مجله ژئوفیزیک ایران

مجله ژئوفیزیک ایران

A pattern recognition approach to reservoir modeling: comparative performance of CNN and gradient boosting in heterogeneous carbonate reservoirs

نوع مقاله : مقاله پژوهشی‌

نویسندگان
1 M.Sc., Department of Artificial Intelligence, Asmary Field Services Company, Tehran, Iran
2 Ph.D., Department of Training, Asmary Field Services Company, Tehran, Iran
10.30499/ijg.2026.547572.1726
چکیده
Missing intervals or unreliable well-log measurements pose a persistent challenge for subsurface characterization, particularly for curves critical to porosity, lithology, and velocity analysis. This study investigates two machine-learning strategies for reconstructing missing logs: a hybrid Multivariate Imputation by Chained Equations with Gradient Boosted Trees (MICE+GBT), and also Convolutional Neural Network (CNN). The prediction targets are three essential logs-neutron porosity (NPHI), bulk density (RHOB), and compressional travel time (DT). Each reconstructed artificial log from complementary measurements including resistivity, Photoelectric Factor (PEF), and spectral gamma-ray. A rigorous preprocessing workflow was applied, followed by evaluation under a well-level cross-validation scheme to simulate deployment on unseen wells. Performance was measured using Mean Squared Error (MSE), Mean Absolute Error (MAE), correlation coefficient (R), and coefficient of determination (R²).  This research utilizes two separate methods to estimate absent well logs in the Sarvak Formation, a diverse carbonate reservoir noted for intricate pore configurations and variability in lithology. These approaches tackle deficiencies in log data while assessing performance in regulated environments. In the following section, we will outline the dataset, prediction objectives, preprocessing steps, workflows, and evaluation methods. Results indicate that the MICE+GBT approach consistently outperforms Convolutional LSTM across all three target logs, particularly for intervals affected by washouts or tool measurement failures. Beyond statistical performance, the reconstructed curves preserved geological consistency in density–neutron and sonic–density trends, ensuring reliability for downstream reservoir interpretation. The findings demonstrate the practical benefits of adapting ensemble-based imputation methods to petrophysical data, providing a robust and interpretable framework for improving log data alliance in reservoir studies. Results demonstrated that the MICE+GBT workflow consistently delivered accurate, stable, and interpretable predictions across both Danan and Azadegan fields. Its strength was most evident in DT reconstruction, where ConvLSTM struggled with convergence and produced elevated error magnitudes. Ensemble models also yielded narrower error distributions and superior generalization across wells, underscoring their robustness in data-limited carbonate environments. Conversely, the ConvLSTM framework captured local depth-wise dependencies effectively, particularly for NPHI, and showed potential when sufficient training data were available. However, its sensitivity to heterogeneity and tendency toward error dispersion limit its reliability in reservoirs with strong lithological variability. Overall, the findings suggest that ensemble methods presently offer more dependable solutions for carbonate reservoirs with restricted datasets, while deep learning approaches hold promise for future applications given larger, more diverse training corpora. Integrating the interpretability and stability of ensemble models with the representational power of deep learning could form the basis of next-generation workflows for missing log prediction.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

A pattern recognition approach to reservoir modeling: comparative performance of CNN and gradient boosting in heterogeneous carbonate reservoirs

نویسندگان English

Yeganeh Mirakhorloo 1
Forough Zaker Moshfegh 1
Reza Hoveyzavi 2
1 M.Sc., Department of Artificial Intelligence, Asmary Field Services Company, Tehran, Iran
2 Ph.D., Department of Training, Asmary Field Services Company, Tehran, Iran
چکیده English

Missing intervals or unreliable well-log measurements pose a persistent challenge for subsurface characterization, particularly for curves critical to porosity, lithology, and velocity analysis. This study investigates two machine-learning strategies for reconstructing missing logs: a hybrid Multivariate Imputation by Chained Equations with Gradient Boosted Trees (MICE+GBT), and also Convolutional Neural Network (CNN). The prediction targets are three essential logs-neutron porosity (NPHI), bulk density (RHOB), and compressional travel time (DT). Each reconstructed artificial log from complementary measurements including resistivity, Photoelectric Factor (PEF), and spectral gamma-ray. A rigorous preprocessing workflow was applied, followed by evaluation under a well-level cross-validation scheme to simulate deployment on unseen wells. Performance was measured using Mean Squared Error (MSE), Mean Absolute Error (MAE), correlation coefficient (R), and coefficient of determination (R²).  This research utilizes two separate methods to estimate absent well logs in the Sarvak Formation, a diverse carbonate reservoir noted for intricate pore configurations and variability in lithology. These approaches tackle deficiencies in log data while assessing performance in regulated environments. In the following section, we will outline the dataset, prediction objectives, preprocessing steps, workflows, and evaluation methods. Results indicate that the MICE+GBT approach consistently outperforms Convolutional LSTM across all three target logs, particularly for intervals affected by washouts or tool measurement failures. Beyond statistical performance, the reconstructed curves preserved geological consistency in density–neutron and sonic–density trends, ensuring reliability for downstream reservoir interpretation. The findings demonstrate the practical benefits of adapting ensemble-based imputation methods to petrophysical data, providing a robust and interpretable framework for improving log data alliance in reservoir studies. Results demonstrated that the MICE+GBT workflow consistently delivered accurate, stable, and interpretable predictions across both Danan and Azadegan fields. Its strength was most evident in DT reconstruction, where ConvLSTM struggled with convergence and produced elevated error magnitudes. Ensemble models also yielded narrower error distributions and superior generalization across wells, underscoring their robustness in data-limited carbonate environments. Conversely, the ConvLSTM framework captured local depth-wise dependencies effectively, particularly for NPHI, and showed potential when sufficient training data were available. However, its sensitivity to heterogeneity and tendency toward error dispersion limit its reliability in reservoirs with strong lithological variability. Overall, the findings suggest that ensemble methods presently offer more dependable solutions for carbonate reservoirs with restricted datasets, while deep learning approaches hold promise for future applications given larger, more diverse training corpora. Integrating the interpretability and stability of ensemble models with the representational power of deep learning could form the basis of next-generation workflows for missing log prediction.

کلیدواژه‌ها English

Gradient boosting tree(GBT)
petrophysical Well Logs
conventional long short-term memory (CONVLSTM)
convolutional nerural network (CNN)
machine learning (ML)
Hu, Wenyi, and Brian W. Horn. "Fourth International Meeting for Applied Geoscience & Energy." . ISSN (Online): 1949-4645. (2024)
Artun, E., et al. "An Integrated Workflow for Data Analytics-Assisted Reservoir Management with Incomplete Well Log Data." SPE Journal 30.02 (2025): 486-506.
Mukherjee, Bappa, Kalachand Sain, and Xinming Wu. "Missing log prediction using machine learning perspectives: A case study from upper Assam basin." Earth Science Informatics 17.4 (2024): 3071-3093.
Al-Mudhafar, Watheq J., et al. "Machine learning with hyperparameter optimization applied in facies-supported permeability modeling in carbonate oil reservoirs." Scientific Reports 15.1 (2025): 12939.
Maldonado-Cruz, Eduardo, John T. Foster, and Michael J. Pyrcz. "Sonic well-log imputation through machine-learning-based uncertainty models." Petrophysics 64.02 (2023): 253-270.
Gardner, G. H. F., L. W. Gardner, and ARw Gregory. "Formation velocity and density—The diagnostic basics for stratigraphic traps." Geophysics 39.6 (1974): 770-780.
Castagna, John P., Michael L. Batzle, and Raymond L. Eastwood. "Relationships between compressional-wave and shear-wave velocities in clastic silicate rocks." geophysics 50.4 (1985): 571-581.
Lopes, Rui L., and Alípio M. Jorge. "Assessment of predictive learning methods for the completion of gaps in well log data." Journal of Petroleum Science and Engineering 162 (2018): 873-886.
Pham, N., and E. Zabihi Naeini. "Missing well log prediction using deep recurrent neural networks." 81st EAGE Conference and Exhibition 2019. Vol. 2019. No. 1. European Association of Geoscientists & Engineers, 2019.
Shan, Liqun, et al. "CNN-BiLSTM hybrid neural networks with attention mechanism for well log prediction." Journal of Petroleum Science and Engineering 205 (2021): 108838.
Lin, Lei, et al. "MWLT: Transformer-based missing well log prediction." Available at SSRN 4236228 (2023).
Lin, Lei, et al. "A deep-learning framework for borehole formation properties prediction using heterogeneous well-logging data: A case study of a carbonate reservoir in the Gaoshiti-Moxi area, Sichuan Basin, China." Geophysics 89.1 (2024): WA295-WA308.
Kiss, Viktória, and Norbert Péter Szabó. "Correlation-based imputation method for estimating missing well log data in a Hungarian groundwater well." MULTIDISZCIPLINÁRIS TUDOMÁNYOK: A MISKOLCI EGYETEM KÖZLEMÉNYE 12.3 (2022): 89-106.
Alimohammadi, Hamzeh, Saman Mahmoudi, and Shengnan Chen. "Single and multi-well synthetic well log generation using multivariate analysis." Abu Dhabi International Petroleum Exhibition and Conference. SPE, 2020.
Kanfar, Rayan, et al. "Real-time well log prediction from drilling data using deep learning." arXiv preprint arXiv:2001.10156 (2020).
Hallam, Antony, Debajoy Mukherjee, and Romain Chassagne. "Multivariate imputation via chained equations for elastic well log imputation and prediction." Applied Computing and Geosciences. ISSN (Online): 2666-9997. (2022).
Mukherjee, Bappa, et al. "Deep learning-aided simultaneous missing well log prediction in multiple stratigraphic units: a case study from the Bhogpara oil field, Upper Assam, Northeast India." Earth Science Informatics. ISSN (Online): 1865-0481. (2024).