Measuring Ultrasonic Characterisation to Determine the Impact of Toc and the Stress Field on Shale Gas Anisotropy

While the majority of natural gas is produced from conventional sources, there is significant growth from unconventional sources, including shale-gas reservoirs. To produce gas economically, candidate shale typically requires a range of characteristics, including a relatively high total organic carbon (TOC) content, and it must be gas mature. Mechanical and dynamic elastic properties are also important shale characteristics that are not well understood as there have been a limited number of investigations of well-preserved samples. In this study, the elastic properties of shale samples are determined by measuring wave velocities. Arrays of ultrasonic transducers are used to measure five independent wave velocities, which are used to calculate the elastic properties of the shale. The results indicated that for the shale examined in this research, P- and S-wave velocities vary depending on the isotropic stress conditions with respect to the fabric and TOC content. It was shown that the isotropic stress significantly impacts velocity. In addition, S-wave anisotropy was significantly affected by increasing stress anisotropy. Stress orientation, with respect to fabric orientation, was found to be an important influence on the degree of anisotropy of the dynamic elastic properties in the shale. Furthermore, the relationship between acoustic impedance (AI) and TOC was established for all the samples

Measuring Elastic Properties to determine the influence of TOC on Synthetic Shale Samples

This paper describes the factors that control elastic properties of organic shale, which is crucial for exploration and successful gas production from unconventional reservoirs. Mechanical and dynamic elastic properties are main shale characteristics that are not yet well understood as there have been a limited number of investigations involving organic rich shale samples. Synthetic shale core samples whose clay mineralogy, non-clay mineral content and Total Organic Carbon (TOC) content are known can be used to study variations of elastic parameters in a controlled experimental environment including in-situ stress conditions. More than 20 synthetic shale samples were created for our investigations under reservoir stress conditions with different mineral composition and TOC percentage. Ultrasonic transducers were used to measure body wave velocities, which were then used to calculate the elastic properties of different shale samples. The results demonstrate that P- and S-wave velocities vary with changing TOC under isotropic stress conditions. It is shown that the velocities of P-and S-waves are inversely proportional to TOC content. In addition, the increase in the TOC produced a decrease in density from approximately 2.4 g/cc to 2.15 g/cc and increase in porosity from approximately 16% to 20%

Shale elastic property relationships as a function of total organic carbon content using synthetic samples

Understanding the main factors that control elastic properties of organic shale is crucial for exploration and successful gas production from unconventional reservoirs. Mechanical and dynamic elastic properties are important shale characteristics that are not yet well understood as there have been a limited number of investigations involving organic rich shale samples. Synthetic shale core samples whose clay mineralogy, non-clay mineral content and Total Organic Carbon (TOC) content are known can be used to study variations of elastic parameters in a controlled experimental environment including in-situ stress conditions. A total of 17 synthetic shale samples with different mineral composition and TOC percentage were created for our investigations under isotropic stressed and unstressed conditions. Ultrasonic transducers were used to measure body wave velocities, which were then used to calculate the elastic properties of different shale samples. The results demonstrate that P- and S-wave velocities vary under isotropic stress conditions with respect to the TOC and clay mineral content. It is shown that isotropic stress significantly impacts velocity and the velocities of P- and S-waves are inversely proportional to TOC content. In addition, the increase in the TOC content reduced density and increased shale porosity. This study presents equations that allow us to estimate shale TOC content using compressional and shear wave velocities and density

Shale elastic property relationships as a function of TOC content using synthetic samples

Copyright 2016, Unconventional Resources Technology Conference (URTeC). Understanding the main factors that control elastic properties of organic shale is crucial for exploration and successful gas production from unconventional reservoirs. Mechanical and dynamic elastic properties are important shale characteristics that are not yet well understood as there have been a limited number of investigations involving organic rich shale samples. Synthetic shale core samples whose clay mineralogy, non-clay mineral content and Total Organic Carbon (TOC) content are known can be used to study variations of elastic parameters in a controlled experimental environment including in-situ stress conditions. A total of 17 synthetic shale samples with different mineral composition and TOC percentage were created for our investigations under isotropic stressed and unstressed conditions. Ultrasonic transducers were used to measure body wave velocities, which were then used to calculate the elastic properties of different shale samples. The results demonstrate that P- and S-wave velocities vary under isotropic stress conditions with respect to the TOC and clay mineral content. It is shown that isotropic stress significantly impacts velocity and the velocities of P- and S-waves are inversely proportional to TOC content. In addition, the increase in the TOC content reduced density and increased shale porosity. This study presents equations that allow us to estimate shale TOC content using compressional and shear wave velocities and density. This paper has been published in Journal of Petroleum Science and Engineering (Altowairqi et al., 2015)

The effect of annealing conditions: temperature, time, ramping rate and atmosphere on nanocrystal Cu2ZnSnS4 (CZTS) thin film solar cell properties

Cu2ZnSnS4 (CZTS) nanoparticles were fabricated successfully using the hot injection method; CZTS films were deposited by spin coating of nanocrystal ink. The aim of this work is to study the effect of annealing parameters: temperature, time, ramping rate and atmosphere on CZTS thin film structure and optical properties. XRD, Raman Spectroscopy, SEM, EDX mapping are used to analyse the films and they demonstrate the increase in quality and improvement in the crystallinity of CZTS and the homogeneity of elements which is one of the important factors for CZTS thin film solar cells. The crystallinity, structure and chemical composition of CZTS thin films increased and improved under annealing in H2S+N2 atmosphere which demonstrated that annealing at 500 oC for 1 h with a ramping rate of 10 oC/min under H2S+N2 atmosphere is a suitable condition for the fabrication of CZTS thin films used in solar cell devices

Green Assessment of Chromatographic Methods Used for the Analysis of Four Methamphetamine Combinations with Commonly Abused Drugs

Numerous agents with anxiolytic or stimulant effects have the potential to be overused, and their misuse is associated with serious side effects. In Saudi Arabia, the estimated percentage of Saudis who abuse drugs is around 7–8% and the age range is 12–22 years. Methamphetamine, captagon, tramadol, heroin, and cannabis/cannabinoids have been proven to be the most commonly abused drugs in Saudi Arabia, with methamphetamine being at the top of the list. The present study focuses on the chromatographic analytical methods used for the analysis of methamphetamine in combination with commonly abused drugs, aiming to point out the greenest among them. These mixtures have been chosen as they are analyzed periodically and frequently in criminal evidence and forensic medicine. Therefore, the chances of hazards for analysts and the environment are high if the mixtures are not handled appropriately. This study aims to compare 23 chromatographic methods used for the analysis of methamphetamine mixtures in four major combinations, and to assess their greenness by using three greenness assessment tools, namely, NEMI, ESA and AGREE, to recommend the greenest analytical method. The NEMI results were proven to have low discriminating abilities and, accordingly, the comparisons are based on ESA and AGREE scores. The analysis results show that the safest methods with the most eco-friendly results (based on ESA and AGREE) are the GC-MS method proposed by Mohammed et al. to analyze methamphetamine and captagon mixtures (ESA = 79 and AGREE = 0.57), the UHPLC–MS-MS method proposed by Busardò et al. to analyze methamphetamine and cannabis/cannabinoid mixtures (ESA = 78 and AGREE = 0.57), the LC-MS method proposed by Herrin et al. to analyze methamphetamine and tramadol mixtures (ESA = 81 and AGREE = 0.56), and the LC-MS method proposed by Postigo-et al to analyze methamphetamine and heroin mixtures (ESA = 76 and AGREE = 0.58)

Green Assessment of Chromatographic Methods Used for the Analysis of Four Methamphetamine Combinations with Commonly Abused Drugs

Numerous agents with anxiolytic or stimulant effects have the potential to be overused, and their misuse is associated with serious side effects. In Saudi Arabia, the estimated percentage of Saudis who abuse drugs is around 7–8% and the age range is 12–22 years. Methamphetamine, captagon, tramadol, heroin, and cannabis/cannabinoids have been proven to be the most commonly abused drugs in Saudi Arabia, with methamphetamine being at the top of the list. The present study focuses on the chromatographic analytical methods used for the analysis of methamphetamine in combination with commonly abused drugs, aiming to point out the greenest among them. These mixtures have been chosen as they are analyzed periodically and frequently in criminal evidence and forensic medicine. Therefore, the chances of hazards for analysts and the environment are high if the mixtures are not handled appropriately. This study aims to compare 23 chromatographic methods used for the analysis of methamphetamine mixtures in four major combinations, and to assess their greenness by using three greenness assessment tools, namely, NEMI, ESA and AGREE, to recommend the greenest analytical method. The NEMI results were proven to have low discriminating abilities and, accordingly, the comparisons are based on ESA and AGREE scores. The analysis results show that the safest methods with the most eco-friendly results (based on ESA and AGREE) are the GC-MS method proposed by Mohammed et al. to analyze methamphetamine and captagon mixtures (ESA = 79 and AGREE = 0.57), the UHPLC–MS-MS method proposed by Busardò et al. to analyze methamphetamine and cannabis/cannabinoid mixtures (ESA = 78 and AGREE = 0.57), the LC-MS method proposed by Herrin et al. to analyze methamphetamine and tramadol mixtures (ESA = 81 and AGREE = 0.56), and the LC-MS method proposed by Postigo-et al to analyze methamphetamine and heroin mixtures (ESA = 76 and AGREE = 0.58)

Study of Co-Doped K2Ti6O13 Lead-Free Ceramic for Positive Temperature Coefficient Thermistor Applications

Cobalt-doped potassium hexa-titanate (Cox:K2Ti6O13 (x = 0.05, 0.10, 0.15 mole%)) ceramics were synthesized by the solid-state reaction method. The XRD patterns confirmed single-phase development in a monoclinic symmetry of various samples, and they were used for different structural calculations of Cox:K2Ti6O13 ceramics. The dielectric constant, tanδ, electrical modulus, and ac conductivity of Co-doped K2Ti6O13 were studied in the temperature range of 100–500 °C. Anomalies were observed in graphs of the dielectric constant versus temperature, showing the transition phase in the studied samples. Dielectric peaks at transition temperature decreased with an increasing frequency, and the peaks shifted toward higher temperatures, illustrating the relaxation of the dielectric materials. The composition with x = 0.10 showed low dielectric loss and a higher dielectric constant and can be utilized for high-temperature dielectric material. Small doping of cobalt improved the ac conductivity of K2Ti6O13 ceramics due to the increase in the spin–phonon interaction and dominant electron hopping conduction; however, the conductivity diminished with substantial doping because of the contraction of the tunnel space and ambushing of conduction electrons. The uniqueness of this study is in the high dielectric optimization of lead-free ceramic Cox:K2Ti6O13 and the discovery of positive temperature coefficients of the resistivity of these ceramic samples

Study of Co-Doped K₂Ti₆O₁₃ Lead-Free Ceramic for Positive Temperature Coefficient Thermistor Applications

Cobalt-doped potassium hexa-titanate (Cox:K2Ti6O13 (x = 0.05, 0.10, 0.15 mole%)) ceramics were synthesized by the solid-state reaction method. The XRD patterns confirmed single-phase development in a monoclinic symmetry of various samples, and they were used for different structural calculations of Cox:K2Ti6O13 ceramics. The dielectric constant, tanδ, electrical modulus, and ac conductivity of Co-doped K2Ti6O13 were studied in the temperature range of 100–500 °C. Anomalies were observed in graphs of the dielectric constant versus temperature, showing the transition phase in the studied samples. Dielectric peaks at transition temperature decreased with an increasing frequency, and the peaks shifted toward higher temperatures, illustrating the relaxation of the dielectric materials. The composition with x = 0.10 showed low dielectric loss and a higher dielectric constant and can be utilized for high-temperature dielectric material. Small doping of cobalt improved the ac conductivity of K2Ti6O13 ceramics due to the increase in the spin–phonon interaction and dominant electron hopping conduction; however, the conductivity diminished with substantial doping because of the contraction of the tunnel space and ambushing of conduction electrons. The uniqueness of this study is in the high dielectric optimization of lead-free ceramic Cox:K2Ti6O13 and the discovery of positive temperature coefficients of the resistivity of these ceramic samples