Interpretational challenges related to studies of chalk particle surfaces in scanning and transmission electron microscopy

Research output: Contribution to journalJournal articleResearchpeer-review

64 Downloads (Pure)

Abstract

Scanning and transmission electron microscopy (SEM and TEM) are capable of characterising the morphology and structure of sub-micron size substances attached to chalk particle surfaces. Some characteristics, however, may originate from sample preparation or reflect interaction between sample and the electron beam. Misinterpretation of surface features may lead to wrong conclusions regarding grain surface properties and cementation level and thus to erroneous characterisation of hydrocarbon reservoirs with respect to e.g. wettability, mechanical strength and maximum burial depth. In SEM, conductive coatings may mask surface details or generate artificial ornamentations, and carbon adhesive discs may cause the chalk surface to be covered with a thin carbon film. Electron beam acceleration voltage controls the degree of detail revealed by the electron beam, but in SEM a high electron beam acceleration voltage may provoke bending or curling of ultrathin particles. Recent organic filaments may be confused with clay flakes, and authigenic non-carbonate minerals may have formed in the pore fluid and settled during fluid removal. In TEM, the high acceleration voltage may cause beam damage to calcite and transform the outermost atomic layers into Ca oxide. Thin graphite membranes observed by TEM may be contamination from the carbon film supporting the sample, and overlapping chalk particles in samples formed by drying of a suspension may give the impression of being cemented together. In TEM residual adhesive from the ion-milling process can be confused with cementation features.
Original languageEnglish
JournalBulletin of the Geological Society of Denmark
Volume66
Pages (from-to)151-165
ISSN0011-6297
Publication statusPublished - 2018

Keywords

  • Scanning electron microscopy
  • Transmission electron microscopy
  • Chalk
  • Surface coating
  • Surface ornamentation
  • Image interpretation

Cite this

@article{ff09657e53d84ebd939f77ac59efc31d,
title = "Interpretational challenges related to studies of chalk particle surfaces in scanning and transmission electron microscopy",
abstract = "Scanning and transmission electron microscopy (SEM and TEM) are capable of characterising the morphology and structure of sub-micron size substances attached to chalk particle surfaces. Some characteristics, however, may originate from sample preparation or reflect interaction between sample and the electron beam. Misinterpretation of surface features may lead to wrong conclusions regarding grain surface properties and cementation level and thus to erroneous characterisation of hydrocarbon reservoirs with respect to e.g. wettability, mechanical strength and maximum burial depth. In SEM, conductive coatings may mask surface details or generate artificial ornamentations, and carbon adhesive discs may cause the chalk surface to be covered with a thin carbon film. Electron beam acceleration voltage controls the degree of detail revealed by the electron beam, but in SEM a high electron beam acceleration voltage may provoke bending or curling of ultrathin particles. Recent organic filaments may be confused with clay flakes, and authigenic non-carbonate minerals may have formed in the pore fluid and settled during fluid removal. In TEM, the high acceleration voltage may cause beam damage to calcite and transform the outermost atomic layers into Ca oxide. Thin graphite membranes observed by TEM may be contamination from the carbon film supporting the sample, and overlapping chalk particles in samples formed by drying of a suspension may give the impression of being cemented together. In TEM residual adhesive from the ion-milling process can be confused with cementation features.",
keywords = "Scanning electron microscopy, Transmission electron microscopy, Chalk, Surface coating, Surface ornamentation, Image interpretation",
author = "Hjuler, {Morten Leth} and Hansen, {Vidar Folke} and Fabricius, {Ida Lykke}",
year = "2018",
language = "English",
volume = "66",
pages = "151--165",
journal = "Bulletin of the Geological Society of Denmark",
issn = "0011-6297",
publisher = "Dansk Geologisk Forening",

}

Interpretational challenges related to studies of chalk particle surfaces in scanning and transmission electron microscopy. / Hjuler, Morten Leth; Hansen, Vidar Folke; Fabricius, Ida Lykke.

In: Bulletin of the Geological Society of Denmark, Vol. 66, 2018, p. 151-165.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Interpretational challenges related to studies of chalk particle surfaces in scanning and transmission electron microscopy

AU - Hjuler, Morten Leth

AU - Hansen, Vidar Folke

AU - Fabricius, Ida Lykke

PY - 2018

Y1 - 2018

N2 - Scanning and transmission electron microscopy (SEM and TEM) are capable of characterising the morphology and structure of sub-micron size substances attached to chalk particle surfaces. Some characteristics, however, may originate from sample preparation or reflect interaction between sample and the electron beam. Misinterpretation of surface features may lead to wrong conclusions regarding grain surface properties and cementation level and thus to erroneous characterisation of hydrocarbon reservoirs with respect to e.g. wettability, mechanical strength and maximum burial depth. In SEM, conductive coatings may mask surface details or generate artificial ornamentations, and carbon adhesive discs may cause the chalk surface to be covered with a thin carbon film. Electron beam acceleration voltage controls the degree of detail revealed by the electron beam, but in SEM a high electron beam acceleration voltage may provoke bending or curling of ultrathin particles. Recent organic filaments may be confused with clay flakes, and authigenic non-carbonate minerals may have formed in the pore fluid and settled during fluid removal. In TEM, the high acceleration voltage may cause beam damage to calcite and transform the outermost atomic layers into Ca oxide. Thin graphite membranes observed by TEM may be contamination from the carbon film supporting the sample, and overlapping chalk particles in samples formed by drying of a suspension may give the impression of being cemented together. In TEM residual adhesive from the ion-milling process can be confused with cementation features.

AB - Scanning and transmission electron microscopy (SEM and TEM) are capable of characterising the morphology and structure of sub-micron size substances attached to chalk particle surfaces. Some characteristics, however, may originate from sample preparation or reflect interaction between sample and the electron beam. Misinterpretation of surface features may lead to wrong conclusions regarding grain surface properties and cementation level and thus to erroneous characterisation of hydrocarbon reservoirs with respect to e.g. wettability, mechanical strength and maximum burial depth. In SEM, conductive coatings may mask surface details or generate artificial ornamentations, and carbon adhesive discs may cause the chalk surface to be covered with a thin carbon film. Electron beam acceleration voltage controls the degree of detail revealed by the electron beam, but in SEM a high electron beam acceleration voltage may provoke bending or curling of ultrathin particles. Recent organic filaments may be confused with clay flakes, and authigenic non-carbonate minerals may have formed in the pore fluid and settled during fluid removal. In TEM, the high acceleration voltage may cause beam damage to calcite and transform the outermost atomic layers into Ca oxide. Thin graphite membranes observed by TEM may be contamination from the carbon film supporting the sample, and overlapping chalk particles in samples formed by drying of a suspension may give the impression of being cemented together. In TEM residual adhesive from the ion-milling process can be confused with cementation features.

KW - Scanning electron microscopy

KW - Transmission electron microscopy

KW - Chalk

KW - Surface coating

KW - Surface ornamentation

KW - Image interpretation

M3 - Journal article

VL - 66

SP - 151

EP - 165

JO - Bulletin of the Geological Society of Denmark

JF - Bulletin of the Geological Society of Denmark

SN - 0011-6297

ER -