Browsing by Author "Biswal, Lisa"

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    Advanced Applications of Polymers for Enhanced Oil Recovery
    (2014-11-06) ShamsiJazeyi, Hadi; Hirasaki, George J; Verduzco, Rafael; Tour, James; Biswal, Lisa
    With the increasing global demand for crude oil, it is essential to increase the oil production in economic ways. This requires a significant increase in application of advanced technologies in this area. Enhanced Oil Recovery (EOR) processes are known as series of different advanced technologies, which can be used to increase the oil production from a given oil reservoir. The traditional use of polymers in EOR is almost limited to increasing viscosity of the aqueous fluids injected into the reservoir. By increasing the viscosity of the injected fluids, more areas of the reservoir can be swept, and therefore more oil is expected to be recovered. In this thesis proposal, a number of advanced polymer applications for EOR are investigated. Polymers are known as a very promising class of materials with wide range of properties, especially combined with other advanced materials, such as nanoparticles. Therefore, there is a huge potential for developing new application of polymers in EOR processes. The first application introduced in this thesis is to use polymers as sacrificial adsorption agents for anionic surfactants. In a subclass of EOR, known as chemical EOR, surfactants are injected to lower the interfacial tension of oil and brine, resulting in recovery of more oil. However, one of the challenges facing these processes is the adsorption of surfactants onto the reservoir rock, which requires excessive injection of surfactant to compensate for the adsorption. This significantly increases the cost of the chemical EOR to values much more than what is actually needed for oil recovery. In second chapter of this thesis, sodium polyacrylate is introduced as a sacrificial adsorption agent, a chemical that is injected to decrease the adsorption of anionic surfactant. The results show that the material cost of chemical EOR can be reduced by up to 80% in case of using polyacrylate as a sacrificial agent for anionic surfactants. In addition, application of polyacrylate as a sacrificial agent for zwitterionic surfactants was investigated. In spite the significant reduction seen in the adsorption of anionic surfactants once polyacrylate is used, adsorption of zwitterionic surfactants is only slightly reduced after adding polyacrylate. In order to understand the reasons behind this dismal reduction, the effect of pH on adsorption of lauryl betaine (as the zwitterionic surfactant in this study) is studied. Based on the experimental data, a hypothetic mechanism is introduced to explain the adsorption properties of betaine. This hypothetic mechanism also explains why polyacrylate shows a very slight reduction in adsorption of zwitterionic surfactants while it significantly reduces adsorption of anionic surfactants. Finally, the effect of polymer coating on interfacial properties of nanoparticles in the absence or presence of surfactants is studied. Interfacial properties of polymer-coated nanoparticles in EOR have been traditionally limited to only emulsions (Pickering Emulsions). In this thesis, we have provided experimental evidence that polymer-coated nanoparticles can migrate to micro-emulsion phases even in the absence of emulsions. Some of these polymer-coated nanoparticles are dispersed in aqueous solutions, but they will precipitate in the micro-emulsion phase once mixed with the oil. This observation by itself can be used in EOR applications through understanding the fact that aqueous stability of nanoparticles is not the sufficient condition for nanoparticles to remain stable when injected into oil reservoirs. Many previous researchers have only focused on stability of nanoparticles in aqueous solutions as the only requirement for stability of nanoparticles even after injection into oil reservoir. This assumption is challenged based on our work in this thesis.
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    Dynamics of semiflexible paramagnetic colloidal chains under a rotational magnetic field
    (2019-04-12) Kuei, Steve; Biswal, Lisa
    The rich dynamics of stiff and flexible filaments in flow and their propensity for non-reciprocal orbits is relevant for both naturally occurring and industrially relevant phenomena, such as flagellar motion and polymer processing, as well as for developing applications, such as microfluidic scale propulsion and fluid manipulation. However, the connection between a filament’s elastic properties, the external driving forces, and its resulting dynamics is not well understood; in particular, both computational and theoretical results indicate that the scaling behaviors of fibers in the intermediate semiflexible regime deviate from the results expected from rigid and flexible fibers. We synthesize paramagnetic colloidal particle chains, and then utilize a rotating magnetic field as an external force, with which we are able to experimentally identify and probe various dynamical regimes. By complementing our studies with Brownian dynamics simulations of a bead-spring chain as well as theoretical arguments, we find that the dynamics of the system depend on the dimensionless Mason and magnetoelastic numbers, and use them to elucidate, predict, and optimize fiber dynamics.
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    Foam rheology of zwitterionic anionic blends in porous media
    (2016-03-30) Muthuswamy, Aarthi; Hirasaki, George; Miller, Clarence; Verduzco, Rafael; Biswal, Lisa; Tomson, Mason
    Blending of certain types of surfactants is known to promote synergism as studied by bulk measurements. This study analyzes if such synergistic interactions are beneficial for foam rheology in porous media. Foam experiments were conducted systematically in porous media, at different ratios of zwitterionic and anionic surfactants, both in the presence and absence of crude oil. Interfacial studies were conducted to explain the behavior of surfactant mixtures with respect to foam rheology in porous media. The zwitterionic surfactants used in this study were C12 straight chain betaine- Lauryl betaine (LB), C12 straight chain sultaine- Lauryl sultaine (LS), C18 tailed amido betaine (Rhodia A), C 18-22 tailed amido sultaine (Rhodia B), C 18-22 tailed amido betaine - with more C 22 (Rhodia C) and C 18-22 tailed amido betaine -with more C18 (Rhodia D). LB and LS surfactants had a viscosity close to that of water ~1 cP at room temperature. On the other hand 0.5 wt% of Rhodia A, Rhodia B, Rhodia C and Rhodia D were viscoelastic and shear thinning fluids due to the presence of wormlike micelles. Rheological studies which were conducted at room temperature revealed that salinity had a prominent effect on Rhodia A. On increasing salinity from ~ 4% to 12%, the relaxation time of Rhodia A increased by three orders of magnitude, thereby causing the weakly viscoelastic surfactant solution to change to a strongly viscoelastic solution. On the other hand salinity had a negligible effect on Rhodia B, Rhodia C and Rhodia D. When 1 wt% surfactant solutions of Rhodia A, B, C or D were mixed with ~ 35% synthetic crude oil (mass basis), all surfactant solutions lost viscosity and viscoelasticity except Rhodia C. Crude oil had an adverse effect on Rhodia A perhaps due to the conversion of wormlike micelles to spherical micelles. Rhodia B and D had lower elastic and viscous moduli most likely due to the shortening of the wormlike micelles. Additional tests were done to study the flow of these complex fluids in a 100 Darcy silica sand pack. Rhodia A, B and D showed no elongational effects during flow in porous media. Their shear thinning apparent viscosities in porous media were very close to the rheometric data in shear flow. Rhodia C exhibited yield stress behavior and hence could not be injected in a porous medium. Zwitterionic surfactants Rhodia A/LB/LS were blended with anionic Alpha Olefin Sulfonate AOS 14-16 (AOS) surfactant at specific ratios - one with high and one with low bulk mass ratio of zwitterionic to anionic. Rhodia A which was weakly viscoelastic by itself, when blended with AOS in the ratio 9:1 respectively (by mass) produced a strongly viscoelastic solution. Nitrogen foam experiments were conducted in 100 Darcy silica sand at 25° C for Rhodia A and AOS blends and, in Bentheimer sandstone cores at 45° C, for LB/AOS blends and LS/AOS blends. Zwitterionic surfactants of this type have been reported to be “foam boosters” for bulk foams when added to anionic surfactant. Rhodia A betaine was a weak foamer both in the presence and absence of oil. However when blended with AOS (9:1 ratio), its foam strength significantly improved in the absence of oil. In the presence of oil the viscoelastic surfactant helped generate strong foam in fewer pore volumes (PVs- a dimensional unit of time) but took a longer time than AOS to propagate through the sand pack. In the case of LB/AOS and LS/AOS surfactant systems, the zwitterionic (LB, LS) foam by itself was weak, but AOS and the blends of zwitterionic and AOS had strong foam with comparable foam rheology. The regular solution theory approach of Rubingh combined with Rosen’s application to water-air film interfaces and its adaption to oil-water interfaces was applied to understand this behavior, especially the high foam strength observed when the poor-foaming zwitterionics were added to the strong foamer AOS. It was found that the zwitterionic-anionic blends exhibited synergistic interactions. The Gibbs surface excess calculations suggested that the synergistic interactions promoted tighter packing at the interface thereby helping the poorly foaming zwitterionic surfactant to exhibit strong foam rheology in porous media. Interestingly, AOS surfactant by itself had tight packing at the interface. The trends observed in porous media were well explained by the Gibbs surface excess calculations. However, the synergism did not lead to improvement in foam performance in porous media beyond that seen for AOS alone. Additionally foam strength in the presence of water flood residual oil was weak for the pure zwitterionic surfactants, but the blends with higher mole fraction of AOS and pure AOS had comparable foam performance. Again AOS by itself was able to achieve good mobility control in displacing residual oil. The addition of zwitterionic surfactant had apparently not boosted the foam performance of AOS in porous media in the presence of oil as well. Interfacial shear rheology for the LB/AOS and LS/AOS systems were performed and it showed that none of the surfactants possessed interfacial shear viscosity. Qualitative film drainage studies were conducted and it was observed that a small addition of LB to AOS helped in creating very stable black film and substantially increased the longevity of the film more than AOS itself. However all these thin film studies failed to offer any explanation to porous media foam studies but perhaps help develop an understanding on bulk foam studies. In the case of Rhodia A:AOS 9:1 viscoelastic blend, an injection strategy can be proposed where in a small slug of A:AOS 9:1 blend can be injected which can aid in quicker foam generation followed by a large AOS slug which can help in faster propagation and hence more efficient oil recovery. Anionic AOS 14-16 surfactant did not need a foam booster contrary to the opinion in literature that a betaine surfactant (coco amido propyl betaine) is needed to boost the foam strength of an anionic surfactant (AOS 16-18) in the presence and absence of crude oil in porous media.
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    Measuring in-situ capillary pressure of a flowing foam system in porous media
    (Elsevier, 2022) Vavra, Eric; Puerto, Maura; Bai, Chutian; Ma, Kun; Mateen, Khalid; Biswal, Lisa; Hirasaki, George
    Hypothesis: Capillary pressure (Pc) is an intrinsic property of aqueous foams that has been demonstrated to play an important role in lamella rupture. Thus, directly measuring in-situ capillary pressure of a foam flowing through porous media has potential to greatly improve understanding of this complex process. Experiments: A capillary pressure probe was constructed and validated. Direct measurements of capillary pressure were made at ambient conditions during foam quality scan experiments in a transparent 1.41 × 10−10 m2 (143-Darcy) homogenous sand pack conducted at constant gas velocity. The foam texture was simultaneously visualized at the wall of the sand pack via microscope. Findings: In the low-quality regime, a plateauing trend in Pc was identified. In-situ microscopic visualization of the flowing foam revealed that gas bubbles were convecting with a fine discontinuous texture while Pc is at the plateau value Ppc. In the high-quality regime, the measured capillary pressures first decreased with increasing quality before increasing again at the driest qualities. These changes in Pc correlated with foam bubbles becoming coarser with increasing injected gas fractional flow before transitioning to continuous-gas flow at the slowest and driest injection conditions. These findings have been previously unreported for steady-state flow conditions and shall have significant implications for the general physical description of foam flow in porous media.