OSource: Talos Energy Inc.n the Mexican side of the Gulf of Mexico lies a carbon-rich reservoir known as the Zama field. It was recently discovered approximately 60 km off the coast of Tabasco, Mexico, in July 2017. It resides in block 7 of the Suerte Basin and is expected to hold up to two billion barrels of oil equivalent (Boe/d).

The Zama field is governed by Mexico’s National Hydrocarbons Commission (CNH) who approved a $325 m budget for appraisal drilling at Zama in September 2018. It is the first of Mexico’s offshore blocks to be awarded to a private operator who is now working to better define the resource potential.

The Zama appraisal program is being conducted by Talos Energy who is operating the Ensco 8503 floating drilling rig. Talos Energy is part of a consortium of vested partners inclusive of Sierra Oil & Gas, a company of DEA Deutsche Erdoel AG, and Premier Oil Plc who own drilling rights in the Zama field.

The first appraisal well, Zama-2, was drilled to a true vertical depth (TVD) of 10,759 ft and was completed on January 20, 2019. It fulfilled its objective of confirming the geological model and determining the oil-water contact. The well logged approximately 581 ft of gross TVD oil pay before reaching the oil-water contact, which is estimated to be 100 ft deeper than anticipated at 11,254 ft TVD. Zama-2 was completed 28 days ahead of schedule and 25% below initially projected costs.

Zama-2 ST1 appraisal well

Talos Energy recently reported an update on the second of three appraisal penetrations being drilled by the Consortium. The main goals of the Zama-2 ST1 appraisal well were to test the northern limits of the reservoir, acquire a whole core and perform well flow tests.

Zama-2 ST1 was drilled 589 ft updip of the Zama-2 generating the following results:

• The well logged 873 ft of gross TVD oil pay.
• A net-to-gross ratio range of 68% to 73% was observed through multiple penetrations.
• 714 ft of whole core was captured with 98% recovery.
• Well tests observed a flow rate of 7,900 Boe/d.
• Hydrocarbons produced were 94% oil with an API gravity ranging from 26 to 30 degrees and 6% natural gas.

The second appraisal well confirmed a consistent net-to-gross ratio and the captured whole core is the longest ever acquired from a single well offshore of Mexico.

The well was cased and perforated along 248 gross ft and flow rates were reported without stimulation through two separate tests. Flow rates were restricted and each zone was shut-in for an extended period to limit pressure drawdown and extend the radius around the well to be tested. The tests concluded that there were no indications of depletion nor were any significant barriers within the reservoir observed.

Zama-2 ST1 was drilled to a total depth of 11,643 ft. It was completed nine days ahead of schedule and 16% below initially projected costs. Flow tests were completed five days ahead of schedule and 30% below initially projected costs. The continued success of the ZAMA appraisal program supports initial observations and the field is on track to deliver a final investment decision in the near future. The final stage of the appraisal program includes a third appraisal well, Zama-3, to be drilled south of the original exploration well, Zama-1. Its objective is to collect another whole core while delineating reservoir continuity and quality in the southern portion of the field.