Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations

We propose a new approach to improve spectral gamma-ray (SGR) logging forward modeling by considering the radioactive minerals present in the rock as gamma-ray sources. This is based on the radioactive attenuation theory. The assumptions are: 1) minerals with K40, U238, and Th232 content are conside...

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Autores: Lechuga Lagos, Francisco Miguel, Aquino López , Ambrosio, Valdez Grijalva, Miguel Ángel, Campos Enríquez , José Oscar
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2024
País:México
Institución:UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO
Repositorio:Geofísica Internacional
Idioma:español
OAI Identifier:oai:revistagi.geofisica.unam.mx:article/1710
Acceso en línea:http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/1710
Access Level:acceso abierto
Palabra clave:Registro de rayos gamma espectral
Modelado directo
Minerales radioactivos
Formaciones sedimentarias
Radioisótopos K40
U238
Th232
Spectral gamma-ray logging
Forward modeling
Radioactive minerals
Sedimentary formations
K40
Th232 radioisotopes
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oai_identifier_str oai:revistagi.geofisica.unam.mx:article/1710
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network_name_str México
repository_id_str
dc.title.none.fl_str_mv Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations
Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations
title Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations
spellingShingle Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations
Lechuga Lagos, Francisco Miguel
Registro de rayos gamma espectral
Modelado directo
Minerales radioactivos
Formaciones sedimentarias
Radioisótopos K40
U238
Th232
Spectral gamma-ray logging
Forward modeling
Radioactive minerals
Sedimentary formations
K40
U238
Th232 radioisotopes
title_short Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations
title_full Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations
title_fullStr Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations
title_full_unstemmed Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations
title_sort Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formations
dc.creator.none.fl_str_mv Lechuga Lagos, Francisco Miguel
Aquino López , Ambrosio
Valdez Grijalva, Miguel Ángel
Campos Enríquez , José Oscar
author Lechuga Lagos, Francisco Miguel
author_facet Lechuga Lagos, Francisco Miguel
Aquino López , Ambrosio
Valdez Grijalva, Miguel Ángel
Campos Enríquez , José Oscar
author_role author
author2 Aquino López , Ambrosio
Valdez Grijalva, Miguel Ángel
Campos Enríquez , José Oscar
author2_role author
author
author
dc.subject.none.fl_str_mv Registro de rayos gamma espectral
Modelado directo
Minerales radioactivos
Formaciones sedimentarias
Radioisótopos K40
U238
Th232
Spectral gamma-ray logging
Forward modeling
Radioactive minerals
Sedimentary formations
K40
U238
Th232 radioisotopes
topic Registro de rayos gamma espectral
Modelado directo
Minerales radioactivos
Formaciones sedimentarias
Radioisótopos K40
U238
Th232
Spectral gamma-ray logging
Forward modeling
Radioactive minerals
Sedimentary formations
K40
U238
Th232 radioisotopes
description We propose a new approach to improve spectral gamma-ray (SGR) logging forward modeling by considering the radioactive minerals present in the rock as gamma-ray sources. This is based on the radioactive attenuation theory. The assumptions are: 1) minerals with K40, U238, and Th232 content are considered radioactive sources uniformly distributed in the rock; 2) the measured radioactivity is proportional to the concentration of radioactive minerals and inversely proportional to the rock bulk density; 3) the radioactivity is only attenuated by absorption of gamma-rays. The forward modeling was tested using a synthetic case of sandstone with clay minerals and brine-saturated pores to analyze the sensitivity of SGR to changes in illite/smectite-illite/mica ratios and sandstone porosities. Finally, it was further validated with 44 core samples, of which 22 are from two shale gas and 22 from two clastic formations. The Pearson correlation coefficient applied to measure the misfit between the simulated and observed K, U, Th, and SGR data attained values of 0.82, 0.83, 0.61, and 0.57, respectively. A further improvement to 0.87, 0.85, 0.65, and 0.69 was achieved when applying joint inversion for data where illite/smectite and illite/mica ratios were not specified. The correlation between the simulated and observed data supports the viability of the proposed SGR forward modeling approach method.
publishDate 2024
dc.date.none.fl_str_mv 2024-04-01
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/1710
10.22201/igeof.2954436xe.2024.63.2.1710
url http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/1710
identifier_str_mv 10.22201/igeof.2954436xe.2024.63.2.1710
dc.language.none.fl_str_mv spa
language spa
dc.relation.none.fl_str_mv http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/1710/2282
http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/1710/2283
dc.rights.none.fl_str_mv Derechos de autor 2024 Geofísica Internacional
https://creativecommons.org/licenses/by-nc-sa/4.0/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv Derechos de autor 2024 Geofísica Internacional
https://creativecommons.org/licenses/by-nc-sa/4.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Universidad Nacional Autónoma de México. Instituto de Geofísica
publisher.none.fl_str_mv Universidad Nacional Autónoma de México. Instituto de Geofísica
dc.source.none.fl_str_mv Geofisica Internacional; Vol. 63 No. 2 (2024): April 1, 2024; 817-834
Geofísica Internacional; Vol. 63 Núm. 2 (2024): Abril 1, 2024; 817-834
2954-436X
0016-7169
10.22201/igeof.2954436xe.2024.63.2
reponame:Geofísica Internacional
instname:UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO
instacron:UNAM
instname_str UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO
instacron_str UNAM
institution UNAM
reponame_str Geofísica Internacional
collection Geofísica Internacional
repository.name.fl_str_mv
repository.mail.fl_str_mv
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spelling Forward modeling of spectral gamma-ray (SGR) logging in sedimentary formationsForward modeling of spectral gamma-ray (SGR) logging in sedimentary formationsLechuga Lagos, Francisco MiguelAquino López , Ambrosio Valdez Grijalva, Miguel Ángel Campos Enríquez , José Oscar Registro de rayos gamma espectralModelado directoMinerales radioactivosFormaciones sedimentariasRadioisótopos K40U238Th232Spectral gamma-ray loggingForward modelingRadioactive mineralsSedimentary formationsK40U238Th232 radioisotopesWe propose a new approach to improve spectral gamma-ray (SGR) logging forward modeling by considering the radioactive minerals present in the rock as gamma-ray sources. This is based on the radioactive attenuation theory. The assumptions are: 1) minerals with K40, U238, and Th232 content are considered radioactive sources uniformly distributed in the rock; 2) the measured radioactivity is proportional to the concentration of radioactive minerals and inversely proportional to the rock bulk density; 3) the radioactivity is only attenuated by absorption of gamma-rays. The forward modeling was tested using a synthetic case of sandstone with clay minerals and brine-saturated pores to analyze the sensitivity of SGR to changes in illite/smectite-illite/mica ratios and sandstone porosities. Finally, it was further validated with 44 core samples, of which 22 are from two shale gas and 22 from two clastic formations. The Pearson correlation coefficient applied to measure the misfit between the simulated and observed K, U, Th, and SGR data attained values of 0.82, 0.83, 0.61, and 0.57, respectively. A further improvement to 0.87, 0.85, 0.65, and 0.69 was achieved when applying joint inversion for data where illite/smectite and illite/mica ratios were not specified. The correlation between the simulated and observed data supports the viability of the proposed SGR forward modeling approach method.Proponemos un nuevo enfoque para mejorar el modelado directo del registro de rayos gamma espectral (SGR) al considerar los minerales radioactivos presentes en la roca como fuentes de rayos gamma. Este se basa en la teoría de la atenuación radiactiva. Los supuestos son: 1) los minerales con contenido de K40, U238, y Th232 son considerados fuentes radiactivas que están uniformemente distribuidas en la roca; 2) la radiactividad medida es proporcional a la concentración de minerales radiactivos e inversamente proporcional a la densidad aparente de la roca; 3) la radiactividad solo se atenúa por absorción de rayos gamma. El modelado directo fue probado usando un caso sintético de arenisca con minerales arcillosos y poros saturados con salmuera para analizar la sensibilidad de SGR a cambios en las relaciones de ilita/esmectita e ilita/mica y porosidades de la arenisca. Finalmente, el enfoque fue validado con 44 muestras de núcleo, siendo 22 de dos formaciones de gas en lutita y 22 de dos formaciones clásticas. El coeficiente de correlación de Pearson se aplicó para medir el desajuste entre los datos simulados y medidos de K, U, Th y SGR, obteniéndose valores de 0.82, 0.83, 0.61 y 0.57 respectivamente, y una mejora adicional de 0.87, 0.85, 0.65 y 0.69, respectivamente, fueron alcanzados aplicando inversión conjunta para los datos donde las relaciones ilita/esmectita e ilita/mica no fueron especificadas. La correlación lograda entre los datos simulados y observados sustenta la viabilidad del nuevo enfoque para el modelado directo propuesto de SGR.Universidad Nacional Autónoma de México. Instituto de Geofísica2024-04-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttp://revistagi.geofisica.unam.mx/index.php/RGI/article/view/171010.22201/igeof.2954436xe.2024.63.2.1710Geofisica Internacional; Vol. 63 No. 2 (2024): April 1, 2024; 817-834Geofísica Internacional; Vol. 63 Núm. 2 (2024): Abril 1, 2024; 817-8342954-436X0016-716910.22201/igeof.2954436xe.2024.63.2reponame:Geofísica Internacionalinstname:UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICOinstacron:UNAMspahttp://revistagi.geofisica.unam.mx/index.php/RGI/article/view/1710/2282http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/1710/2283Derechos de autor 2024 Geofísica Internacionalhttps://creativecommons.org/licenses/by-nc-sa/4.0/info:eu-repo/semantics/openAccessoai:revistagi.geofisica.unam.mx:article/17102024-08-16T17:32:12Z
score 15,811543

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