Zama Oil Discovery, Mexico
The Zama oil discovery is located in Block 7 of the Sureste Basin off the shore of Mexico, at a water depth of roughly 165m.
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.
Talos Energy is the current operator of the project and holds 35% interest in the block, while partners Sierra Oil and Gas, and Premier Oil, hold 40% and 25% interest respectively.
The developers have announced plans to appraise the field in order to ascertain the extent of the discovery.
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.
The production sharing agreement for the block was executed by the developers in 2015 alongside the agreement for Block 2.
The two blocks are estimated to contain a combined 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.
It encountered an oil-bearing interval of 1,100ft (335m), containing between 558ft and 656ft (170m-200m) of net oil pay.
The well is not planned for immediate testing, however the developers are currently installing a 9-7/8in liner to protect the discovered reservoirs until further appraisal plans are finalised.
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 comprises 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 drilling programme is expected to commence in 2018 and will target exploratory prospects to depths of 14,000ft (4,267m).
Zama prospect development
Significant appraisal, engineering and design work will be required to move forward with the development of the field.
Appraisal activities will be undertaken in 2018, with first oil planned within five years. Conceptual engineering works are expected to commence shortly.
A fixed-platform development is planned to be used due to the size of the discovery.
The 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.
The developers plan to leverage the existing infrastructure and manufacturing plants available in Mexico to facilitate the field's development.