Talos Energy has completed drilling of the Zama-1 exploration well in offshore Mexico in collaboration with joint venture partners Sierra Oil and Gas and Premier Oil.
Last month, oil was discovered at the well at depths of 166m.
A preliminary evaluation indicated a contiguous gross oil bearing interval of more than 335m, with 170m-200m of net oil pay in Upper Miocene sandstones with no water contact.
The well was drilled to a total depth of 4,109m confirming the base of the reservoir section, with no penetration of an oil-water-contact.
It also did not encounter any additional source of hydrocarbons following the discovery.
The initial gross original oil in place estimates the discovery to host around 1.4 billion to two billion barrels, exceeding pre-drill estimations.
Some of the resources are expected to extend to the neighbouring block.
Initial assessments of the hydrocarbon samples contain light oil carrying API gravities between 28° and 30° and some associated gas.
Talos Energy president and CEO Tim Duncan said: “To announce such a historic discovery less than two years after being awarded the block, safely and without incident, is an excellent example of the benefits of having smaller operators participate in the reforms, we can match the operational sophistication of our larger peers, but with a heightened sense of urgency.
“We look forward to our appraisal activities on Zama and continuing to explore additional prospects on our acreage.”
The well was spud using a moored floating drilling rig Ensco 8503.
Currently, Talos is evaluating all data procured through the drilling campaign and assessing the ideal way to appraise and develop the discovery.
Talos owns a 35% participation interest in the discovery, while Sierra and Premier hold 40% and 25% participation interests respectively.