When Mexico gambled on ending decades of state control of its energy industry, officials said they hoped the move would promote investment and give the country access to technical expertise. That wager now appears to be paying off.

The government began auctioning off rights two years ago to drill in parts of the Gulf of Mexico. On Tuesday, an international consortium of energy companies said they had discovered a large oil field, and another firm said it had discovered more oil than expected in a separate area.

The overhaul of the Mexican oil and gas sector in recent years eventually ended the state energy company’s seven-decade domestic monopoly on exploration and production. The aim was to arrest years of declining oil output, blamed on a slow-moving public sector that lacked the technology to exploit opportunities in deep-sea drilling, or shale oil and gas.

The two announcements on Tuesday appeared to suggest that Mexico’s strategy, which was met with criticism when it was first pushed through, was succeeding.