largest supply
Self-contained rewrite: where are the largest reserves of petroleum in the us