Ensco 8503 rig going back to Mexico for more Zama drilling

A semi-submersible drilling rig that last year helped find the two-billion barrel Zama discovery, in what was Mexico’s first private offshore well in history, is set to return to the Mexican waters where the operator will be working to learn more about the discovery ahead of the final investment decision in 2019.

Ensco 8503 – Photo by Cris DeWitt – Image shared with photographer’s permission

In an operational update on Thursday, Premier Oil, a partner in the Talos-operated Zama-1 discovery in the Block 7, said the appraisal drilling at the discovery would start in the fourth quarter of 2018, using the Ensco 8503 semi-submersible drilling rig. The rig is currently in the U.S. Gulf of Mexico, where it has a contract with Deep Gulf Energy, until mid-August, 2018.

Sharing plans on Zama drilling, Premier Oil CEO Tony Durant said on Thursday: “We’re moving forward with the appraisal program of the Zama discovery and we expect at least one if not two wells to spud in the second half of the year.”

Talos and Premier Oil have together with PEMEX submitted a notice of pre-unitisation agreement for the Zama discovery to SENER, the Mexican Ministry of Energy, for approval.

The reason for this is the fact that the Zama field extends to a nearby block owned by Pemex. Such an agreement is used to define how parties to licenses which contain a common hydrocarbon reservoir will jointly evaluate the reservoir to submit a common field development plan, including a plan for unitization.

Approval of the appraisal programme by the CNH, the Mexican hydrocarbons regulator, is anticipated during the third quarter.

Elsewhere in Mexico, two weeks ago, Premier signed the PSCs for its three new Mexico licenses – Block 30 in the Sureste Basin and Blocks 11 and 13 in the Burgos Basin.

The company plans to start working on maturing the prospectivity of these blocks with the Wahoo prospect on Block 30, which exhibits DHIs analogous to those on Zama, being the priority for early drilling.


As previously said, the Zama-1 well is the first offshore exploration well drilled by a private company in Mexico. The well was spudded on May 21, 2017, some 60 kilometers (37 miles) offshore Dos Bocas utilizing the Ensco 8503 drilling rig, and completed in late July the same year.

The entire Zama Field is estimated to hold between 1.5 billion and 2 billion barrels of oil equivalent and is considered one of the largest shallow water fields discovered in the past 20 years.

Talos, the U.S. based operator of the block containing the Zama project has previously said it expected to announce the final investment decision for the project in 4Q 2019 or 1Q 2020, with first oil expected in 2022. Production would be ramping up through 2024, as additional facilities are installed in the field.

Talos has said that Zama discovery could contribute nearly 10% of Mexico’s oil production by 2024.

The plan is to develop Zama with three production platforms across the structure. The field will continue to be developed through 2024 when Platform C is expected to be installed.

Offshore Energy Today Staff