scholarly journals Porosity and permeability determinations of organic rich Posidonia shales based on 3D analyses by FIB-SEM microscopy

2016 ◽  
Author(s):  
Georg H. Grathoff ◽  
Markus Peltz ◽  
Frieder Enzmann ◽  
Stephan Kaufhold
Keyword(s):  
Organic Matter ◽  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Navier Stokes ◽  
Pore Size Distributions ◽  
Two Samples ◽  
Segmented Images ◽  
Porosity And Permeability ◽  
Organic Particles

Abstract. The goal of this study is to better understand the porosity and permeability in shales to improve modelling fluid and gas flow related to shale diagenesis. Two samples (WIC and HAD) were investigated, both Mid Jurassic Posidonia organic rich shales from central Germany of different maturity (WIC R0 0.53 % and HAD R0 1.45 %). The method for image collection was Focused Ion Beam (FIB) microscopy coupled with Scanning Electron Microscopy (SEM). For image and data analysis Avizo and GeoDict was used. Porosity was calculated from segmented 3D FIB based images and permeability was simulated by a Navier Stokes-Brinkman solver in the segmented images. Results show that the quantity and distribution of pore clusters and pores (> 40 nm) are similar. The largest pores are located within carbonates and clay minerals, whereas the smallest pores are within the matured organic matter. Orientation of the pores calculated as pore paths showed minor directional differences between the samples, possibly due to maturation. Both samples have no axis connectivity of pore clusters in the x, y, and z direction on the scale of 10 to 20 of micrometer, but do show connectivity on the micrometer scale. The volume of organic matter in the studied volume is representative of the TOC in the samples. Organic matter does show axis connectivity in the x, y, and z direction. With increasing maturity the porosity in organic matter increases from close to 0 to more than 5 %. These pores are small and in the large organic particles have little connection to the mineral matrix. Continuous pore size distributions are compared with Mercury Intrusion Porosimetry (MIP) data. Minor differences are caused by resolution limits of the FIB-SEM and by the development of small pores during the maturation of the organic matter. Calculations show no permeability when only considering visible pores due to the lack of axis connectivity. Adding the organics with a background permeability of 1e-22 m2 to the calculations, the total permeability increased by one to two orders of magnitude depending on the direction of flow boundary conditions. Our results compare well with experimental data from the literature suggesting that upscaling may be possible in the future.

scholarly journals Porosity and permeability determination of organic-rich Posidonia shales based on 3-D analyses by FIB-SEM microscopy

Solid Earth ◽  
2016 ◽  
Vol 7 (4) ◽  
pp. 1145-1156 ◽  
Author(s):  
Georg H. Grathoff ◽  
Markus Peltz ◽  
Frieder Enzmann ◽  
Stephan Kaufhold
Keyword(s):  
Organic Matter ◽  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Navier Stokes ◽  
Permeability Coefficients ◽  
Pore Size Distributions ◽  
Two Samples ◽  
Order Of Magnitude ◽  
Porosity And Permeability

Abstract. The goal of this study is to better understand the porosity and permeability in shales to improve modelling fluid and gas flow related to shale diagenesis. Two samples (WIC and HAD) were investigated, both mid-Jurassic organic-rich Posidonia shales from Hils area, central Germany of different maturity (WIC R0 0.53 % and HAD R0 1.45 %). The method for image collection was focused ion beam (FIB) microscopy coupled with scanning electron microscopy (SEM). For image and data analysis Avizo and GeoDict was used. Porosity was calculated from segmented 3-D FIB based images and permeability was simulated by a Navier Stokes–Brinkman solver in the segmented images. Results show that the quantity and distribution of pore clusters and pores (≥  40 nm) are similar. The largest pores are located within carbonates and clay minerals, whereas the smallest pores are within the matured organic matter. Orientation of the pores calculated as pore paths showed minor directional differences between the samples. Both samples have no continuous connectivity of pore clusters along the axes in the x, y, and z direction on the scale of 10 to 20 of micrometer, but do show connectivity on the micrometer scale. The volume of organic matter in the studied volume is representative of the total organic carbon (TOC) in the samples. Organic matter does show axis connectivity in the x, y, and z directions. With increasing maturity the porosity in organic matter increases from close to 0 to more than 5 %. These pores are small and in the large organic particles have little connection to the mineral matrix. Continuous pore size distributions are compared with mercury intrusion porosimetry (MIP) data. Differences between both methods are caused by resolution limits of the FIB-SEM and by the development of small pores during the maturation of the organic matter. Calculations show no permeability when only considering visible pores due to the lack of axis connectivity. Adding the organic matter with a background permeability of 1 × 10−21 m2 to the calculations, the total permeability increased by up to 1 order of magnitude for the low mature and decreases slightly for the overmature sample from the gas window. Anisotropy of permeability was observed. Permeability coefficients increase by 1 order of magnitude if simulations are performed parallel to the bedding. Our results compare well with experimental data from the literature suggesting that upscaling may be possible in the future as soon as maturity dependent organic matter permeability coefficients can be determined.

Gas flow modeling for focused ion beam (FIB) repair processes

2004 ◽  
Author(s):  
Mohamed S. El-Morsi ◽  
Alexander C. Wei ◽  
Gregory F. Nellis ◽  
Roxann L. Engelstad ◽  
Sybren Sijbrandij ◽  
...  
Keyword(s):  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Flow Modeling ◽  
Repair Processes

High-Precision Gas Sensor Based on Photonic Bandgap Fiber Cell

2009 ◽  
Vol 147-149 ◽  
pp. 131-136 ◽  
Author(s):  
Joanna Pawłat ◽  
Xue Feng Li ◽  
Tadashi Sugiyama ◽  
Takahiro Matsuo ◽  
Yurij Zimin ◽  
...  
Keyword(s):  
Gas Flow ◽  
Focused Ion Beam ◽  
Photonic Bandgap ◽  
Ion Beam ◽  
Sample Volume ◽  
Gas Cell ◽  
Gas Concentration ◽  
Photonic Bandgap Fiber ◽  
New Device ◽  
Microstructured Optical Fiber

As one of applications for Microstructured Optical Fiber, a new device for measurement of low gas concentration was designed. In the developed system the Photonic Bandgap Fiber (PBGF) was used as a gas cell. Proposed technique allowed reducing gas sample volume to 0.01 cc. The gas flow inside core of fiber was simulated and result was confirmed experimentally. During the experimental work several types of fibers of various parameters were specially designed, produced and used. Core diameters ranged from 10.9 μm to 700 μm. Various cutting techniques for fibers such as using the fiber cleaver, Focused Ion Beam and Cross Section Polisher were investigated.

Computing elastic properties of organic-rich source rocks using digital images

2021 ◽  
Vol 40 (9) ◽  
pp. 662-666
Author(s):  
Mita Sengupta ◽  
Shannon L. Eichmann
Keyword(s):  
Organic Matter ◽  
Elastic Properties ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Rock Physics ◽  
Flow Property ◽  
Source Rocks ◽  
Digital Rock ◽  
Rock Structure ◽  
Imaging Resolution

Digital rocks are 3D image-based representations of pore-scale geometries that reside in virtual laboratories. High-resolution 3D images that capture microstructural details of the real rock are used to build a digital rock. The digital rock, which is a data-driven model, is used to simulate physical processes such as fluid flow, heat flow, electricity, and elastic deformation through basic laws of physics and numerical simulations. Unconventional reservoirs are chemically heterogeneous where the rock matrix is composed of inorganic minerals, and hydrocarbons are held in the pores of thermally matured organic matter, all of which vary spatially at the nanoscale. This nanoscale heterogeneity poses challenges in measuring the petrophysical properties of source rocks and interpreting the data with reference to the changing rock structure. Focused ion beam scanning electron microscopy is a powerful 3D imaging technique used to study source rock structure where significant micro- and nanoscale heterogeneity exists. Compared to conventional rocks, the imaging resolution required to image source rocks is much higher due to the nanoscale pores, while the field of view becomes smaller. Moreover, pore connectivity and resulting permeability are extremely low, making flow property computations much more challenging than in conventional rocks. Elastic properties of source rocks are significantly more anisotropic than those of conventional reservoirs. However, one advantage of unconventional rocks is that the soft organic matter can be captured at the same imaging resolution as the stiff inorganic matrix, making digital elasticity computations feasible. Physical measurement of kerogen elastic properties is difficult because of the tiny sample size. Digital rock physics provides a unique and powerful tool in the elastic characterization of kerogen.

scholarly journals Characterization of a Si-SiO2 Mixture Generated from SiO(g) and CO(g)

2019 ◽  
Vol 50 (6) ◽  
pp. 2667-2680 ◽  
Author(s):  
Andrea Broggi ◽  
Merete Tangstad ◽  
Eli Ringdalen
Keyword(s):  
Photoelectron Spectroscopy ◽  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Liquid Silicon ◽  
Inert Gas ◽  
Dissolved Carbon ◽  
Sic Particles ◽  
Transmission Electron ◽  
A Minor

Abstract The reaction between SiO(g) and CO(g) is a relevant intermediate reaction in the silicon production process. One of the products generated from this gas mixture is called by its color, brown condensate. In this paper, SiO(g) and CO(g) are produced from SiO2-SiC pellets. The reaction between the two gases occurred on SiC particles. Inert gas was injected at different flows. The SiC particles were collected, and the brown condensate deposited on them was characterized by electron probe microanalysis, X-ray photoelectron spectroscopy, and focused ion beam preparation samples for transmission electron microscope analysis. The brown condensate consists of a mixture of Si spheres embedded in a SiO2 matrix. The compound generates in the temperature range from 1400 °C to 1780 °C (1673 K to 2053 K), and in the SiO(g) partial pressure range between 0.534 and 0.742, depending on the inert gas flow. SiC crystallites are located at the Si-SiO2 interface. Carbides are believed to generate from the reaction between liquid silicon and CO(g). Carbides may also precipitate from reaction between dissolved carbon and liquid silicon, but to a minor extent. Both mechanisms are believed to happen above the melting point of silicon and in the softening range of silica.

scholarly journals Gas flow through atomic-scale apertures

2020 ◽  
Vol 6 (51) ◽  
pp. eabc7927
Author(s):  
Jothi Priyanka Thiruraman ◽  
Sidra Abbas Dar ◽  
Paul Masih Das ◽  
Nasim Hassani ◽  
Mehdi Neek-Amal ◽  
...  
Keyword(s):  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Atomic Scale ◽  
Gas Flows ◽  
Narrow Channels ◽  
Molecular Separation ◽  
Transmission Electron ◽  
Ultralow Concentrations ◽  
Atomic Limit

Gas flows are often analyzed with the theoretical descriptions formulated over a century ago and constantly challenged by the emerging architectures of narrow channels, slits, and apertures. Here, we report atomic-scale defects in two-dimensional (2D) materials as apertures for gas flows at the ultimate quasi-0D atomic limit. We establish that pristine monolayer tungsten disulfide (WS2) membranes act as atomically thin barriers to gas transport. Atomic vacancies from missing tungsten (W) sites are made in freestanding (WS2) monolayers by focused ion beam irradiation and characterized using aberration-corrected transmission electron microscopy. WS2 monolayers with atomic apertures are mechanically sturdy and showed fast helium flow. We propose a simple yet robust method for confirming the formation of atomic apertures over large areas using gas flows, an essential step for pursuing their prospective applications in various domains including molecular separation, single quantum emitters, sensing and monitoring of gases at ultralow concentrations.

scholarly journals Confinement Effect on Porosity and Permeability of Shales

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jan Goral ◽  
Palash Panja ◽  
Milind Deo ◽  
Matthew Andrew ◽  
Sven Linden ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Marcellus Shale ◽  
3D Models ◽  
Digital Rock ◽  
Organic Mineral ◽  
Porosity And Permeability ◽  
Different Depths ◽  
Shale Reservoirs ◽  
Oil Gas

AbstractPorosity and permeability are the key factors in assessing the hydrocarbon productivity of unconventional (shale) reservoirs, which are complex in nature due to their heterogeneous mineralogy and poorly connected nano- and micro-pore systems. Experimental efforts to measure these petrophysical properties posse many limitations, because they often take weeks to complete and are difficult to reproduce. Alternatively, numerical simulations can be conducted in digital rock 3D models reconstructed from image datasets acquired via e.g., nanoscale-resolution focused ion beam–scanning electron microscopy (FIB-SEM) nano-tomography. In this study, impact of reservoir confinement (stress) on porosity and permeability of shales was investigated using two digital rock 3D models, which represented nanoporous organic/mineral microstructure of the Marcellus Shale. Five stress scenarios were simulated for different depths (2,000–6,000 feet) within the production interval of a typical oil/gas reservoir within the Marcellus Shale play. Porosity and permeability of the pre- and post-compression digital rock 3D models were calculated and compared. A minimal effect of stress on porosity and permeability was observed in both 3D models. These results have direct implications in determining the oil-/gas-in-place and assessing the production potential of a shale reservoir under various stress conditions.

scholarly journals Three-Dimensional Morphology and Connectivity of Organic Pores in Shale from the Wufeng and Longmaxi Formations at the Southeast Sichuan Basin in China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Tao Jiang ◽  
Zhijun Jin ◽  
Zongquan Hu ◽  
Wei Du ◽  
Zhongbao Liu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Shale Gas ◽  
Focused Ion Beam ◽  
Structural Characteristics ◽  
Ion Beam ◽  
Organic Content ◽  
Future Research ◽  
Upper Ordovician ◽  
Longmaxi Formation ◽  
Organic Pores

Organic pores play an important role in shale reservoirs. Organic pores occur where shale gas was produced and accumulated. However, there is little scientific understanding of the distribution and connectivity of organic pores. Organic pore types and their structural characteristics were studied using a total organic carbon (TOC), thin section, focused ion beam scanning electron microscope (FIB-SEM), and nano-CT. The samples were from the Wufeng Formation in the Upper Ordovician and Longmaxi Formations from the lower Silurian. The results show that organic matter is mainly concentrated in the Wufeng Formation and the bottom of the Longmaxi Formation and that the middle and upper parts of the Longmaxi Formation contain a low amount of organic matter. The shale of the Wufeng-Longmaxi Formation has high maturity, and its organic pores are well developed. There are three types of organic pores: algae, graptolite, and pyrobitumen pores. The pore connectivity of shale with a high organic content is better than that of shale with a low organic content. The volume of the organic pores accounts for more than 50% of the volume of the organic matter. Majority of the organic pores have an aperture smaller than 100 nm and are round, nearly circular, and elliptical in morphology. Most of the organic pores in a shale formation are developed in pyrobitumen, and most of the larger organic pores are concentrated at the center of solid pyrobitumen. The organic pores in pyrobitumen have the best connectivity and are the most favorable reservoir spaces and migration channels for shale gas, which is a crucial point of reference for future research of shale gas.

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