The Experts below are selected from a list of 3648 Experts worldwide ranked by ideXlab platform
Patrick S Doyle - One of the best experts on this subject based on the ideXlab platform.
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site selective in situ grown calcium carbonate Micromodels with tunable geometry porosity and wettability
Advanced Functional Materials, 2016Co-Authors: Ankur Gupta, Sehoon Chang, Patrick S DoyleAbstract:Micromodels with simplified porous microfluidic systems are widely used to mimic the underground oil-reservoir environment for multiphase flow studies, enhanced oil recovery, and reservoir network mapping. However, previous Micromodels cannot replicate the length scales and geochemistry of carbonate because of their material limitations. Here a simple method is introduced to create calcium carbonate (CaCO3) Micromodels composed of in situ grown CaCO3. CaCO3 nanoparticles/polymer composite microstructures are built in microfluidic channels by photopatterning, and CaCO3 nanoparticles are selectively grown in situ from these microstructures by supplying Ca2+, CO32− ions rich, supersaturated solutions. This approach enables us to fabricate synthetic CaCO3 reservoir Micromodels having dynamically tunable geometries with submicrometer pore-length scales and controlled wettability. Using this new method, acid fracturing and an immiscible fluid displacement process are demonstrated used in real oil field applications to visualize pore-scale fluid–carbonate interactions in real time.
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photopatterned oil reservoir Micromodels with tailored wetting properties
Lab on a Chip, 2015Co-Authors: Patrick S DoyleAbstract:Micromodels with a simplified porous network that represents geological porous media have been used as experimental test beds for multiphase flow studies in the petroleum industry. We present a new method to fabricate reservoir Micromodels with heterogeneous wetting properties. Photopatterned, copolymerized microstructures were fabricated in a bottom-up manner. The use of rationally designed copolymers allowed us to tailor the wetting behavior (oleophilic/phobic) of the structures without requiring additional surface modifications. Using this approach, two separate techniques of constructing microstructures and tailoring their wetting behavior are combined in a simple, single-step ultraviolet lithography process. This microstructuring method is fast, economical, and versatile compared with previous fabrication methods used for multi-phase micromodel experiments. The wetting behaviors of the copolymerized microstructures were quantified and demonstrative oil/water immiscible displacement experiments were conducted.
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Photopatterned oil-reservoir Micromodels with tailored wetting properties
Lab on a Chip, 2015Co-Authors: Hyundo Lee, Seung Goo Lee, Patrick S DoyleAbstract:We present a new method to fabricate oil-reservoir Micromodels with heterogeneous wetting properties.Micromodels with a simplified porous network that represents geological porous media have been used as experimental test beds for multiphase flow studies in the petroleum industry. We present a new method to fabricate reservoir Micromodels with heterogeneous wetting properties. Photopatterned, copolymerized microstructures were fabricated in a bottom-up manner. The use of rationally designed copolymers allowed us to tailor the wetting behavior (oleophilic/phobic) of the structures without requiring additional surface modifications. Using this approach, two separate techniques of constructing microstructures and tailoring their wetting behavior are combined in a simple, single-step ultraviolet lithography process. This microstructuring method is fast, economical, and versatile compared with previous fabrication methods used for multi-phase micromodel experiments. The wetting behaviors of the copolymerized microstructures were quantified and demonstrative oil/water immiscible displacement experiments were conducted.
M. Mrozowski - One of the best experts on this subject based on the ideXlab platform.
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Grouping macromodels by using multilevel model order reduction
2008 17th International Conference on Microwaves Radar and Wireless Communications MIKON 2008, 2008Co-Authors: J. Podwalski, Lukasz Kulas, M. MrozowskiAbstract:This article introduces a novel technique of grouping macromodels for the FDTD method. The new technique is based on the multilevel model order reduction scheme. Macromodel grouping allows one to increase the simulation speed in comparison to not-grouped macromodels with the same good (or even better) accuracy. The scheme uses the ENOR algorithm for efficient model order reduction.
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Multilevel model order reduction
IEEE Microwave and Wireless Components Letters, 2004Co-Authors: Lukasz Kulas, M. MrozowskiAbstract:We present a multilevel Model Order Reduction scheme for enhancing numerical analysis of electromagnetic fields by means of grid based techniques. The scheme allows one to create nested macromodels and combine macromodels with the Fast Frequency Sweep. The implementation of the method is illustrated on the Finite Difference Frequency Domain technique and efficient nodal order reduction algorithm (ENOR) but the concept can easily be applied also for other mesh based methods and other order reduction schemes.
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A fast high-resolution 3-D finite-difference time-domain scheme with macromodels
IEEE Transactions on Microwave Theory and Techniques, 2004Co-Authors: Lukasz Kulas, M. MrozowskiAbstract:A fast three-dimensional (3-D) finite-difference time-domain (FD-TD) scheme of high spatial resolution is presented. Increased resolution is obtained by combining the standard FD-TD algorithm with macromodels of highly refined volumes created by a model-order reduction technique. New updated equations for macromodels are derived and the numerical costs involved in using 3-D macromodels are estimated. Excellent performance has been observed during numerical tests for high-refinement factors.
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Implementing the concept of a macromodel in the FTDT method
14th International Conference on Microwaves Radar and Wireless Communications MIKON 2002, 2002Co-Authors: M. MrozowskiAbstract:© 2002 Telecommunications Res. Inst.This paper introduces a novel method of incorporating macromodels into the FDTD (finite difference time domain) algorithm. Macromodels are generated by model order reduction applied to state equations in the FDFD method for a higher resolution grid of the chosen subspace. This approach allows one to analyse a structure with a locally denser mesh and thus increases calculation accuracy and reduces the overall computation time.
K T Christensen - One of the best experts on this subject based on the ideXlab platform.
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Micro‐PIV measurements of multiphase flow of water and liquid CO2 in 2‐D heterogeneous porous Micromodels
Water Resources Research, 2020Co-Authors: Yaofa Li, Farzan Kazemifar, Gianluca Blois, K T ChristensenAbstract:We present an experimental study of pore-scale flow dynamics of liquid CO2 and water in a two-dimensional heterogeneous porous micromodel, inspired by the structure of a reservoir rock, at reservoir-relevant conditions (80 bar, 21 °C). The entire process of CO2 infiltration into a water-saturated micromodel was captured using fluorescence microscopy and the micro-PIV method, which together reveal complex fluid displacement patterns and abrupt changes in velocity. The CO2 front migrated through the resident water in an intermittent manner, forming dendritic structures, termed fingers, in directions along, normal to, and even opposing the bulk pressure gradient. Such characteristics indicate the dominance of capillary fingering through the micromodel. Velocity burst events, termed Haines jumps, were also captured in the heterogeneous micromodel, during which the local Reynolds number was estimated to be ∼21 in the CO2 phase, exceeding the range of validity of Darcy's law. Furthermore, these drainage events were observed to be cooperative (i.e., across multiple pores simultaneously), with the zone of influence of such events extending beyond tens of pores, confirming, in a quantitative manner, that Haines jumps are non-local phenomena. After CO2 completely breaks through the porous section, shear-induced circulations caused by flowing CO2 were also observed, in agreement with previous studies using a homogeneous porous micromodel. To our knowledge, this study is the first quantitative measurement that incorporates both reservoir-relevant conditions and rock-inspired heterogeneity, and thus will be useful for pore-scale model development and validation.
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micro piv measurements of multiphase flow of water and liquid co2 in 2 d heterogeneous porous Micromodels
Water Resources Research, 2017Co-Authors: Yaofa Li, Farzan Kazemifar, Gianluca Blois, K T ChristensenAbstract:We present an experimental study of pore-scale flow dynamics of liquid CO2 and water in a two-dimensional heterogeneous porous micromodel, inspired by the structure of a reservoir rock, at reservoir-relevant conditions (80 bar, 21 °C). The entire process of CO2 infiltration into a water-saturated micromodel was captured using fluorescence microscopy and the micro-PIV method, which together reveal complex fluid displacement patterns and abrupt changes in velocity. The CO2 front migrated through the resident water in an intermittent manner, forming dendritic structures, termed fingers, in directions along, normal to, and even opposing the bulk pressure gradient. Such characteristics indicate the dominance of capillary fingering through the micromodel. Velocity burst events, termed Haines jumps, were also captured in the heterogeneous micromodel, during which the local Reynolds number was estimated to be ∼21 in the CO2 phase, exceeding the range of validity of Darcy's law. Furthermore, these drainage events were observed to be cooperative (i.e., across multiple pores simultaneously), with the zone of influence of such events extending beyond tens of pores, confirming, in a quantitative manner, that Haines jumps are non-local phenomena. After CO2 completely breaks through the porous section, shear-induced circulations caused by flowing CO2 were also observed, in agreement with previous studies using a homogeneous porous micromodel. To our knowledge, this study is the first quantitative measurement that incorporates both reservoir-relevant conditions and rock-inspired heterogeneity, and thus will be useful for pore-scale model development and validation.
Yaofa Li - One of the best experts on this subject based on the ideXlab platform.
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Micro‐PIV measurements of multiphase flow of water and liquid CO2 in 2‐D heterogeneous porous Micromodels
Water Resources Research, 2020Co-Authors: Yaofa Li, Farzan Kazemifar, Gianluca Blois, K T ChristensenAbstract:We present an experimental study of pore-scale flow dynamics of liquid CO2 and water in a two-dimensional heterogeneous porous micromodel, inspired by the structure of a reservoir rock, at reservoir-relevant conditions (80 bar, 21 °C). The entire process of CO2 infiltration into a water-saturated micromodel was captured using fluorescence microscopy and the micro-PIV method, which together reveal complex fluid displacement patterns and abrupt changes in velocity. The CO2 front migrated through the resident water in an intermittent manner, forming dendritic structures, termed fingers, in directions along, normal to, and even opposing the bulk pressure gradient. Such characteristics indicate the dominance of capillary fingering through the micromodel. Velocity burst events, termed Haines jumps, were also captured in the heterogeneous micromodel, during which the local Reynolds number was estimated to be ∼21 in the CO2 phase, exceeding the range of validity of Darcy's law. Furthermore, these drainage events were observed to be cooperative (i.e., across multiple pores simultaneously), with the zone of influence of such events extending beyond tens of pores, confirming, in a quantitative manner, that Haines jumps are non-local phenomena. After CO2 completely breaks through the porous section, shear-induced circulations caused by flowing CO2 were also observed, in agreement with previous studies using a homogeneous porous micromodel. To our knowledge, this study is the first quantitative measurement that incorporates both reservoir-relevant conditions and rock-inspired heterogeneity, and thus will be useful for pore-scale model development and validation.
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micro piv measurements of multiphase flow of water and liquid co2 in 2 d heterogeneous porous Micromodels
Water Resources Research, 2017Co-Authors: Yaofa Li, Farzan Kazemifar, Gianluca Blois, K T ChristensenAbstract:We present an experimental study of pore-scale flow dynamics of liquid CO2 and water in a two-dimensional heterogeneous porous micromodel, inspired by the structure of a reservoir rock, at reservoir-relevant conditions (80 bar, 21 °C). The entire process of CO2 infiltration into a water-saturated micromodel was captured using fluorescence microscopy and the micro-PIV method, which together reveal complex fluid displacement patterns and abrupt changes in velocity. The CO2 front migrated through the resident water in an intermittent manner, forming dendritic structures, termed fingers, in directions along, normal to, and even opposing the bulk pressure gradient. Such characteristics indicate the dominance of capillary fingering through the micromodel. Velocity burst events, termed Haines jumps, were also captured in the heterogeneous micromodel, during which the local Reynolds number was estimated to be ∼21 in the CO2 phase, exceeding the range of validity of Darcy's law. Furthermore, these drainage events were observed to be cooperative (i.e., across multiple pores simultaneously), with the zone of influence of such events extending beyond tens of pores, confirming, in a quantitative manner, that Haines jumps are non-local phenomena. After CO2 completely breaks through the porous section, shear-induced circulations caused by flowing CO2 were also observed, in agreement with previous studies using a homogeneous porous micromodel. To our knowledge, this study is the first quantitative measurement that incorporates both reservoir-relevant conditions and rock-inspired heterogeneity, and thus will be useful for pore-scale model development and validation.
Anthony R. Kovscek - One of the best experts on this subject based on the ideXlab platform.
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A micromodel investigation of two‐phase matrix‐fracture transfer mechanisms
Water Resources Research, 2020Co-Authors: Edgar R. Rangel-german, Anthony R. KovscekAbstract:[1] Micromodels employing a two-dimensional representation of pore space were used to observe directly (via microscope) water imbibition into a matrix and matrix-fracture interactions between wetting and nonwetting fluids. Within a single field of view, some pores are responsible for the uptake of water, whereas immediately adjacent pores expel nonwetting phase into the fracture. When water flow through fractures is relatively slow and fluid transfer from the fracture is relatively rapid, imbibition is microscopically cocurrent and micromodel observations teach that uptake of the wetting phase by the matrix correlates directly with the volume of water injected. This mode of transfer is coined a filling fracture. On the other hand, when fractures fill with water quickly relative to the rate of matrix-fracture transfer, the mass of water imbibed scales with the square root of time. Here imbibition is found to be countercurrent at the pore level. In the countercurrent mode, significant channeling of the nonwetting phase through the continuous wetting phase is observed that reduces the efficiency of water infiltration. Overall, it is found that the rate of water uptake from a fracture into an unsaturated matrix and the pore-level pattern of water infiltration depend critically on the rate of water infiltration through fractures.
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Creation of a dual-porosity and dual-depth micromodel for the study of multiphase flow in complex porous media
Lab on a Chip, 2017Co-Authors: Cynthia M. Ross, Sophie Roman, Anthony R. KovscekAbstract:Silicon-based microfluidic devices, so-called Micromodels in this application, are particularly useful laboratory tools for the direct visualization of fluid flow revealing pore-scale mechanisms controlling flow and transport phenomena in natural porous media. Current microfluidic devices with uniform etched depths, however, are limited when representing complex geometries such as the multiple-scale pore sizes common in carbonate rocks. In this study, we successfully developed optimized sequential photolithography to etch micropores (1.5 to 21 μm width) less deeply than the depth of wider macropores (>21 μm width) to improve the structural realism of an existing single-depth micromodel with a carbonate-derived pore structure. Surface profilimetry illustrates the configuration of the dual-depth dual-porosity micromodel and is used to estimate the corresponding pore volume change for the dual-depth micromodel compared to the equivalent uniform- or single-depth model. The flow characteristics of the dual-depth dual-porosity micromodel were characterized using micro-particle image velocimetry (μ-PIV), relative permeability measurements, and pore-scale observations during imbibition and drainage processes. The μ-PIV technique provides insights into the fluid dynamics within microfluidic channels and relevant fluid velocities controlled predominantly by changes in etching depth. In addition, the reduction of end-point relative permeability for both oil and water in the new dual-depth dual-porosity micromodel compared to the equivalent single-depth micromodel implies more realistic capillary forces occurring in the new dual-depth micromodel. Throughout the imbibition and drainage experiments, the flow behaviors of single- and dual-depth Micromodels are further differentiated using direct visualization of the trapped non-wetting phase and the preferential mobilization of the wetting phase in the dual-depth micromodel. The visual observations agree with the relative permeability results. These findings indicate that dual-porosity and dual-depth Micromodels have enhanced physical realism that is pertinent to oil recovery processes in complex porous media.
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particle velocimetry analysis of immiscible two phase flow in Micromodels
Advances in Water Resources, 2016Co-Authors: Sophie Roman, Anthony R. Kovscek, Cyprien Soulaine, Moataz Abu Alsaud, Hamdi A TchelepiAbstract:Abstract We perform micro-PIV measurements in Micromodels using very simple optical equipment combined with efficient image acquisition and processing. The pore-scale velocity distributions are obtained for single-phase flow in porous media with a typical pore size of 5–40 µm at a resolution of 1.8 μ m × 1.8 μ m vector grid. Because the application of micro-PIV in Micromodels is not standard, extensive effort is invested into validation of the experimental technique. The micro-PIV measurements are in very good agreement with numerical simulations of single-phase flows, for which the modeling is well established once the detailed pore geometry is specified and therefore serves as a reference. The experimental setup is then used with confidence to investigate the dynamics of immiscible two-phase flow in Micromodels that represent natural complex porous media (e.g., sandstone). For unstable immiscible two-phase flow experiments, micro-PIV measurements indicate that the flow is highly oscillatory long before the arrival of the invading interface. The dynamics are accompanied with abrupt changes of velocity magnitude and flow direction, and interfacial jumps. Following the passage of the front, dissipative events, such as eddies within the aqueous phase, are observed in the micro-PIV results. These observations of complex interface dynamics at the pore scale motivate further measurement of multiphase fluid movement at the sub-pore scale and requisite modeling.
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Microvisual investigation of polymer retention on the homogeneous pore network of a micromodel
Journal of Petroleum Science and Engineering, 2015Co-Authors: Anthony R. KovscekAbstract:Abstract A new experimental technique is reported for visualization of polymer retention on the solid surfaces of porous media. Etched silicon Micromodels with well-characterized pore networks were used during single-phase flow to examine the retention of 0.2 wt% partially hydrolyzed polyacrylamide (HPAM) solution. Image analysis included an image subtraction and an RGB-based global thresholding technique for quantification of polymer retention/adsorption. Results are reported as the percentage of porosity occupied by immobile polymer. Three factors were investigated including the salinity of displacing water, the change of wettability of the micromodel surface, and mechanical degradation of polymer. With respect to salinity in displacing water, the experiment confirmed that 5 wt% NaCl results in less polymer retention (6.3±0.3%) than without NaCl (7.5±0.3%). The increase in Na + concentration was sufficient to induce contraction of the size of the flexible HPAM molecules and, therefore, decrease the thickness of polymer adsorption on the grain. Two methods were used to alter the initially strongly water-wet surface of the micromodel. Wettability was changed by the deposition of crude oil and CTAB (cetyl trimethylammonium bromide) in aqueous solution. The Micromodels treated using crude oil and CTAB showed polymer retention of 15.0±0.3%% and 5.0±0.3%%, respectively. Oil-wet Micromodels aged by crude oil showed larger polymer retention than the polymer retention on water-wet Micromodels (7.5±0.3%). Otherwise, the polymer retention on the CTAB treated micromodel was lower than the polymer retention on the water-wet micromodel. Finally, polymer solution flowed through a 7 µm filter was tested. Average polymer retention was 4.3±0.3% and this is 3.2±0.3% point lower than the value of unfiltered polymer solution. Further investigation of microgels within pore networks provided a chance to demonstrate that a size and structural flexibility of microgel leading to a transition from mobile to immobile conditions.
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Creation of a dual-porosity micromodel for pore-level visualization of multiphase flow
Journal of Petroleum Science and Engineering, 2012Co-Authors: Markus Buchgraber, Cynthia M. Ross, M. Al-dossary, Anthony R. KovscekAbstract:Abstract This paper describes the creation and testing of an etched-silicon micromodel that has the features and characteristics of a dual-porosity pore system mimicking those found in certain carbonate reservoir rocks. This micromodel consists of a two-dimensional (2D) pore network etched into a silicon wafer with a bonded glass cover that permits direct visual examination of pore-level displacement mechanisms and pore-network characteristics during fluid flow experiments. The approach began by creating a mosaic of images from a carbonate thin section of a sample with both high porosity and permeability using a scanning electron microscope (SEM) in back-scattered mode (BSE). Connections based on high-pressure mercury injection data were made to ensure that the 2D connectivity in the imaged pore structure was representative of the three dimensional (3D) pore network of the carbonate sample. Microelectronic photolithography techniques were then adapted to create Micromodels for subsequent fluid flow experiments. Micromodel surfaces were made oil- or water-wet by various techniques. One of the main advantages of having a representative carbonate dual-porosity micromodel is the ability to observe pore-level mechanisms of multiphase flow and interpret petrophysical properties. Another advantage is that multiple replicates are available with identical conditions for each new experiment. Micromodel utility is demonstrated here through the measurement of porosity, permeability, fluid desaturation patterns, and recovery factors.