Tanager 1 well offshore Guyana not commercially viable on its own- Ratio Petroleum Energy

Last Updated on Tuesday, 17 November 2020, 8:10 by Denis Chabrol

The Tanager 1 well, which is located offshore Guyana, is a non-commercial discovery on a standalone basis, Ratio Petroleum Energy has said.

The Stena Carron drillship began work on the exploration well on August 11. It was the deepest drilled in the Guyana-Suriname basin to date, reaching a total depth of 7,633 metres.

ExxonMobil’s Esso Production & Exploration Guyana drilled the well on the Kaietur Block. Exxon has a 35% stake in the licence, while Cataleya Energy has 25%, Ratio Guyana 25% and a subsidiary of Hess Corp. has 15%.

Energy Voice reports that the well found 16 metres of net oil pay in high-quality Maastrichtian sandstone reservoirs. Based on information gathered during drilling, the Maastrichtian reservoir has provided heavier oil than that from the Liza Phase 1. The well also found reservoirs at the deeper Santonian and Turonian layers. These require more analysis, Westmount Energy said.

Westmount holds a minor stake in Ratio and a 5.4% stake in Cataleya Energy’s parent.

Partners on the block will carry out a review of the data from the Tanager 1 well. The discovery confirms the Cretaceous petroleum system and Liza play continue into the block, downdip from the Stabroek Block.

The companies will recalibrate the seismic on the block. A 5,750 square km 3D survey in 2017 on Kaietur’s south found a number of prospects.

Pick and mix

Westmount’s executive chairman Gerard Walsh said the Tanager-1 had been a “mixed bag – confirming the extension of the Liza play fairway onto the Kaieteur Block but apparently coming up short at the deeper stratigraphic levels.”

The well was targeting a stacked pay. It needed to succeed at a number of levels to be commercially viable as a standalone development, he continued.

“However, these deeper results must be viewed in the context of the very limited number of penetrations of these deeper plays to date – indicating that exploration of these deeper plays, offshore Guyana, is at an early part of the learning curve,” Walsh said.

Westmount also has a stake in the Canje Block. ExxonMobil plans to drill the Bulletwood-1 well in late December or early 2021. This prospect is independent of Tanager 1.

“Bulletwood-1 will target a circa 500 million barrel ‘Liza look-alike’ confined channel complex of Maastrichtian-Campanian age,” Walsh continued.