Browsing by Author "Zhang, Leilei"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Application of magnetic nanoparticles as demulsifiers for surfactant-enhanced oil recovery(Wiley, 2023) Zhang, Leilei; Bai, Chutian; Zhang, Zhuqing; Wang, Xinglin; Nguyen, Thao Vy; Vavra, Eric; Puerto, Maura; Hirasaki, George J.; Biswal, Sibani LisaNonionic surfactants are increasingly being applied in oil recovery processes due to their stability and low adsorption onto mineral surfaces. However, these surfactants lead to the production of emulsified oil that is extremely stable and difficult to separate by conventional methods. This research characterizes the stability of crude oil mixed with a nonionic surfactant, L24–22, in a brine solution. When subjected to gravity separation, a middle oil-rich and bottom water-rich emulsion are generated for various water–oil ratios. Thermal treatments can effectively break oil-rich emulsions, but the bottom water layer remains contaminated with micron-sized crude oil droplets. A magnetic nanoparticle treatment is shown to demulsify the crude oil emulsions, dropping the total organic carbon (TOC) in the water layer from 1470 to 30 ppm.Item Characterizing the Influence of Organic Carboxylic Acids and Inorganic Silica Impurities on the Surface Charge of Natural Carbonates Using an Extended Surface Complexation Model(American Chemical Society, 2019) Song, Jin; Rezaee, Sara; Zhang, Leilei; Zhang, Zhuqing; Puerto, Maura; Wani, Omar B.; Vargas, Francisco; Alhassan, Saeed; Biswal, Sibani L.; Hirasaki, George J.In this work, we developed an extended surface complexation model (SCM) that successfully fits all tested ζ-potential data (63 in total) of synthetic calcite and three natural carbonates (Iceland spar, Indiana limestone, “SME” rock from a Middle East field) in brines with divalent ions in a wide range of ionic strengths (0.001–0.5 M). To develop this extended model, our previous reported SCM is first optimized by incorporating the ζ-potential of synthetic calcite in a wide range of ionic strength (0.001–0.5 M) along with previously published data for parameter refitting. The model is then applied to predict the surface charge of synthetic calcite in concentrated solutions up to 5 M NaCl to reveal the role of high salinity in calcite wettability. Eventually, the model is extended to fit the ζ-potential of natural carbonates by adding surface reactions for impurities such as silica and organic-based carboxylic acids. The coverage of the organic impurities is found to be essential for explaining why the ζ-potential of natural carbonates is more negative compared to that of synthetic calcite. Naphthenic acid (assumed to have one carboxylic group) and humic/fulvic acid (assumed to have six carboxylic groups) are tested in the model calculation as possible sources of surface impurities to demonstrate the effect of the number of carboxylic groups in the acid molecule. Finally, the effect of a humic acid pretreatment on the ζ-potential of synthetic calcite is investigated experimentally to verify the assumption that absorbed organic impurities on the calcite surface contribute significantly to a more negatively charged natural carbonate surface when compared to that of pure calcite surfaces.Item Evaluating the Transport Behavior of CO2ﾠFoam in the Presence of Crude Oil under High-Temperature and High-Salinity Conditions for Carbonate Reservoirs(American Chemical Society, 2019) Jian, Guoqing; Zhang, Leilei; Da, Chang; Puerto, Maura; Johnston, Keith P.; Biswal, Sibani L.; Hirasaki, George J.An amine-based surfactant, Duomeen TTM, was evaluated for foam flooding in carbonate rock at high temperature (120 °C), high salinity (22% total dissolved solids), and CO2–oil miscible conditions. We demonstrate enhanced oil recovery by utilizing CO2 foam under miscible conditions in the presence of crude oil. The foam was generated in situ by both co-injection and surfactant alternating gas injection modes. Foam transport and propagation were characterized as a function of the foam quality, shear rate, permeability, surfactant concentration, and method of injection. Finally, we utilize the experimental results to obtain the parameters for the STARS foam model by optimizing multiple variables related to the dry out, shear thinning, and surfactant concentration effects on foam transport. Enhanced oil recovery utilizing CO2 foam under miscible conditions in the presence of SMY crude oil was able to decrease oil saturation to 3.0%. It was also determined that significantly more injected pore volumes were required for the foam to reach the steady state in the presence of SMY crude oil. A foam simulation process in a heterogeneous reservoir is conducted applying the parameters obtained. The TTM CO2 foam generated significantly reduces the mobility of CO2 in the high permeability layers, which results in an improved swept volume in the low permeability zone that significantly improves oil recovery when epoil = 1 and fmoil = 0.5. Oil saturation parameters play important roles in the effectiveness of CO2 foam: large epoil and small fmoil will reduce the efficiency for TTM CO2 foam.Item Foam EOR for Carbonate Reservoirs: from Lab Evaluation to Pilot Field Test(2020-04-23) Zhang, Leilei; Biswal, Sibani L.; Hirasaki, George J.Enhanced oil recovery (EOR) techniques have changed how we recover oil more efficiently. The injection of surfactant foamed gas can mitigate the poor sweep efficiency caused by reservoir heterogeneity, density differential, and viscous fingering effects. How to tune foam strength, foam rheology, and foam collapse properties depends highly on reservoir conditions. This dissertation provides comprehensive study of foam transport design in porous media including formulation screening, lab scale evaluation, pilot field test, and produced emulsion treatment. These studies provide a full life cycle analysis for EOR foam. Low surfactant adsorption is required to control the cost of successful foam applications. In carbonate reservoirs, cationic surfactants and nonionic surfactants usually have low adsorption compare to more commonly used anionic surfactants. The studied switchable cationic surfactant (TTM) adsorption is low on pure carbonate surface, but relatively high on natural carbonate surface due to the presence of siliceous minerals. The diamine surfactant adsorption is dominated by electrostatic attraction. Lower adsorption can be achieved by modifying the electrostatic interaction by: (a) decreasing the solution pH, (b) adding ions for charge screening (effectiveness: monovalentItem Two-Step Adsorption of a Switchable Tertiary Amine Surfactant Measured Using a Quartz Crystal Microbalance with Dissipation(American Chemical Society, 2019) Chen, Yi-Lin; Zhang, Leilei; Song, Jin; Jian, Guoqing; Hirasaki, George; Johnston, Keith; Biswal, Sibani LisaThe adsorption of a switchable cationic surfactant, N,N,N′-trimethyl-N′-tallow-1,3-diaminopropane (DTTM, Duomeen TTM), at the silica/aqueous solution interface is characterized using a quartz crystal microbalance with dissipation (QCM-D). The adsorption isotherms reveal that changes in the solution pH or salinity affect surfactant adsorption in competing ways. In particular, the combination of the degree of protonation of the surfactant and electrostatic interactions is responsible for surfactant adsorption. The kinetics of adsorption is carefully measured using the real-time measurement of a QCM-D, allowing us to fit the experimental data with analytical models. At pH values of 3 and 5, where the DTTM is protonated, DTTM exhibits two-step adsorption. This is representative of a fast step in which the surfactant molecules are adsorbed with head-groups orientated toward the surface, followed by a slower second step corresponding to formation of interfacial surfactant aggregates on the silica surface.