"oil trade" is correct and usable in written English.
You can use it in both formal and informal contexts. For example, "Oil trade is a major component of the global economy."
The international oil trade has switched toward Asia.
AMERICA'S chokehold on Iran's oil trade is tightening.
"It's going to trade like gold or oil trade.
That's a fifth of the oil trade worldwide.
The 1970s were good for Rich as he expanded the previously undeveloped oil trade.
One-fifth of the world's oil trade slips by its coast along the Strait of Hormuz.
Many of the accounts contained proceeds from the country's booming oil trade.
But relations warmed in the 1990's, and oil trade boomed.
In the space of decade China has built up an incredible array of infrastructure to handle its seaborne oil trade.
The disclosures about the oil trade with Iran come at a delicate time for the Kurdish region.
By the 1830s the palm oil trade had surpassed slave trading, and it has maintained its importance.
