After dealing with plummeting oil prices this year, things could get worse for the two biggest U.S. oil companies. However, it won’t do any lasting damaging to the behemoths thanks to a profitable refining business.

Exxon and Chevron have strong refining operations that have helped them weather the decrease in oil prices, enabling them to actually increase profits in the third quarter. In fact, refining and chemicals can actually benefit from decreasing oil prices, according to the Associated Press.

The global price of oil is down 18 percent since the start of the third quarter, which cut into the companies’ revenues: a 4 percent slip for Exxon, and 8 percent for Chevron.

The reason why low oil prices often mean more profits for refining and chemical operations is that it means raw material costs less, raising the profit margins for the activity. Exxon’s refining operations jumped 38 percent compared to last year, and Chevron’s tripled. That pushed Exxon’s earnings up 3 percent for the quarter to $8.07 billion, while Chevron rose 13 percent to $5.59 billion.

The oil companies say that rising profits from refining prove it’s a bad idea to follow the recent trend of spinning off those operations to appeal to investors. ConocoPhillips, Marathon, and Hess have all gotten out of the refining business.

Exxon CEO Rex Tillerson said remaining integrated gives the company a competitive advantage, which is important to have in the face of the market rollercoaster oil prices are often subject to.

In contrast, international oil companies such as BP and ConocoPhillips saw their earnings dip because of the oil prices.

However, the earnings rise for Exxon and Chevron could vanish in the fourth quarter if oil prices stay low. In that situation, refining profits probably won’t be enough to make up for the difference.

Despite the global downturn in oil, Exxon pledged to continue investing in new projects.

Exxon plans to boost oil and gas production to up to 4 million barrels of oil per day by year’s end as it looks to reverse a trend of low output. The oil giant’s production had fallen 4.7 percent this past quarter compared to last year, with production at 3.83 million barrels of oil per day — the lowest since 2009.