WILLEMSTAD – A geological study examining the Bonaire Basin has identified additional sedimentary formations that could potentially have generated oil and natural gas beneath the waters surrounding Curaçao and Bonaire.
The research, published October 29, 2026, by petroleum geologist Marcel P.T. Chin-A-Lien, revises earlier assumptions about the rocks responsible for petroleum generation in the region.
One of the most important changes concerns the Agua Clara Formation, a geological layer known from Venezuela's Falcón Basin.
Earlier modeling by the researcher treated this formation primarily as a geological seal, capable of preventing oil and gas from escaping from deeper reservoirs.
However, the new study draws on earlier geochemical research linking oil from Venezuela's Cumarebo field to organic material found in Agua Clara rocks.
Based on that evidence, Chin-A-Lien concludes that the formation can function both as a petroleum source and as a seal, depending on its burial depth and geological history.
Where the rocks are buried deeply enough, they may have experienced sufficient temperatures to generate hydrocarbons.
In shallower areas, the same formation may instead act as an impermeable barrier that helps retain petroleum generated elsewhere.
The report suggests that this dual function could be relevant to the Bonaire Basin, particularly in deeply buried sections south of Curaçao.
Another revision concerns older marine sedimentary rocks dating from the Eocene geological period.
The researcher has expanded the possible age range of the basin's primary petroleum source rocks to include formations older than previously considered.
The study also discusses black shale layers associated with Bonaire's Washikemba Formation as a speculative additional source.
However, the author cautions that these older rocks may have been subjected to excessive heating or geological alteration, limiting their petroleum potential.
The report does not establish that any of these formations have generated commercial quantities of petroleum offshore Curaçao.
No direct source-rock samples from the central Bonaire Basin were obtained for the study.
Instead, the findings rely on geological comparisons, previously published research and modeling.
Chin-A-Lien argues that identifying the correct source rocks is essential because future exploration must establish not only where oil and gas could accumulate, but also whether the necessary hydrocarbons were generated in the first place.
The report recommends additional offshore sampling, temperature measurements and geochemical investigations to test these possibilities.