Mexico's national oil company Pemex has signed a deal with US based investment firms BlackRock and First Reserve to begin the second phase of a pipeline that will bring natural gas from the Eagle Ford shale to cities hundreds of miles south of the border.

Pemex CEO Emilio Lozoya-Austin signed the deal with representatives from both companies in Mexico City on Thursday last week.

Under the 25 year deal, BlackRock is investing US$4.6 billion and First Reserve is investing US$30 million in the Los Ramones II natural gas pipeline, earning them a combined 45% control of the ambitious energy project.

The Los Ramones pipeline will transport natural gas from Texas to Mexico and is intended to facilitate imports of cheap US gas and lower Mexico's high commercial electricity rates.