Understanding variations in reservoir porosity in the Eagle Ford Shale using scanning electron microscopy: implications for basin modelling

2020 ◽  
Vol 484 (1) ◽  
pp. 229-239 ◽  
Author(s):  
Mark Osborne ◽  
Herbert Volk

AbstractReliable evaluation of shale-play potential requires robust geological models that can simulate the generation and retention of petroleum, porosity and permeability in source rocks from first principles, and that can be implemented in basin modelling software. To be predictive, such basin models need to be calibrated against observations from real shale plays. A key control on the amount of retained petroleum is the porosity in the shale and the abundance of organic matter. Scanning electron microscopy of argon-ion milled shale samples can potentially reveal systematic variations in the amount of porosity, pore types and distributions across a range of thermal maturities. These observed variations in porosity can be used to calibrate basin modelling outputs and refine predictive models. For these reasons BP has conducted scanning electron microscopy studies of shale plays including the Eagle Ford Shale, a carbonate-rich mudstone sequence of Cenomanian to Turonian age. The results clearly show that the mean pore size decreases as thermal maturity increases and that organic matter-hosted pores are absent in low thermal maturity samples (where vitrinite random reflectance Ro <0.7) and become increasingly more abundant as thermal maturity increases). In moderately mature samples there are organic matter hosted pores that range in pore size from 5 to 500 nm. In highly mature samples, small (<50 nm) organic matter-hosted pores predominate. Our studies reveal that porosity evolution in this organic-rich, fine-grained, carbonate mudrock shows a strong correlation with increasing thermal maturity.

1980 ◽  
Vol 37 (4) ◽  
pp. 640-646 ◽  
Author(s):  
R. P. Reid ◽  
C. H. Pharo ◽  
W. C. Barnes

Apatite is a common accessory mineral in the source rocks for the glacial debris supplying sediments to many Canadian lakes. A method has been developed which uses scanning electron microscopy and energy dispersive X-ray emission spectrometry for direct identification of apatite. This method has been used to examine the apatite content of various size fractions in Kamloops Lake sediments. Apatite concentrations obtained by this direct examination correlate well (r > 0.999) with apatite concentrations determined by chemical analyses and indicate that, in addition to comprising as much as 70% of the total phosphorus load, apatite may comprise as much as one-third of the "dissolved" (< 0.45 μm) inorganic phosphorus load. Consequently the use of classical (e.g. Vollenweider 1968; Vollenweider and Dillon 1974) methods of estimating lake trophic state from inorganic phosphorus concentrations in lake water must be done with care, recognizing that the bulk of inorganic phosphorus in lakes deriving sediment from glaciated igneous or metamorphic terrains may be in the form of apatite.Key words: apatite, lake, trophic state, phosphorus load, scanning electron microscopy


1985 ◽  
Vol 22 (12) ◽  
pp. 1930-1944 ◽  
Author(s):  
Tylon O. Willingham ◽  
Bartholomew Nagy ◽  
Lois Anne Nagy ◽  
David H. Krinsley ◽  
David J. Mossman

The Elliot Lake – Blind River, Ontario, paleoplacer deposits in the basal Matineda Formation, lowermost member of the 2.25–2.45 Ga old Huronian Supergroup, contain organic matter chemically consistent with kerogen. This substance is also referred to as thucholite. Uranium ores and some gold occur here, and these minerals may be in close association with the kerogen. Two uraniferous and auriferous stratiform kerogens, obtained from the Denison Mines Limited's Denison mine and Rio Algom Limited's Stanleigh mine, have been analyzed by combined high-vacuum pyrolysis – gas chromatography – mass spectrometry and by neutron activation. The reflectances of these samples have also been determined. Related samples containing dispersed kerogen have been examined by backscattered scanning electron microscopy. The polymer-like matrix of the two stratiform kerogens consists of aromatic, alkyl aromatic hydrocarbon, and sulphur moieties and contains 20 and 32% uranium with gold abundances in the parts per billion range. The reflectances of the two stratiform kerogens are generally higher than those of the dispersed kerogens; the atomic H/C ratios of the former are −0.6 and −0.4. Backscattered scanning electron microscopy and petrographic observations reveal a complex diagenetic history. Stratigraphic position and supportive analytical data suggest that the stratiform kerogens were probably derived from ancient mats of cyanobacteria, subjected to various radiation-induced reactions, and, at least in part, were affected in a manner similar to the surrounding rocks. The latter experienced physical and chemical diagenetic reactions, which often caused repeated mineral fracturing and led to the local development of authigenic carbonates and feldspar. Some of the chemical nature and history of the stratiform kerogens resemble those of the Witwatersrand carbon seam kerogens.


2016 ◽  
Vol 49 (2) ◽  
pp. 585-593 ◽  
Author(s):  
Sophie Cersoy ◽  
Pauline Martinetto ◽  
Pierre Bordet ◽  
Jean Louis Hodeau ◽  
Elsa Van Elslande ◽  
...  

Carbon black materials have been frequently used from prehistory as pigments for drawings and paintings and also as dyes, inks and cosmetics, since they are easy to make by burning organic matter. However, the carbonaceous phases they form are often ill-ordered and not easy to characterize. Five carbon black Roman micro samples found in vessels in houses in Pompeii were studied. These precious powders correspond to mixed phase samples that contain both crystalline and ill-ordered components. Here, a methodological approach that accomplishes the identification, quantification and mapping of the different phases in these heterogeneous samples using synchrotron-based techniques is proposed. The results were compared with those from scanning electron microscopy. Information about the nature of the mixtures and the origin of carbon black pigments is obtained. The use of charred vegetable materials is concluded, independently of the shape and the nature of the container.


2007 ◽  
Vol 534-536 ◽  
pp. 157-160 ◽  
Author(s):  
M.A. Dar ◽  
S.G. Ansari ◽  
Rizwan Wahab ◽  
Young Soon Kim ◽  
Hyung Shik Shin

Maghemite and hematite nanospheres were synthesized by using the Sol-gel technique. The structural properties of these nanosphere powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM),and pore size distribution.Hematite phase shows crystalline structures.The mean particle size that resulted from BET and XRD analyses were 4.9 nm and 2 nm. The field emission scanning electron microscopy shows iron-oxide powder is composed of nanosized particles, but in nanosized aggregates (agglomeration of particles). It can be seen from transmission electron microscopy that the size of the particles are very small which is in good agreement with the FESEM and the Xray diffraction. TEM and FESEM confirmed that the iron-oxide powder is composed of sizes from 8 nm to 10 nm. The BET and pore size method were employed for specific surface area determination.


Author(s):  
Lenin Jose Huerta ◽  
Rebeca Torres Fajardo ◽  
Juan Primera Ferrer

  En este trabajo se investigó la síntesis de xerogeles de sílice por la vía de los atranos, y se evaluó la influencia de la concentración del agente iniciador (HCl) y la presencia o no del surfactante (CTAB), sobre el tiempo de gelificación y las propiedades texturales de los materiales obtenidos. Las caracterizaciones se realizaron mediante: isotermas de adsorción-desorción de nitrógeno, microscopía electrónica de barrido y calorimetría diferencial de barrido. Los tiempos de gelificación aumentaron en la medida que se disminuyó la concentración del HCl y, en general, los xerogeles preparados presentaron una buena rigidez cuando estos se dejaron a tiempos mayores de 20 horas. La distribución de tamaño de poro (determinada mediante la técnica BJH) para los xerogeles calcinados preparados sin surfactante presentaron un sistema de poro bien definido de 16,4 nm en promedio, mientras los xerogeles calcinados preparados con surfactante no presentaron una distribución de tamaño de poro bien definida, ambos casos mostraron áreas superficiales de alrededor de 580 m2/g. Por calorimetría diferencial de barrido se observaron dos picos para la muestra de xerogel sin surfactante, uno alrededor de 80 °C debido a la evaporación del agua y el otro a 265 °C atribuido a la descomposición de la materia orgánica presente en el gel; para la muestra de xerogel con surfactante se observó un pico bien definido a 130 °C, atribuido a la pérdida del agua. Por microscopía electrónica de barrido, en los xerogeles calcinados se observaron poros con tamaños alrededor de los 15 nm.   Palabra clave: Xerogel, atrano, surfactante, sílice, gelificación.   Abstract In this work, the synthesis of silica xerogels by the atrane way was investigated, evaluating: concentration influence of the initiating agent (HCl) and the presence or not of the surfactant (CTAB), over gelation time, and the textural properties of the obtained materials. Characterizations were carried out by nitrogen adsorption-desorption isotherms, scanning electron microscopy, and differential scanning calorimetry. Gelation times increased as the HCl concentration decreased, and, in general, xerogels prepared presented good rigidity when they were aging for times greater than 20 hours. Pore size distribution (determined by the BJH technique) for the calcined xerogels prepared without surfactant presented a well-defined pore system of 16.4 nm on average, while the calcined xerogels prepared with surfactant did not present a well-defined pore size distribution, both cases showed surface areas of around 580 m2/g. In differential scanning calorimetry, two peaks were observed for the xerogel sample without surfactant, one around 80 °C due to water evaporation, and the other one at 265 °C attributed to the decomposition of organic matter present in the gel; for the surfactant xerogel sample, a well-defined peak was observed at 130 °C, attributed to the loss of water. By scanning electron microscopy, pores with sizes around 15 nm in calcined xerogels were observed.   Keywords: Xerogel, atrane, surfactant, silica, gelation.  


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1364
Author(s):  
Saloua Biyada ◽  
Mohammed Merzouki ◽  
Hamada Imtara ◽  
Mohamed F. Alajmi ◽  
Karima Elkarrach ◽  
...  

To date, compost maturation monitoring is carried out by physical-chemical and microbiological analysis, which could be considered an overweening consumption of time and products. Nowadays, spectroscopy is chosen as a simple tool for monitoring compost maturity. In the present investigation, spectroscopy analysis was performed in the interest of corroborating the compost maturity. This goal was achieved by using the X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. X-ray diffraction analysis showed the presence of the cellulose fraction in compost samples. At the same time, the intensity of pics decreased depending on composting time, thus proving that there was organic matter degradation. Infrared and scanning electron microscopy analysis allow for confirming these results. The correlation between spectroscopies analysis and physical-chemical properties was employed by partial least squares-regression (PLS-R) model. PLS-R model was applied to build a model to predict the compost quality depending on the composting time, the results obtained show that all the parameters analysis are well predicted. The current study proposed that final compost was more stabilized compared with the initial feedstock mixture. Ultimately, spectroscopy techniques used allowed us to confirm the physical-chemical results obtained, and both of them depict maturity and stability of the final compost, thus proving that spectral techniques are more reliable, fast, and promising than physical-chemical analyses.


2020 ◽  
Author(s):  
Srinivas Ramachandra ◽  
Abdulla Abdal-hay ◽  
Pingping Han ◽  
Ryan Lee ◽  
Saso Ivanovski

&lt;p&gt;&lt;strong&gt;Introduction&lt;/strong&gt;: Biofilms are 3-dimensional (3D) aggregates of microorganisms that are associated with a wide range of diseases. Although there have been several studies investigating biofilm formation on two-dimensional substrates, the use of 3D substrates may result in more representative and clinically relevant models. Accordingly, the aim of this study was to compare the growth of biofilms in the 3D substrates against biofilms grown in 2D substrates.&lt;br /&gt;&lt;strong&gt;Material and Methods:&lt;/strong&gt; Two grams of medical grade polycaprolactone (PCL) were loaded into a plastic Luer-lock 3 ml syringe and a 23G needle was used as a spinneret. The syringe was placed in a melt electro-writing (MEW) device to obtain fine fibers under controlled parameters. The 3-dimensional MEW PCL scaffolds were manufactured and characterised with an overall thickness of ~ 0.8 mm, with ~ 15 &amp;#956;m diameter fibers and ordered pore sizes of either 100 or 250 &amp;#181;m. PCL films employed as 2D substrates were manufactured by dissolving 10 gms of PCL in 100 ml chloroform and stirred for 3 h to obtain a transparent solution. Then, the solution was cast in glass petri dishes and dried to remove all organic solvents. In addition, commercial hydroxyapatite discs were also used as 2D controls. Unstimulated saliva from six healthy donors (gingival health) were used to grow biofilms. The formed biofilms were assessed at day 4, day 7 and day 10 using crystal violet assay, confocal microscopy, scanning electron microscopy and next-generation 16s sequencing.&lt;br /&gt;&lt;strong&gt;Results:&lt;/strong&gt; The results demonstrates that 3D PCL scaffolds dramatically enhanced biofilm biomass and thickness growth compared to that of the 2D controls. Confocal microscopy of biofilms at day 4 stained with SYTO 9 and propidium iodide showed thickness of biofilms in 2D substrates were 39 &amp;#181;m and 81&amp;#181;m for hydroxyapatite discs and PCL films, respectively. Biofilms in 3D substrates were 250 &amp;#181;m and 338 &amp;#181;m for MEW PCL 100&amp;#181;m pore size and MEW PCL 250 &amp;#181;m pore size, respectively. Similar results were noticed at day 7 and day 10. Scanning electron microscopy showed biofilm bridges formed over the fibers of the MEW scaffolds. Pilot trials of next generation sequencing detected similar taxa in biofilms formed in 3D scaffolds compared to that of 2D substrates.&lt;br /&gt;&lt;strong&gt;Discussion:&lt;/strong&gt; We have successfully investigated a 3D biofilm growth model using 3D medical grade PCL scaffolds. Thicker biofilms can be conveniently grown using this inexpensive static model. This will facilitate 3D microbial community studies that are more clinically relevant and improve our understanding of biofilm-associated disease processes.&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt;


2000 ◽  
Vol 78 (2) ◽  
pp. 135-148 ◽  
Author(s):  
Erwin L Zodrow ◽  
Zbynek Šimunek ◽  
Arden R Bashforth

Fossil cuticles were extracted from leaves attributed to Cordaites principalis (Germar) Geinitz (Cordaitales) that were collected from Upper Carboniferous strata in Nova Scotia (Sydney and Stellarton sub-basins) and in Newfoundland (Bay St. George sub-basin). The quality of the cuticular preservation is directly related to the thermal maturity and the grain size and angularity of sediments entombing the fossil leaves. Detailed transmitted light and scanning electron microscopy of the cuticles revealed that five distinct cuticular morphotypes could be recognized, demonstrating the variability in epidermal morphology of leaves belonging to one taxon. Two morphotypes show dissimilar and discrete epidermal characteristics, whereas three morphotypes form, more or less, a morphological continuum. Comparison with cuticles from Euramerican and Angaran floral provinces suggests that only one morphotype is in common with cuticles described from Europe, while four morphotypes are new for the Carboniferous.Key words: cuticle, Cordaites, Carboniferous, Canada.


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