The deal permits Pemex and ExxonMobil to exchange ideas regarding oil and gas extraction, while maintaining strict guidelines against profitable ventures with private, foreign firms.
Mexican law prohibits Pemex from entering into profit-sharing ventures with other companies, a law that is expected to come under review in the coming months and could be subjected to a congressional vote come April.
President Felipe Calderon is reportedly interested in opening up the Mexican energy sector to outside investment but faces stiff opposition from some Mexican lawmakers who are wary of diluting profits despite assertions from experts that output would most certainly increase with the help of foreign energy giants.
"The government wants to propose an ambitious energy reform that would include opening downstream oil -- and possibly deep sea drilling -- to private investment, but a number of factors are pushing it to wait for a more appropriate time to publicly announce a proposal," said Enrique Bravo, an analyst with the New York-based Eurasia Group.
Pemex profits account for a large portion of the Mexican budget and fund most of the country's social projects, a condition that makes it untouchable to many federal officials.
Recent reports show that Pemex output has peaked in recent years, with 2004 representing the height of production.
Pemex operational output fell 5.3 percent in 2007, according to officials, with daily production down to 3.08 million barrels per day. For three months last year, production actually fell below the 3 million bpd mark.
Last year's production report for the country's largest oil field, Cantarell, was even worse than the national average.
Cantarell's production fell to 1.2 million barrel per day during the last month in 2007, a 16 percent drop from the previous year.
Jaime Brito, an analyst with the U.S.-based energy consulting firm PFC Energy, told United Press International that Pemex "is up to its neck in debt."
Mexico is still holding out hope that a new oil field discovered in 2006 will help Pemex bolster its production levels in the coming years.
Extraction from the new field is unlikely for another decade, Luis Ramirez, Pemex chief executive, said at the time. That would give officials plenty of time to ascertain the viability of the new field and determine whether its production levels could live up to expectations.
That would certainly be news well received in Washington, where the Bush administration has stressed the need to reduce U.S. dependence on the Middle East for its energy needs and is looking to Mexico to increase its production. America's southern neighbor already sends on average 1.8 million bpd across the border.
That increase likely won't happen, even in the long term, without the help of oil giants like ExxonMobil and others. Whether Mexican lawmakers allow that to happen remains to be seen.