excessive engine oil comsumption a quart about every 500 miles
1 quart every 500 miles is not considered excessive.
How many miles on it and have you changed the oil you use? When did it start using oil? What changed from before the oil problem?
I’d sell that thing as fast as I could.
Have you put the car on jackstands, got under there on a creeper, and made absolutely sure there’s no oil leak to take care of first . . . ?!
Not sure if you have the 4cyl ecotech motor, but they were know for oil consumption issues. A quick search shows 2011-2013 Captiva sports and several other GM cars had a warranty extension for a PCV issue that caused the problem. Yours is not likely covered under the extension but might be experiencing a similar issue.
GM considers significantly more than 1 quart in 2000 miles excessive: www.gmls4.com/index.php?topic=414.0 Therefore you have a problem even by GM standards, assuming the vehicle is actually burning oil. Follow @db4690 's advice and check for a leak.
I think it’s excessive but that doesn’t matter. If I had such a car I’d be extra vigilant about keeping it topped up, and would buy inexpensive oil that meets the carmaker’s standards.