Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Nuclear magnetic resonance characterization of porosity-preserving microcrystalline quartz coatings in Fontainebleau Sandstones

Marta Henriques Jacomo, Ricardo Ivan Ferreira Trindade, Marsha French, Lucas-Oliveira Everton, Elton Tadeu Montrazi and Tito Jose Bonagamba
Nuclear magnetic resonance characterization of porosity-preserving microcrystalline quartz coatings in Fontainebleau Sandstones
AAPG Bulletin (September 2019) 103 (9): 2117-2137

Abstract

The almost-pure quartz-cemented Fontainebleau Formation (Paris Basin, France) sandstones are known to preserve their porosity because of microcrystalline quartz coatings. Here, we use nuclear magnetic resonance (NMR) techniques, petrography, scanning electron microscopy, porosity and permeability measurements, hysteresis, and mercury injection capillary pressure curves to identify and analyze their porosity structure. Nuclear magnetic resonance experiments include transverse relaxation time (T (sub 2) ) distributions and T (sub 2) -filtered T (sub 2) -T (sub 2) exchange (T (sub 2) F-TREx), a technique that provides estimates on the diffusion coupling by comparing the evolution of families of pores in T (sub 2) distributions at different exchange times. Samples were divided according to their texture, composition, and abundance of microcrystalline quartz crystals, comprising group 1 samples with very low amounts of coatings and group 2 samples with entire grains coated by microquartz. Both groups show three (or four) peaks in NMR 2-MHz T (sub 2) distribution at approximately 1 (peak A), 10 (super -1) (peak B), and 10 (super -2) s (peak C); group 2 samples present a slight shift to shorter T (sub 2) times in comparison with other samples. The longest T (sub 2) peak A is because of intergranular macropores, whereas the shortest peak C is because of the microporosity associated with the microcrystalline quartz coating at the surface of the pores. Peak B is also because of microporosity associated with microcrystalline quartz, but with a different surface/volume ratio being likely related to flat-shaped pores within the microcrystalline coating. The T (sub 2) F-TREx indicates the proton exchange is higher between macropores and the pore surface micropores (peak C) than between macropores and the internal flat-shaped micropores; no exchange between the two sets of micropores can be observed. Our results show the potential of NMR techniques in characterizing the microporosity in Fontainebleau sandstones, which is key for the mechanism of porosity preservation in these rocks.


ISSN: 0149-1423
EISSN: 1558-9153
Coden: AABUD2
Serial Title: AAPG Bulletin
Serial Volume: 103
Serial Issue: 9
Title: Nuclear magnetic resonance characterization of porosity-preserving microcrystalline quartz coatings in Fontainebleau Sandstones
Affiliation: Universidade de Sao Paulo, Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Sao Paulo, Brazil
Pages: 2117-2137
Published: 20190915
Text Language: English
Publisher: American Association of Petroleum Geologists, Tulsa, OK, United States
References: 65
Accession Number: 2019-088992
Categories: Sedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables
N48°00'00" - N50°00'00", E01°00'00" - E05°00'00"
Secondary Affiliation: Colorado School of Mines, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States
Update Code: 2019
Close Modal

or Create an Account

Close Modal
Close Modal