A high temperature retarder HTR-300L applied in long cementing interval

With regard to slow development or super retarding happening at the top of cement slurry in deep and ultra-deep wells with long cementing intervals, a new type of retarder HTR-300L was developed and its properties were evaluated. Thickening property tests at different temperatures for slurries with HTR-300L and IR, DSC and TG analysis show that: HTR-300L has good temperature-resistance performance and stable molecular structure. It can be used at the bottom hole circulating temperature of 70 to 200 °C. The thickening time of the slurry can be regulated effectively by adjusting the additive amount of HTR-300L. Thickening property tests for slurries with different salt contents show that HTR-300L has good salt-resistance performance and can be used in salty cement slurry. Strength development, thickening time, fluidity and API filtration of slurries with HTR-300L were studied at different top-bottom temperature differences. The results show that: The slurry with HTR-300L develops well in strength at large temperature difference and can overcome super retarding of the top of the slurry in long cementing interval. HTR-300L is applicable for large temperature range and can be used for slurries with both high and low densities. The slurry with HTR-300L has good overall performance, easy to regulate and control, and can satisfy cementing requirements for long cementing interval. Key words: retarder, cementing, long cementing interval, slurry, thickening tim

Magneto-optical and luminescent properties of Tb doped Ge-B-X (X=Ga/La) glasses

International audienceExtensive efforts have been devoted to magneto-optical (MO) glass, owing to its remarkable potential in modern optics, encompassing diverse applications such as optical isolation, modulation, and sensing. Although the Tb ions doped glass has good MO properties, high concentrations of Tb ions tend to cluster, resulting in glass crystallization. To further improve the performance of MO glass, we must improve the solubility of Tb ions and inhibit the oxidation of paramagnetic Tb3+ to diamagnetic Tb4+ by adjusting the glass composition. In this work, we conducted a comparative study on GeO2-B2O3-X2O3 glasses doped with Tb2O3 (TGBX, where X represents Ga or La) to elucidate the effects of Ga2O3 and La2O3 on glass properties. Our findings reveal that TGBG glasses exhibit superior MO performance compared to TGBL glasses. Notably, the Verdet constant of TGBG glass with 45 mol.% Tb2O3 at 650 nm reaches 105 rad/(T·m). Although TGBL glass exhibits a lower Verdet constant, its higher glass network connectivity and higher concentration of Tb3+ ions suggest its potential for preparing larger-sized glasses with an increased Tb3+ molar ratio

Valence state regulation of Terbium in all-inorganic amorphous solid for magnetic field sensing

International audienceTb3+ doped glass has emerged as a promising magneto-optical (MO) material due to the high transparency, high Verdet constant, as well as easy processing characteristics. Although Tb3+ possesses the highest paramagnetic susceptibility, is usually impacted by inactive Tb4+. Regulating the valence state and quantitatively calculating the effective concentration of the mixed-valence metal elements doped in all-inorganic amorphous matrix is quite difficult. Here, a modified model for quantitatively calculating the effective concentration of Tb3+ was proposed and the oxidation of Tb3+ to Tb4+ was inhibited through controlling the surrounding electron accepter or diminishing the charge transfer activity in all-inorganic amorphous matrix. A high effective concentration of Tb3+ among all valence Tb ions was achieved. Based on it, the assembled magnetic field sensor showed a high Verdet constant of 68.82 rad/(T·m) at 650 nm and a sensing sensitivity of 0.17 rad/T. This work provides insights of ionic valence state regulation to rationally improve the properties of all-inorganic amorphous solid for MO applications, such as magnetic field sensing

High Verdet Constant Glass for Magnetic Field Sensors

Due to the high transparency, high Verdet constant, as well as easy processing properties, rare-earth ion-doped glasses have demonstrated great potential in magneto-optical (MO) applications. However, the variation in the valence state of rare-earth ions (Tb3+ to Tb4+) resulted in the decreased effective concentration of the paramagnetic ions and thus degraded MO performance. Here, a strategy was proposed to inhibit the oxidation of Tb3+ into Tb4+ as well as improve the thermal stability by tuning the optical basicity of glass networks. Moreover, the depolymerization of the glass network was modulated to accommodate more Tb ions. Thus, a record high effective concentration (14.19 × 1021/cm3) of Tb ions in glass was achieved, generating a high Verdet constant of 113 rad/(T·m) at 650 nm. Lastly, the first application of MO glass for magnetic field sensors was demonstrated, achieving a sensitivity of 0.139 rad/T. We hope our work provides guidance for the fabrication of MO glass with high performance and thermal stability and could push MO glass one step further for magnetic sensing applications

All-Inorganic Glass Scintillators: Scintillation Mechanism, Materials, and Applications

International audienceGlass scintillators have several benefits compared to the currently used single or polycrystalline scintillators, including non-hygroscopicity, mechanical ruggedness, ease of producing customizable shapes, and low-cost synthesis. The combination of the inert glass matrix and the embedded highly scintillating center render them significant materials for medical imaging and therapy, non-destructive probing, nuclear monitoring, and high-energy physics. Recently, great progress has been made in exploring new kinds of glass scintillator materials, improving imaging resolution for radiation detection, and developing an enormous range of commercial products. However, the majority of efforts have been devoted to the variation of materials, while rationally designing this new family of scintillators toward expected properties and applications is still lacking. In this review, the focus is specifically on advances in glass scintillators, including the scintillation fundamentals, material designing rule, and current application status, as well as future challenges and future directions