不同热模拟方式下烃源岩干酪根演化特征红外光谱分析

发布时间：2018-02-19 21:15

  本文关键词： 生排烃模拟 PVT-L共控 红外光谱 烃源岩　出处：《石油实验地质》2017年01期 　论文类型：期刊论文

【摘要】：烃源岩的生烃过程是在地层孔隙空间内有机质受温度、上覆岩层静岩压力和高地层流体压力(PVT-L共控)等多种作用下的一种复杂的物理化学反应过程。然而目前常用的生烃模拟实验(高压釜加水生烃模拟)大多是在一个低流体压力、无静岩压力、相对较大的生烃空间下进行的,与实际地质情况差异较大。选用南襄盆地泌阳凹陷核三段未熟泥岩分别开展了PVT-L共控和常规高压釜方式加水模拟实验,不同演化阶段干酪根的傅里叶变换红外光谱对比分析表明:(1)伴随着脂族结构裂解、含氧基团脱落及芳香结构缩合,干酪根演化明显呈现出缓慢生油、快速生油和结束生油3个阶段;(2)脂肪度参数IAL、饱芳比参数IL/R和含氧度参数IO表明,同等温度条件下常规高压釜加水模拟脂肪链和含氧基团的热裂解反应更为剧烈,PVT-L共控模拟则相对平缓,380℃时仍伴随有较强的生烃能力;(3)PVT-L共控模拟条件下饱和烃的芳构化程度更低,可能与其限定空间内较高的流体压力有关;(4)含氧度在成熟中期间歇的轻微增大,暗示水对干酪根生烃过程也许有重要的作用。2种不同模拟方式下干酪根红外光谱特征上的差别,暗示其在生烃反应机理上存在较大差异,在热模拟实验研究中要根据研究目的合理选择模拟方式,设置实验条件。
[Abstract]:The hydrocarbon generation process of source rocks is that the organic matter is heated in the pore space of strata. There is a complicated physicochemical reaction process under the action of static rock pressure and high formation fluid pressure (PVT-L co-control) in overlying strata. However, most of the commonly used hydrocarbon-generating simulation experiments (hydrocarbon-generating simulation in autoclave) are at a low fluid pressure. In the absence of static rock pressure and relatively large hydrocarbon generation space, it is quite different from the actual geological conditions. PVT-L co-control and conventional autoclave water addition simulation experiments were carried out in the unripe mudstone of the third member of the Miyang Depression in Nanxiang Basin. Fourier transform infrared spectroscopy (FTIR) analysis of kerogen at different stages of evolution showed that the evolution of kerogen showed slow oil generation, which was accompanied by the decomposition of lipids, the exfoliation of oxygenated groups and the condensation of aromatic structures, and the evolution of kerogen was characterized by slow oil generation. The three stages of rapid oil generation and ending oil generation, I. e., IL/R, IL/R and oxygen content, showed that the parameters of fat degree, satiety ratio, and oxygen content of the three stages of oil generation were as follows:. At the same temperature, the conventional autoclave with water to simulate the pyrolysis reaction of fat chain and oxygen-containing group is more intense than PVT-L co-control simulation, but it is still accompanied by a strong hydrocarbon generating ability and saturated hydrocarbon under the condition of co-controlled simulation at 380 鈩，

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