Migration of Fluids in Sedimentary Basins
Migration of Fluids in Sedimentary Basins
复制标题
沉积盆地中流体的运移
DOI：
10.1306/2f918194-16ce-11d7-8645000102c1865d
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发表时间：
1979
期刊：
影响因子：
3.5
通讯作者：
S. Neglia
中科院分区：
文献类型：
--
作者：
S. Neglia
控制沉积盆地中水和烃类运移的基本机制最终与盆地构造历史、岩石性质、压实作用和温度状况有关，这些因素本身是相互依赖的。沉积岩的压实作用在沉积物的渐进埋藏过程中促进了水的排出。岩石的物理化学性质决定了排出的水向地表的迁移以及盆地中各种参数的分布，如水力势、盐度、热流、温度和胶结作用。本文所用的初次运移是指烃类在生成后不久的运移;二次运移是指烃类的延迟运动。石油在泥质岩中很难运移。除了在水中的胶体或真正溶解或三维油湿干酪根网络中的流动之外，从源岩中去除石油的一种可能方法是通过其溶解在更深处产生的高压气体中。盆地的部分并通过断层和裂缝等优先路径出现。油的分子蒸馏发生是因为其在液相中的蒸气压高于在气相中的蒸气压。在岩性柱的上部，发生反凝析作用，在小型压实塑性盖层之下开始形成天然气和凝析气藏。由于气柱的高驱替压力，气体可以穿过盖层并分散到地面，而凝析油留在原地。小压实泥质盖层的孔径分布负责上升气体的化学和同位素分馏;因此，在地层柱的上层发现几乎纯的同位素轻甲烷。高挥发油易被循环水降解，特别是在硫酸根离子、硫化氢和细菌的存在下，并逐渐转化为重油。勘探工作者在勘探新油气田时可使用的地球化学工具包括同位素分析、水力势、盐度、温度、胶结作用、成熟度和显示图。
The basic mechanisms governing the migration of water and hydrocarbons in sedimentary basins are related ultimately to basinal structural history, rock properties, compaction, and temperature regime, which themselves are interdependent. Compaction of the sedimentary rocks promotes the expulsion of water during the progressive burial of the sediments. The physical-chemical properties of the rocks are responsible for the migration of the expelled water toward the surface and for the distribution in the basin of various parameters such as hydraulic potential, salinity, heat flow, temperature, and cementation. Primary migration is used herein to refer to migration of hydrocarbons soon after their generation; secondary migration refers to their delayed movement. Oil has difficulty migrating in shaly rocks. A possible way of removing oil from a source rock, in addition to the colloidal or true solubilization in water or the flow in a three-dimensional oil-wet kerogen network, is through its solubilization in high-pressure gas generated in the deeper part of the basin and coming up through preferential paths such as faults and fractures. Molecular distillation of the oil occurs because its vapor pressure in the liquid phase is higher than the vapor pressure in the gaseous phase. In the upper part of a lithologic column, retrograde condensation occurs and gas and condensate accumulations start to form below little compacted plastic caprocks. Owing to the high displacement pressures of the gaseous column, gas can pass through the caprock and disperse to the surface while the condensate remains in place. The pore-size distribution of the little compacted shaly caprock is responsible for the chemical and isotopic fractionation of the rising gas; almost pure and isotopically light methane thus is found in the upper layers of a stratigraphic column. High-volatile oil can be easily degraded by circulating water, especially in the presence of sulfate ions, hydrogen sulfide, and bacteria, and transformed progressively to heavy oil. Geochemical tools which can be used by explorationists in prospecting for new oil and gas fields include isotope analysis, hydraulic potential, salinity, temperature, cementation, maturity, and maps of shows.