Oil Bubble Research Articles

Experimental Simulation of the Zones Characteristics Considering Oily Bubble Behavior During in Situ Combustion

A linear combustion tube experiment with halfway fire extinguishing was utilized to reconstruct the combustion region distributions based on apparent characteristics of burnt oil-bearing quartz, temperature profile, and oil saturation field distribution between a gas injection well and a production well, etc. The gas composition and fluid composition in each region could be obtained. Following, a high-temperature-high-pressure visualization system was utilized to simulate experimentally the flue-gas flow in the crude oil. A flow characteristics simulation using such process parameters as system injected fluid composition and temperature condition based on the above test results of the combustion tube was conducted. The characteristics of each region were qualitatively described, the flow characteristics of the flue gas was visualized, and the oil bubble enhancement mechanism causing crude oil movement with flue gas was semiquantitatively determined. The results of the combustion tube simulation showed tha...

Open surface multifunctional droplet manipulation platform fabricated by micromilling

Superhydrophobic surfaces patterned with hydrophilic groove structures have promising applications in microfluidics. In this work, hydrophilic groove patterns with stable wettability were created directly on superhydrophobic Al surface by micromilling. Feasibility of applying diverse milled hydrophilic patterns, including dimples, ring grooves and reservoirs connected by winding channels in a variety of droplet manipulations, such as water/oil/air storage, water transport, etc. was tried out. Experimental results showed that the milled dimples and ring grooves on the superhydrophobic background can function as a multifunctional platform for storing micro-liter sized water, oil and gas bubbles; two milled reservoirs connected by a milled channel can serve as a open surface microfluidics to transport liquid using Laplace pressure difference. On the basis of the liquid transport between two reservoirs, more sophisticated liquid handling such as droplet separation and mixing were achieved by transporting liquid among multiple reservoirs. It is thus clear that the micromilling is a quite suitable approach to create complex hydrophilic groove structures on superhydrophobic background for applications to diverse interface-driven microfluidics.

Intraretinal Migration of Emulsified Silicone Oil: Association With Cystoid Macular Edema and Surgical Treatment

Purpose: The purpose of this article is to report the detailed stages of intraretinal silicone oil infiltration, and to describe a new surgical treatment for this condition. Methods: An observational case series is presented. Results: We report 2 patients who had undergone repair of complex diabetic retinal detachment and subsequently developed intraretinal migration of emulsified silicone oil, cystoid macular edema (CME), and lamellar macular hole (LMH). Surgical removal of the incarcerated oil bubbles rapidly restored foveal anatomy in both cases. Possible risk factors for intraretinal oil migration are discussed. Conclusions: Emulsified silicone oil droplets can penetrate the retina, resulting in CME and LMH. While severe CME in this setting is usually recalcitrant to pharmacotherapy, vitrectomy with expression of oil droplets may result in rapid and longstanding resolution.

Silicone Oil Droplets in Vitreous after Intravitreal Bevacizumab Injection

Intravitreal injection of Bevacizumab for various retinal vascular disorders has become the mainstay of treatment. The injection of Bevacizumab is usually dispensed through local pharmacies after formulating from a larger vial under sterile conditions. We report an interesting finding of silicone oil bubble in vitreal cavity after intravitreal Bevacizumab injection. This is attributed to the fact that the syringes used for dispensing bevacizumab are coated with silicone oil that acts as a lubricant. These silicone oil droplets can lead to floaters and other possible complications. We report two cases of such occurrence and propose strategies to avoid this complication. Keywords: Bevacizumab, diabetic macular edema, silicone oil, ranibizumab.

Investigation of a free rising bubble with mass transfer by an arbitrary Lagrangian–Eulerian method

The dissolution of bubbles with large volume change is numerically investigated by employing an arbitrary Lagrangian–Eulerian (ALE) method. To describe the mechanisms of the mass transfer from the bubble to the surrounding liquid, the species conservation equation is solved in the liquid phase, and the interfacial mass transfer is modeled based on the concentration gradient at the interface. Moreover, an accelerating reference method is developed to synchronize the computational domain with the bubble/drop motion and also to minimize the computational cost. The applicability of the proposed numerical approach is verified by benchmark tests, i.e., the dynamic behavior of a free rising bubble/drop and the dissolution of a rising bubble. Then the dissolving processes of an oxygen bubble in silicon oil are simulated, and the calculated shrinkage of the bubble size agrees well with experimental results. Moreover, the bubble motion is found to have a strong effect on the dissolution, and reasonable agreement is obtained between the predicted results and the experimental data in terms of the Sherwood and Reynolds numbers. Furthermore, based on the accurate calculation of the bubble surface and the corresponding transport of the dissolving gas, the thickness of the concentration boundary layer and the local Sherwood number are studied quantitatively. It is found that the thickness increases gradually with the cap angle, while on the contrary, the Sherwood number decreases, indicating that the thickness of the concentration boundary layer dominates the mass transfer behavior at the bubble surface.

Tar reduction in biomass syngas using heat exchanger and vegetable oil bubbler

Abstract A heat exchanger and vegetable oil bubbling system was designed and tested for biomass-generated syngas cooling and cleaning. The fully enclosed heat exchanger contained water at 15 °C, with syngas having to travel 35 m3/s. Using canola oil, the bubbler was tested at 70 and 100 mm oil depths and 5 and 10 mm syngas bubble sizes to determine the effect of tar removal. The results showed that tar removal efficiency was significantly affected by oil depth and bubble size; however, the interaction between bubble size and oil depth was not significant. About 60% of tars was removed by the heat exchanger alone and 96% of the remaining tars was removed by the oil bubbler when used in series with the heat exchanger. Overall, tar reduction efficiency of 98.5% was achieved with the heat exchanger plus oil bubbler having oil depth of 100 mm and syngas bubble size of 5 mm. Heat exchanger removed most of the tars by cooling the syngas below its dew point but syngas tars with low dew point was absorbed in the oil bubbler.

Deformation of bubbles in transformer oil at the action of alternating electric field

Abstract The experimental investigations of the deformation of bubbles floating in transformer oil under the action of uniform electric field were performed. The model based on the lattice Boltzmann equation method for the electrohydrodynamic flows accompanying this process was developed. The degree of deformation of bubbles observed in experiments is in agreement with the one obtained in simulations. Comparison with theoretical calculations show that the experimental data on the deformation of bubbles in transformer oil under the action of strong alternating electric field with a magnitude up to 4 kV/mm are reasonably explained by a model with a changeless surface tension.

How To Obtain Six Different Superwettabilities on a Same Microstructured Pattern: Relationship between Various Superwettabilities in Different Solid/Liquid/Gas Systems.

A range of different superwettabilities were obtained on femtosecond laser-structured Al surfaces. The formation mechanism of each superwetting state is discussed in this paper. It is revealed that the underwater oil droplet and bubble wettabilities of a solid surface have a close relationship with its water wettability. The laser-induced hierarchical microstructures showed superhydrophilicity in air but showed superoleophobicity/superaerophobicity after immersion in water. When such microstructures were further modified with a low-surface-energy monolayer, the wettability of the resultant surface would turn to superhydrophobicity with ultralow water adhesion in air and superoleophilicity/superaerophilicity in water. The understanding of the relationship among the above-mentioned six different superwettabilities is highly important in the design of various superwetting microstructures, transforming the structures from one superwetting state to another state and better using the artificial superwetting materials.

Experimental Study of Foamy Oil Solution Gas Drive Process in an Etched Glass Micromodel

Foamy oil phenomenon is of great significance for the exploitation of some heavy oil reservoirs. Many researchers have conducted a lot of research on foamy oil, but there is still no systematic research on why foamy oil phenomenon only appears in some special heavy oil reservoirs. Therefore, it is of great significance to study the formation of foamy oil in depth. This paper simulates the process of three kinds of heavy oil solution gas drive processes with different types of heavy oil under the formation conditions in an etched glass micromodel, and the flow characteristics of gas bubbles in the micromodel were observed. The results show that the location of gas bubbles nucleation was mainly distributed in the main channel and the rock surface of the micromodel. Compared with gas bubbles in the foamy oil, the dispersed gas bubbles in the conventional heavy oil had a shorter existence time and no obvious foamy oil phenomenon, the size of gas bubbles in the conventional heavy oil was larger, and the migration, growth and coalescence rate were faster.

Underwater manipulation of oil droplets and bubbles on superhydrophobic surfaces via switchable adhesion.

An ultraviolet light-responsive superwetting surface was produced by wire electrical discharge machining of a TC4 alloy. The processed surface remained superoleophobic and superaerophobic in water, when it was either superhydrophobic or superhydrophilic in air. The surface exhibited an adhesion switching of oil droplets and bubbles underwater. The switching provides a new method to manipulate oil droplet or bubble motion and transportation underwater.

Efficacy of silicone oil removal with 23 G transconjunctival sutureless trocar-cannulas and gas-fluid exchange

Objective To evaluate the efficacy of silicone oil removal with 23-gauge transconjunctival trocar-cannulas and gas-fluid exchange. Methods The data of 39 patients received vitrectomy and silicone oil tamponade were analyzed retrospectively. Silicone oil was removed through the 23 G cannula more than 2 months later. The residual oil was removed by gas-liquid exchange. The vitreous cavity was filled with air partly. Results The time for draining out the silicone oil was 3.5-6.5 min , with average of (4.63±0.98) min and the time of complete operation was 15-35 min, with average of (20.1±6.2) min, respectively. The postoperative BCVA improved in 29 cases (74.4%), unchanged in 5 cases (12.8%), and experienced mild deterioration in 5 cases (12.8%). Three cases with residual oil bubbles were observed. No vitreous hemorrhage, retinal redetachment or choroid detachment occurred during the follow-up. IOP was 6 mmHg in 1 case (1 mmHg=0.133 kPa), and the water leakage of the puncture site was sewed up. Conclusion The surgery of silicone oil removal with 23G transconjunctival sutureless trocar-cannulas and gas-fluid exchange is effective, safe and quick. Key words: Silicone oil, removal, 23-gauge, cannula, sutureless, transconjunctival; Gas-fluid exchange

Impact of oil velocity on partial discharge characteristics induced by bubbles in transformer oil

Bubble is a typical insulation defect in transformer oil, which can easily initiate partial discharge (PD) during the operation of transformer. Moreover, it migrates along with the oil flow and may be deformed due to the forced oil circulation and temperature difference within transformer bulk, leading to the complexity of PD characteristics and PD mechanism. However, the understanding of to this phenomenon is not clear. In order to identify it, finite element method was employed to simulate the movement process and deformation of bubbles, as well as electric field distribution under the conditions with different oil flow rates. In addition, numerous experiments were performed, mainly including the change of PD ϕ-q and ϕ-n patterns with oil flow rates. By comparing the simulation and experimental results, it is found that PDs are mainly concentrated in the negative half-cycle. Electric force causes bubbles to stretch along the electric field direction. At the stationary condition, bubbles eventually exhibit horizontal stretching and cause maximum electric field distortion. However, bubbles eventually exhibit vertical stretching in flowing oil. Flowing oil can significantly reduce PD intensity. The PD intensity declines rapidly with the increase of the flow velocity, and then increases slowly.

A high sensitive multi-parameter micro sensor for the detection of multi-contamination in hydraulic oil

A high sensitive multi-parameter micro sensor consisted of a microfluidic chip and a sensing unit is presented. The sensing unit, which composed of a dual-coil and two silicon steel sheets, is embedded in the simple microfluidic chip with a straight microchannel structure. The micro sensor can be used not only as an inductive sensor to distinguish between ferromagnetic and non-ferromagnetic metal particles, but also as a capacitive sensor to distinguish between water droplets and bubbles in hydraulic oil. The simulation results show that both the magnetic field and the electric field of the sensing unit are enhanced under the effect of the silicon steel sheets. In the experiments, the number of turns of the coil was optimized first, and then the comparative experimental results show that the detection amplitudes of both iron and copper particles were increased about four times compare with the sensing unit without silicon steel sheets, which verified the simulation results. Using the simple micro sensor, without any complicated external circuits, in the inductance detection experiments, we demonstrate the successful detection of 33 μm iron particles and 90 μm copper particles in hydraulic oil; and in the capacitance detection experiments, we can detect 100 μm water droplets and 180 μm bubbles in hydraulic oil. For both the inductance and capacitance detection, the results of particles with different sizes were in good agreement with the simulation results.

Effectiveness of supercritical-CO2 and N2 huff-and-puff methods of enhanced oil recovery in shale fracture networks using microfluidic experiments

Current oil recovery methods in hydraulically fractured shale reservoirs have a low recovery efficiency of about 10%. The objective of this work is to investigate the effectiveness of nitrogen and supercritical carbon dioxide in the huff-and-puff method for enhanced oil recovery as a means to re-energize reservoirs and improve recovery rates. We conduct direct visualization experiments with a microfluidic system to reveal the mechanisms and to quantify the recovery rates of oil from fracture networks. We compared the effectiveness of water, nitrogen and supercritical carbon dioxide at reservoir conditions in a process mimicking the huff-and-puff method in both dead-end and connected fracture systems. The microfluidic chips were made of glass and placed in a confining pressure system pressurized to 10 MPa, 50 °C. The system was allowed to equilibrate, and then depressurized to simulate huff-and-puff oil recovery. Fluorescence microscope images were continuously taken to visualize and calculate residual oil saturation as a function of pressure drawdown. As the system was depressurized from 10 MPa, gas exsolution from the oil liquid phase, including bubble nucleation, growth, and coalescence, appeared to be the main driver for mobilizing oil from the fracture networks. Injection of supercritical CO2 resulted in the highest recovery rate with an average end-point recovery of about 90% in the connected fracture network and 60% in the dead-end fracture network. N2 has lower solubility in oil and hence showed a lower recovery rate of 40% in the connected fracture network and 25% in the dead-end fracture network. Injection of water had no effect on oil mobilization since water is insoluble, immiscible and incompressible. The main mechanism of enhanced recovery was gas exsolution from the liquid phase as pressure was decreased below the bubble point pressure. Because the gas was distributed throughout the oil phase, bubble nucleation, growth, coalescence, and elongation occurred throughout the fracture network. Expansion of the gas forced oil out of the network through piston displacement in continuous oil areas and film flow in the dispersed oil areas. Bubbles began as spheres and grew until they touched the fracture walls where they elongated along the fracture length. The bubble growth rate depended on local mass transfer from liquid to gas phase and gas volume expansion due to pressure drop. The efficiency of the huff-and-puff process is dependent on the solubility and miscibility of the injection fluid with oil. High gas solubility allows for more bubble nucleation, growth and expansion during the depressurization cycle.

Amplitude-Frequency Characteristics of the Oscillations of Methane Gas Bubbles in Oil

The author presents an analytical solution to the problem of acoustic-wave-induced oscillations of methane gas bubbles in an oil reservoir at bottom-hole conditions. The amplitude-frequency characteristics are computed for realistic reservoir temperature, pressure, and dissolved gas parameters that make the oil compressibility, density, and viscosity quite different from those of the degassed oil at surface conditions. The author compares the damping decrement of these ultrasonic oscillations to those at normal atmospheric-pressure surface conditions. The solution allowed the author to estimate the ultrasonic vibration frequency range that is optimal and most effective for improving the flow characteristics in a producing reservoir in the near-well zone at a realistic bottom-hole regime.

Sandwich technique using a combination of perfluoropropane and silicone oil for inferior retinal detachment.

We report a novel surgical sandwich technique using a combination of intraocular perfluoropropane (C3F8) and silicone oil for inferior retinal detachment (RD). After conventional pars plana vitrectomy and posterior vitreous detachment induction, fluid-gas exchange using 14% C3F8 was done. This was followed by silicone oil injection using automated infusion pump to 50% fill of the vitreous cavity under direct visualization to achieve formation of two bubbles – gas bubble superiorly and silicone oil inferiorly. The patient was subsequently asked to maintain upright position. The two immiscible bubbles of C3F8 and silicone oil provide tamponade to superior and inferior retina, respectively. With time, gas bubble reduces in size with a gradual superior shift of silicone oil. This novel sandwich technique achieves complete attachment of retina and reduces the risk of retinal redetachment in inferior RDs by adequately tamponading the inferior retina.

Modeling an Ascending Nitrogen Gas Bubble in a Medium Crude Oil by Lattice Boltzmann Method

The study and modeling of oil biphasic systems, liquid-liquid and liquid-gas, focus mainly on the details of the modifications and application of the numerical methods itself. The correspondence between theoretical and experimental results and the information needed to apply a certain numerical method, usually remain in the background. On the other hand, in the particular case of the prediction of minimum miscibility pressure, extremely important parameter in oil exploration, references that show qualitative and numerical data associated with the characterization of the systems are scarce. The above reasons motivated the realization of this work. We used the Lattice Boltzmann Equation method to model a two-dimensional system of the displacement of a nitrogen gas bubble through a medium crude oil, under different pressure conditions keeping the temperature constant. According to experimental data, the bubble is not miscible by the crude, under a pressure range of 5000 psi to 6500 psi; nevertheless, the bubble is miscible in the range of 7000 psi to 7500 psi. Throughout simulations performed under similar conditions, we showed that it can be inferred the critical pressure range of miscibility of a medium crude oil.

Comparison of cavitation bubbles evolution in viscous media

There have been tried many types of liquids with different ranges of viscosity values that have been tested to form a single cavitation bubble. The purpose of these experiments was to observe the behaviour of cavitation bubbles in media with different ranges of absorbance. The most of the method was based on spark to induced superheat limit of liquid. Here we used arrangement of the laser-induced breakdown (LIB) method. There were described the set cavitation setting that affects the size bubble in media with different absorbance. We visualized the cavitation bubble with a 60 kHz high speed camera. We used here shadowgraphy setup for the bubble visualization. There were observed time development and bubble extinction in various media, where the size of the bubble in the silicone oil was extremely small, due to the absorbance size of silicon oil.

Interaction of positive streamers in air with bubbles floating on liquid surfaces: conductive and dielectric bubbles

The interaction of plasmas sustained in humid air with liquids produces reactive species in both the gas phase and liquid for applications ranging from medicine to agriculture. In several experiments, enhanced liquid reactivity has been produced when the liquid is a foam or a bubble coated liquid. To investigate the phenomena of streamers interacting with bubbles a two-dimensional computational investigation has been performed of streamer initiation and propagation on and inside hemispherical bubble-shells floating on a liquid surface. Following prior experiments, water and oil bubble-shells with an electrode located outside and inside the bubble were investigated. We found that positive air streamers interact differently with conductive water and dielectric oil bubbles. The streamer propagates along the external surface of a water bubble while not penetrating through the bubble due to screening of the electric field by the conducting shell. If the electrode is inserted inside the bubble, the path of the streamer depends on how deeply the electrode penetrates. For shallow penetration, the streamer propagates along the inner surface of the bubble. Due to the low conductivity of oil bubble-shells, the electric field from an external electrode penetrates into the interior of the bubble. The streamer can then be re-initiated inside the bubble.

Experiments on the mass transfer of gas bubbles in mineral oil

The present experimental work uses the rotary chamber technique to observe bubbles rising in oil in a levitated position. Sizes from 0.3 mm to 8 mm are covered. Main bubble gases are oxygen, nitrogen and argon. The oil is white oil. The focus of the investigation is on the mass transfer rate of the bubble gas into the undersaturated oil. Constituent quantities are the rise velocity and the bubble shape. While velocity and shape show a low-key behavior the transfer rates are unusual. The normalized mass transfer in terms of the Sherwood number exhibits three zones. Both, the large bubble and the small bubble zone obey Sh∝Ar1/3. However, they are substantially shifted with respect to each other and connected by a transition zone. From arguments concerning the bubble drag we conclude that large bubbles have a mobile interface which develops into an immobile one for the smaller bubbles. Thus the state of the interface affects the mass transfer rate heavily.