The paper discusses the issue of oil-in-place estimation for liquid-saturated shales in Lower Paleozoic (Silurian and Ordovician) organic-rich formations of the Baltic Basin in North Poland. The authors adopted a geochemical method based on Rock Eval results which directly measure hydrocarbon content present in rock samples. Its application on a real data set required the implementation of correction procedures to consider also those oil compounds which were lost before Rock Eval measurements were taken or are not recorded in parameter. It was accomplished through the introduction of two correction coefficients: —for evaporation loss and —for heavier compounds underestimation. The first one was approximated on the basis of published results and known properties of crude oil, while the second one was addressed with laboratory experimental procedure which combines Rock Eval pyrolysis and rock sample extraction with organic solvents. The calculation formulas were implemented in the 3D geological model of shale formations reproducing their geometry as well as the spatial variability of the petrophysical and geochemical properties. Consequently, the results of oil-in-place estimation were also available as 3D models, ready for visualization and interpretation in terms of delineation of most favorable zones or well placement. The adopted geochemical method and the results of oil-in-place estimation it produced were confronted with standard volumetric method. Although both of them are volumetric methods, the results depend on different sets of rock properties, which is an advantage for result comparison reasons. The study revealed that the geochemical method of oil-in-place estimation in liquid-rich shales after appropriate adjustment, considering shale formation and reservoir fluid dependent conditions, could provide reliable results and be implemented on the early stage of shale exploration process in a condition of production data inaccessibility.

中文翻译：

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利用 3D 高分辨率地质模型域中的地球化学和岩石物理数据估算富含液体的页岩地层中的石油资源量：波罗的海盆地案例研究

本文讨论了波兰北部波罗的海盆地下古生界（志留纪和奥陶纪）富含有机物地层中液体饱和页岩的原位油估计问题。作者采用了基于岩石评估结果的地球化学方法，该方法直接测量岩石样品中存在的碳氢化合物含量。它在实际数据集上的应用需要实施校正程序，以考虑在进行岩石评估测量之前丢失或未记录在参数中的那些油化合物。它是通过引入两个校正系数来实现的：——蒸发损失和——重化合物的低估。第一个是根据已发表的结果和原油的已知特性近似得出的，而第二个是通过实验室实验程序解决的，该程序将岩石评估热解和岩石样品提取与有机溶剂相结合。计算公式在页岩地层的 3D 地质模型中实施，再现了它们的几何形状以及岩石物理和地球化学特性的空间变异性。因此，就地油估计的结果也可作为 3D 模型提供，准备好在最有利区域或井位的划定方面进行可视化和解释。所采用的地球化学方法及其产生的原位油估计结果与标准体积法相比较。尽管它们都是体积法，但结果取决于不同的岩石属性集，这对于结果比较来说是一个优势。