Mexico’s oil regulator on Thursday approved exploration plans for four deepwater areas operated by Royal Dutch Shell , after it gave the green light to five others earlier this week, committing the oil major to invest at least $791 million.

The plans stipulate that the Anglo-Dutch company could invest up to $1.06 billion in the four blocks, mostly dedicated to drilling at least six new wells.

One of the blocks is in the Perdido Fold Basin, which straddles the U.S.-Mexico maritime border in the Gulf of Mexico, while the other three are further south in the Salina Basin.

On Tuesday, the regulator, known as the National Hydrocarbons Commission, or CNH, approved Shell exploration plans for five other deepwater areas in the same two basins which included investment commitments of at least $397 million and as much as $1.316 billion.

Taken together, Shell could invest up to $2.4 billion in the nine deepwater areas over the next four years and will drill at least 13 wells in the projects.

The blocks are not expected to begin producing oil and gas until 2026 at the earliest, said CNH Commissioner Sergio Pimentel.

Shell won exploration and production rights to the nine deepwater blocks at an auction run by the CNH in early 2018.