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以鄂尔多斯盆地陇东地区三叠系延长组低渗透砂岩油藏为例,基于大量基础地质、地球物理和地球化学分析资料,指出鄂尔多斯盆地陇东地区延长组石油富集主要受稳定构造背景、低孔渗储层与高效优质烃源岩良好配置等多种因素控制。以长7油页岩为主、多层段有效烃源岩的高效生烃是石油富集的基础,低渗储层与高效烃源岩的直接大面积接触及烃源岩的异常高压驱动下的高效排油是低渗储层石油富集的关键;稳定的构造背景和低渗透储层的强烈非均质性是石油保存的根本。在延长组储层普遍致密的背景下,有效烃源岩的排烃范围和有效储层的分布共同控制了石油富集地区。勘探实践已表明,大型内陆坳陷湖盆低渗储层富油理论可有效指导油气勘探,已发现了亿吨级大油气田。
Taking the low permeability sandstone reservoir of Triassic Yanchang Formation in Longdong area of Ordos Basin as an example, based on a large amount of basic geologic, geophysical and geochemical analysis data, it is pointed out that the oil enrichment of Yanchang Formation in Longdong area of Ordos Basin is mainly influenced by the stable structural background and low Porosity and permeability reservoirs and high-quality source rock good configuration and other factors control. Based on Chang 7 oil shale, efficient hydrocarbon generation from multiple layers of effective source rocks is the basis of petroleum enrichment. The direct large-area contact between low-permeability reservoirs and high-efficiency source rocks and the abnormally high pressure driven by source rocks Efficient oil discharge is the key to petroleum enrichment in low-permeability reservoirs. Stable structural background and strong heterogeneity of low-permeability reservoirs are fundamental to petroleum preservation. Under the condition of generally dense reservoirs in Yanchang Formation, the hydrocarbon expulsion range of effective source rocks and the distribution of effective reservoirs jointly control the petroleum-rich areas. Exploration practice has shown that the theory of oil enrichment in low-permeability reservoirs of large inland depression lacustrine reservoirs can effectively guide oil and gas exploration, and large-scale billion-ton oil and gas fields have been discovered.