Ghawar peaked a number of years ago(at over 6 mbd)

HO, where are you getting your stats on Ghawar? (I looked at the linked page, and didn't find a cite there either).

Greg Croft has different stats:

The Ghawar Field was discovered in 1948. Production began in 1951 and reached a peak of 5.7 million barrels per day in 1981.

http://www.gregcroft.com/ghawar.ivnu
It may take a bit to go back through the posts to find it, since I suspect it may predate TOD.  It may have been that it came from Matt Simmons, but I don't really remember and so will need to go back and look.  Sorry for the confusion, I'll start looking.
Still looking - there was some information here that was useful as you follow the leads through, in regard to the use of 4-D seismic to map the ingress of water through Ghawar, but it refers to the Croft numbers. Continuing . . . .