Global oil and gas companies are increasingly narrowing their exploration and production activities to fewer regions and plays to make sure they are invested in the most profitable barrels when oil demand starts to decline later this decade, Rystad Energy said in a recent update.
“Analyzing subsurface information is crucial in this process to understand which plays, countries and basins provide the best opportunities in terms of reservoir productivity,” the Norway-based consultancy group said. It recently launched reservoir and source rock parameters in its upstream solutions to help clients evaluate and benchmark plays on a global scale.
“Most of the volumes produced between 2000 and 2020 are of the Cretaceous period, delivering about 341 billion barrels of oil equivalent in total,” Rystad Energy said. “Jurassic plays come in second with about 189 billion boe, while the youngest plays of Neogene and Paleogene follow with 155 billion and 106 billion boe, respectively.”
Older plays including Permian, Devonian, Triassic and Carboniferous together contributed around 247 billion boe.
With around 23 discoveries to date offshore Guyana, 20 of which were made at the ExxonMobil-operated Stabroek block, geological experts posit that the Guyana basin stands as the most exciting exploration hotspot, with the U.S. oil major leading the way in showcasing the basin’s outstanding prospectivity.
Precambrian era Guyana rivers key to prolific basin’s formation
In a report seen by OilNOW from Wood Mackenzie, the experts described the basin as being a well-developed half-graben whose principal source rock is the world-class Canje formation which is of Cenomanian to Turonian age.
WoodMac officials said this is equivalent to source beds found in some of the world’s most envied hydrocarbon provinces like Venezuela, Colombia and Trinidad. OilNOW understands that the Guyana basin source rock is very mature, and migration is known to have occurred over distances greater than 200 kilometres.
Thus far, three plays have been established in the basin. WoodMac experts noted that most discoveries by ExxonMobil in the Stabroek Block have been made in Late Cretaceous, turbidite sandstone reservoirs in stratigraphic traps while adding that reservoir quality is understood to be excellent, with multi-Darcy permeability. The Liza-3 appraisal well, for example, was deepened into early Cretaceous sandstone, making the Liza Deep discovery.
OilNOW understands that the Ranger discovery which is 100 kilometres to the northwest of the Liza cluster, opened a Cretaceous-aged carbonate build-up with a Tertiary clastic cover. It is described as a large structural trap with a four-way closure.
Westwood Energy Group has said more oil and gas were discovered in stratigraphic traps than any other trap type in the last decade and the Guyana-Suriname basin remains one of the most prolific.
