which is the biggest oil refining company on the earth?

Answer 1

Saudi Aramco, the national oil company of Saudi Arabia is the largest oil corporation in the world and the world's largest in terms of proven crude oil reserves and production.
Saudi Aramco is responsible for 99 percent of the Kingdom's proven crude oil reserves of 259,200 billion barrels (41.2 109m³) -- about a quarter of the world's total. That is more than double the total of Iraq, the country with the world's second largest reserves, and nearly 12 times the reserves of the United States. Recent production has averaged some 8 million barrels (1,300,000 m³) per day. That is more than twice the output of the next highest producer and nearly five times greater than the largest U.S. oil company.
they expect to double the number of it's oil rigs by the end of this year.

Answer 2

Depends on how you define "biggest".

I believe the company that does oil refining and has the largest total asset value is Exxon Mobile.

Answer 3

It is ExxonMobil, ExxonMobil is not only the world's biggest oil and gas company but also the world's biggest seller of petroleum products with With $422.3bn market value.