Eugene Island Block 330 Oil Field - Depletion Rate

Depletion Rate

The oil field is best known for the controversy surrounding its depletion rate. According to a 1999 Wall Street Journal article:

Something mysterious is going on at Eugene Island 330. Production at the oil field, deep in the Gulf of Mexico off the coast of Louisiana, was supposed to have declined years ago. And for a while, it behaved like any normal field: Following its 1973 discovery, Eugene Island 330's output peaked at about 15,000 barrels per day (2,400 m3/d). By 1989, production had slowed to about 4,000 barrels per day (640 m3/d). Then suddenly -- some say almost inexplicably -- Eugene Island's fortunes reversed. The field, operated by PennzEnergy Co., is now producing 13,000 barrels per day (2,100 m3/d), and probable reserves have rocketed to more than 400 million barrels from 60 million. —Christopher Cooper, Wall Street Journal

However, Richard Heinberg provides his own figures:

Production from Eugene Island had achieved 20,000 barrels per day (3,200 m3/d) by 1989; by 1992 it had slipped to 15,000 bbl/d (2,400 m3/d), but recovered to reach a peak of 30,000 bbl/d (4,800 m3/d) in 1996. Production from the reservoir has dropped steadily since then. —Richard Heinberg, Energy Bulletin

The source of additional oil was analyzed as migrating through faults from deeper and older formations below the probable Jurassic and Early Cretaceous age. The oil contains biomarkers closely related to other very old oils which were long trapped in deep formations.

Eugene Island 330's fame comes from its status as an unusual anomaly. Most petroleum scientists believe that the depletion profile is adequately explained by replenishment from deeper reservoirs of normal biologically derived petroleum.

In regard to oil depletion concerns, while the rate went up again in the early 1990s along with the overall estimated recoverable petroleum, the rate has since declined.