Astrocycle Identification and High Sedimentation Rates Sedimentary Filling Response Characteristics in the YingXiongLing Shale of Westren Qaidam Basin
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摘要: 柴达木盆地英雄岭页岩油勘探开发潜力巨大,但目前在旋回地层学方面的工作较为薄弱,本文通过对英雄岭页岩发育的下干柴沟组上段地层开展4口井的频谱分析,综合岩心、测井、地化分析等方面的成果,识别出该套地层中的多组米兰科维奇旋回,并依据404.858ka的长偏心率周期建立了英雄岭页岩“浮动”天文标尺,估算出下干柴沟组上段地层沉积时间在4.86Ma、平均沉积速率达到了340.44m/Ma,明确了高沉积速率是英雄岭页岩的重要特征之一。基于长偏心率周期分析的总有机碳含量沉积响应特征表明柴达木盆地英雄岭页岩的有机碳富集程度受沉积速率控制明显,随着沉积速率的增大,总有机碳含量呈升高趋势,当沉积速率超过450m/Ma时,受到碎屑稀释效应影响,总有机碳出现显著下降。基于岁差周期建立的沉积构造响应模式发现,当岁差参数处于最小值时,主要发育贫有机质层状灰云岩,而岁差参数处于最大值时,主要发育富有机质纹层状灰云岩。英雄岭页岩表现出的这种明显轨道强迫响应,将有助于页岩油有利层段预测,可为今后英雄岭页岩油高效勘探开发提供一些新思路。Abstract: Abstract:The exploration and development potential of YingXiongLing shale oil in the Qaidam Basin is huge, but the work on Cyclostratigraphy is relatively weak at present, This article conducts a spectral analysis of four wells in the upper section of the Lower Ganchaigou Formation, which is developed in the YingXiongLing shale, Based on the results of core analysis, logging, and geochemical analysis, multiple sets of Milankovitch cycles in this set of strata have been identified, Based on 404.858ka long eccentricity period, the "floating" astronomical scale of YingXiongLing shale is established. It is estimated that the sedimentary time of the upper member of the Lower Ganchaigou Formation is 4.86Ma, and the average sedimentary rate is 340.44m/Ma, It has been clarified that high sedimentation rate is one of the important characteristics of the YingXiongLing shale. The sedimentary response characteristics of Total organic carbon content based on the long eccentricity period analysis show that the organic carbon enrichment degree of the YingXiongLing shale in the Qaidam Basin is controlled by the sedimentary rate, With the increase of deposition rate, the content of Total organic carbon increases. When the deposition rate exceeds 450m/Ma, Total organic carbon decreases significantly due to the dilution effect of debris. The sedimentary structure response model established based on the precession period found that when the precession parameter is at the minimum value, the main development is poor organic matter layered limestone, while when the precession parameter is at the maximum value, the main development is rich organic matter Laminated limestone. The obvious orbital forced response exhibited by the YingXiongLing shale will help predict favorable sections of shale oil and provide some new ideas for efficient exploration and development of YingXiongLing shale oil in the future.
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Key words:
- Qaidam /
- basinYingXiongLing Shale /
- Astrocycle /
- Sedimentation rate /
- Filling response
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