--> Analogues Provide Insight Into Cretaceous Deep-Water Clastic Systems on the Irish Atlantic Margin

2018 AAPG International Conference and Exhibition

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Analogues Provide Insight Into Cretaceous Deep-Water Clastic Systems on the Irish Atlantic Margin

Abstract

Ireland’s Atlantic Margin has a number of Late Palaeozoic to Cenozoic basins which are largely underexplored with only 52 exploration and appraisal wells drilled to date. In recent years Ireland has experienced a surge in exploration activity with the issuing of 28 Licensing Options following the 2015 Atlantic Margin Licensing Round, bringing the number of Atlantic active exploration authorisations to its highest levels since offshore exploration began in the 1970’s. Major O&G companies have been drawn to the diversity of play types in the area, in particular the Jurassic tilted fault blocks that have been successfully explored offshore East Canada and the Cretaceous fan play which has been prolific on the equatorial margin. With a focus on the Porcupine Basin we investigate the Cretaceous deep-water clastic systems which are considered to be analogous to the same play type proven in the equatorial margin. These clastic systems contain significant potential for hydrocarbons in both stratigraphic and combination traps. Exploration in the Porcupine Basin to date has primarily targeted large structural traps, with only a few wells drilled on stratigraphic/combination traps and only 2 wells drilled on 3D seismic data. In recent years a significant amount of 3D data has been acquired in the basin, in 2017 alone more than 11000km2 of 3D data were acquired in the Porcupine Basin. 3D seismic data are essential in identifying deep-water stratigraphic prospects, assessing the trap integrity and identifying access to a source rock. The Cretaceous fan play in the Porcupine Basin comprises Early Cretaceous deep-water sandstones that pinch out laterally or are draped over structural highs. These reservoirs are charged by mature Late Jurassic and possibly Early Cretaceous source rocks. The recent drilling of the Drombeg fan by Providence Resources and JV partners in the South Porcupine Basin in 2017 has proven the reservoir development of these Early Cretaceous fan systems and while live hydrocarbons were not encountered by the well, the possible presence of bitumen in drill cuttings may provide some encouragement for the source elements of the Cretaceous Fan hydrocarbon play (Providence Resources 2017). The proven reservoir development in the Drombeg fan, the access to new and high quality 3D data, and the investigation of analogues along strike on the Atlantic margin provides us with further insight into the potential of these deep-water clastic systems Offshore Ireland.