基于SSMO-SSA-LGBM算法的致密砂岩储层岩性识别研究

    Research on lithology identification of tight sandstone reservoirs based on SSMO-SSA-LGBM algorithm

    • 摘要: 为了解决致密砂岩储层各岩性之间类别不均衡且测井响应相似度高,严重影响机器学习岩性自动识别效果问题,本文提出SSMO-SSA-LGBM模型:将SVM算法与过采样技术SMOTE结合组成SSMO模型,对训练集中岩性数据较少的样本进行平衡化处理得到新合成样本,并将其与原始训练集组成新训练集用于训练和构建LGBM模型,由于LGBM模型训练时使用较多超参数,因此采用麻雀优化搜索算法SSA对其进行超参寻优以获得最佳参数组合。以华池S区延10致密砂岩测井数据为基础,训练构建SSMO-SSA-LGBM模型,采用 KNN、Adaboost、随机森林等模型进行对比。研究表明,经SSMO模型平衡化后,LGBM模型对少数类识别性能增强;SSA算法全局优化搜索经较少次数迭代获得LGBM最优超参数;SSMO-SSA-LGBM模型预测性能达到最优,在测试集和验证集上多次运行结果准确率均稳定在94%以上,验证该模型在华池S区的应用效果较好。

       

      Abstract: In order to solve the problem of imbalanced classification and high similarity of logging responses among different rock types in tight sandstone reservoirs, which seriously affects the automatic recognition effect of machine learning rock types, this paper proposes the SSMO-SSA-LGBM model: combining SVM algorithm with oversampling technique SMOTE to form the SSMO model, balancing the samples with fewer lithology data in the training set to obtain new composite samples, and combining them with the original training set to form a new training set for training and constructing the LGBM model. Due to the use of many hyperparameters during LGBM model training, the sparrow optimization search algorithm SSA is used to optimize its hyperparameters and seek the best parameter combination, forming the SSMO-SSA-LGBM combination model. Based on the lithological data of Yan10 tight sandstone in Huachi S area, an SSMO-SSA-LGBM model was trained and constructed, and compared using models such as KNN, Adaboost, and random forest. Research has shown that after oversampling by the SSMO model, the LGBM model enhances its performance in minority class recognition; The SSA algorithm global optimization search obtains the optimal hyperparameter of LGBM through fewer iterations, achieving optimal predictive performance. After multiple runs on the test and validation sets, the accuracy of the prediction results remains stable at over 94%, verifying the good application effect of the model in Huachi S area.

       

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