Supplementary files for: A review of oil and gas seepage in the Nuussuaq Basin, West Greenland – implications for petroleum exploration

The Nuussuaq Basin in West Greenland has an obvious exploration potential. Most of the critical elements are well documented, including structures that could form traps, reservoir rocks, seals, and oil and gas seepage that document petroleum generation. And yet, we still lack a full understanding of the petroleum systems, especially the distribution of mature source rocks in the subsurface and the vertical and lateral migration of petroleum into traps. A recently proposed anticlinal structural model could be very interesting for exploration if evidence of source rocks and migration pathways can be found. In this paper we review all existing, mostly unpublished, data on gas observations from Nuussuaq. Furthermore, we present new oil and gas seepage data from the vicinity of the anticline. Occurrence of gas within a few kilometres on both sides of the mapped anticline have a strong thermogenic fingerprint suggesting an origin from oil-prone source rocks with a relatively low thermal maturity. Petroleum was extracted from an oil-stained hyaloclastite sample collected in the Aaffarsuaq valley in 2019 close to the anticline. Biomarker analyses revealed the oil to be a variety of the previously characterised ‘Niaqornaarsuk type’, reported to be formed from Campanian-age source rocks. Our new analysis places the ‘Niaqornaarsuk type’ 10 km from previously documented occurrences and further supports the existence of Campanian age deposits developed in source rock facies in the region.

西格陵兰努苏阿克盆地（Nuussuaq Basin）具有显著的勘探潜力。其多数关键成藏要素均已得到详实记录，包括可构成圈闭（trap）的构造、储集岩、盖层，以及证实油气生成的油气渗漏现象。然而，当前学界对该盆地的油气系统（petroleum system）仍缺乏完整认知，尤其是地下成熟烃源岩（mature source rock）的分布格局，以及油气向圈闭的垂向与侧向运移规律。近期提出的背斜构造模型（anticlinal structural model）若能找到烃源岩与运移通道的佐证，将对勘探工作极具参考价值。本文综述了目前已有的、绝大多数尚未正式发表的努苏阿克盆地天然气观测数据。此外，我们还公布了该背斜周边区域的新增油气渗漏数据。在已测绘的背斜两侧数公里范围内产出的天然气，均带有强烈的热成因指纹特征，表明其源自热成熟度相对较低的生油型烃源岩。2019年，研究团队在阿法尔苏瓦克谷（Aaffarsuaq valley）靠近该背斜的位置采集到一块油染玻璃质碎屑岩（hyaloclastite）样品，并从中提取出石油。生物标志物分析（biomarker analysis）结果显示，该石油属于此前已被表征的“尼夸尔苏克型（Niaqornaarsuk type）”原油，该类原油被认为形成于坎潘期（Campanian）烃源岩。本次新增的分析结果将“尼夸尔苏克型”原油的已知分布范围拓展至距此前记录点10公里处，进一步佐证了该区域存在发育于烃源岩相（source rock facies）中的坎潘期沉积地层。