I think the tent was already in place capturing oil and gas in Jan 1988 when we arrived on the scene. Work by the Luyendyk-Liefer group compared seeps to hi res seismic (chirp or 3.5 KHz or something ) from Pete Fischer from 1976, and the seeps in the area of production have (greatly?) diminished.

A little easier to put such structures in place a a few tens of meters water depth than in 1.5 km that B.P. is dealing with.
Chris