The Rosebank hydrocarbon discovery in 2004 proved that intra-lava sandstones form attractive reservoirs in the Faroe–Shetland Basin and the new volcanic play triggered the need for suitable analogues to describe and assess sedimentology, reservoir architecture, compartmentalization, and connectivity of intra-lava siliciclastic units. The onshore Kangerlussuaq Basin in East Greenland offers the opportunity to study Paleogene intra-lava siliciclastic sandstones and their interaction with lavas, on the scale of the Rosebank Field. The focus of this study is a siliciclastic-dominated intra-lava unit, 4–10 m thick, exposed in almost vertical cliff sections over distances of several kilometers. The unit reflects a short return to siliciclastic deposition following initiation of volcanic activity and extrusion of the first lava flows in the area. Deposition took place as shoreface and delta progradation in a marine-influenced, shallow embayment. Lateral variations in sedimentary facies distribution and geometry are prominent and were largely governed by an interplay of base-level variations and autocyclic processes, the surface roughness and type of substratum on which deposition took place, and differential block movements before and during deposition. Presence of local topographic barriers are of key importance and influenced the lava–sediment interaction and the resulting 3D-geometry of lava flows and sediment bodies. In addition, compartmentalization of the intra-lava sandstone unit is observed and is controlled by the offset across normal faults, intersecting dikes, and to a lesser extent by invasive and eroding lavas.A depositional model is suggested that incorporates the detailed sedimentological and 3D photogrammetric observations and presents a possible explanation for the contrasting architecture of the intra-lava unit observed in three areas located a few kilometers apart. The model embraces the complex interplay between siliciclastic and volcanic settings and reveals important aspects to consider when recoverable volumes of hydrocarbons are estimated in intra-volcanic subsurface reservoirs in volcanic rifted margins with poor seismic imaging of the relatively thin intra-lava reservoirs.

中文翻译：

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东格陵兰康克鲁斯瓦克一个广泛的硅质碎屑岩内熔岩单元的沉积学和储层结构

2004 年 Rosebank 碳氢化合物的发现证明，熔岩内砂岩在法罗-设得兰盆地形成了有吸引力的储层，而新的火山活动引发了对合适的类似物的需求，以描述和评估熔岩内硅质碎屑的沉积学、储层结构、分区和连通性单位。东格陵兰的陆上康克鲁斯瓦克盆地提供了在 Rosebank 油田范围内研究古近系熔岩内硅质碎屑砂岩及其与熔岩相互作用的机会。这项研究的重点是一个以硅质碎屑为主的熔岩内单元，4-10 m 厚，在几公里的距离内几乎垂直的悬崖部分暴露。该单位反映了火山活动开始和该地区第一批熔岩流喷出后，硅质碎屑沉积的短暂恢复。沉积发生在受海洋影响的浅海湾中的岸面和三角洲海积。沉积相分布和几何形状的横向变化很突出，主要受基础变化和自旋过程、沉积发生地的表面粗糙度和类型以及沉积前和沉积过程中不同块体运动的相互作用控制。局部地形障碍的存在至关重要，并影响熔岩与沉积物的相互作用以及由此产生的熔岩流和沉积物体的 3D 几何形状。此外，观察到熔岩内砂岩单元的分隔，并受正常断层、相交堤坝的偏移控制，并在较小程度上受到侵入和侵蚀熔岩的控制。提出了一个沉积模型，该模型结合了详细的沉积学和 3D 摄影测量观测，并为在相距几公里的三个区域观察到的熔岩内单元的对比结构提供了可能的解释。该模型包含硅质碎屑岩和火山环境之间复杂的相互作用，并揭示了在火山裂谷边缘的火山内地下储层中估算可采油气量时要考虑的重要方面，而相对较薄的熔岩内储层的地震成像较差。