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    基于RF−AdaBoost模型的储层隔夹层智能识别及其油水阻挡作用研究

    RF-AdaBoost-based intelligent identification of reservoir barriers and study of their oil–water blocking mechanisms

    • 摘要: 针对塔里木盆地LN油田致密砂岩储层非均质性强、隔夹层测井响应模糊等识别难题,提出一种基于随机森林(random forest, RF)与自适应增强(AdaBoost)集成学习的隔夹层识别方法。该方法以岩心薄片识别结果为基础,结合多种测井参数构建复合特征体系,利用ADASYN方法扩充样本数量,并采用网格搜索法优化随机森林超参数后嵌入AdaBoost框架,通过加权迭代提升小样本识别的稳定性与准确性。基于研究区7口井的测井数据开展建模分析,对比了RF−AdaBoost、AdaBoost、单一RF及KNN 4种模型的识别性能,结果显示,RF−AdaBoost模型在测试集中平均F1分数为94.33%,在识别泥质、钙质和物性3类隔夹层方面均表现出良好精度与边界清晰度。在识别结果的基础上进一步结合连井剖面与注采关系开展阻隔作用分析,识别结果与地质特征、生产响应相吻合,表明此方法能够有效识别储层中的隔夹层,并揭示其在油水运移过程中的层间封隔与侧向导流特性。研究表明,该方法适用于非岩心条件下的隔夹层识别,具备较强的实用性与推广价值,可为致密储层开发中的井位部署、注采优化和剩余油挖潜提供技术支持。

       

      Abstract: To overcome the challenges of strong heterogeneity and ambiguous log responses in identifying barriers in the tight sandstone reservoirs of Oilfield LN in the Tarim Basin, this study proposes a novel method (RF-AdaBoost) that integrates the random forest (RF) algorithm and adaptive boosting (AdaBoost) ensemble learning. The method constructs a sensitive multi-feature sample set from core thin-section and log data and applies ADASYN for sample augmentation. A grid search-optimized RF model, with the enhanced hyperparameters including the depth of decision trees, the number of estimators, and feature sampling rate, is then embedded within the AdaBoost framework, where iterative weighting is employed to significantly enhance the robustness and accuracy in identifying fine-scale barriers. The results of a comparative analysis of four models: RF-AdaBoost, k-Nearest Neighbors (KNN), RF, and AdaBoost, based on log data from 7 wells in the study area, indicate that the RF-AdaBoost model achieves an average F1-score of 94.33% on the test set and outperforms KNN, RF, and AdaBoost by 9.56%, 3.13%, and 2.45%, respectively. It demonstrates strong anti-noise capability, with a performance degradation of less than 3% under 20% simulated noise. It also exhibits high accuracy in distinguishing the boundaries of argillaceous, calcareous, and petrophysical property-controlled barrier types. The identification results, integrated with cross-well sections and the injection-production relationship, reveal flow regulation effects, which are consistent with geologic features and production performance. This demonstrates the method's capability to accurately identify barriers and characterize their dual functions of inter-layer sealing and lateral fluid diversion during hydrocarbon migration. The proposed RF-AdaBoost model provides a robust solution for intelligent barrier recognition in tight sandstone formations, especially under non-coring and low signal-to-noise ratio conditions. It offers technical support for fine-scale reservoir characterization and optimized waterflood development planning.

       

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