Browsing by Author "Puerto, Maura C."

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    Recyclable amine-functionalized magnetic nanoparticles for efficient demulsification of crude oil-in-water emulsions
    (Royal Society of Chemistry, 2018) Wang, Qing; Puerto, Maura C.; Warudkar, Sumedh; Buehler, Jack; Biswal, Sibani L.
    Produced water from the oil and gas industry often contains stable crude oil-in-water emulsions that are typically difficult to treat with conventional separation methods. Amine-functionalized nanoparticles have demonstrated effective destabilization of crude oil-in-water emulsions by associating with natural surfactants present at the oilﾖwater interface leading to separation of oil from water under an external magnetic field. Effects of magnetic demulsifier concentration, reaction time and initial oil content of emulsion on the demulsification efficiency were investigated. The demulsification efficiency of emulsions can reach as high as 99.7% by the magnetic demulsifier. Our findings characterize the demulsification process as a function of nanoparticle concentration and elucidate the governing interactions between NH2-MNPs and emulsion droplets. Another important feature of this magnetic demulsifier is its capability to be recovered by solvent-washing and reused for subsequent demulsification cycles. The recovered magnetic demulsifier was proven to be effective in demulsifying O/W emulsion for at least 6 cycles, revealing its recyclability. Demulsification of O/W emulsions with NH2-MNPs has great potential as an efficient strategy for oil removal from produced water.
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    Transport of Components and Phases in a Surfactant/Foam
    (2013-07-24) Lopez Salinas, Jose; Hirasaki, George J.; Miller, Clarence A.; Tomson, Mason B.; Biswal, Sibani Lisa; Puerto, Maura C.
    The transport of components and phases plays a fundamental role in the success of an EOR process. Because many reservoirs have harsh conditions of salinity, temperature and rock heterogeneity, which limit process options, a robust system with flexibility is required. Systematic experimental study of formulations capable to transport surfactant as foam at 94°C, formulated in sea water, is presented. It includes methodology to conduct core floods in sand packs using foaming surfactants and to develop “surfactant blend ratio- salinity ratio maps” using equilibrium phase behavior to determine favorable conditions for oil recovery in such floods. Mathematical model able to reproduce the foam strength behavior observed in sand packs with the formulations studied is presented. Visualization of oil recovery mechanism from matrix is realized using a model system of micro-channels surrounded by glass beads to mimic matrix and fractures respectively. The observations illustrate how components may distribute within the matrix, thereby releasing oil into the fractures. The use of chemicals to minimize adsorption is required when surfactant adsorption is important. The presence of anhydrite may limit the use of sodium carbonate to reduce adsorption of carbonates. A methodology is presented to estimate the amount, if any, of anhydrite present in the reservoir. The method is based on brine software analysis of produced water compositions and inductively coupled plasma (ICP) analysis of core samples. X-ray powder diffraction (XRD) was used to verify the mineralogy of the rock. X-ray photoelectron spectroscopy (XPS) was used to obtain surface composition for comparison with bulk composition of the rock. Adsorption of surfactants was measured using dynamic and static adsorption experiments. Determining the flow properties of the rock samples via tracer analysis permitted the simulation of the dynamic adsorption process using a mathematical model that considers the distribution of adsorbed materials in the three different regions of pore space. Using this method allows one to predict adsorption in a reservoir via simulation.