The immense nanotechnology advances in other industries provided opportunities to rapidly develop various applications of nanoparticles in the oil and gas industry. In particular, nanoparticle has shown its capability to improve the emulsion stability by generating so-called Pickering emulsion, which is expected to improve EOR processes with better conformance control. Recent studies showed a significant synergy between nanoparticles and very low concentration of surfactant, in generating highly stable emulsions. This study's focus is to exploit the synergy's benefit in employing such emulsions for improved mobility control, especially under high-salinity conditions.
Hydrophilic silica nanoparticles were employed to quantify the synergy of nanoparticle and surfactant in oil-in-brine emulsion formation. The nanoparticle and/or the selected surfactant in aqueous phase and decane were co-injected into a sandpack column to generate oil-in-brine emulsions. Four different surfactants (cationic, nonionic, zwitterionic, and anionic) were examined, and the emulsion stability was analyzed using microscope and rheometer.
Strong and stable emulsions were successfully generated in the combinations of either cationic or nonionic surfactant with nanoparticles, while the nanoparticles and the surfactant by themselves were unable to generate stable emulsions. The synergy was most significant with the cationic surfactant, while the anionic surfactant was least effective, indicating the electrostatic interactions with surfactant and liquid/liquid interface as a decisive factor. With the zwitterionic surfactant, the synergy effect was not as great as the cationic surfactant. The synergy was greater with the nonionic surfactant than the zwitterionic surfactant, implying that the surfactant adsorption at oil-brine interface can be increased by hydrogen bonding between surfactant and nanoparticle when the electrostatic repulsion is no longer effective.
In generating highly stable emulsions for improved control for adverse-mobility waterflooding in harsh-condition reservoirs, we show a procedure to find the optimum choice of surfactant and its concentration to effectively and efficiently generate the nanoparticle-stabilized emulsion exploiting their synergy. The findings in this study propose a way to maximize the beneficial use of nanoparticle-stabilized emulsions for EOR at minimum cost for nanoparticle and surfactant
The design, fabrication and calibration of a new thrust stand for conducting thrust andaeroacoustic measurements concurrently in a fully anechoic chamber is discussed. The new thrust stand employs the scale-force measurement technique and is designed to accommodate multi-stream nozzles (core and bypass flow streams). Each stream has a dedicated helium air mixture system thereby permitting a multitude of test conditions. The methodology for designing the thrust stand is described and uses a notch type flexure which demonstrates high repeatability over extended thrust ranges. Calibration is performed with elevated pressure inside the plenum to characterize the effect of increased pressure on the flexure performance. A further qualification of the thrust measurement accuracy is conducted using a small arsenal of nozzles comprising method of characteristics contours. Surveys of the far-field pressure are then conducted during various operating points along the startup curve of a Mach 1.71 rectangular supersonic nozzle.
CO2/water foams are of interest for mobility control in CO2 EOR and as energized fracture fluids, or hybrid processes that combine aspects of both processes. In fracturing applications, it would be desirable to lower the water level as much as possible to minimize the production of wastewater and formation damage. It is challenging to stabilize ultra dry foams with extremely high internal phase gas fraction given the high capillary pressure and the rapid drainage rate of the lamellae between the gas bubbles. However, we demonstrate that these ultra dry CO2-in-water foams may be stabilized with surfactants that form viscoelastic wormlike micelles in the aqueous phase. These wormlike micelles are formed by tuning the surfactant packing parameter with electrolytes or a second oppositely-charged surfactant to stabilize ultradry CO2-in-water foams with foam qualities as high as 0.98 and apparent viscosities more than 100 cP up to 90 °C. Applicability of these foams for improved oil recovery is evaluated by running multiphase flow injection simulations in a case-study oil reservoir.
We present biodegradable gold nanoparticles with plasmon resonances in the NIR region that can provide a crucial link between the enormous potential of metal nanoparticles for cancer imaging and therapy and translation into clinical practice.