Guyana’s upcoming Yellowtail crude grade to be country’s first light sweet grade

Guyana's Yellowtail crude grade, expected to hit the market in Q3, will be a light-sweet grade, making it an outlier from the other three Guyana grades currently in production and putting it in direct competition with Argentina's Medanito or US WTI.

Yellowtail will have an API of 36.5 and a sulfur content of 0.25%, according to a preliminary assay seen by Platts late May 1.

ExxonMobil did not reply to a request for comment on the assay. The company leads the consortium developing Guyana's Stabroek Block, which is also the origin of the other three Guyanese crudes in production, all of which are medium sweets.

The consortium consists of ExxonMobil (45%), with Hess Corp. (30%) and CNOOC (25%) as partners.

Liza crude has an API of 32 and sulfur content of 0.58%, Unity Gold has an API of 34 and a sulfur content of 0.41%, and Payara Gold has an API of 29 and a sulfur content of 0.60%, according to publicly available assays on ExxonMobil's website.

One source said the assay suggests Yellowtail will be closer in quality to West Texas grades before a recent trend toward lighter barrels, such as West Texas Light.

"The Midland basin legacy production looked closer to that with 39 to 41 API," the source said.

Another source mentioned that Yellowtail has an "API similar to a lot of Nigerian [crudes], etc. but still higher sulfur than a lot of them, so [it] will probably trade like a Nemba or something similar."

Yellowtail will begin producing in the third quarter -- as much as three months sooner than the previous timeline.

Yellowtail, is the fourth and largest oil development on Stabroek to date. It is on course to start up with an initial gross production capacity of around 250,000 b/d, Hess said in its first-quarter earnings release.

So far, the Stabroek Block is producing well over 600,000 b/d of oil from three developments: Liza Phase One, which began producing around 150,000 b/d from the Destiny FPSO in December 2019; Liza Phase Two, which began producing around 240,000 b/d from the Unity FPSO in February 2022; and Payara, which began producing at least 220,000 b/d from the Prosperity FPSO in November 2023.

Yellowtail will use the One Guyana FPSO that arrived offshore Guyana on April 15, to produce the field's oil.