Research on prediction methods of formation pore pressure based on machine learning. Issue 6 (10th March 2022)

• Record Type: Journal Article
• Authors: Huang, Honglin; Li, Jun; Yang, Hongwei; Wang, Biao; Gao, Reyu; Luo, Ming; Li, Wentuo; Zhang, Geng; Liu, Liu
• Other Names: Tsai Sang‐Bing guestEditor.; Wu Chia‐Huei guestEditor.; Liu Xuexin guestEditor.
• Is Part Of: Energy science & engineering. Volume 10:Issue 6(2022)
• Page Start: 1886
• Page End: 1901
• Publication Date: 2022-03-10
• Subjects: effective stress -- formation physical property and lithology -- logging data -- machine learning -- pore pressure; Energy industries -- Periodicals; Energy development -- Periodicals; Power resources -- Periodicals; 621.042
• DOI: 10.1002/ese3.1112
• Languages: English
• ISSNs: 2050-0505

Abstract

Abstract: Formation pressure is the most fundamental data in oil and gas drilling and production; it has an important position in the entire cycle of oil and gas extraction. However, most current prediction methods are limited to parametric methods with fixed models; such that the accuracy does not meet requirements. This is especially true for deeper layers of marine sedimentary basins where the safety density window is extremely narrow. In this study, we propose a novel method to predict pore pressure using machine learning techniques. For the first time, the effective stress (direct output variable) was accurately predicted by a combination of four input variables (2900 sets of data, of which 90% is the training subset and 10% is the testing subset), including longitudinal velocity, porosity, mud content, and density. As such, an accurate prediction of the formation pressure was achieved based on the effective stress theorem. The performance of machine learning techniques was verified by comparing and analyzing the prediction results with traditional parametric single and multivariate models; whereby the best algorithm was chosen by structural optimization and comparative analysis of five algorithms (multilayer perceptron neural network, radial basis neural network, support vector machine, random forest, and gradient boosting machine). Compared with the methods based on parametric one‐dimensional and multivariate models, the machine learning‐based method was determined to possess high accuracy, adequate self‐adaptation, and high fault tolerance ( D 2 = 0.9981, RMSE = 0.00718 g/cm 3 ). Moreover, the multilayer perceptual neural network algorithm outperformed other machine learning algorithms in terms of goodness of fit, generalization, and prediction accuracy, with D 2 = 0.9981 and RMSE = 0.00709 g/cm 3 . The formation pressure prediction model developed in this study is not affected by the mechanical depositional environment and is applicable to sandy mudstone formations, such that it can be a useful and highly accurate alternative to the traditional formation pressure prediction methods with fixed parameter forms. Abstract : Using machine learning (ML), we presented a new method to predict formation pore pressure. In this paper, three types of ML algorithms (five kinds of algorithms: multilayer perception neural network, radial basis function neural network, support vector machine, random forest, and gradient boosting machine) are applied to the prediction of Pp of offshore exploration wells in Yinggehai Basin, South China Sea, and the hyperparameter optimization of each algorithm is carried out to improve the model performance.