Analysts are looking closely at the exploration campaigns targeting the Bulletwood prospect in Guyana and Bonboni in neighbouring Suriname which are testing the upper cretaceous play in a basin where billions of barrels of oil equivalent have been found and potentially several more remain yet to be discovered.
The ExxonMobil-operated Stabroek block has already delivered around 9 billion barrels of oil equivalent resources and the Liza discovery came onstream in December 2019.
“So, the play was eventually extended further to the southeast, into Suriname at the start of 2020,” said Jamie Collard, Senior Analyst at Westwood Global Energy Group.
In addition to the 18 discoveries made by ExxonMobil at Stabroek, so far 4 discoveries have been made at Suriname’s Block 58 – Maka Central, Sapakara West, Kwaskwasi and Keskesi – by Apache and Total.
But Collard pointed out that despite these successes, there have also been some failures.
“So, we had Tullow encountering…heavy oil at Joe and Jethro, testing tertiary plays. We had Repsol trying to extend the upper cretaceous play into the shallow waters, so back towards the shelf, at Carapa, and made a non-commercial discovery with 4 metres of net pay,” Collard stated. “We then had Exxon trying to extend the play further outward at Tanager, encountering heavier oil and 16 metres of pay, and that…is another non-commercial discovery.”
Collard also mentioned the drill campaign by ExxonMobil and Petronas at the Sloanea prospect, saying this was an effort to extend the play further to the South-East. He said while the Sloanea announcement only referred to the find as a ‘hydrocarbon discovery’, Westwood assumes this refers to gas and believes that it is probably non-commercial.
“So, we’ve chosen two more tests of the upper cretaceous play, one at Bulletwood on the Guyana side which is a 50 kilometre step out from proven areas that’s actually drilling at the moment and then one on the Suriname side at Bonboni, which is trying to do something similar,” he said.
Bonboni is located in the North Central portion of Block 58 and will be the 5th prospect being targeted by Total and Apache on that acreage. Already, Maersk Drilling has been awarded contracts for the deepwater rigs Maersk Valiant and Mærsk Developer for exploration and appraisal drilling on the block.
“Certainly, the recent result of a heavier fluid in Tanager to the North-West of Bulletwood has certainly increased the risk regarding fluid quality in the basin floor,” said Dr. Helen Doran, Senior Associate at Westwood. She said while the details on the cause of the heavy fluid have not yet been released, the most likely cause would be a lower matured fluid from the source rock.
“Additional risks to Bulletwood really just include the volume and quality of reservoir. We’re still trying to piece together how much reservoir is getting under, beyond the Liza and cluster area. And of course, the nature…of the trap,” Dr. Doran pointed out.
The Bulletwood-1 prospect was spudded on December 31 at the ExxonMobil-operated Canje block, targeting an estimated 500 million barrels of oil equivalent resources.