scholarly journals Mineral compositional controls on the porosity of black shales from the Wufeng and Longmaxi Formations (Southern Sichuan Basin and its surroundings) and insights into shale diagenesis

2018 ◽  
Vol 36 (4) ◽  
pp. 665-685
Author(s):  
Mei Han ◽  
Chao Han ◽  
Zuozhen Han ◽  
Zhigang Song ◽  
Wenjian Zhong ◽  
...  
Keyword(s):  
Organic Matter ◽  
Pore Size ◽  
Pore Volume ◽  
Total Pore Volume ◽  
Black Shales ◽  
Carbonate Content ◽  
Pore Sizes ◽  
Pore Size Distributions ◽  
Shale Composition ◽  
The Relationship

The effects of brittle minerals in shale diagenesis on shale pores remain controversial and it is difficult to quantify directly. However, the relationship between brittle minerals and shale pores could provide indirect guidance regarding diagenesis processes in post-mature marine shales. In this study, the pore size distribution was determined, and the relationship between pore volume and shale composition was examined in shale samples with different total organic carbon contents from the Wufeng and Longmaxi Formations, with the objective of distinguishing pore size ranges in organic matter and inorganic minerals, respectively, and studying shale diagenesis. The samples of the Wufeng and Longmaxi shales are composed of clay minerals, calcite, dolomite, quartz, feldspar, and some minor components. The pore size distributions, which were determined using nitrogen adsorption isotherm analysis of shale and kerogen, show similar trends for pore sizes less than approx. 6.5 nm but different trends for larger pore sizes. Mercury injection saturation shows that macropores account for 14.4–22% of the total pore volume. Based on a series of crossplots describing the relationships between shale composition and pore volume or porosity associated with different pore sizes as well as on scanning electron microscopy observations, organic matter pores were found to comprise most of the micro-mesopores (pore diameters < 6.5 nm). Organic matter pores and intraparticle pores associated with carbonate constitute the majority of mesopores (pore diameters 6.5–50 nm). Finally, interparticle pores associated with quartz comprise the majority of the macropores. The mesopores associated with carbonate were formed by dissolution during diagenesis, whereas the macropores associated with quartz are the remainders of the original interparticle pores. Mesopore volumes increase with increasing carbonate content while macropore volumes decrease due to the ‘pore size controlled solubility’ effect, which causes dissolved calcium carbonate to precipitate in larger macropores.

Effect of Heat-Treatment in Ar Atmosphere on Pore Structure of Carbonaceous Materials from Polysiloxane

2014 ◽  
Vol 602-603 ◽  
pp. 279-284
Author(s):  
Li Qun Duan ◽  
Chen Chen Zhang ◽  
Qing Song Ma ◽  
Zhao Hui Chen
Keyword(s):  
Heat Treatment ◽  
Pore Structure ◽  
Pore Size ◽  
Pore Volume ◽  
Average Pore Size ◽  
Total Pore Volume ◽  
Treatment Temperature ◽  
Carbonaceous Materials ◽  
Average Pore ◽  
Pore Size Distributions

Nanoporous carbonaceous materials derived from polysiloxane were first prepared by pyrolysis at 1300°C followed with hydrofluoric acid (HF) etching treatment. Their thermal stability of pore structure in inert condition was investigated in this paper by nitrogen adsorption technique in detail. The specific surface area (SSA) and pore volume (total pore volume, micropore volume, mesopore volume) decreased continually in the heat-treatment temperature range of 1000~1400°C. The average pore size almost kept the same with the raw sample. However, when the temperature exceeded 1400°C, the micropore interconnection began transforming to mesopore structure, which led to the decline of SSA and the increase of average pore size. Furthermore, the pore size distributions (PSDs) curves showed that heat-treatment had an advantage on the transition process of pore structure from disorder to regularity to some extent when heat-treated in the range 1000~1400°C for the most possible reason of relief of residue strain in the carbonaceous materials.

Relationship between pore size distributions and physical properties of clay soils

Soil Research ◽  
1974 ◽  
Vol 12 (2) ◽  
pp. 107 ◽  
Author(s):  
ID Sills ◽  
LAG Aylmore ◽  
JP Quirk
Keyword(s):  
Particle Size ◽  
Pore Size ◽  
Pore Volume ◽  
Total Pore Volume ◽  
Particle Size Analysis ◽  
The Other ◽  
Clay Soils ◽  
Size Analysis ◽  
Size Distributions ◽  
Pore Size Distributions

Pore size distributions using mercury injection and nitrogen sorption techniques were determined on a number of soils classified as clays on the basis of particle size analysis. Some of these soils exhibit markedly different consistencies during texturing and undergo changes in texture during prolonged manipulation, e.g. subplastic, superplastic and self-mulching soils. The pore size distributions for these soils do not differ significantly from those obtained for the normal labile clay soil in the pore size range 2 nm to 50 �m. The clay soils examined, with the exception of the krasnozem, have the majority of their pore volume within pores smaller than 10 nm with the predominant pore size centred around 3 nm plate separation. In the case of the krasnozem, the particle size analysis does not correspond to the texture assessment as a clay loam. Surface and subsoil samples of the krasnozem have high porosities and predominant plate separations of 6 nm. They consequently possess significantly different pore size distributions from the other clays. In the case of the surface sample, only a small proportion of its total pore volume is in pores smaller than 10 nm. These differences in pore structure observed between the krasnozem and the other soils examined may result from differences in mineralogy, and in particular from the high sesquioxide content of the krasnozem.

Effect of air-drying and critical point drying on the porosity of clay soils

1984 ◽  
Vol 21 (1) ◽  
pp. 181-185 ◽  
Author(s):  
C. R. De Kimpe
Keyword(s):  
Organic Matter ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Critical Point ◽  
Size Distribution ◽  
Pore Volume ◽  
Organic Matter Content ◽  
Total Pore Volume ◽  
Clay Soils ◽  
Critical Point Drying

Samples from four surface and one subsurface horizons of clay-rich soils from Quebec were air-dried and critical point dried. In the latter samples, the total pore volume was 19–84% larger than in the former samples. The total pore volume, determined by mercury intrusion porosimetry and density measurements, was subdivided into large (> 8.8 μm), medium, and small (< 0.19 μm) pores. The effect of drying on these pores was estimated. Medium-sized pores were affected most by the drying technique, followed next by the large pores, and finally by the small pores. The modifications due to drying could not be explained adequately by shrinkage and it was assumed, from the pore-size distribution curves, that organic matter content had a buffer effect on particle reorganization. Keywords: critical point drying, clay soils, pore volume, pore-size distribution, organic matter.

Pore-Size Distributions for Organic-Shale-Reservoir Rocks From Nuclear-Magnetic-Resonance Spectra Combined With Adsorption Measurements

SPE Journal ◽  
2015 ◽  
Vol 20 (04) ◽  
pp. 824-830 ◽  
Author(s):  
Richard F. Sigal
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Pore Size ◽  
Surface Relaxation ◽  
Size Distributions ◽  
Pore Sizes ◽  
Pore Size Distributions ◽  
Shale Reservoirs ◽  
Organic Shale ◽  
Nuclear Magnetic

Summary The behavior of fluids in nanometer-scale pores can have a strong functional dependence on the pore size. In mature organic-shale reservoirs, the nuclear-magnetic-resonance (NMR) signal from methane decays by surface relaxation. The methane NMR spectrum provides an uncalibrated pore-size distribution for the pores that store methane. The distribution can be calibrated by calculating a pore-wall-surface area from a methane-Langmuir-adsorption isotherm. When this method was applied to samples from a reservoir in the dry-gas window, the pores containing methane had pore sizes that ranged from 1 to approximately 100 nm. Approximately 20–40% of the pore volume was in pores smaller than 10 nm, where deviation from bulk-fluid behavior can be significant. The samples came from two wells. The surface relaxivity for the sample from Well 2 was somewhat different from the relaxivity for the two samples from Well 1. Samples that adsorbed more methane had smaller pore sizes. This methodology to obtain pore-size distributions should be extendable to more-general organic-shale reservoirs.

The thermal conductivity of polymethylsilsesquioxane aerogels and xerogels with varied pore sizes for practical application as thermal superinsulators

2014 ◽  
Vol 2 (18) ◽  
pp. 6525-6531 ◽  
Author(s):  
G. Hayase ◽  
K. Kugimiya ◽  
M. Ogawa ◽  
Y. Kodera ◽  
K. Kanamori ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Pore Size ◽  
Gas Pressure ◽  
Practical Application ◽  
Practical Applications ◽  
Pore Sizes ◽  
The Relationship

The relationship between the thermal conductivity, gas pressure and pore size of polymethylsilsesquioxane aerogels and xerogels has been investigated for practical applications.

The Influence of Sinterng Temperature on the Phase, Microstructure and Textual Properties of Hollow Hydroxyapatite Microspheres

2011 ◽  
Vol 239-242 ◽  
pp. 2274-2279 ◽  
Author(s):  
Ying Chun Wang ◽  
Wen Hai Huang ◽  
Ai Hua Yao ◽  
De Ping Wang
Keyword(s):  
Specific Surface ◽  
Pore Size ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Sintering Temperature ◽  
Total Pore Volume ◽  
Precipitation Method ◽  
Simple Method ◽  
Air Atmosphere

A simple method to prepare hollow hydroxyapatite (HAP) microspheres with mespores on the surfaces is performed using a precipitation method assisted with Li2O-CaO-B2O3(LCB) glass fabrication process. This research is concerned with the effect of sintering temperature on the microstructure evolution, phase purity, surface morphology, specific surface area, and porosity after sintering process. The microspheres were sintered in air atmosphere at temperatures ranging from 500 to 900 °C. The starting hollow HAP microspheres and the sintered specimens were characterized by scanning electron microscope, X-ray diffractometer, specific surface area analyzer, and Hg porosimetry, respectively. The as-prepared microspheres consisted of calcium deficient hydroxyapatite. The results showed that the as-prepared hollow HAP microspheres had the highest specific surface areas, and the biggest total pore volume. The pore size distribution of the as-prepared hollow HAP microspheres were mainly the mesopores in the range of 2～40 nm. The specific surface area and total pore volume of hollow HAP microspheres decreased with increasing sintering temperature. Whereas the mean pore size increased with increasing sintering temperature. It showed that at 700°C, Ca-dHAP decomposes into a biphasic mixture of HAP and β-calcium phosphate(TCP).

Two sides of the same inverse problem, in identifying the pore size distribution based on experiments with non-Newtonian fluids

2021 ◽  
Author(s):  
Martin Lanzendörfer
Keyword(s):  
Inverse Problem ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Forward Problem ◽  
Size Distributions ◽  
Pore Sizes ◽  
Pore Size Distributions ◽  
Flow Through ◽  
Effective Pore Size

&lt;p&gt;Following the capillary bundle concept, i.e. idealizing the flow in a saturated porous media in a given direction as the Hagen-Poiseuille flow through a number of tubular capillaries, one can very easily solve what we would call the &lt;em&gt;forward problem&lt;/em&gt;: Given the number and geometry of the capillaries (in particular, given the pore size distribution), the rheology of the fluid and the hydraulic gradient, to determine the resulting flux. With a Newtonian fluid, the flux would follow the linear Darcy law and the porous media would then be represented by one constant only (the permeability), while materials with very different pore size distributions can have identical permeability. With a non-Newtonian fluid, however, the flux resulting from the forward problem (while still easy to solve) depends in a more complicated nonlinear way upon the pore sizes. This has allowed researchers to try to solve the much more complicated &lt;em&gt;inverse problem&lt;/em&gt;: Given the fluxes corresponding to a set of non-Newtonian rheologies and/or hydraulic gradients, to identify the geometry of the capillaries (say, the effective pore size distribution).&lt;/p&gt;&lt;p&gt;The potential applications are many. However, the inverse problem is, as they usually are, much more complicated. We will try to comment on some of the challenges that hinder our way forward. Some sets of experimental data may not reveal any information about the pore sizes. Some data may lead to numerically ill-posed problems. Different effective pore size distributions correspond to the same data set. Some resulting pore sizes may be misleading. We do not know how the measurement error affects the inverse problem results. How to plan an optimal set of experiments? Not speaking about the important question, how are the observed effective pore sizes related to other notions of pore size distribution.&lt;/p&gt;&lt;p&gt;All of the above issues can be addressed (at least initially) with artificial data, obtained e.g. by solving the forward problem numerically or by computing the flow through other idealized pore geometries. Apart from illustrating the above issues, we focus on &lt;em&gt;two distinct aspects of the inverse problem&lt;/em&gt;, that should be regarded separately. First: given the forward problem with &lt;em&gt;N&lt;/em&gt; distinct pore sizes, how do different algorithms and/or different sets of experiments perform in identifying them? Second: given the forward problem with a smooth continuous pore size distribution (or, with the number of pore sizes greater than &lt;em&gt;N&lt;/em&gt;), how should an optimal representation by &lt;em&gt;N&lt;/em&gt; effective pore sizes be defined, regardless of the method necessary to find them?&lt;/p&gt;

The rhythmic expression of mid-Cretaceous Oceanic Anoxic Event 2 at IODP Sites U1513 and U1516 (southwest of Australia) 

2021 ◽  
Author(s):  
Sietske Batenburg ◽  
Kara Bogus ◽  
Matthew Jones ◽  
Kenneth Macleod ◽  
Mathieu Martinez ◽  
...  
Keyword(s):  
Organic Matter ◽  
Indian Ocean ◽  
Water Column ◽  
North Atlantic ◽  
Black Shales ◽  
Carbonate Content ◽  
Intergovernmental Panel ◽  
Oceanic Anoxic Event ◽  
Oceanic Anoxic Event 2 ◽  
Anoxic Event

&lt;p&gt;The widespread deposition of organic-rich black shales during the mid-Cretaceous hothouse at ~94 Ma marked a climatic extreme that is particularly well studied in the Northern Hemisphere. The expression of Oceanic Anoxic Event 2 (OAE 2) in the NH was characterised by low oceanic oxygen concentrations, likely caused by the input of nutrients through volcanism and/or weathering in combination with a peculiar geography in which the proto-North Atlantic was semi-restricted (Jenkyns, 2010; Trabucho Alexandre et al., 2010). The extent of water column anoxia outside the North Atlantic and Tethyan domains remains poorly resolved, as few Southern Hemisphere records have been recovered that span OAE 2, and only a portion of those Indian and Pacific Ocean localities experienced anoxia and organic matter deposition (Dickson et al., 2017; Hasegawa et al., 2013).&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Here we present new results from IODP Expedition 369 offshore southwestern Australia. Sedimentary records across the Cenomanian-Turonian transition from Sites U1513 and U1516 in the Mentelle Basin (Indian Ocean) display rhythmic lithologic banding patterns. The OAE 2 interval is marked by a dramatic drop in carbonate content and the occurrence of several thin organic-rich black bands. The spacing of dark bands within a rhythmic sequence suggests a potential orbital control on organic matter deposition at our study sites. Time series analyses of high-resolution (cm-scale) elemental data from XRF-core scanning reveal the imprint of periodicities that can be confidently linked to Earth&amp;#8217;s orbital parameters. The new OAE 2 records from Sites U1516 and U1513 allow us to i) evaluate existing time scales over the Cenomanian-Turonian transition, and ii) investigate the mechanisms leading to a recurrent lack of oxygen in the Indian Ocean.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Climatic mechanisms translating changes in insolation to variations in organic matter deposition may have included variations in nutrient input from nearby continents and shifts in water column structure affecting local to regional stratification versus deep water formation and advection. Investigating ventilation of the deep sea during the OAE2 interval is of heightened relevance as current global warming is leading to a worldwide expansion of oxygen minimum zones&amp;#160;(P&amp;#246;rtner et al., 2019).&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;Dickson, A.J., et al., 2017. Sedimentology 64, 186&amp;#8211;203.&lt;/p&gt;&lt;p&gt;Hasegawa, et al., 2013. Cretaceous Research 40, 61&amp;#8211;80.&lt;/p&gt;&lt;p&gt;Jenkyns, H.C., 2010. Geochemistry, Geophysics, Geosystems 11, Q03004.&lt;/p&gt;&lt;p&gt;P&amp;#246;rtner, H.O., et al., 2019. IPCC Intergovernmental Panel on Climate Change: Geneva, Switzerland.&lt;/p&gt;&lt;p&gt;Trabucho Alexandre, J., et al., 2010. Paleoceanography 25, PA&lt;/p&gt;

scholarly journals Enhanced pore space analysis by use of μ-CT, MIP, NMR, and SIP

2018 ◽  
Author(s):  
Zeyu Zhang ◽  
Sabine Kruschwitz ◽  
Andreas Weller ◽  
Matthias Halisch
Keyword(s):  
Pore Size ◽  
Pore Volume ◽  
Pore Space ◽  
Volume Distribution ◽  
Micro Computed Tomography ◽  
Pore Size Distributions ◽  
Scale Characterization ◽  
Relevant Range ◽  
Good Agreement

Abstract. We investigate the pore space of rock samples with respect to different petrophysical parameters using various methods, which provide data upon pore size distributions, including micro computed tomography (μ-CT), mercury intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), and spectral induced polarization (SIP). The resulting cumulative distributions of pore volume as a function of pore size are compared. Considering that the methods differ with regard to their limits of resolution, a multiple length scale characterization of the pore space geometry is proposed, that is based on a combination of the results from all of these methods. The approach is demonstrated using samples of Bentheimer and Röttbacher sandstone. Additionally, we compare the potential of SIP to provide a pore size distribution with other commonly used methods (MIP, NMR). The limits of resolution of SIP depend on the usable frequency range (between 0.002 Hz and 100 Hz). The methods with similar resolution show a similar behavior of the cumulative pore volume distribution in the overlapping pore size range. We assume that μ-CT and NMR provide the pore body size while MIP and SIP characterize the pore throat size. Our study shows that a good agreement between the pore radii distributions can only be achieved if the curves are adjusted considering the resolution and pore volume in the relevant range of pore radii. The MIP curve with the widest range in resolution should be used as reference.

scholarly journals Experimental Investigation of the Macroscopic Behavior and Microstructure Property Evolution of Hardened Cement Consolidated Tailings

Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 6 ◽  
Author(s):  
Xiang Sun ◽  
Yunbing Hou
Keyword(s):  
Compressive Strength ◽  
Pore Size ◽  
Pore Volume ◽  
Mercury Intrusion Porosimetry ◽  
Mining Industry ◽  
Total Pore Volume ◽  
Hardened Cement ◽  
Curing Period ◽  
Strength Tests ◽  
Curing Age

Surface cement consolidated tailings disposal has recently been proposed to manage tailings in the modern mining industry because it can reduce or eliminate the disadvantages of traditional tailings storage. In this study, the evolution of the macro performance and microstructure characteristics of cement consolidated tailing samples during the curing period were determined by unconfined compressive strength tests, permeability tests, scanning electron microscopy (SEM) observations, and mercury intrusion porosimetry (MIP) tests, respectively. The results show that the curing time notably affected the macro performance and microstructural properties of the hardened cement consolidated tailings samples. As the curing age increases, the compressive strength increases nonlinearly and the growth rate decreases; the permeability decreases rapidly first, then gradually stabilizes, and finally reaches a stable value; the morphology of the hydration products and microstructures continues to evolve with the hydration process; the total pore volume decreases slightly, whereas the critical pore size decreases significantly. The proportion of the pore volume in different pore size ranges can also be affected by the curing age, which results in a large pore (>200 nm) decrease, and the small pores (<200 nm) increased. In this process, the filling effect plays a major role.

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