This paper presents a case study on the prediction of hydrocarbon reservoirs within coal-bearing formations of the Upper Palaeozoic. The target reservoirs are low-permeability low-pressure tight-sandstone reservoirs in the Daniudi Gas Field, Ordos Basin, China. The prime difficulty in reservoir prediction is caused by the interbedding coal seams within the formations, which generate low-frequency strong-amplitude reflections in seismic profiles. To tackle this difficulty, first, we undertook a careful analysis regarding the stratigraphy and lithology of these coal-bearing formations within the study area. Then, we conducted a geostatistical inversion using 3D seismic data and obtained reservoir parameters including seismic impedance, gamma ray, porosity and density. Finally, we carried out a reservoir prediction in the coal-bearing formations, based on the reservoir parameters obtained from geostatistical inversion and combined with petrophysical analysis results. The prediction result is accurately matched with the actual gas-test data for the targeted four segments of the coal-bearing formations.

中文翻译：

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含煤地层油气藏预测

本文介绍了上古生界含煤地层油气藏预测的案例研究。目标储层为鄂尔多斯盆地大牛地气田低渗透低压致密砂岩储层。储层预测的主要困难是由地层内的互层煤层引起的，这些煤层在地震剖面中产生低频强振幅反射。为解决这一难题，我们首先对研究区内这些含煤地层的地层和岩性进行了仔细分析。然后，我们使用 3D 地震数据进行了地质统计反演，并获得了包括地震阻抗、伽马射线、孔隙度和密度在内的储层参数。最后，我们在含煤地层中进行了储层预测，基于地质统计反演获得的储层参数并结合岩石物理分析结果。预测结果与含煤地层目标四段的实际试气数据准确匹配。