Thermal maturity and reservoir quality of the Velkerri Formation, Beetaloo Sub-basin, Northern Territory

2020 ◽  
Vol 60 (2) ◽  
pp. 697
Author(s):  
Claudio Delle Piane ◽  
I. Tonguç Uysal ◽  
Mohinudeen Faiz ◽  
Zhejun Pan ◽  
Julien Bourdet ◽  
...  
Keyword(s):  
Gas Adsorption ◽  
Gas Permeability ◽  
Light And Electron Microscopy ◽  
Organic Content ◽  
Northern Territory ◽  
Thermal Maturity ◽  
Microscopy Imaging ◽  
Petroleum Systems ◽  
Adsorbed Gas

The Proterozoic (~1.43 Ga) Velkerri Formation (McArthur Basin, Northern Territory) is believed to host one of the world’s oldest petroleum systems. Drilling and production tests demonstrated the encouraging potential of this unconventional gas resource and current efforts are aimed at better defining the extent of the gas and liquid-rich portions of this shale play. In this context, we conducted a comprehensive characterisation of specimens from the Amungee Member of the Velkerri Formation (previously referred to as the Middle Velkerri) sampled along a thermal maturity gradient from wells drilled across the Beetaloo Sub-basin. The scope of our analysis was to shed light on how the organic matter in the Velkerri Formation is affected by thermal maturity and how this affects the pore structure of the host rock. To this end, we integrated light and electron microscopy imaging with Raman spectroscopy and pyrolysis techniques to define the maturity of the sediments and visualise the shale pore network. In concert with the direct imaging, bulk samples were experimentally tested to measure their gas permeability and gas adsorption capacity. The results indicate that porosity is mostly organic-hosted with pore size dominated by meso- and micro-pores (i.e. <50 nm). Methane adsorption isotherms measured at temperatures up to 80°C also show that organic content is one of the main factors controlling the amount of adsorbed gas in the Velkerri shale.

scholarly journals Effect of Kerogen Thermal Maturity on Methane Adsorption Capacity: A Molecular Modeling Approach

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3764 ◽  
Author(s):  
Saad Alafnan ◽  
Theis Solling ◽  
Mohamed Mahmoud
Keyword(s):  
Molecular Modeling ◽  
Adsorption Capacity ◽  
Gas Adsorption ◽  
Material Balance ◽  
Methane Adsorption ◽  
Source Rocks ◽  
Thermal Maturity ◽  
Reserve Estimation ◽  
Adsorbed Gas ◽  
Key Factor

The presence of kerogen in source rocks gives rise to a plethora of potential gas storage mechanisms. Proper estimation of the gas reserve requires knowledge of the quantities of free and adsorbed gas in rock pores and kerogen. Traditional methods of reserve estimation such as the volumetric and material balance approaches are insufficient because they do not consider both the free and adsorbed gas compartments present in kerogens. Modified versions of these equations are based on adding terms to account for hydrocarbons stored in kerogen. None of the existing models considered the effect of kerogen maturing on methane gas adsorption. In this work, a molecular modeling was employed to explore how thermal maturity impacts gas adsorption in kerogen. Four different macromolecules of kerogen were included to mimic kerogens of different maturity levels; these were folded to more closely resemble the nanoporous kerogen structures of source rocks. These structures form the basis of the modeling necessary to assess the adsorption capacity as a function of the structure. The number of double bonds plus the number and type of heteroatoms (O, S, and N) were found to influence the final configuration of the kerogen structures, and hence their capacity to host methane molecules. The degree of aromaticity increased with the maturity level within the same kerogen type. The fraction of aromaticity gives rise to the polarity. We present an empirical mathematical relationship that makes possible the estimation of the adsorption capacity of kerogen based on the degree of polarity. Variations in kerogen adsorption capacity have significant implications on the reservoir scale. The general trend obtained from the molecular modeling was found to be consistent with experimental measurements done on actual kerogen samples. Shale samples with different kerogen content and with different maturity showed that shales with immature kerogen have small methane adsorption capacity compared to shales with mature kerogen. In this study, it is shown for the first time that the key factor to control natural gas adsorption is the kerogen maturity not the kerogen content.

scholarly journals Coloration principles of the Great purple emperor butterfly (Sasakia charonda)

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Doekele G. Stavenga ◽  
Hein L. Leertouwer ◽  
Kentaro Arikawa
Keyword(s):  
Thin Film ◽  
Light And Electron Microscopy ◽  
Film Properties ◽  
Microscopy Imaging ◽  
Orange Yellow ◽  
White Spots ◽  
Sasakia Charonda ◽  
Scale Types ◽  
Wing Scales ◽  
Optical Basis

AbstractThe dorsal wings of male Sasakia charonda butterflies display a striking blue iridescent coloration, which is accentuated by white, orange-yellow and red spots, as well as by brown margins. The ventral wings also have a variegated, but more subdued, pattern. We investigated the optical basis of the various colors of intact wings as well as isolated wing scales by applying light and electron microscopy, imaging scatterometry and (micro)spectrophotometry. The prominent blue iridescence is due to scales with tightly packed, multilayered ridges that contain melanin pigment. The scales in the brown wing margins also contain melanin. Pigments extracted from the orange-yellow and red spots indicate the presence of 3-OH-kynurenine and ommochrome pigment. The scales in the white spots also have multilayered ridges but lack pigment. The lower lamina of the scales plays a so-far undervalued but often crucial role. Its thin-film properties color the majority of the ventral wing scales, which are unpigmented and have large windows. The lower lamina acting as a thin-film reflector generally contributes to the reflectance of the various scale types.

scholarly journals K-Mean Cluster Analysis for Better Determining the Sweet Spot Intervals of the Unconventional Organic-Rich Shale: A Case Study

2018 ◽  
Vol 7 (2) ◽  
pp. 200-213
Author(s):  
Muhammad Nur Ali Akbar ◽  
Septian Tri Nugraha
Keyword(s):  
Organic Matter ◽  
Water Saturation ◽  
Laboratory Data ◽  
Organic Content ◽  
Brittleness Index ◽  
Sweet Spot ◽  
Typing Method ◽  
Log Data ◽  
Gas Saturation

Abstract The petrophysical analysis is the crucial task for evaluating the quality of unconventional organic-rich shale and tight gas reservoirs. The presence of organic matter and the ultra-tight with over complex pore system have remained a lack of understanding of how to evaluate the extensive parameters of porosity considering organic content, gas saturation, organic richness, brittleness index, and sweet spot interval by only using conventional log. Therefore, this study offers effectively applied techniques and better analysis for interpreting these parameters by maximizing and integrating geological, geochemical, rock mechanical and engineering data. In general, the field data used in this study are from the first dedicated well for source rock exploration in the North Sumatra Basin, Indonesia. The developed method was derived by using conventional log. All interpretation results were validated by laboratory data measurements of routine and special core analysis, petrography, total organic carbon (TOC) and organic maturation, and brittleness index (BI) calculation. Moreover, the high quality of NMR log data was used as well to ensure our developed techniques present good estimations. Briefly about the methods, we started to determine the total and effective porosity based on the density log by including the presence of organic matter and multi-mineral analysis in these estimations. Then, we used the revised water saturation-TOC of water saturation while the TOC was predicted in advance by averaging three results from the correlation of TOC-Density, modified CARBOLOG and Passey’s ΔlogR methods. Equally important, in order to obtain the reliable gas saturation prediction, we used saturation exponent (n), cementation factor (m), and the tortuosity factor (a) parameters which obtained from laboratory measurement of formation resistivity factor and resistivity index (FFRI). In addition, the brittleness index was predicted based on sonic log data. Finally, all parameters needed for determining gas shale sweet spot have been made. Then, we developed a way to evaluate the sweet spot interval by using K-mean clustering. In conclusion, this clustering result properly follows the shale quality index parameters which consist of organic richness and maturation, brittleness index, the storage capacity of porosity and gas saturation. This study shows that these petrophysical applied techniques leads us to interpret the best position of shale interval to be developed with a simple, fast, and accurate prediction way. Furthermore, as a novelty, this method can be used as rock typing method and obviously can reduce uncertainty and risks in organic-rich shale exploration.

scholarly journals The Effects of 1-Methylcyclopropene Treatment on the Fruit Quality of ‘Idared’ Apples during Storage and Transportation

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 490
Author(s):  
Kazimierz Tomala ◽  
Maria Małachowska ◽  
Dominika Guzek ◽  
Dominika Głąbska ◽  
Krystyna Gutkowska
Keyword(s):  
Shelf Life ◽  
Gas Permeability ◽  
Modified Atmosphere Packaging ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Low Oxygen ◽  
Control Groups ◽  
Long Distance ◽  
Postharvest Treatment

1-Methylcyclopropene (1-MCP) is applied as an inhibitor of ethylene action, which is widely used in postharvest technology to prolong the shelf life of many fruits. The aim of the study was to assess the possibility to apply 1-MCP treatment to maintain the quality of ‘Idared’ apples for long-distance transportation. The studied apples were assessed in three groups: (I) 1-MCP postharvest treatment; (II) 1-MCP postharvest treatment with Modified Atmosphere Packaging (MAP) selected gas permeability bags; and (III) control groups (with neither 1-MCP treatment, nor dedicated packaging). Apples were subjected to storage in the Ultra Low Oxygen (ULO) chamber that was applied for 0 weeks, 10 weeks and 20 weeks (three periods of storage); simulated long-distance transport (6 weeks); and simulated distribution, which was applied for 0 days, 5 days, 10 days, and 15 days (4 periods of distribution). The obtained 36 groups (three postharvest treatments per three periods of storage per four periods of distribution) were analyzed to assess firmness, total soluble solids (TSS) and titratable acidity (TA). There were differences between firmness values for control groups and those with 1-MCP applied, which were characterized by higher values of firmness (p < 0.05). Groups with 1-MCP and MAP applied combined were characterized by higher values of TSS than control groups (p < 0.05). The majority of groups with 1-MCP applied alone were characterized by higher values of TA than control groups (p < 0.05), but values for samples attributed to 1-MCP and MAP combined were not higher than for 1-MCP alone. It may be concluded that 1-MCP applied postharvest contributed to higher results of firmness and TA of ‘Idared’ apples after long-distance transportation, but combining 1-MCP with MAP did not contribute to further differences for TA. However, for TSS the observed influence was inconclusive. It may be stated that 1-MCP is a beneficial treatment for ‘Idared’ apples for long-distance transportation as it prolongs their shelf life and improves firmness.

scholarly journals Experimental research on desorption characteristics of gas-bearing coal subjected to mechanical vibration

2020 ◽  
Vol 38 (5) ◽  
pp. 1454-1466
Author(s):  
Xuexi Chen ◽  
Liang Zhang ◽  
Maoliang Shen
Keyword(s):  
Coalbed Methane ◽  
Gas Adsorption ◽  
Mechanical Vibration ◽  
Particle Diameter ◽  
Reference Value ◽  
Desorption Rate ◽  
Gas Desorption ◽  
Adsorbed Gas ◽  
Vibration Parameters ◽  
Adsorption Desorption

Mechanical vibration can induce coal and gas outburst accidents, and can also promote the exploitation of coalbed methane. In this paper, a vibration-adsorption-desorption experiment system was established, the effects of coal sample particle diameter, gas pressure, and vibration frequency on gas desorption were studied. Mechanical vibration can generate a shear force in the adsorbed gas and promote gas desorption, but there are appropriate vibration parameters. Within the range of experimental parameters, the larger the amplitude, the more favorable for gas desorption. The change rules of gas desorption rate and desorption quantity under different conditions are basically the same, showing a power function shape with time increase, and most of the desorption quantity was completed within the first 5 minutes. The gas desorption rate and desorption quantity were positively related to the gas adsorption pressure. The results have great reference value for preventing gas outbursts and promoting gas exploitation.

scholarly journals Priorities for improved management of acute rheumatic fever and rheumatic heart disease: analysis of cross-sectional continuous quality improvement data in Aboriginal primary healthcare centres in Australia

2020 ◽  
Vol 44 (2) ◽  
pp. 212 ◽  
Author(s):  
Judith M. Katzenellenbogen ◽  
Daniela Bond-Smith ◽  
Anna P. Ralph ◽  
Mathilda Wilmot ◽  
Julie Marsh ◽  
...  
Keyword(s):  
Rheumatic Fever ◽  
Best Practice ◽  
Age Groups ◽  
Northern Territory ◽  
Age Group ◽  
Adult Transition ◽  
Continuous Quality ◽  
Transition Care ◽  
Rheumatic Heart

ObjectiveThis study investigated the delivery of guideline-recommended services for the management of acute rheumatic fever (ARF) and rheumatic heart disease (RHD) in Australian primary healthcare centres participating in the Audit and Best Practice for Chronic Disease (ABCD) National Research Partnership project. MethodsARF and RHD clinical audit data were collected from 63 Aboriginal centres in four Australian jurisdictions using the ABCD ARF/RHD audit tool. Records of up to 30 patients treated for ARF and/or RHD were analysed per centre from the most recent audit conducted between 2009 and 2014. The main outcome measure was a quality of ARF and RHD care composite indicator consisting of nine best-practice service items. ResultsOf 1081 patients, most were Indigenous (96%), female (61%), from the Northern Territory and Queensland (97%) and &lt;25 years of age (49%). The composite indicator was highest in the 0–14 year age group (77% vs 65–67% in other age groups). Timely injections and provision of client education are important specific areas for improvement. Multiple regression showed age &gt;15 years to be a significant negative factor for several care indicators, particularly for the delivery of long-acting antibiotic injections and specialist services in the 15–24 year age group. ConclusionsThe results suggest that timely injection and patient education are priorities for managing ARF and RHD, particularly focusing on child-to-adult transition care. What is known about the topic?The burden of rheumatic fever and RHD in some Aboriginal communities is among the highest documented globally. Guideline-adherent RHD prevention and management in primary health care (PHC) settings are critically important to reduce this burden. Continuous quality improvement (CQI) is a proven strategy to improve guideline adherence, using audit cycles and proactive engagement of PHC end users with their own data. Previously, such CQI strategies using a systems approach were shown to improve delivery of ARF and RHD care in six Aboriginal health services (three government and three community controlled). What does this paper add?This paper focuses on the variation across age groups in the quality of ARF and/or RHD care according to nine quality of care indicators across 63 PHC centres serving the Aboriginal population in the Northern Territory, Queensland, South Australia and Western Australia. These new findings provide insight into difference in quality of care by life stage, indicating particular areas for improvement of the management of ARF and RHD at the PHC level, and can act as a baseline for monitoring of care quality for ARF and RHD into the future. What are the implications for practitioners?Management plans and innovative strategies or systems for improving adherence need to be developed as a matter of urgency. PHC professionals need to closely monitor adherence to secondary prophylaxis at both the clinic and individual level. RHD priority status needs to be assigned and recorded as a tool to guide management. Systems strengthening needs to particularly target child-to-adult transition care. Practitioners are urged to keep a quick link to the RHDAustralia website to access resources and guidelines pertaining to ARF and RHD (https://www.rhdaustralia.org.au/arf-rhd-guideline, accessed 3 October 2019). CQI strategies can assist PHC centres to improve the care they provide to patients.

scholarly journals No-Reference Quality Assessment Method for Blurriness of SEM Micrographs with Multiple Texture

Scanning ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Hui Wang ◽  
Xiaojuan Hu ◽  
Hui Xu ◽  
Shiyin Li ◽  
Zhaolin Lu
Keyword(s):  
Quality Assessment ◽  
Local Variation ◽  
Assessment Method ◽  
Microscopy Imaging ◽  
Sem Micrographs ◽  
Quality Assessment Method ◽  
Gestalt Perception ◽  
Reference Quality ◽  
Selection Of

Scanning electron microscopy (SEM) plays an important role in the intuitive understanding of microstructures because it can provide ultrahigh magnification. Tens or hundreds of images are regularly generated and saved during a typical microscopy imaging process. Given the subjectivity of a microscopist’s focusing operation, blurriness is an important distortion that debases the quality of micrographs. The selection of high-quality micrographs using subjective methods is expensive and time-consuming. This study proposes a new no-reference quality assessment method for evaluating the blurriness of SEM micrographs. The human visual system is more sensitive to the distortions of cartoon components than to those of redundant textured components according to the Gestalt perception psychology and the entropy masking property. Micrographs are initially decomposed into cartoon and textured components. Then, the spectral and spatial sharpness maps of the cartoon components are extracted. One metric is calculated by combining the spatial and spectral sharpness maps of the cartoon components. The other metric is calculated on the basis of the edge of the maximum local variation map of the cartoon components. Finally, the two metrics are combined as the final metric. The objective scores generated using this method exhibit high correlation and consistency with the subjective scores.

Mechanisms Controlling Dormancy in the Arid Zone Grass Aristida contorta. II. Anatomy of the Hull

1974 ◽  
Vol 22 (4) ◽  
pp. 647 ◽  
Author(s):  
JJ Mott ◽  
PW Tynan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Gas Permeability ◽  
Arid Zone ◽  
Light And Electron Microscopy ◽  
Anatomical Change ◽  
Definitive Statement ◽  
Scanning Electron

The anatomy of the hull directly over the embryo was examined by light and electron microscopy in long-term dormant and non-dormant grains of A. contorta. A lipid-containing layer was noted, covering the surface of the inner epidermis of the hull, and examination by scanning electron microscopy showed that although the layer was intact in all dormant grain examined, it was fractured in non-dormant grain. A definitive statement on the function of these cracks is not possible, but they appear to be an anatomical change leading to increased gas permeability of the hull of non-dormant grains.

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