Spectral gamma-ray logging of the Gres d'Annot, SE France: An outcrop analogue to geophysical facies mapping and well-log correlation of sand-rich turbidite reservoirs

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F15%3A00107794" target="_blank" >RIV/00216224:14310/15:00107794 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0264817214003213" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0264817214003213</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.marpetgeo.2014.10.010" target="_blank" >10.1016/j.marpetgeo.2014.10.010</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Spectral gamma-ray logging of the Gres d'Annot, SE France: An outcrop analogue to geophysical facies mapping and well-log correlation of sand-rich turbidite reservoirs

Popis výsledku v původním jazyce

Spectral gamma-ray (GRS) logging is a powerful tool in cyclo- and sequence stratigraphy of carbonate depositional systems. In siliciclastic systems with low chemical maturity, the multi-component character of sediment complicates the interpretation of such logs. This work focuses on understand better the relationships between GRS logs and siliciclastic facies stacking patterns, using GRS measurements combined with lithology, modal composition and geochemistry. This study is focused on outcrops in the St. Antonin-Annot-Grand Coyer-Chalufy areas of the Oligocene Gres d'Annot Formation (SE France). The studied siliciclastics reveal moderately high total radioactivity and mean concentrations of K: 3.8 %, U: 4.5 ppm and Th: 13 ppm. U and Th are predominantly contained within heavy minerals and so tend to be concentrated in mudstones and heterolithic sand-mud facies whereas sandstone and conglomerate fades have slightly higher levels of K due to higher contents of K-feldspars and micas. The abundance of minerals containing radioactive elements and the relatively low compositional contrast between different fades are considered the main reasons why the standard gamma-ray measurements provide only a limited proxy for lithology in this case. Two complete regressive-to-transgressive cycles were identified based on combined Th and Th/K logs and facies stacking patterns. The cycle boundaries are marked by shifts towards coarse-grained facies, abrupt increase of U and Th concentrations and Th/K ratio within the proximal deposits at the St. Antonin section. In the distal Chalufy section, the response of the gamma-ray proxies to fades shifts is reversed. These boundaries, interpreted as basal surfaces of forced regression, can be correlated with prominent erosional surfaces at the Annot section. GRS logging is a sensitive method capable of indicating changes of genetic depositional units in sand-rich turbidite systems. However, detailed facies analysis, mineralogy and geochemistry producing the radioactive signal are necessary to correctly interpret such logs.

Název v anglickém jazyce

Spectral gamma-ray logging of the Gres d'Annot, SE France: An outcrop analogue to geophysical facies mapping and well-log correlation of sand-rich turbidite reservoirs

Popis výsledku anglicky

Spectral gamma-ray (GRS) logging is a powerful tool in cyclo- and sequence stratigraphy of carbonate depositional systems. In siliciclastic systems with low chemical maturity, the multi-component character of sediment complicates the interpretation of such logs. This work focuses on understand better the relationships between GRS logs and siliciclastic facies stacking patterns, using GRS measurements combined with lithology, modal composition and geochemistry. This study is focused on outcrops in the St. Antonin-Annot-Grand Coyer-Chalufy areas of the Oligocene Gres d'Annot Formation (SE France). The studied siliciclastics reveal moderately high total radioactivity and mean concentrations of K: 3.8 %, U: 4.5 ppm and Th: 13 ppm. U and Th are predominantly contained within heavy minerals and so tend to be concentrated in mudstones and heterolithic sand-mud facies whereas sandstone and conglomerate fades have slightly higher levels of K due to higher contents of K-feldspars and micas. The abundance of minerals containing radioactive elements and the relatively low compositional contrast between different fades are considered the main reasons why the standard gamma-ray measurements provide only a limited proxy for lithology in this case. Two complete regressive-to-transgressive cycles were identified based on combined Th and Th/K logs and facies stacking patterns. The cycle boundaries are marked by shifts towards coarse-grained facies, abrupt increase of U and Th concentrations and Th/K ratio within the proximal deposits at the St. Antonin section. In the distal Chalufy section, the response of the gamma-ray proxies to fades shifts is reversed. These boundaries, interpreted as basal surfaces of forced regression, can be correlated with prominent erosional surfaces at the Annot section. GRS logging is a sensitive method capable of indicating changes of genetic depositional units in sand-rich turbidite systems. However, detailed facies analysis, mineralogy and geochemistry producing the radioactive signal are necessary to correctly interpret such logs.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GA205%2F09%2F1257" target="_blank" >GA205/09/1257: Využití gamaspektrometrie při studiu provenience siliciklastických sedimentů</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2015

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Marine and Petroleum Geology

ISSN

0264-8172

e-ISSN

1873-4073

Svazek periodika

60

Číslo periodika v rámci svazku

FEB

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

17

Strana od-do

1-17

Kód UT WoS článku

000348886500001

EID výsledku v databázi Scopus

2-s2.0-84919391128