基于米氏旋回理论的高频层序识别与划分—以南八仙油气田下油砂山组为例
- 收稿日期:
2023-09-07
- 网络出版日期:
2024-03-11
摘要: 【目的】通过分析地球轨道周期性变化对气候周期性变化的影响，探讨柴达木盆地下油砂山组的气候变化特征，基于米兰科维奇理论对柴达木盆地下油砂山组建立高分辨率的天文年代标尺，识别和划分高频层序。【方法】首先，利用Laskar算法计算北纬35°夏至日14.5~23.8 Ma期间地球轨道参数变化周期，确定了该沉积期米氏旋回理论和米氏旋回周期比。然后南八仙油气田的仙中39井、仙中8-9井及仙中8-12井为例，对自然伽马数据进行频谱和连续小波变换分析；最后，根据轨道周期计算出下油砂山组平均沉积速率，并建立了仙中39井的“浮动”天文年代标尺。【结果】通过频谱和连续小波变换分析发现，新近系下油砂山组主要受400 ka和95 ka偏心率周期控制。根据计算结果，下油砂山组平均沉积速率为0.094 41 m/ka，沉积持续时间为7.2 Ma。基于400 ka长偏心周期曲线和95 ka短偏心周期曲线作为基准曲线，共鉴定出18个四级准层序组和72个五级准层序。【结论】结果表明，下油砂山组中所记录的气候变化明显受到旋回的控制和驱动。基于米兰科维奇理论识别与划分，能够减少主观因素的影响，提高划分结果的准确性，可以更准确地刻画沉积物中的气候变化特征。这些研究成果有助于深入理解地球气候演变规律，并为油气勘探和资源评价提供重要参考。
Identification and division of high-frequency sequence based on Milakovitch cycle: A case study of Xiayoushashan Formation in Nanbaxian oil and gas field
- Received Date:
2023-09-07
- Available Online:
2024-03-11
Abstract: [Objective] By analyzing the influence of the periodic change of earth orbit on the periodic change of climate, this paper discusses the climate change characteristics of the Lower Oil Sand Mountain Formation in Qaidam Basin, and establishes a high-resolution astronomical scale for the Lower Oil Sand Mountain in Qaidam Basin based on Milankovitch theory to identify and divide high-frequency sequences. [Methods] Firstly, Laskar algorithm is used to calculate the variation period of the earth's orbital parameters during the summer solstice at 35 north latitude from 14.5~23.8 Ma, and the Miocene cycle theory and Miocene cycle ratio in this sedimentary period are determined. Then, taking wells Xianzhong 39, Xianzhong 8-9 and Xianzhong 8-12 in Nanbaxian oil and gas field as examples, the natural gamma data are analyzed by frequency spectrum and continuous wavelet transform. Finally, according to the orbital period, the average sedimentation rate of the Lower Youshashan Formation is calculated, and the "floating" astronomical scale of well Xianzhong 39 is established. [Results] Through the analysis of frequency spectrum and continuous wavelet transform, the Neogene Lower Youshashan Formation is mainly controlled by eccentricity periods of 400 ka and 95 ka. The average sedimentation rate of the Lower Youshashan Formation is 0.094 41 m/ka, and the sedimentation duration is 7.2 Ma. Based on the 400 ka long eccentric period curve and 95 ka short eccentric period curve as benchmark curves, 18 fourth-order quasi-sequence groups and 72 fifth-order quasi-sequence groups were identified. [Conclusion] The results show that the climate change recorded in the Lower Youshashan Formation is obviously controlled and driven by cycles. Identification and division based on Milankovitch theory can reduce the influence of subjective factors, improve the accuracy of division results, and more accurately describe the climate change characteristics in sediments. These research results are helpful to deeply understand the evolution law of the earth's climate and provide important reference for oil and gas exploration and resource evaluation.
热依扎·沙依热阿特汗, 姚宗全, 张源智, 郑彬, 张士超, 刘少鹏. 基于米氏旋回理论的高频层序识别与划分—以南八仙油气田下油砂山组为例[J]. 沉积学报. doi: 10.14027/j.issn.1000-0550.2024.020
Identification and division of high-frequency sequence based on Milakovitch cycle: A case study of Xiayoushashan Formation in Nanbaxian oil and gas field[J]. Acta Sedimentologica Sinica. doi: 10.14027/j.issn.1000-0550.2024.020
| Citation: |
Identification and division of high-frequency sequence based on Milakovitch cycle: A case study of Xiayoushashan Formation in Nanbaxian oil and gas field[J]. Acta Sedimentologica Sinica. doi: 10.14027/j.issn.1000-0550.2024.020
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