[3] It can be found in the southwestern offshore portion of Ireland and is part of a series of interconnected basins linked to a failed rift structure associated with the opening of the Northern Atlantic Ocean.

[5] The Porcupine Basin lies on the Caledonian metamorphic basement and preserves up to 12 km of sedimentary strata from Late Palaeozoic to Quaternary which includes significant hydrocarbon reservoirs.

This stretching is especially found in the southern part of the basin as a result of rotation of the Porcupine Ridge away from the Irish shelf.

One hypothesis connects their formation to the seepage of hydrocarbons, either along faults or from former gas-hydrate layers, as a response to glacial-interglacial changes in current patterns and sea levels.

Another hypothesis relates their distribution to nutrient fluxes driven by specific oceanic conditions, notably the interaction of internal waves, formed at the boundary between different water masses, with the continental slope.

[3] Modelling of hydrocarbon generation shows that the main Jurassic source rocks in the Porcupine Basin are mature to overmature.

Hydrocarbon generation started in Late Cretaceous times for the deepest Jurassic sequences, and is still ongoing today along the edges of the basin.