Lithofacies and origin of the Late Triassic muddy gravity-flow deposits in the Ordos Basin, central China
Lithofacies and origin of the Late Triassic muddy gravity-flow deposits in the Ordos Basin, central China
复制标题
鄂尔多斯盆地晚三叠世泥质重力流沉积岩相及成因
DOI：
10.1016/j.marpetgeo.2017.05.005
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发表时间：
2017
影响因子：
4.2
通讯作者：
van Loon A. J.
中科院分区：
文献类型：
--
作者：
Yang Renchao;Fan Aiping;Han Zuozhen;van Loon A. J.
晚三叠世延长组细粒沉积物。通过岩心分析和地球物理测井研究了鄂尔多斯盆地中的三个主要油气藏。该组泥岩部分为层状，部分为非层状，各类泥岩根据其结构和结构可分为八类。它们代表了各种环境，从三角洲前缘和水下扇到深水环境。部分沉积物被改造，并最终成为沉积从水下重力流，如泥流，浊流和hyperpycnal流，很容易发展的粘土丰富的三角洲斜坡。这种重力流沉积的沉积物显示出丰富的软沉积变形构造。认识这种构造，识别细粒沉积物为重力流沉积，对于勘探潜在的油气藏具有重要意义。由于细粒沉积物对油气勘探变得越来越重要，并且由于湖相延长组中的沉积物的沉积过程与三角洲和前三角洲细粒沉积物的沉积过程完全相同，因此本文提供的沉积学分析不仅对理解延长组这样的深湖沉积物很重要，也有助于更好地了解细粒前三角洲深海沉积物的堆积及其作为烃源岩和储集岩的潜力。
Fine-grained sediments from the Late Triassic Yanchang Fm. in the Ordos Basin (central China) were studied by core analysis and geophysical logging. Part of the mudstones in this formation are stratified, part of them are unstratified; the various mudstones can be subdivided into eight types on the basis of their structures and textures. They represent a variety of environments, ranging from delta fronts and subaqueous fans to deep-water environments. Part of the sediments were reworked and became eventually deposited from subaqueous gravity flows, such as mud flows, turbidity currents and hyperpycnal flows that easily developed on the clay-rich deltaic slopes. The sediments deposited by such gravity flows show abundant soft-sediment deformation structures. Understanding of such structures and recognition of fine-grained sediments as gravity-flow deposits is significant for the exploration of potential hydrocarbon occurrences. Because fine-grained deposits become increasingly important for hydrocarbon exploration, and because the sediments in the lacustrine Yanchang Formation were deposited by exactly the same processes that play a role in the accumulation of deltaic and prodeltaic fine-grained sediments, the sedimentological analysis provided here is not only important for the understanding of deep lacustrine sediments like the Yanchang Formation, but also for a better insight into the accumulation of fine-grained prodeltaic deep-marine sediments and their potential as hydrocarbon source rocks and reservoir rocks.