基于改进广义S变换时频分析的“板状”断控油藏油柱高度预测

    Prediction of oil column heights in fault-controlled tabular reservoirs through time-frequency analysis based on improved generalized S-transform

    • 摘要: 塔里木盆地北部坳陷碳酸盐岩断控领域油气资源丰富。断控“板状”油藏油水界面的识别是该类油藏效益开发的关键工作。钻井探测油藏油水界面的成本高、工程实现难度大, 而采用地球物理的方法识别油水界面是一种高效措施。文章提出一种基于广义S变换时频分析的应用方法, 通过大量过井地震道时频分析结果与开发动态分析数据联合分析, 发现地震资料主频随深度/时间的变化与油层厚度具有正相关关系, 提出采用地震道时频道集能量包络异常拐点判别油水界面的思路。实验表明, 针对“板状”油藏, 当油柱厚度OCH< 120 m时, 分析结果存在不确定性; 当120≤OCH≤250 m时, 分析结果基本可靠; 当OCH> 250 m时, 油层厚度可靠。应用表明, 在富满油田某区某断裂破碎带预测油层厚度主体为200~520 m, 与当地开发实际相符, 可指导开发实践。

       

      Abstract: The fault-controlled carbonate area in the northern depression of the Tarim Basin possesses abundant oil and gas resources.Identifying the oil-water contact (OWC) of fault-controlled tabular reservoirs is critical for their effective exploitation.However, OWC identification through drilling is costly and challenging.In contrast, it is efficient to identify the OWC using geophysical methods.This study proposed a time-frequency analysis method based on generalized S-transform.As revealed by the joint analysis of extensive time-frequency analysis results of through-well seismic channels and production performance analysis data, the depth/time-varying main frequency of seismic data is positively correlated with the oil layer thickness.Hence, this study proposed to identify the OWC using the abnormal inflection point of the energy envelope of seismic channel time-frequency gather.Experimental results demonstrate that oil layer thickness results obtained are uncertain, generally reliable, and reliable in the case of oil column height (OCH)< 120 m, 120 m≤OCH≤250 m, and OCH≥250 m, respectively.The method proposed in this study was applied to a fault fracture zone of an area of the Fuman oilfield, obtaining the main predicted oil layer thicknesses between 200 m and 520 m, aligning with the actual exploitation results.Therefore, the method of this study can be employed to guide exploitation.

       

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