Namibia – Brazil: Where memes collide and where we go next
From outdated to new memes: How recent discoveries in Namibia’s Orange Basin are shaping exploration strategies for Brazil’s Pelotas Basin
The father of modern macroeconomics John Maynard Keynes wrote that “the difficulty lies not so much in developing new ideas as in escaping from old ones”. This issue is the beating heart of exploration, which is built upon both confounding the expectations of our predecessors and doing it before the competitors. The received wisdom of memes are the ideas that explorers use as the glue to hold disparate or uncertain data together in a framework required to define risk and value. But as the statistician George Box almost said; all memes are wrong. And although some may be useful, they can equally be disastrously misleading.
The evolution of exploration memes
In Namibia’s Orange Basin, the understanding of the deepwater hydrocarbon system had become wrapped in a cluster of ideas that led most of the industry astray until Shell and TotalEnergies drilled Graff and Venus respectively in 2022. The memes had evolved in the data-poor atmosphere of uncertainty where the absence of evidence was all one had, so it stood for evidence of absence. Yet, these have now been passed through the excoriating fire of an extraordinarily successful drilling campaign and many pre-existing models have been eviscerated in the process. New memes have evolved, becoming fitter in the process to deep water passive margin exploration in general, so these are the new exploration memes that will take us forward to the next frontier – the Pelotas Basin of Brazil.
Hydrocarbon systems have never been so vulnerable to critical thinking-driven analysis – not because we have particularly new ideas about how the key risk elements combine or interact, but because recent deepwater drilling experience and 2024 technology have crushed the uncertainties in our exploration models, letting the memes evolve and become fitter.
When Richard Dawkins coined the term “meme” to mirror “gene”, he was representing a cultural idea, like geologic models – earth visions in our imaginations that are capable of replicating and evolving to better fit or mitigate increasingly available data. Models of deepwater gravity-driven clastic sedimentation, such as “turbidite depositional systems”, adapting through observation and experience.
Such as embracing the “contourite” meme – becoming mixed systems and changing the way turbidite flows are understood to deposit sediments in deep water settings. See, for instance, Bryan Cronin’s brilliant recent work in the Ghanaian margin.
Impact of exploration discoveries
In the Orange Basin, a number of exploration memes of received “truths” had grown over the decades of exploration, evolving in a survival of the fittest sense to work around the available data. However, these had conflated with each other to cast a negative light on all aspects of the hydrocarbon system off the shelf. Some of these memes included that the inner basin had no source rock, had no sand, had poor quality sand, was gas prone, and further outboard the outer basin had no sand, no source rock, immature source rock, no migration, no traps, no seals and was too deep water. These had become the received wisdom, with no evidence that this was or wasn’t the case. Or even against the evidence such as the thick source rock on the oceanic crust in DSDP361 drilled in 1974.
Lessons from Venus and Graff
Total Energies’ drilling of Venus and Shell’s drilling of Graff in 2022 represented a Chicxulub evolution event to deepwater exploration memes, as the historically negative models in Orange went to the flames, and sneaky preadapted memes became better fit to the new data. To be fair, the dying memes were not built of unwarranted concerns, quite the reverse, but the negative baggage they brought was not supported by any data, only the absence of evidence. These memes were self-replicating received biases, and not the useful kind. For an excellent series on biases in exploration analysis, a great starting place is Marc Bond’s LinkedIn posts.
Post the Venus and Graff oil discoveries, we appreciate that the clastic sediments are mixed systems, have re-thought their water depth of deposition, rethought the thermal history and thermal blanketing that supports the results of Seismic Thermometry and generates oil in the Aptian, confirmed the trapping potential created during syn-drift SDR to MORB transitions and counter regional dip mega-trap creation, and re-imagined the potential for innovative mixed system slope traps. These plays are no longer high-risk, because the technology we have, when applied in the right meme framework, solves the problem for you, alchemically turning the old high risk “frontier well” terror meme into the low-risk quiet confidence of the future.
Future directions and opportunities
In the foldout presented here, a “quick look” data post-stack time migrated (in 2.5 D mode) and depth converted line that was available for interpretation before the last shot of the 2024 Pelotas MC 3D programme, is compared at the same depth and horizontal scale to its near conjugate margin, a 2023 MC 3D pre-stack time migrated and depth converted section from beyond the outer high in Namibia. Pelotas, like Orange, had acquired a number of hydrocarbon system memes that were not helpful: Mud rich delta, Aptian source not present, source too deep, gas prone, too hot, too cold, no structure, and too deep water. This foldout lights the blue touch paper that will immolate those memes and allow fitter memes, evolved in the data-rich Orange Basin, to supersede them.
Moving beyond old memes
The meme that the Pelotas and Orange Basins are “not at all similar” is the first dinosaur on the Barbie as the transition from SDR to oceanic crust is present on both sections in mirror order. The Aptian source rock is visible on either margin as is the outboard counter regionally dipping overlying soft clastic fan of Aptian / Albian age – the amplitude on the foldout is just a function of processing maturity in these two examples. The Venus play in Orange = Venus play in Pelotas. That sections above the Lower Cretaceous are different is obvious and thanks to dynamic topography. The Namibian section comprises 3 km of Upper Cretaceous instability-induced mass transport deposits, whilst the Brazilian margin comprises a well-bedded Cretaceous and Tertiary sequence. Yet, this is of secondary importance as both isopach’s over the Aptian are the same, in the same water depth and possessing the same crustal structure, illustrating that the proven Aptian hydrocarbon maturity in Orange is quite reasonably exactly that in Pelotas, and Pelotas is therefore an oil play too. That the overlying Upper Cretaceous confined channel system in Pelotas is also still present and clearly imaged on fast-track data is one would imagine, a bonus.
Between 2022 and 2024, Searcher has been blessed by being able to play a role in the collection of six huge multi-client 3D datasets across the new play fairways in the South Atlantic – five with our amazing partner Shearwater. Sharing observations from these datasets as soon as we can with the industry via our weapon of choice; GEO EXPRO Magazine, has been a joy. Now it’s time to review the exploration memes that collided in the Orange Basin, find the evidence-rooted ideas that actually work, and take them across the Atlantic.
