吉木萨尔页岩油压裂施工曲线智能预测方法

Intelligent Prediction Method of Fracturing Treatment Curves for Jimsar Shale Oil

  • 摘要: 砂堵严重制约了吉木萨尔页岩油示范区的压裂施工安全和施工效率,施工压力变化是砂堵最直接的响应信号,准确预测施工压力是超前预警砂堵的关键。基于LSTM、BiLSTM和GRU等3种机器学习方法,建立了多变量时序施工压力预测模型,利用网格搜索算法和贝叶斯优化算法优化模型的超参数,同时使用五折交叉验证方法,防止模型过拟合。以均方误差、均方根误差和平均绝对误差为评价指标,评估了预测模型的性能,并以实际压裂段开展了模型应用。研究结果表明:具有五折交叉验证和丢弃率等于0.30的BiLSTM模型,相比于具有相同约束的LSTM和GRU模型,均方误差分别降低了67.6%和89.9%,均方根误差分别降低了43.1%和68.3%,平均绝对误差分别降低了28.6%和67.6%。由此可知,具有五折交叉验证和丢弃率等于0.30的BiLSTM模型具有较好的泛化能力和鲁棒性,预测施工压力更加可靠。研究结果可为吉木萨尔页岩油示范区压裂施工压力的预测提供模型和方法。

     

    Abstract: The screenout severely restricts the safety and efficiency of fracturing treatment in Jimsar Shale Oil. The change in treatment pressure is the most direct response signal of the screenout. Accurate prediction of treatment pressure is the key to achieving early warning against screenout. Based on three machine learning methods, namely LSTM, BiLSTM, and GRU, a multivariate time-series treatment pressure prediction model was established. Grid search algorithms and Bayesian optimization algorithms were used to optimize the model’s hyperparameters, while five-fold cross-validation was employed to prevent overfitting. The performance of the prediction model was evaluated using mean squared error, root mean squared error, and mean absolute error as metrics, and the model was applied to actual fracturing sections. The research results indicate that the BiLSTM model with five-fold cross-validation and dropout rate set to 0.3 outperforms the LSTM and GRU models under the same constraints, with mean squared error reductions of 67.6% and 89.9%, mean squared root error reductions of 43.1% and 68.3%, and mean absolute error reductions of 28.6% and 67.6%, respectively. Therefore, the BiLSTM model with five-fold cross-validation and dropout rate set to 0.3 demonstrates superior generalization capability and robustness, making it more reliable for predicting treatment pressure. The research findings provide a model and method for the prediction of treatment pressure in Jimsar Shale Oil fracturing treatments.

     

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