The Mesozoic Cameros Basin, northern Spain, was inverted during the Cenozoic Alpine orogeny when the Tithonian – Upper Cretaceous sedimentary fill was uplifted and partially eroded. Tar sandstones outcropping in the southern part of the basin and pyrobitumen particles trapped in potential source rocks suggest that hydrocarbons have been generated in the basin and subsequently migrated. However, no economic accumulations of oil or gas have yet been found. This study reconstructs the evolution of possible petroleum systems in the basin from initial extension through to the inversion phase, and is based on structural, stratigraphic and sedimentological data integrated with petrographic and geochemical observations. Petroleum systems modelling was used to investigate the timing of source rock maturation and hydrocarbon generation, and to reconstruct possible hydrocarbon migration pathways and accumulations. In the northern part of the basin, modelling results indicate that the generation of hydrocarbons began in the Early Berriasian and reached a peak in the Late Barremian – Early Albian. The absence of traps during peak generation prevented the formation of significant hydrocarbon accumulations. Some accumulations formed after the deposition of post‐extensional units (Late Cretaceous in age) which acted as seals. However, during subsequent inversion, these reservoir units were uplifted and eroded. In the southern sector of the basin, hydrocarbon generation did not begin until the Late Cretaceous due to the lower rates of subsidence and burial, and migration and accumulation may have taken place until the initial phases of inversion. Sandstones impregnated with bitumen (tar sandstones) observed at the present day in the crests of surface anticlines in the south of the basin are interpreted to represent the relics of these palaeo‐accumulations. Despite a number of uncertainties which are inherent to modelling the petroleum systems evolution of an inverted and overmature basin, this study demonstrates the importance of integrating multidisciplinary and multi‐scale data to the resource assessment of a complex fold‐and‐thrust belt.

中文翻译：

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折叠推力带设置中的石油系统建模：倒置的 CAMEROS 盆地，西班牙中北部

西班牙北部的中生代卡梅罗斯盆地在新生代高山造山运动期间发生倒转，当时提通阶 - 上白垩统沉积充填被抬升和部分侵蚀。盆地南部出露的焦油砂岩和被困在潜在烃源岩中的焦沥青颗粒表明，在盆地中产生了碳氢化合物并随后运移。然而，尚未发现石油或天然气的经济积累。本研究基于构造、地层和沉积学数据，结合岩石学和地球化学观测，重建了盆地中可能的石油系统从初始延伸到反转阶段的演化过程。石油系统建模用于研究烃源岩成熟和油气生成的时间，并重建可能的油气运移途径和聚集。在盆地北部，模拟结果表明，油气的生成始于早贝里阿阶，并在晚巴雷米亚—早阿尔比安期达到高峰。峰生成期间没有圈闭阻止了大量油气聚集的形成。一些堆积物在后伸展单元（晚白垩世）沉积后形成，起到密封作用。然而，在随后的反演过程中，这些储层单元被抬升和侵蚀。在盆地南部，由于下沉和埋藏速率较低，直到白垩纪晚期才开始生烃，并且可能在反转的初始阶段之前发生运移和聚集。目前在盆地南部地表背斜的顶部观察到的含沥青的砂岩（焦油砂岩）被解释为代表这些古堆积物的遗迹。尽管在模拟倒置和过成熟盆地的石油系统演化过程中存在许多固有的不确定性，但本研究证明了将多学科和多尺度数据整合到复杂褶皱逆冲带资源评估中的重要性。