Error correction of vitrinite reflectance in matured black shales: A machine learning approach

Vitrinite reflectance (Ro) analysis is a maturity indication parameter for oil or gas prone source rocks in evaluating hydrocarbon potentials. As a result of challenges in Ro calculations from pyrolysis results, finding a way to estimate the maturity of source rocks has been an interesting subject f...

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Main Authors: Esther Boateng Owusu, George Mensah Tetteh, Solomon Asante-Okyere, Haylay Tsegab
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2022-01-01
Series:Unconventional Resources
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2666519022000048
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author Esther Boateng Owusu
George Mensah Tetteh
Solomon Asante-Okyere
Haylay Tsegab
author_facet Esther Boateng Owusu
George Mensah Tetteh
Solomon Asante-Okyere
Haylay Tsegab
author_sort Esther Boateng Owusu
collection DOAJ
description Vitrinite reflectance (Ro) analysis is a maturity indication parameter for oil or gas prone source rocks in evaluating hydrocarbon potentials. As a result of challenges in Ro calculations from pyrolysis results, finding a way to estimate the maturity of source rocks has been an interesting subject for researchers. There is a current need to improve the Ro calculated from the temperature at which the maximum rate of hydrocarbon generation occurs (Tmax) during maturation of shale formations. As this will go a long way to accelerate decision making and help avoid excessive expenditure costs on maturity determination using measured Ro for source rock samples while saving time. After the application of the conventional multiple linear regression analysis, the present study employed machine learning methods of random forest (RF), decision tree (DT), gradient boosting machine (GBM), ensembles and bagger (EnB), and multivariate adaptive regression splines (MARS) models for improving the calculated Ro of matured black shales. Total organic carbon (TOC), oxygen index (OI), the amount of carbon dioxide produced during pyrolysis of kerogen (S3), and vitrinite reflectance measurement (Ro) were used as inputs to estimate the error margin between the calculated vitrinite reflectance and measured vitrinite reflectance. The predictions from the models were then summed with the calculated vitrinite reflectance to produce an improved vitrinite reflectance measurement. The model that generated the most improved vitrinite reflectance measurement, thus, having the least amount of statistical error was selected. EnB achieved the highest accuracy with a correlation coefficient (R) of 0.82 and coefficient of determination (R2) of 0.67 for the improved Ro model. Therefore, a conclusion can be drawn from the results that EnB can adequately improve the Ro of matured rocks through error correction.
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spelling doaj.art-b60bd0607158401d93df0dd2faec7ec42023-03-24T04:23:25ZengKeAi Communications Co., Ltd.Unconventional Resources2666-51902022-01-0124150Error correction of vitrinite reflectance in matured black shales: A machine learning approachEsther Boateng Owusu0George Mensah Tetteh1Solomon Asante-Okyere2Haylay Tsegab3University of Mines and Technology, Department of Petroleum Geosciences and Engineering, School of Petroleum Studies, Tarkwa, Ghana; Corresponding author.University of Mines and Technology, Department of Geological Engineering, Faculty of Mineral Resources Technology, Tarkwa, GhanaUniversity of Mines and Technology, Department of Petroleum and Natural Gas Engineering, School of Petroleum Studies, Tarkwa, GhanaUniversiti Technologi Petronas, Department of Petroleum Geoscience, 32610, Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia; Universiti Teknologi PETRONAS, Southeast Asia Carbonate Research Laboratory, Department of Geoscience, Perak Darul Ridzuan, 32610, Bander Seri Iskander, Tronoh, Perak, MalaysiaVitrinite reflectance (Ro) analysis is a maturity indication parameter for oil or gas prone source rocks in evaluating hydrocarbon potentials. As a result of challenges in Ro calculations from pyrolysis results, finding a way to estimate the maturity of source rocks has been an interesting subject for researchers. There is a current need to improve the Ro calculated from the temperature at which the maximum rate of hydrocarbon generation occurs (Tmax) during maturation of shale formations. As this will go a long way to accelerate decision making and help avoid excessive expenditure costs on maturity determination using measured Ro for source rock samples while saving time. After the application of the conventional multiple linear regression analysis, the present study employed machine learning methods of random forest (RF), decision tree (DT), gradient boosting machine (GBM), ensembles and bagger (EnB), and multivariate adaptive regression splines (MARS) models for improving the calculated Ro of matured black shales. Total organic carbon (TOC), oxygen index (OI), the amount of carbon dioxide produced during pyrolysis of kerogen (S3), and vitrinite reflectance measurement (Ro) were used as inputs to estimate the error margin between the calculated vitrinite reflectance and measured vitrinite reflectance. The predictions from the models were then summed with the calculated vitrinite reflectance to produce an improved vitrinite reflectance measurement. The model that generated the most improved vitrinite reflectance measurement, thus, having the least amount of statistical error was selected. EnB achieved the highest accuracy with a correlation coefficient (R) of 0.82 and coefficient of determination (R2) of 0.67 for the improved Ro model. Therefore, a conclusion can be drawn from the results that EnB can adequately improve the Ro of matured rocks through error correction.http://www.sciencedirect.com/science/article/pii/S2666519022000048Rock-eval pyrolysisVitrinite reflectanceMatured black shalesMultiple linear regressionMachine learning
spellingShingle Esther Boateng Owusu
George Mensah Tetteh
Solomon Asante-Okyere
Haylay Tsegab
Error correction of vitrinite reflectance in matured black shales: A machine learning approach
Unconventional Resources
Rock-eval pyrolysis
Vitrinite reflectance
Matured black shales
Multiple linear regression
Machine learning
title Error correction of vitrinite reflectance in matured black shales: A machine learning approach
title_full Error correction of vitrinite reflectance in matured black shales: A machine learning approach
title_fullStr Error correction of vitrinite reflectance in matured black shales: A machine learning approach
title_full_unstemmed Error correction of vitrinite reflectance in matured black shales: A machine learning approach
title_short Error correction of vitrinite reflectance in matured black shales: A machine learning approach
title_sort error correction of vitrinite reflectance in matured black shales a machine learning approach
topic Rock-eval pyrolysis
Vitrinite reflectance
Matured black shales
Multiple linear regression
Machine learning
url http://www.sciencedirect.com/science/article/pii/S2666519022000048
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