Large volumes of hydrocarbons reside in volcanically influenced sedimentary basins. Despite having a good conceptual understanding of how magmatism impacts the petroleum systems of such basins, we still lack detailed case studies documenting precisely how intrusive magmatism influences, for example, trap development and reservoir quality. Here we combine 3D seismic reflection, borehole, petrographical and palaeothermometric data to document the geology of borehole 5/22-1, NE Irish Rockall Basin, offshore western Ireland. This borehole (Errigal) tested a four-way dip closure that formed to accommodate emplacement of a Paleocene–Eocene igneous sill-complex during continental break-up in the North Atlantic. Two water-bearing turbidite-sandstone-bearing intervals occur in the Upper Paleocene; the lowermost contains thin (c. 5 m), quartzose-feldspathic sandstones of good reservoir quality, whereas the upper is dominated by poor-quality volcaniclastic sandstones. Palaeothermometric data provide evidence of anomalously high temperatures in the Paleocene–Eocene succession, suggesting the poor reservoir quality within the target interval is likely to reflect sill-induced heating, fluid flow, and related diagenesis. The poor reservoir quality is also probably the result of the primary composition of the reservoir, which is dominated by volcanic grains and related clays derived from an igneous-rock-dominated, sediment source area. Errigal appeared to fail due to a lack of hydrocarbon charge: that is, the low bulk permeability of the heavily intruded Cretaceous mudstone succession may have impeded the vertical migration of sub-Cretaceous-sourced hydrocarbons into supra-Cretaceous reservoirs. Break-up-related magmatism did, however, drive the formation of a large structural closure, with data from Errigal at least proving high-quality, Upper Paleocene deep-water reservoirs. Future exploration targets in the NE Irish Rockall Basin include: (i) stratigraphically trapped Paleocene–Eocene deep-water sandstones that onlap the flanks of intrusion-induced forced folds; (ii) structurally trapped, intra-Cretaceous, deep-water sandstones incorporated within intrusion-induced forced folds; and (iii) more conventional, Mesozoic fault-block traps underlying the heavily intruded Cretaceous succession (e.g. Dooish). Similar plays may exist on other continental margins influenced by break-up magmatism. Supplementary material: Borehole-related reports, and litho- and composite logs are available at https://doi.org/10.6084/m9.figshare.c.4803267

中文翻译：

---

与裂谷相关的岩浆作用影响爱尔兰近海 NE Irish Rockall 盆地的石油系统开发

大量碳氢化合物存在于受火山影响的沉积盆地中。尽管对岩浆活动如何影响此类盆地的石油系统有很好的概念性理解，但我们仍然缺乏详细的案例研究来准确记录侵入岩浆活动如何影响圈闭发育和储层质量。在这里，我们结合了 3D 地震反射、钻孔、岩石学和古测温数据，以记录爱尔兰西部近海爱尔兰罗科尔盆地东北部爱尔兰洛克尔盆地 5/22-1 钻孔的地质情况。这个钻孔 (Errigal) 测试了一个四向倾角闭合，该闭合形成以适应北大西洋大陆分裂期间古新世-始新世火成岩复合岩的就位。上古新世有两个含水浊积岩—砂岩层；最下层包含薄（约 5 m），储层质量较好的石英长石砂岩，而上部以劣质火山碎屑砂岩为主。古温度测量数据提供了古新世-始新世序列异常高温的证据，表明目标层段内储层质量差可能反映了基岩引起的加热、流体流动和相关的成岩作用。储层质量差也可能是储层主要成分的结果，主要成分是火山颗粒和来自火成岩为主的沉积物源区的相关粘土。由于缺乏碳氢化合物充注，Errigal 似乎失败了：也就是说，严重侵入的白垩纪泥岩层序的低体积渗透率可能阻碍了白垩纪以下烃类向白垩纪上储层的垂直运移。然而，与破裂相关的岩浆作用确实推动了大型构造闭合的形成，来自 Errigal 的数据至少证明了高质量的上古新世深水储层。东北爱尔兰 Rockall 盆地的未来勘探目标包括： (i) 地层上被困的古新世-始新世深水砂岩，它们覆盖在侵入引起的强迫褶皱的侧翼上；(ii) 包含在侵入引起的强迫褶皱中的结构性围困、白垩纪内、深水砂岩；(iii) 更传统的中生代断块圈闭位于严重侵入的白垩纪序列（例如 Dooish）之下。受破裂岩浆作用影响的其他大陆边缘可能存在类似的成藏作用。补充材料：钻孔相关报告、岩性和复合测井可在 https://doi.org/10.6084/m9.figshare.c.4803267 获得