The Zama-1 discovery well was drilled by the Ensco 8503 floating drilling rig. Credit: Talos Energy.
The Zama oil discovery is located in Block 7 of the Sureste Basin offshore Mexico. Credit: Talos Energy.
Zama is estimated to contain between 1.4 and two billion barrels of oil equivalent. Credit: Keppel Offshore & Marine.

The Zama oil discovery is located in Block 7 of the Sureste Basin off the shore of Mexico, at a water depth of approximately 165m.

The field was discovered by the Zama-1 well in July 2017, the first exploration well to be drilled by the private sector in Mexico.

Talos Energy is the current operator of the project and holds 35% interest in the block, while partners Sierra Oil and Gas holds 40% and Premier Oil holds 25%.

Mexico’s National Hydrocarbons Commission approved a $325m budget for appraisal drilling at Zama in September 2018.

The appraisal wells for the field are expected to be drilled by 2019 and first oil from the offshore field is expected by 2022.

Block 7 Sureste Basin details

Sureste basin is a proven hydrocarbon province and includes the Saline, Campeche-Sigsbee and Villharmosa uplift basins. Deposits in the basin range from the late-Triassic to Holocene ages.

Block 7 covers an area of 122,000 acres and is located in the shallow offshore waters of the Sureste Basin.

A production sharing agreement for the block was signed by the developers in 2015 alongside that for Block 2.

The two blocks combined are estimated to contain 162,904 gross acres of high-profile prospects and well-established plays.

Details of the Zama prospect discovery

The Zama-1 discovery well was drilled by the Ensco 8503 floating drilling rig to a depth of 11,100ft (3,383m).

The primary objective of the well was to prove the existence of hydrocarbons in the tertiary clastic reservoirs.

The well encountered an oil-bearing interval of 1,100ft (335m), containing between 558ft and 656ft (170m and 200m) of net oil pay.

Geology and reserves

The Upper Miocene age Zama discovery was identified as a three-way dip structure sealed against a salt feature through the analysis of reprocessed seismic data.

The field is estimated to contain P90 (high) and P10 (best) gross reserves, ranging from 1.4 to two billion barrels of oil equivalent, with a possibility to extend off the block.

It mainly has light oil featuring API gravities between 28° and 30°, along with associated gases.

Appraisal on Zama

Talos plans to drill deeper prospects following the installation of the liner, targeting the Zama Main and Zama Deep targets.

Existing seismic data along with data from the Zama-1 well will be evaluated to properly identify the drilling prospects.

“The field was discovered by the Zama-1 well in July 2017, which is the first exploration well to be drilled by the private sector in Mexico.”

The drilling programme is expected to be completed by the end of 2019 and will target exploratory prospects to depths up to 14,000ft (4,267m).

Appraisal drilling will also be carried out using the Ensco 8503 floating drilling rig. The appraisal plan includes the drilling of two wells along with a sidetrack and a well test.

The first appraisal well Zama-2 will be drilled up to a depth of 500m.

Zama prospect development

Significant appraisal, engineering and design work will be required to move forward with the development of the field.

The Zama field is planned to be developed with three production platforms.

Each platform installation will comprise a single jacket and topsides and will be able to support production rates of up to 100,000 barrels of oil per day (bopd).

The development will also feature a single drill centre with wells drilled from the platform.

Produced oil will be transported via a pipeline to the Dos Bocas terminal located onshore, approximately 70km away from the project site.