Direct Multi‐Modal Inversion of Geophysical Logs Using Deep Learning

Abstract Geosteering of wells requires fast interpretation of geophysical logs which is a non‐unique inverse problem. Current work presents a proof‐of‐concept approach to multi‐modal probabilistic inversion of logs using a single evaluation of an artificial deep neural network (DNN). A mixture densi...

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Main Authors: Sergey Alyaev, Ahmed H. Elsheikh
Format: Article
Language:English
Published: American Geophysical Union (AGU) 2022-09-01
Series:Earth and Space Science
Subjects:
Online Access:https://doi.org/10.1029/2021EA002186
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author Sergey Alyaev
Ahmed H. Elsheikh
author_facet Sergey Alyaev
Ahmed H. Elsheikh
author_sort Sergey Alyaev
collection DOAJ
description Abstract Geosteering of wells requires fast interpretation of geophysical logs which is a non‐unique inverse problem. Current work presents a proof‐of‐concept approach to multi‐modal probabilistic inversion of logs using a single evaluation of an artificial deep neural network (DNN). A mixture density DNN (MDN) is trained using the ”multiple‐trajectory‐prediction” loss functions, which avoids mode collapse typical for traditional MDNs, and allows multi‐modal prediction ahead of data. The proposed approach is verified on the real‐time stratigraphic inversion of gamma‐ray logs. The multi‐modal predictor outputs several likely inverse solutions/predictions, providing more accurate and realistic solutions compared to a deterministic regression using a DNN. For these likely stratigraphic curves, the model simultaneously predicts their probabilities, which are implicitly learned from the training geological data. The stratigraphy predictions and their probabilities obtained in milliseconds from the MDN can enable better real‐time decisions under geological uncertainties.
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spelling doaj.art-88fabc735dad4c2fa588b6d39184bffd2022-12-22T03:48:16ZengAmerican Geophysical Union (AGU)Earth and Space Science2333-50842022-09-0199n/an/a10.1029/2021EA002186Direct Multi‐Modal Inversion of Geophysical Logs Using Deep LearningSergey Alyaev0Ahmed H. Elsheikh1NORCE Norwegian Research Centre Bergen NorwayHeriot‐Watt University Edinburgh UKAbstract Geosteering of wells requires fast interpretation of geophysical logs which is a non‐unique inverse problem. Current work presents a proof‐of‐concept approach to multi‐modal probabilistic inversion of logs using a single evaluation of an artificial deep neural network (DNN). A mixture density DNN (MDN) is trained using the ”multiple‐trajectory‐prediction” loss functions, which avoids mode collapse typical for traditional MDNs, and allows multi‐modal prediction ahead of data. The proposed approach is verified on the real‐time stratigraphic inversion of gamma‐ray logs. The multi‐modal predictor outputs several likely inverse solutions/predictions, providing more accurate and realistic solutions compared to a deterministic regression using a DNN. For these likely stratigraphic curves, the model simultaneously predicts their probabilities, which are implicitly learned from the training geological data. The stratigraphy predictions and their probabilities obtained in milliseconds from the MDN can enable better real‐time decisions under geological uncertainties.https://doi.org/10.1029/2021EA002186geophysical inversionmulti‐modal inversiondeep neural networkmixture density networkwell‐log interpretationstratigraphic‐based geosteering
spellingShingle Sergey Alyaev
Ahmed H. Elsheikh
Direct Multi‐Modal Inversion of Geophysical Logs Using Deep Learning
Earth and Space Science
geophysical inversion
multi‐modal inversion
deep neural network
mixture density network
well‐log interpretation
stratigraphic‐based geosteering
title Direct Multi‐Modal Inversion of Geophysical Logs Using Deep Learning
title_full Direct Multi‐Modal Inversion of Geophysical Logs Using Deep Learning
title_fullStr Direct Multi‐Modal Inversion of Geophysical Logs Using Deep Learning
title_full_unstemmed Direct Multi‐Modal Inversion of Geophysical Logs Using Deep Learning
title_short Direct Multi‐Modal Inversion of Geophysical Logs Using Deep Learning
title_sort direct multi modal inversion of geophysical logs using deep learning
topic geophysical inversion
multi‐modal inversion
deep neural network
mixture density network
well‐log interpretation
stratigraphic‐based geosteering
url https://doi.org/10.1029/2021EA002186
work_keys_str_mv AT sergeyalyaev directmultimodalinversionofgeophysicallogsusingdeeplearning
AT ahmedhelsheikh directmultimodalinversionofgeophysicallogsusingdeeplearning