Browsing by Author "Zhao, Yue"

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    A New Kinetic Assay Method for Effective Scale Inhibitor Concentration Determination with Low Detection Limit
    (SPE, 2022) Dai, Zhaoyi; Ko, Saebom; Wang, Xin; Dai, Chong; Paudyal, Samridhdi; Zhao, Yue; Li, Wei; Leschied, Cianna; Yao, Xuanzhu; Lu, Yi-Tsung; Kan, Amy; Tomson, Mason
    Scale inhibitors are widely used for mineral scale control in various industries, including oil and gas productions, geothermal energy acquisitions, and heat exchanger scale control to mention a few. In most applications, these scale inhibitors are effective at substoichiometric concentrations (e.g., 1 mg/L or lower), and the optimization of these applications is based on the ability to accurately measure the effective inhibitor concentration at such low concentrations. For example, the continuous treatment injection rate, the squeeze treatment frequency, or the batch treatment schedule need to be optimized to ensure the minimum inhibitor concentration (MIC) is achieved during production. However, the non- or low-phosphorous polymeric scale inhibitor concentration determination is difficult using inductively coupled plasma (ICP)-optic emission spectroscopy/mass spectrometry or ion chromatography, especially at mg/L level concentrations due to their high detection limits. The recently developed hyamine method or high-pressure liquid chromatography (HPLC) method involves intensive labor and high costs. Furthermore, in the complex oilfield operational conditions, the presence of other chemicals (e.g., surfactants, biocides, and corrosion inhibitors), the potential degradation of scale inhibitors and the use of combination scale inhibitors require the measurement of effective scale inhibitor concentration, which cannot be accomplished by the traditional methods. In this study, a new kinetic assay method has been developed to determine the effective scale inhibitor concentration with limits of detection (LODs) less than or around 0.1 mg/L for most cases. This method uses a continuous stirring tank reactor (CSTR) apparatus and is developed based on the linear correlation between the effective inhibition concentration and the measured critical time when laser signal changes. The results show that the inhibitor concentrations of various non- or low-phosphorous polymeric scale inhibitors in synthetic field brine, laboratory solutions, and real oilfield brines can be accurately determined at mg/L level, or lower, with less than 10% error. The method is robust, accurate, and much less time- or labor-consuming than other existing methods especially for non- or low-phosphorous polymeric scale inhibitors.
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    Gypsum scale formation and inhibition kinetics with implications in membrane system
    (Elsevier, 2022) Dai, Zhaoyi; Zhao, Yue; Paudyal, Samridhdi; Wang, Xin; Dai, Chong; Ko, Saebom; Li, Wei; Kan, Amy T.; Tomson, Mason B.
    Water desalination using membrane technology is one of the main technologies to resolve water pollution and scarcity issues. In the membrane treatment process, mineral scale deposition and fouling is a severe challenge that can lead to filtration efficiency decrease, permeate quality compromise, and even membrane damage. Multiple methods have been developed to resolve this problem, such as scale inhibitor addition, product recovery ratio adjustment, periodic membrane surface flushing. The performance of these methods largely depends on the ability to accurately predict the kinetics of mineral scale deposition and fouling with or without inhibitors. Gypsum is one of the most common and troublesome inorganic mineral scales in membrane systems, however, no mechanistic model is available to accurately predict the induction time of gypsum crystallization and inhibition. In this study, a new gypsum crystallization and inhibition model based on the classical nucleation theory and a Langmuir type adsorption isotherm has been developed. Through this model, it is believed that gypsum nucleation may gradually transit from homogeneous to heterogeneous nucleation when the gypsum saturation index (SI) decreases. Such transition is represented by a gradual decrease of surface tension at smaller SI values. This model assumes that the adsorption of inhibitors onto the gypsum nucleus can increase the nucleus superficial surface tension and prolong the induction time. Using the new model, this study accurately predicted the gypsum crystallization induction times with or without nine commonly used scale inhibitors over wide ranges of temperature (25–90 °C), SI (0.04–0.96), and background NaCl concentration (0–6 mol/L). The fitted affinity constants between scale inhibitors and gypsum show a good correlation with those between the same inhibitors and barite, indicating a similar inhibition mechanism via adsorption. Furthermore, by incorporating this model with the two-phase mineral deposition model our group developed previously, this study accurately predicts the gypsum deposition time on the membrane material surfaces reported in the literature. We believe that the model developed in this study can not only accurately predict the gypsum crystallization induction time with or without scale inhibitors, elucidate the gypsum crystallization and inhibition mechanisms, but also optimize the mineral scale control in the membrane filtration system.
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    Kinetics of BaSO4-BaxSr1-xSO4-SrSO4 mineral crystallization: Prediction and control
    (2021-09-29) Zhao, Yue; Tomson, Mason
    Mineral crystallization is ubiquitous in various industrial processes. Among all the mineral scales, sulfate minerals, such as barite (BaSO4) and celestite (SrSO4), are commonly discovered during the production. Due to the wide coexistence of Ba2+ and Sr2+, BaxSr1-xSO4 solid solution is also frequently discovered in industrial processes. Scale inhibitors have been widely used as one of the most efficient methods for sulfate scale control. In this work, a systematic study of the crystallization and inhibition kinetics of barite-BaxSr1-xSO4-celestite mineral systems are conducted to have a better knowledge of sulfate scale formation prediction and control. The celestite crystallization and inhibition kinetics is experimentally studied by measuring the induction time of celestite under wide ranges of celestite saturation index (SI = 0.7 – 1.9), temperature (T = 25 – 90 ℃) without and with inhibitors. Based on the experimental results and literature data, a semiempirical and a mechanistic celestite crystallization and inhibition model have been developed based upon readily available parameters such as celestite SI (or other brine compositions) and T. The celestite crystallization and inhibition mechanistic model is developed based on classical nucleation theory (CNT) and polynuclear growth mechanism. The inhibition mechanism behind this model is assumed to be Langmuir type inhibitor adsorption onto nuclei surface and the change of the interfacial energy between the nuclei and the aqueous phase due to the inhibitor adsorption. Good agreements between the experimental results and calculated results with these two models can be found. Both the semiempirical model and the mechanistic model can be applied to predict the minimum inhibitor concentration (MIC) and provide a better celestite scale management strategy. The mechanistic model could also be widely adopted in other disciplines, such as elucidation of the inhibition mechanisms or new scale inhibitors design guidance. The mechanistic model developed is also applied to barite crystallization and inhibition kinetics predictions based on the barite induction time measurements at the conditions of barite SI 0.81 – 3.26 and T 4 to 90 °C with or without inhibitors. The induction times predicted with this newly developed model matches well with the experimental results. The barite mechanistic model could help us further understand the mechanisms of the scale inhibition. The effects of other commonly seen species, silica and the related divalent ion-silicate (Ca, Mg-silicate and Fe(II)-silicate), on barite inhibition were also investigated. It can be found that Fe2+ ions shows detrimental impacts on the phosphonate inhibitor; while the formation of Fe(II)-silicate complex/interactions helps partially recover the detrimental impacts of Fe2+ on phosphonate inhibitors. The studies about barite in this work could help provide a more accurate barite scale management strategy during productions. The induction times of BaxSr1-xSO4 solid solution were also measured without or with scale inhibitors at the conditions of barite saturation index (SI) from 1.5 to 1.8, temperature (T) from 40 to 70 ℃, [Sr2+]/[Ba2+] ratios from 0 to 15 with celestite SI < 0. The results showed that the BaxSr1-xSO4 solid solution's induction time increases with [Sr2+]/[Ba2+] ratio at a fixed experimental condition. Based on the experimental results, a semiempirical Ba-Sr-SO4 solid solution crystallization and inhibition model is firstly developed with good predictions results. Then, to have a better understanding of the mechanisms of BaxSr1-xSO4 solid solution crystallization and inhibition, the non-equilibrium BaxSr1-xSO4 solid solution composition empirical model is developed with the composition measurement results at the conditions of SIbarite from 0.9 to 1.5, [Sr2+]/[Ba2+] molality ratio from 0.33 to 30, temperature (T) from 50 to 90 ℃ and ionic strength (IS) from 0.01 M to 3 M as NaCl. With the composition of the BaxSr1-xSO4 solid solution predicted at a certain experimental condition, the mechanistic model developed for celestite and barite can be extrapolated to BaxSr1-xSO4 solid solution. The properties of the BaxSr1-xSO4 solid solution in the mechanistic model can be calculated with the properties of the pure end member minerals BaSO4 and SrSO4 determined. The BaxSr1-xSO4 solid solution induction time measurement results are used to evaluate the mechanistic model developed. The good agreements between the measured induction time and the calculated induction time with the mechanistic model can be found. The semiempirical and the mechanistic BaxSr1-xSO4 solid solution model proposed will significantly improve the sulfate scale management strategy when Ba2+ and Sr2+ coexist in the oilfield. Furthermore, the mechanistic BaxSr1-xSO4 solid solution model has the potential to be applied to the crystallization and inhibition kinetics predictions of BaxSr1-xSO4 solid solution with any composition or other binary mineral systems due to the sound theoretical basis behind the model.
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    Non-equilibrium BaxSr1-xSO4 solid solution compositions at elevated Sr2+ concentration, ionic strength, and temperature
    (Elsevier, 2022) Zhao, Yue; Dai, Zhaoyi; Wang, Xin; Dai, Chong; Paudyal, Samridhdi; Ko, Saebom; Li, Wei; Kan, Amy T.; Tomson, Mason
    The BaxSr1-xSO4 solid solution is ubiquitously present in both geological and industrial processes, where they mostly form under non-equilibrium conditions. Compared with those formed under equilibrium conditions, the BaxSr1-xSO4 solid solution formed at non-equilibrium condition has significantly higher Sr incorporation at the same aqueous phase compositions. The solid composition of BaxSr1-xSO4 formed at non-equilibrium condition is critical for the study of chemical palaeoceanography as well as the solid solution nucleation and growth kinetics. However, few studies have been conducted to investigate the composition of the BaxSr1-xSO4 solid solution when it precipitates at non-equilibrium conditions. In this study, the distribution coefficient of Ba2+ and Sr2+ between the BaxSr1-xSO4 solid solution and the aqueous phases (KD,Sr-Barite) at non-equilibrium conditions was studied with barite saturation index (SIbarite) from 0.9 to 1.5, [Sr2+]/[Ba2+] molality ratio from 0.33 to 30, temperature (T) from 50 to 90 °C and ionic strength (IS) from 0.01 M to 3 M as NaCl, with celestite being undersaturated. The composition of the BaxSr1-xSO4 solid solution formed at non-equilibrium conditions can then be calculated from the KD,Sr-Barite values. The results show that the KD,Sr-Barite value decreases with the increase of aqueous Sr2+ concentration at fixed SIbarite and T conditions. The IS effect on the KD,Sr-Barite value is small. Based on the experimental results, a new empirical model is developed to accurately predict the measured compositions of BaxSr1-xSO4 solid solution at non-equilibrium conditions under a wide T and IS conditions as follows (the plot of the predicted log10KD,Sr-Barite versus the measured log10KD,Sr-Barite with : Several theoretical models have also been compared against the experimental data. The birth and spread crystal growth model (B + S model) could accurately predict the solid composition of BaxSr1-xSO4 at higher barite SI and/or higher T conditions (barite SI = 1.5 at 70 °C and barite SI = 1.2–1.5 at 90 °C with [Sr2+]/[Ba2+] = 0.33–10). However, the B + S model predictions show larger deviations at lower SI and/or lower T conditions (barite SI = 0.9 and 1.2 at 50 °C and barite SI = 0.9 at 70 °C with [Sr2+]/[Ba2+] = 0.33–10 in this study). For other theoretical models, such as the CNT model and the BCF model, the predicted solid compositions of BaxSr1-xSO4 are significantly higher than the measured results. This quantitative study of the BaxSr1-xSO4 solid solution compositions could help reconstruct oceanic physical conditions and chemistry. It also establishes a solid foundation to further investigate the kinetics of the BaxSr1-xSO4 solid solution formation during non-equilibrium geological and industrial processes.
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    Prediction Models of Barite Crystallization and Inhibition Kinetics: Applications for Oil and Gas Industry
    (MDPI, 2021) Dai, Chong; Dai, Zhaoyi; Zhao, Yue; Wang, Xin; Paudyal, Samiridhdi; Ko, Saebom; Kan, Amy T.; Tomson, Mason B.
    Barite is one of the most common mineral scales in the oilfield and its formation can sequester toxic strontium (Sr) and radium (Ra). Various scale inhibitors are widely used to inhibit its formation. The inhibition efficiencies of 18 common inhibitors were tested using an improved kinetic turbidity method over broad oil and gas production conditions. A theoretical and a semi-empirical barite crystallization and inhibition model were developed for the 18 most used scale inhibitors. Both models can work under a broad range of production conditions and are carefully reviewed against all available experimental data. These models have shown wide applications in industrial operations, field testing, and laboratory testing. Using the new models and testing method, a novel fast inhibitor performance testing method was proposed and validated. Furthermore, the barite crystallization and inhibition models also work well to predict the inhibition performance of mixed inhibitors. This study not only advanced barite scale inhibition in an efficiency and low-cost way during oil and gas production, but also provided new insights on understanding the fate and transport of toxic Sr and Ra.