Not Shell - well, it might have been Shell at one time but the painted-over sign would have shown the Flying Red Horse and Mobil logo, as I remembered seeing it on my trips to Las Vegas as a roadie in 1977. Never stopped there - would buy gas at the Douglas station in Baker. That place is now a Shell!

I'm guessing Yates Well was supplied by whoever was the Mobil distributor in Las Vegas. Back then, California and Nevada gas was the same stuff.