Cushing Inventories - See for yourself Sattelite vHere, some fun for you oil bugs.
You can see the oil storage inventory levels at Cushing Oklahoma. There is a membrane across the top of the oil, and the lower the level, the more the shadow the sun casts.
I'll bet the Russians and the Chinese use their Sats to keep tabs on this. The Saudis are building underground vaults, I can see why.
https://maps.google.ca/maps?hl=en&ie=UTF8&ll=35.948481,-96.736164&spn=0.038425,0.06978&t=h&z=14