If the heavier components (ethane, propane, butane) are present in any significant quantity, they are fractioned out of the natural gas before it is delivered to the customer. They’re valuable!
“Natural gas” as delivered to the customer is nearly pure methane. The characteristic smell is a mercaptan added to make the odorless hydrocarbon detectable by humans.
One of my college chemistry professors made the error of wearing his nice leather-soled Florsheim shoes in his lab. While in the lab, he managed to dribble some methyl mercaptan on the floor and stepped in it. The vent hoods in the lab carried off the smell. Not so when he got into his car to go home. The car suddenly smelled like a large pile of fresh dog poop. He realized the problem, drove his car over to the nearest trash can in the parking lot and dropped his Florsheim shoes into the trash can.