论文部分内容阅读
巨厚的深海沉积物为寻找石油提供了一个新的目标,亚要求有一种革新的方法来勘探碳氢化合物。劳伦斯冲积扇是北大西洋西部的一个巨大的深海冲积扇(深2000～5000米),至少自早第三纪以来一直是新斯科夏岸外的主要沉积中心。过去二、三百万年中,这个现代沉积蓝遭到侵蚀的冲积扇的地貌发育主要与陆上的冰川史密切相关。劳伦斯冲积扇上方的陆坡是发生快速沉积和滑坡的场所。上部扇的支流网可能注入了三条大的沟道系统,后者在宽阔而不对称的堤垄之间切割深达800米。这些沟道广泛地迂回穿过下部扇,然后通过前扇舌瓣而突然消失。劳伦斯冲积扇与典型的海底冲积扇模式之间的差异,部分是由于沉积物的淤泥质和供给系统而造成的。沟道沉积含有巨厚的粗砾层,该砾石层可能在沟道末端变为砂质舌辩。上述两者若有适当的来源和圈闭,可形成良好的储油层主体。在冲积扇结构中,细粒沉积物很重要。在晚第四纪—全新世层系中,浊积层、等深流沉积层和半深海沉积层交互产出。这些沉积物的分布,特别是对于细粒浊积层中的构遣序列、结构变化和组构类型的认识,可用于阐明冲积扇某些部分的沉积环境的特征。在今后的碳氢化合物勘探中,这种方法将证明是有用的。
Thick, deep-sea sediments provide a new destination for oil exploration and Asia calls for a revolutionary approach to hydrocarbon exploration. The Lawrence alluvial fan is a huge deep-sea alluvial fan (2,000 to 5,000 meters deep) in the western North Atlantic that has been a major sedimentary center off the Nova Scotia since at least the earliest Tertiary. Over the past two or three million years, the alluvial fan erosion of this modern sedimentary blue has largely been related to the glacial history on land. The slopes above Lawrence alluvial fans are places where rapid deposition and landslides occur. The upper fan tributary network may have injected three large channel systems, which cut deep as far as 800 meters between broad and asymmetrical ridges. These channels extensively roundabout through the lower fan and then suddenly disappear through the front flap. The difference between the Lawrence alluvial fan and the typical submarine alluvial fan pattern is due in part to sediment and sediment supplies. Channel deposition contains a thick layer of gravel that may become a gritty tongue at the end of the channel. If both have proper sources and traps, a good reservoir body can be formed. Fine alluvial deposits are important in alluvial fan structures. In the late Quaternary-Holocene strata, turbidites, isochronous sediments and semi-deep-sea sediments are interactively produced. The distribution of these sediments, especially for the tracing sequence, structural changes and the type of structure in the fine-grained turbidites, can be used to elucidate the characteristics of sedimentary environment in some parts of the alluvial fan. This method will prove useful in future hydrocarbon exploration.