Toarcian source rock potential in the North Celtic Sea Basin, offshore Ireland

Publisher Website
Google Scholar
Abstract
Conditions favourable to the development and preservation of rich oil-prone source rocks are demonstrated for the uppermost Lower Jurassic stage, the Toarcian, in the Irish Sector of the North Celtic Sea Basin (and adjacent South Celtic Sea Basin), located offshore to the south of Ireland. An integrated approach, involving geological and geochemical data and techniques, has permitted the quantification of source rock potential. Wireline log responses in conjunction with existing geochemical analyses have defined net thickness, quality and richness for potential source beds. Up to 450 ft of very good to rich source rocks, capable of generating liquid hydrocarbons, are calculated for marine claystones of Early and Middle-Late Toarcian age. The thickest and best quality source rocks are predicted to occur in Toarcian depocentres, mostly situated along the axis of the North Celtic Sea Basin. One-dimensional burial history modelling suggests that substantial quantities of hydrocarbons were expelled from basinal areas towards the end of the Cretaceous.