Editor’s Note: NGI’s Mexico Gas Price Index, a leader tracking Mexico’s natural gas market reform, is offering the following column by Eduardo Prud’homme as part of a regular series on understanding this process.

GOM fire

One month after the midterm elections offered hope for change in the Mexican energy sector, some worrying signs have again begun to surface. The case of the offshore Zama field is one such example. In early July, Mexico’s Energy Ministry (Sener) said it granted Petróleos Mexicanos (Pemex) operatorship of the Zama shallow water oil deposit. Zama straddles one block operated by Pemex and another operated by Houston-based Talos Energy Inc.

The original award to Talos resulted from a competitive bidding process that sought to maximize the income that the state...