Argentina, an area of world class petroleum potential, has experienced growing demand for high quality, regional datasets in advance of upcoming bid rounds.
The Austral Basin in southern Argentina has in the past been the focus for offshore exploration with up to 2 billion barrels of oil equivalent discovered by 51 exploratory wells. To the east of the Austral Basin, over the Rio Chico High, lies the West Malvinas Basin, formed during the late Triassic/Early Jurassic separation of Antarctica and South America. Only 20 exploration wells have been drilled, with discoveries made at Calamar-1, Salmon-1 and Salmon-2 and oil shows encountered within several other wells.
Offshore exploration activity was revived through the first offshore bid round campaign, which was largely supported by a regional 2D seismic dataset which led to a better understanding of the basin. This was followed by applications for licences by various international and domestic loil companies and ended in the successful award of several blocks, mainly in the southern part of the basin. A regional evaluation exercise was carried out to rank the blocks offered in the West Malvinas basin, integrating the reprocessed 2D seismic data available at the time, together with conditioned well logs and a full petroleum systems evaluation.
In this study, it was found that understanding the lateral distribution of lacustrine shales within the syn-rift grabens, is key to de-risking the presence, distribution and quality of source rock in the Malvinas Basin. Data quality of reprocessed 2D seismic data is critical for the interpretation below the Base Cretaceous Unconformity, which at the same time enables interpretation of the Jurassic source rock section. The impressive results obtained in imaging the deeper section with the latest reprocessing phase, have revealed additional syn-rift grabens in the north of the basin, where acreage remained open after the round. The view on prospectivity in this area has shifted, based on indications of a thicker sedimentary section with access to a potential good quality, oil-prone lacustrine source rock. The area is therefore deemed to have hydrocarbon potential that is worth re-evaluating, in light of the new reprocessed seismic data.