Imaging Texture and Porosity in Mudstones and Shales: Comparison of Secondary and Ion-Milled Backscatter SEM Methods October 20, 2020 Applications, Sample Preparation 0 Observations from a number of unconventional reservoirs lead us to conclude that four major pore types exist in fine-grained reservoir and non-reservoir rocks, that they are effectively connected, and that pore sizes from nanometers to microns must be considered when evaluating size distributions. This paper uses SEM imaging of Haynesville, Horn River, Barnett and Marcellus Shales to illustrate that pore types other than those hosted by organics are present in unconventional shale gas reservoirs, and that they are continuous and connected to kerogen-hosted pores. In addition, we present evidence that the maximum size of pores originating in organic matter is determined by the size of the kerogen mass (in the case of organic particles) or the geometry of enclosing crystals (in the case of amorphous, pore-filling kerogen). Pairs of secondary and ion-milled backscatter SEM images address the misconception that large pores observed in secondary electron images are grain pullouts. For full details: Attached files often contain the full content of the item you are viewing. Be sure and view any attachments. Shale analysis.pdf 10.4 MB Related Articles SEM Backscattered-Electron Images of Paint Cross Sections as Information Source for the Presence of the Lead White Pigment and Lead-Related Degradation and Migration Phenomena in Oil Paintings Scanning electron microscopy backscattered-electron images of paint cross sections show the compositional contrast within the paint system. They not only give valuable information about the pigment composition and layer structure but also about the aging processes in the paint. This article focuses on the reading of backscatter images of lead white-containing samples from traditional oil paintings (17th–19th centuries). In contrast to modern lead white, traditional stack process lead white is characterized by a wide particle size distribution. Changes in particle morphology and distribution are indications of chemical/physical reactivity in the paint. Lead white can be affected by free fatty acids to form lead soaps. The dissolution of lead white can be recognized in the backscatter image by gray ~less scattering! peripheries around particles and gray amorphous areas as opposed to the well-defined, highly scattering intact lead white particles. The small particles react away first, while the larger particles/lumps can still be visible. Formed lead soaps appear to migrate or diffuse through the semipermeable paint system. Lead-rich bands around particles, at layer interfaces and in the paint medium, are indications of transport. The presence of lead-containing crystals at the paint surface or inside aggregates furthermore point to the migration and mineralization of lead soaps. Integrated Preparation and Imaging Techniques for the Microstructural and Geochemical Characterization of Shale by Scanning Electron Microscopy To better understand the influence of microscale geochemical and microstructural relationships on the bulk petrophysical properties of unconventional shale systems, core samples from four producing North American formations were cross-sectioned with an argon ion polisher and imaged with a field emission scanning electron microscope (FE-SEM) using a variety of complementary detectors. We demonstrate distinct advantages of the ion-polishing technique for the preservation of the internal shale structure. Moreover, we show how such preparation affords a wider choice of imaging options for both chemical and structural characterization, such as backscatter electron observation at varying beam potentials coupled with x-ray and cathodoluminescence spectroscopic techniques. Direct Scanning Electron Microscopy Imaging of Ferroelectric Domains After Ion Milling A method for directly observing the ferroelectric domain structure by scanning electron microscopy after argon ion milling has been established. Its advantages are exemplified by exposing the domain structure in three widely used ferroelectric ceramics, BaTiO3, (Na,K)NbO3, and Pb(Ti,Zr)O3. Stable high-resolution images revealing domains with widths <30 nm have been obtained. The domain contrast is caused by electron channeling and is strongly dependent on the sample tilt angle. Owing to a strain- and defect-free surface generated by gentle ion milling, pronounced orientation contrast is observed. New Methods for Cross-Section Sample Preparation Using Broad Argon Ion Beam (Paper Analysis) In 2006, we introduced a new specimen preparation apparatus, Cross-section Polisher (CP), which employs a broad argon ion beam to prepare cross-sections of specimens [1-2]. The principle of the CP is simple: a region of the specimen that is not covered by the masking plate is milled by an argon broad ion beam, as shown in Fig.1. The specimens with irregular shapes and rough surfaces that cannot be embedded prior to ion milling require additional care and consideration prior to ion-milling with CP. Sample Coating for SEM Modern day Scanning Electron Microscopes (SEMs) are capable of imaging at ultralow voltages or low vacuum modes to handle even the most non-ideal sample types without the need for extensive sample preparation. Low voltage, with its inherent low beam penetration into the sample, allows us to examine fine surface morphology. The added advantage to low voltage imaging is the ability to look at nonconductive samples and minimize charging artifacts. Low vacuum, on the other hand, allows us to look at and analyze non-conductive and outgassing samples at higher voltages required for other analytical techniques such as X-ray Analysis (EDS/WDS), Cathodoluminescence (CL) or Electron Backscatter Diffraction (EBSD). Thus, we have the tools to analyze many sample types with minimal to no sample preparation. A question often asked is with the versatility of today’s SEMs, is there any reason to add a conductive coating when preparing samples for the SEM? And if I add a conductive coating, what do I coat it with? There are a lot of options. Designing Better Batteries Through Innovative Microscopy Characterization Scanning Electron Microscopes (SEM) support the development of new LIB technologies with morphological observation at the micrometer to nanometer scale, as well as the chemical analysis needed to create high-performance coatings and powders. Ultra-low voltage imaging combined with signal filtering in the SEM allows direct imaging and analysis of battery constituents (anode and cathode) with nanometer resolution. Additionally, one of the important aspects of the analysis is the ability to probe chemistry of the constituents at nm scale (Fig. 1). JEOL FESEM offers the ability to perform microanalysis with energy dispersive spectroscopy (EDS) at extremely low voltages to pinpoint localized makeup of the specimens and, in particular, low atomic number materials such as carbon and fluorine. Moreover, the unique JEOL Soft X-ray spectrometer (SXES) allows researchers to analyze Li. Showing 0 Comment Comments are closed.