The brand of a gas station has rarely anything to do with a refinery. In fact there are anti-trust laws in place (at least in NY State) that prohibit a franchise from requiring that a franchisee purchase gas only from the franchise. A franchisee is free to purchase gas from any company they desire.
For a majority of gas stations (i.e. all the non brand company owned ones), brand name is a pure marketing agreement and has little to do with anything else (e.g. gas quality).
After Hurricane Sandy, I learned a lot (through TV news and web sites e.g. http://www.governor.ny.gov/press/110320 ... tageupdate
) about how gas distribution works on Long Island NY. All the gas on Long Island comes on barge and one barge company (Northville Industries) has a de facto monopoly on it for the middle section of Long Island. This company pumps gas from barges to a distribution point located at the center of the Island (https://www.waze.com/editor/?zoom=7&lat ... rks=391792
) where all the brands pick up their gas to deliver to the gas stations. You can read more about this on Northville Industries web page (http://www.northville.com/Lipipeline.aspx http://www.northville.com/Locations.aspx
There were long gas lines on Long Island (some of which I had the misfortune to wait on) after Hurricane Sandy and the main reason for these lines was that there were even longer lines at the Northville terminal to fill up the tankers as the terminal had taken a hit from the Hurricane and a secondary reason was that all the NY City gas stations were coming to this terminal to fill up their tankers because NY City terminals were even worse hit.
The main point of this story is that brands have little to do with the tanker truck that shows up to fill up the tanks at the gas station and even less to do with the actual fuel refinery.
The NY Metro area uses about 28 million gallons of gas and diesel every day.