As TotalEnergies is moving ahead developing its deep-water discoveries in Block 58 in Suriname waters, there is a drive to discover more resources nearby. And rather than focusing on deep water, as was done in recent years, the shallows of the Demerara High have come on the radar, again. Not only for TotalEnergies, but also for other explorers; Shell is planning on drilling the Araku Deep-1 in Block 65 and Chevron may have identified another hydrocarbon migration pathway heading south from the kitchen in the north – they will target the Korikori prospect in Block 5.
The shelf has had a few periods of exploration activity before, and it is the information derived from these wells that can subsequently be used as material to learn a bit more about what the French are targeting with Macaw-1 in Block 64.
The closest well was drilled by Tullow in 2021; Goliathberg-Voltzberg North-1 (GVN-1). Did this well drill a similar target as Macaw-1? Both wells are situated on the Demerara High, but it is thought that the Tulllow well was planned in such a way that it tapped into a Canje source rock preserved in a local and small mini-basin on the Demerara shelf. Given that the well was dry, this might indicate that the source rock maturity was insufficient. Another risk that can probably be linked to GVN-1 is migration. Even if the source rock from the local Canje pool would have been in the oil window, hydrocarbon migration would probably have taken place in a radial manner, lacking structural focus, leading to a risk of underfilling reservoirs surrounding the mini-basin.
It looks like there is no mini-basin at the location of the TotalEnergies well, which makes it likely that the company works with a Lower Cretaceous Canje source rock model that migrated from the kitchen in the west. This is the same source rock that also generated the Golden Lane discoveries. However, the distance is long and so far no commercial discoveries were made on the Suriname offshore shelf apart from the Tambaredjo and Calcutta heavy oil fields that are located just onshore. This, however, has shown that long-distance migration does work.
Whether the TotalEnergies well is in the right place to be on the receiving end of a long-distance migration path from the deeper parts of the basin is unknown. In that respect, Demerara-A2-1 drilled by Exxonmobil in 1977 seems to be in that very spot, where migration pathways from the kitchen in the west meet. It’s interesting that this was already understood in the 1970s, using much more rudimentary seismic data.
Another possibility is that Macaw-1 targets a deeper source rock in Jurassic carbonates. These carbonates could also form a potential reservoir, being intercalated with more basinal mudstones that might have generated hydrocarbons. There have been reports of indications that a lacustrine source rock is present on the Demerara High, even though the evidence for that seems a little flaky.
Whatever the play model that TotalEnergies favours, a discovery at Macaw will be a very encouraging sign for Suriname in general and the Demerara High in particular.
