Different controlling factors of pore features between marine shale and transitional shale in the Upper Yangtze region, South China

Author(s):  
Hongyang Jiang ◽  
Zhenxue Jiang ◽  
Xin Li

<p>Compared with marine shale with plentiful research and successful exploration, fewer studies on transitional shale reservoirs limit further exploitation of shale gas. In this paper, comparative analysis, between Lower Silurian marine shale and Upper Permian transitional shale in the Upper Yangtze region, is carried out to analysis pore features of both shales and the main controlling factors, which can provide theoretical guidance for further exploration. A combination of methods is ultilized in terms of organic-chemistry geology measurement, X-ray diffraction (XRD), high-pressure mercury injection, gas adsorption, and focused ion beam milling and scanning electron microscopy (FIB-SEM). The results show that Lower Silurian marine shale and Upper Permian transitional shale have similar organic matter (OM) abundance (2.72% and 2.31%) and thermal degree (2.56wt%Ro and 2.68wt%Ro). However, the kerogen of Lower Silurian shale is type I derived from algae and plankton, while that of Upper Permian shale is mainly type III from higher plant debris. As for mineral composition, Siliceous minerals (> 43wt%) account for the majority in Lower Silurian shale, while clay (> 57wt%) is the main mineral in Upper Permian shale. Variations in material basis trigger to differences in pore characteristics between the two shales. Firstly, the pores in Lower Silurian shale are mostly hosted by OM with an average pore diameter of 7.94 nm, while Upper Permian shale mainly develops pores associated with clay minerals with an average pore diameter of 28.60nm. Moreover, Lower Silurian shale presented relatively higher pore properties than Upper Permian in both average pore volume (0.020ml/g and 0.015ml/g) and average pore surface area (7.99 m<sup>2</sup>/g and 1.2 m<sup>2</sup>/g). Various factors lead to the differences in pore types and pore properties between the two shales. For marine shale, OM with thermal convertibility tend to be mobilizable and porous. OM-hosted pores are the dominated type which is controlled by OM abandauce and thermal degree. However, in transitional shale, OM is featured by phase stability without porous feature. Pores associated with clay flakes are the main type which is controlled by the specifc material composition. Hence, the discrepancies of pore properties may be attributed to material diversities between marine shale and transitional shale.</p>

Fractals ◽  
2018 ◽  
Vol 26 (02) ◽  
pp. 1840016 ◽  
Author(s):  
JUN LIU ◽  
YANBIN YAO ◽  
DAMENG LIU ◽  
YIDONG CAI ◽  
JIANCHAO CAI

Fractal characterization offers a quantitative evaluation on the heterogeneity of pore structure which greatly affects gas adsorption and transportation in shales. To compare the fractal characteristics between marine and continental shales, nine samples from the Lower Silurian Longmaxi formation in the Sichuan basin and nine from the Middle Jurassic Dameigou formation in the Qaidam basin were collected. Reservoir properties and fractal dimensions were characterized for all the collected samples. In this study, fractal dimensions were originated from the Frenkel–Halsey–Hill (FHH) model with N[Formula: see text] adsorption data. Compared to continental shale, marine shale has greater values of quartz content, porosity, specific surface area and total pore volume but lower level of clay minerals content, permeability, average pore diameter and methane adsorption capacity. The quartz in marine shale is mostly associated with biogenic origin, while that in continental shale is mainly due to terrigenous debris. The N[Formula: see text] adsorption–desorption isotherms exhibit that marine shale has fewer inkbottle-shaped pores but more plate-like and slit-shaped pores than continental shale. Two fractal dimensions ([Formula: see text] and [Formula: see text] were obtained at [Formula: see text] of 0–0.5 and 0.5–1. The dimension [Formula: see text] is commonly greater than [Formula: see text], suggesting that larger pores (diameter [Formula: see text][Formula: see text]nm) have more complex structures than small pores (diameter [Formula: see text][Formula: see text]nm). The fractal dimensions (both [Formula: see text] and [Formula: see text]) positively correlate to clay minerals content, specific surface area and methane adsorption capacity, but have negative relationships with porosity, permeability and average pore diameter. The fractal dimensions increase proportionally with the increasing quartz content in marine shale but have no obvious correlation with that in continental shale. The dimension [Formula: see text] is correlative to the TOC content and permeability of marine shale at a similar degree with dimension [Formula: see text], while the dimension [Formula: see text] is more sensitive to those of continental shale than dimension [Formula: see text]. Compared with dimension [Formula: see text], for two shales, dimension [Formula: see text] is better associated with the content of clay minerals but has worse correlations with the specific surface area and average pore diameter.


2013 ◽  
Vol 833 ◽  
pp. 159-164 ◽  
Author(s):  
Xiu Qian Li ◽  
Hai Peng Qiu ◽  
Jian Jiao

The ZrC/SiC multi-components modified C/C composites were prepared by using a hybrid precursor containning polycarbosilane and organic zirconium-contained polymeric precursor as impregnant and C/C composites of low density as preform. The porosity, microstructure and mechanical properties of samples were characterized with mercury injection apparatus, scanning electron microscopy and universal electron testing machine respectively. The results show that the porosity and average pore diameter decrease firstly and increase subsequently with the increase of organic zirconium content of the precursor. When the content of organic zirconium is 50%, the porosity and average pore diameter reach minimum which were7.27% and 0.0795um respectively. The most probabilistic pore diameter shifted from 10-100um to 1-10um at the same time; Meanwhile, the flexural properties also increases and drops immediately as the content of organic zirconium in the precursor adds. When the content of organic zirconium is 25%, the flexural strength reaches maximum of 245.20MPa.The improved flexural properties is attributed to the proper bonding of fiber-matrix interface and the low porosity of samples.


2019 ◽  
Vol 38 (5-6) ◽  
pp. 153-166 ◽  
Author(s):  
Stoja Milovanovic ◽  
Darka Markovic ◽  
Jasna Ivanovic

This study explores utilization of biodegradable and biocompatible polymers for controlled release of natural bioactive substance. For that purpose, poly(ε-caprolactone) (PCL) beads, cellulose acetate (CA) film, and poly lactic- co-glycolic acid (PLGA) flakes were impregnated with thymol by employing environmentally friendly process of supercritical carbon dioxide (scCO2) impregnation. At selected pressure and temperature, prolongation of operating time increased thymol loading. Pure scCO2 did not affect CA film with average pore diameter of approximately 3 µm, while it enabled change of PCL beads and PLGA flakes into foams with average pore diameter approximately 175 µm and 87 µm, respectively. Additionally to scCO2, thymol acted as a plasticizer increasing pore size of polymers up to three times. Kinetic of thymol release from selected samples was tested using phosphate buffer saline at 37°C and successfully described with Korsmeyer–Peppas, zero-order, first-order, and Higuchi models. The suggested method of PCL, CA, and PLGA supercritical impregnation led to development of porous, solvent free, added-value materials that release thymol in a controlled manner from 5 h to several days.


2013 ◽  
Vol 712-715 ◽  
pp. 415-419
Author(s):  
Ming Hua Huang ◽  
Qing Hua Chen ◽  
Li Lei ◽  
Duan Cheng Wang ◽  
Ting Ting Yan

Sol-gel method and freeze-drying method were adopted to prepare the porous HAPw/KGM composite bone scaffolds and ammonia was used as a crosslinking agent. The porosity, average pore diameter, compressive strength and degradation rate in vitro were measured according to the related standard. The curves of each factor and lever affecting comprehensive properties were drew through the orthogonal design L9 (34) experiment. SEM and XRD were applied in characterization. The results show that the optimal preparation program of the composite scaffolds is KGM (2g), HAPw (4.5g), ammonia (0.1 ml) and the freeze temperature (-20 ° C); the prepared scaffolds are porous three-dimensional network structures; the porosity of optimal scaffold is more than 90%; the average pore diameter is between 200-300μm; the compressive strength is about 0.8Mpa and the degradation rate is about 50% within 9 weeks.


1995 ◽  
Vol 4 (3) ◽  
pp. 275-279 ◽  
Author(s):  
M. Conley Wake ◽  
Antonios G. Mikos ◽  
Georgios Sarakinos ◽  
Joseph P. Vacanti ◽  
Robert Langer

We have investigated and quantified the degree of fibrovascular tissue ingrowth in cylindrical poly(vinyl alcohol) (PVA) foams of 12.5 mm diameter, 5 mm thickness, and 71% porosity implanted in the mesentery of rats over a period of 25 days. Fibrovascular tissue penetrated the center of PVA foams 5 days postimplantation yet the void fraction available for cell seeding was 55% and the volume average pore diameter was 190 (±39) μm. By 10 days postimplantation the void fraction had decreased to 32% and the volume average pore diameter was 121 (±20) μm. As time elapsed fibrovascular tissue continued to expand and fill the remaining pore space. At 15 days postimplantation the void space was impractical for cell seeding and continued to decrease through the remainder of the study. Our data suggest that hydrogel foams with a polydispersed pore morphology can be prevascularized with adequate space for cell seeding as the volume of tissue penetrating the foam is limited by the smaller pores in the foam structure; however, available void space for cell seeding decreases with time.


2017 ◽  
Vol 751 ◽  
pp. 363-367
Author(s):  
Peerawith Sumtong ◽  
Apiluck Eiad-Ua

Anodic Aluminum Oxide (AAO) membrane has been successfully fabricated from two-step anodization with aluminum low grade (Al6061). The pore density, the pore diameter, and the interpore distance can be controlled by varying anodization process conditions. However, there are limits to control the mechanical strength and growth of AAO arrays, such as pore density, pore diameter and interpore distance. In this research the self-organized two-step anodization is carried out varying time at 24, 48 and 72 hours, respectively with 40V at the low temperature 2-5°C. The optimum conditions of AAO with two-step anodization is 40V for 48 hr. Finally, AAO substrate is separated from aluminum low-grade and enlarged pore diameter with pore widening process by 5% H3PO4. The physical properties were investigated by mean of field emission scanning electron microscope (FE-SEM) show that the average pore diameter and average interpore distance increase with the anodization time. Al6061 Aluminum substrate can be used to fabricate a nanoporous AAO film with an average pore diameter and average interpore distance larger than 70 and 90 nanometers, respectively but less mechanical stability.


1996 ◽  
Vol 11 (2) ◽  
pp. 518-528 ◽  
Author(s):  
V. Vendange ◽  
Ph. Colomban

Optically clear monolithic (OCM) gels of mesoporous aluminosilicates (average pore diameter 3.6 nm) and alumina (6 nm) have been prepared by slow hydrolysis-polycondensation of alkoxides and converted into OCM mesoporous glasses by heating. In order to change the properties, different ways of modifying the pore size and structure are proposed. We show that addition of boron oxide reduces the average pore diameter. A higher effect can be obtained by addition of a surfactant. In this case the mesoporous matrix becomes microporous (d < 2 nm). Another way of modifying the pore structure consists of introducing nanoprecipitates inside the porosity by an impregnation process. Modifications of the porous structure are different in alumina and aluminosilicates.


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