Petroleum systems framework of significant new oil discoveries in a giant Cretaceous (Aptian–Cenomanian) clinothem in Arctic Alaska
Petroleum systems framework of significant new oil discoveries in a giant Cretaceous (Aptian–Cenomanian) clinothem in Arctic Alaska
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阿拉斯加北极地区一个巨大的白垩纪（阿普天-塞诺曼阶）斜层中重大新石油发现的石油系统框架
DOI：
10.1306/08151817281
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发表时间：
2019
期刊：
影响因子：
3.5
通讯作者：
D. Houseknecht
中科院分区：
文献类型：
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作者：
D. Houseknecht
最近在阿拉斯加北部阿普提安-塞诺马期斜坡体中发现的石油表明，纳努舒克组顶盖和托罗克组前盖-底盖蕴藏着数亿至10亿桶石油。易产油的烃源岩和斜面覆盖在巴罗拱门上，巴罗拱门是科尔维尔前陆盆地和波弗特海裂谷边缘之间的构造枢纽。地层圈闭位于热成熟度良好的区域，沿3万平方公里(10000平方千米)以上的多条运移路径。来自楚科特坎造山带(俄罗斯)的沉积物充填了科尔维尔盆地西部，并溢出到波弗特裂谷肩部，形成了向东和向北的陆架边缘。进积陆架边缘轨迹在中斜面突然转变为“锯齿”轨迹，这是沉积物流入减少的结果。在斜坡体东部的Nanusshk基底顶层组中推断出两种地层圈闭类型：(1)反映强迫海退的低水位体系域，包括位于上坡层序界面上的窄而厚的进积堆积模式；(2)高水位-进积体系域包括在顶盖面上方的宽而薄的叠瓦状准层序。两者都包括被泥岩封闭的地层孤立的砂岩。同一地区托罗克前积相和底积相的圈闭几何形态包括盆底扇、坡面和坡道沉积，它们向上挤压，被泥岩封闭。在斜坡体东部的这些地层圈闭类型中，存在着发现更多石油聚集的巨大潜力。西部可能存在较小的潜力，因为储盖对可能不太发育。
Recent oil discoveries in an Aptian–Cenomanian clinothem in Arctic Alaska demonstrate the potential for hundred-million- to billion-barrel oil accumulations in Nanushuk Formation topsets and Torok Formation foresets–bottomsets. Oil-prone source rocks and the clinothem are draped across the Barrow arch, a structural hinge between the Colville foreland basin and Beaufort Sea rifted margin. Stratigraphic traps lie in a favorable thermal maturity domain along multiple migration pathways across more than 30,000 km2 (10,000 mi2). Sediment from the Chukotkan orogen (Russia) filled the western Colville basin and spilled over the Beaufort rift shoulder, forming east- and north-facing shelf margins. Progradational shelf margin trajectories change abruptly to “sawtooth” trajectories at midclinothem, the result of reduction in sediment influx. Two stratigraphic trap types are inferred in Nanushuk basal topsets in the eastern part of the clinothem: (1) lowstand systems tracts, inferred to reflect forced regression, include a narrow, thick progradational stacking pattern perched on a sequence boundary on the upper slope; and (2) highstand-progradational systems tracts include a broad, thin wedge of shingled parasequences above a toplap surface. Both include stratigraphically isolated sandstone sealed by mudstone. Trap geometries in Torok foreset and bottomset facies in the same area include basin-floor fan, slope-apron, and slope-channel deposits that pinch out upslope and are sealed by mudstone. Significant potential exists for the discovery of additional oil accumulations in these stratigraphic trap types in the eastern part of the clinothem. Less potential may exist in the western part because reservoir–seal pairs may not be well developed.