After 75 years of waiting, the opportunity is nigh: Beginning in 2015, Mexico will reopen its oil and gas reserves to international companies to exploit and profit. It only stands to reason that U.S. producers are best positioned to be at the front of the line to capitalize on the vast array of hydrocarbons becoming available south of its border, but will they?

American producers know all too well the value of being an early entrant into new basins, but the Mexican opportunity is likely to catch them flat-footed. The Mexican energy reform has blossomed like cacti following a rare desert rain.

“The whole energy reform has been amazing because of the pace at which it is happening. All this has happened so fast there has been confusion,” said Jorge Lopez-de-Cardenas of LDC Consulting and a former engineer with Schlumberger Mexico. Lopez spoke to an audience at the Mexican Energy Infrastructure Symposium in November.

The urgency stems from falling revenues funding Mexico’s treasury. One-third of Mexico’s tax base comes from state oil company Pemex, which has held a monopoly since 1938, and Pemex production has steadily declined by 1 million barrels of oil per day (MMbbl/d) since 2004. Only one field represented 60% of Pemex’s production stream, offshore Cantarell, and it is declining rapidly.

Mexico’s push to reform its energy policy is specifically designed to reinvigorate cash flow into the national coffers, with the help of independent companies.

Already, Mexico has established what Pemex, restructured as an independent producer, gets to keep in Round Zero: all of its 13 Bbbl of proved reserves; 83% probable reserves; and 21% of prospective reserves. The rest of Mexico is open, to be parsed out in bidding rounds over time, and Pemex must competitively bid against all other comers.

And the first bidding begins in May—six months!—with five packages offered throughout the year. Mexico’s Round One has something for everyone: 169 diverse blocks of onshore and offshore reserves, conventional and unconventional, exploration and extraction, shallow and deepwater, light and heavy crude, and gas.

The buzz is on. Mexican energy officials stopped by Houston in October, on a road show to exhibit the offered packages. Four-hundred people packed the room, with more turned away at the door.

“Round One encompasses all types of fields,” said Lourdes Melgar, deputy secretary of hydrocarbons for Sener, Mexico’s ministry of energy, at the event. “We selected areas with infrastructure that will allow production sooner.”

Shallow-water oil and extra-heavy oils will be first to be auctioned, representing 43 blocks. Bids are due in May for shallow water and June for heavy oils, also offshore.

Next up is Chicontepec and unconventionals. Chicontepec is a more mature producing onshore region in the state of Veracruz. Here, “you have three types of plays overlapping—shale, tight oil and conventional resources,” explained Juan Carlos Zepeda, chair commissioner for the National Hydrocarbons Commission of Mexico.

Other unconventionals include eight blocks in northern Mexico near the Texas border in the Burgos and Burro-Pichacos basins. These are predominately gas reserves, with less access to infrastructure. Bids are due in August. Another onshore conventional package follows in September.

Perhaps the most anticipated package is the one offering deepwater Gulf of Mexico assets. The last to be bid in October, it features reserves in two areas: 17 blocks in the southern deepwaters offshore Veracruz with 3.2 Bboe of prospective resources; and 11 blocks in Perdido Field with 1.6 Bboe, opposite discoveries on the U.S. international border. In addition, Pemex is seeking partners in three exploration blocks.

The process for licensing Mexican reserves is in place. The remaining wild card is the terms and conditions for the fiscal regime, scheduled to have been released by the end of November but after this writing. With so many positives already established, industry is optimistic the financial structure will incentivize investment.

“While the fiscal regime has not been set out, the royalty rates will be competitive with other countries,” said Dr. Ernesto Marcos Giacoman, at Hart Energy’s Executive Offshore Conference in October.

The data room for shallow-water blocks opens in January. International companies are already in line, several with long-time offices in Mexico waiting for this day. Relationships matter below the border, and those who build them will benefit as first movers.