The Cantarell field reached an early peak in production of 1.1 million barrels per day in April of 1981 from 40 oil wells. By 1994 the production was down to 890,000 barrels of oil per day. At that time, cumulative production was 4.8 billion barrels. In 1995 it was producing 1 million barrels per day and the Mexican government decided to invest in that field to raise the production level. They built 26 new platforms, drilled lots of new wells and built the largest nitrogen extraction facility capable of injecting a billion cubic feet of nitrogen per day to maintain reservoir pressure. Doing this raised the oil production rate in 2001 to 2.2 million barrels per day. Today  the field produces only 480,000 (less than half a million) barrels.
Cantarell text is Copyright 2004, 2007 G.R. Morton. Original at http://home.entouch.net/dmd/cantarell.htm
Cantarell production has dropped off drastically in recent years. In 2009 daily production had fallen to 500,000 barrels per day, (half a million BPD) and is expected to level off around 400,000 BPD. Basically, the acceleration of production with nitrogen injection has recovered more oil but depleted the total field faster. In general aggressive techniques for increasing yields end up meaning that the fall off in production will be steeper.