Which airports have the highest fuel upload?
The best data I could find is in this paper about biofuels, which has data for US airports in 2014. Based on my reading of the chart on page 14 and some conversion:

Airport  Millions of barrels per year
KLAX     48.6
KJFK     43.5
KATL     30.8
KORD     30.5
KSFO     28.3
KMIA     26.0
KDFW     25.4
PANC     19.0


Comparing this to the top US airports in 2013, it is interesting to note that LAX and JFK use significantly more fuel than KATL, despite passenger traffic figures ranked the other way. Also notable is Anchorage showing up here right after DFW, while MIA and ANC are the only ones not in the top 10 by passengers, showing up at 11th and 58th, respectively.

Figures for other countries have been harder to find. This article from 2004 estimates the Dubai International usage at 24.2 million barrels that year, which has certainly grown since then. The 2012-2013 environmental report from Emirates Group lists their consumption at 73.9 million barrels, and half of this figure would be in line with the other numbers available.

I found a similar figure for Heathrow, listing it at 20-25 million liters per day, depending on season, which gives a range of 61.2 to 76.5 million barrels per year, well ahead of the US airports.

Becoming even fuzzier, the pipeline to Narita Airport in Tokyo transported 130 billion liters in its first 30 years of operation, which averages out to 36.3 million barrels per year.