Stefan Iglauer - Academia.edu (original) (raw)

Papers by Stefan Iglauer

Geophysical Research …, 2011

Advances in Multiphase Flow and Heat Transfer (Volume 3), 2012

Mass Transfer - Advanced Aspects, 2011

... Here T is the temperature, p the pressure, R is the universal gas constant, m is the molality... more ... Here T is the temperature, p the pressure, R is the universal gas constant, m is the molality of components dissolved in water, yCO2 is the mole fraction of CO2 in the vapour phase, FCO2 is the fugacity coefficient of CO2, 2 (0) l CO μ is the standard chemical potential of CO2 in ...

Journal of Colloid and Interface Science, 2012

In the context of carbon geo-sequestration projects, brine-CO(2) interfacial tension γ and brine-... more In the context of carbon geo-sequestration projects, brine-CO(2) interfacial tension γ and brine-CO(2)-rock surface water contact angles θ directly impact structural and residual trapping capacities. While γ is fairly well understood there is still large uncertainty associated with θ. We present here an investigation of γ and θ using a molecular approach based on molecular dynamics computer simulations. We consider a system consisting of CO(2)/water/NaCl and an α-quartz surface, covering a brine salinity range between 0 and 4 molal. The simulation models accurately reproduce the dependence of γ on pressure below the CO(2) saturation pressure at 300 K, and over predict γ by ~20% at higher pressures. In addition, in agreement with experimental observations, the simulations predict that γ increases slightly with temperature or salinity. We also demonstrate that for non-hydroxylated quartz surfaces, θ strongly increases with pressure at subcritical and supercritical conditions. An increase in temperature significantly reduces the contact angle, especially at low-intermediate pressures (1-10 MPa), this effect is mitigated at higher pressures, 20 MPa. We also found that θ only weakly depends on salinity for the systems investigated in this work.

International Journal of Adhesion and Adhesives, 2006

Sealants play a vital role in maintaining the weather tightness of modern high-rise buildings. Ty... more Sealants play a vital role in maintaining the weather tightness of modern high-rise buildings. Typical sealed joints comprise an elastomeric sealant, a backing foam and the sides of the joint corresponding to the cladding panels. Conceptually, the sealant should adhere only to the sides of the joint to enable maximum movement capacity of the material to be utilised; this is known as two-sided adhesion. Previous work has shown that the sealant sometimes adheres to the backing material, resulting in three-sided adhesion, and that this results in a decrease in joint performance. The adhesion between the foam and the sealant was studied using tack and peel tests, and the results were compared with measurements of the surface energies of the foams and the surface tensions of the sealants. Adhesion mechanisms are suggested and peel force-surface energy correlations are presented. Implications for the practical application of the results in building construction are made. r

The Journal of Chemical Thermodynamics, 2016

Geophysical Research Letters, 2015

Tenside Surfactants Detergents, 2010

This investigation considers branched alkyl alcohol propoxylated sulfate surfactants as candidate... more This investigation considers branched alkyl alcohol propoxylated sulfate surfactants as candidates for chemcial enhanced oil recovery (EOR) applications. Results show that these anionic surfactants may be preferred candidates for EOR as they can be effective at creating low interfacial tension (IFT) at dilute concentrations, without requiring an alkaline agent or cosurfactant. In addition, some of the formulations exhibit a low IFT at high salinity, and hence may be suitable for use in more saline reservoirs. Adsorption tests onto kaolinite clay indicate that the loss of these surfactants can be comparable to or greater than other types of anionic surfactants. Surfactant performance was evaluated in oil recovery core flood tests. Selected formulations recovered 35 -50 % waterflood residual oil even with dilute 0.2 wt% surfactant concentrations from Berea sandstone cores.

Tenside Surfactants Detergents, 2011

We present a case study of surfactant enhanced oil recovery using Alkyl polyglucoside/1-naphthol ... more We present a case study of surfactant enhanced oil recovery using Alkyl polyglucoside/1-naphthol formulations. Alkyl polyglucosides are a green, non-toxic and renewable surfactant class synthesized out of agricultural raw materials. We measured interfacial tensions versus n-octane and viscosities of these formulations and conducted one coreflood enhanced oil recovery (EOR) experiment where we recovered 82.6 % of initial oil in place demonstrating that these formulations are efficient EOR agents.

Tenside Surfactants Detergents, 2010

We measured interfacial tensions (IFT) of aqueous alkyl polyglucoside (APG) systems formulated wi... more We measured interfacial tensions (IFT) of aqueous alkyl polyglucoside (APG) systems formulated with sorbitan ester-type cosurfactants against n-octane. The study focused on low to ultralow IFT systems which are relevant for enhanced oil recovery (EOR). In addition, we measured equilibrium adsorption concentrations of these surfactants and cosurfactants onto kaolinite clay, commonly found in oil reservoirs. We present one surfactant EOR laboratory flood experiment with one selected APGsorbitan ester formulation with which we recovered 94 % of initial oil in place (IOIP).

SPE/DOE Symposium on Improved Oil Recovery, 2004

TX 75083-3836, U.S.A., fax 01-972-952-9435.

Journal of colloid and interface science, Jan 15, 2016

Precise characterization of wettability of CO2-brine-rock system and CO2-brine interfacial tensio... more Precise characterization of wettability of CO2-brine-rock system and CO2-brine interfacial tension at reservoir conditions is essential as they influence capillary sealing efficiency of caprocks, which in turn, impacts the structural and residual trapping during CO2 geo-sequestration. In this context, we have experimentally measured advancing and receding contact angles for brine-CO2-mica system (surface roughness ∼12nm) at different pressures (0.1MPa, 5MPa, 7MPa, 10MPa, 15MPa, 20MPa), temperatures (308K, 323K, and 343K), and salinities (0wt%, 5wt%, 10wt%, 20wt% and 30wt% NaCl). For the same experimental matrix, CO2-brine interfacial tensions have also been measured using the pendant drop technique. The results indicate that both advancing and receding contact angles increase with pressure and salinity, but decrease with temperature. On the contrary, CO2-brine interfacial tension decrease with pressure and increase with temperature. At 20MPa and 308K, the advancing angle is measured...

Water Resources Research, 2015

ABSTRACT We review the literature data published on the topic of CO2 wettability of storage and s... more ABSTRACT We review the literature data published on the topic of CO2 wettability of storage and seal rocks. We first introduce the concept of wettability and explain why it is important in the context of carbon geo-sequestration (CGS) projects, and review how it is measured. This is done to raise awareness of this parameter in the CGS community, which, as we show later on in this text, may have a dramatic impact on structural and residual trapping of CO2. These two trapping mechanisms would be severely and negatively affected in case of CO2-wet storage and/or seal rock.Overall, at the current state-of-the-art, a substantial amount of work has been completed, and we find that: sandstone and limestone, plus pure minerals such as quartz, calcite, feldspar and mica are strongly water wet in a CO2-water system.oil-wet limestone, oil-wet quartz or coal is intermediate-wet or CO2-wet in a CO2-water system.the contact angle alone is insufficient for predicting capillary pressures in reservoir or seal rocks.the current contact angle data has a large uncertainty.solid theoretical understanding on a molecular level of rock-CO2-brine interactions is currently limited.in an ideal scenario all seal and storage rocks in CGS formations are tested for their CO2-wettability.achieving representative subsurface conditions (especially in terms of the rock surface) in the laboratory is of key importance but also very challenging.

Journal of Colloid and Interface Science, 2016

Energy Procedia, 2014

We report experimental results for acoustic response measurements conducted during injection of s... more We report experimental results for acoustic response measurements conducted during injection of supercritical carbon dioxide into a brine saturated sandstone plug. We measured P-and S-wave velocities (V p , V s ) as a function of effective stress and CO 2 saturation in a sandstone plug. We demonstrate that Gassmann's fluid substitution procedure matches the experimental results well for this sample. A 3.5% reduction of P-wave velocity after injection of two pore volumes of CO 2 into brine-saturated sample was measured. We conclude that measurement of V p can be used to estimate CO 2 saturations in rock. In addition, x-ray computer tomography (CT) images were acquired at reservoir conditions with a resolution of 33 μm, which provided more detailed information about CO 2 saturations and distributions in the rock. It is envisaged that these techniques (seismic and CT) can be combined in the future to enable a more holistic understanding of how fluid-fluid displacement processes are coupled with the acoustic response characteristics of the rock.

Geophysical Research …, 2011

Advances in Multiphase Flow and Heat Transfer (Volume 3), 2012

Mass Transfer - Advanced Aspects, 2011

... Here T is the temperature, p the pressure, R is the universal gas constant, m is the molality... more ... Here T is the temperature, p the pressure, R is the universal gas constant, m is the molality of components dissolved in water, yCO2 is the mole fraction of CO2 in the vapour phase, FCO2 is the fugacity coefficient of CO2, 2 (0) l CO μ is the standard chemical potential of CO2 in ...

Journal of Colloid and Interface Science, 2012

In the context of carbon geo-sequestration projects, brine-CO(2) interfacial tension γ and brine-... more In the context of carbon geo-sequestration projects, brine-CO(2) interfacial tension γ and brine-CO(2)-rock surface water contact angles θ directly impact structural and residual trapping capacities. While γ is fairly well understood there is still large uncertainty associated with θ. We present here an investigation of γ and θ using a molecular approach based on molecular dynamics computer simulations. We consider a system consisting of CO(2)/water/NaCl and an α-quartz surface, covering a brine salinity range between 0 and 4 molal. The simulation models accurately reproduce the dependence of γ on pressure below the CO(2) saturation pressure at 300 K, and over predict γ by ~20% at higher pressures. In addition, in agreement with experimental observations, the simulations predict that γ increases slightly with temperature or salinity. We also demonstrate that for non-hydroxylated quartz surfaces, θ strongly increases with pressure at subcritical and supercritical conditions. An increase in temperature significantly reduces the contact angle, especially at low-intermediate pressures (1-10 MPa), this effect is mitigated at higher pressures, 20 MPa. We also found that θ only weakly depends on salinity for the systems investigated in this work.

International Journal of Adhesion and Adhesives, 2006

Sealants play a vital role in maintaining the weather tightness of modern high-rise buildings. Ty... more Sealants play a vital role in maintaining the weather tightness of modern high-rise buildings. Typical sealed joints comprise an elastomeric sealant, a backing foam and the sides of the joint corresponding to the cladding panels. Conceptually, the sealant should adhere only to the sides of the joint to enable maximum movement capacity of the material to be utilised; this is known as two-sided adhesion. Previous work has shown that the sealant sometimes adheres to the backing material, resulting in three-sided adhesion, and that this results in a decrease in joint performance. The adhesion between the foam and the sealant was studied using tack and peel tests, and the results were compared with measurements of the surface energies of the foams and the surface tensions of the sealants. Adhesion mechanisms are suggested and peel force-surface energy correlations are presented. Implications for the practical application of the results in building construction are made. r

The Journal of Chemical Thermodynamics, 2016

Geophysical Research Letters, 2015

Tenside Surfactants Detergents, 2010

This investigation considers branched alkyl alcohol propoxylated sulfate surfactants as candidate... more This investigation considers branched alkyl alcohol propoxylated sulfate surfactants as candidates for chemcial enhanced oil recovery (EOR) applications. Results show that these anionic surfactants may be preferred candidates for EOR as they can be effective at creating low interfacial tension (IFT) at dilute concentrations, without requiring an alkaline agent or cosurfactant. In addition, some of the formulations exhibit a low IFT at high salinity, and hence may be suitable for use in more saline reservoirs. Adsorption tests onto kaolinite clay indicate that the loss of these surfactants can be comparable to or greater than other types of anionic surfactants. Surfactant performance was evaluated in oil recovery core flood tests. Selected formulations recovered 35 -50 % waterflood residual oil even with dilute 0.2 wt% surfactant concentrations from Berea sandstone cores.

Tenside Surfactants Detergents, 2011

We present a case study of surfactant enhanced oil recovery using Alkyl polyglucoside/1-naphthol ... more We present a case study of surfactant enhanced oil recovery using Alkyl polyglucoside/1-naphthol formulations. Alkyl polyglucosides are a green, non-toxic and renewable surfactant class synthesized out of agricultural raw materials. We measured interfacial tensions versus n-octane and viscosities of these formulations and conducted one coreflood enhanced oil recovery (EOR) experiment where we recovered 82.6 % of initial oil in place demonstrating that these formulations are efficient EOR agents.

Tenside Surfactants Detergents, 2010

We measured interfacial tensions (IFT) of aqueous alkyl polyglucoside (APG) systems formulated wi... more We measured interfacial tensions (IFT) of aqueous alkyl polyglucoside (APG) systems formulated with sorbitan ester-type cosurfactants against n-octane. The study focused on low to ultralow IFT systems which are relevant for enhanced oil recovery (EOR). In addition, we measured equilibrium adsorption concentrations of these surfactants and cosurfactants onto kaolinite clay, commonly found in oil reservoirs. We present one surfactant EOR laboratory flood experiment with one selected APGsorbitan ester formulation with which we recovered 94 % of initial oil in place (IOIP).

SPE/DOE Symposium on Improved Oil Recovery, 2004

TX 75083-3836, U.S.A., fax 01-972-952-9435.

Journal of colloid and interface science, Jan 15, 2016

Precise characterization of wettability of CO2-brine-rock system and CO2-brine interfacial tensio... more Precise characterization of wettability of CO2-brine-rock system and CO2-brine interfacial tension at reservoir conditions is essential as they influence capillary sealing efficiency of caprocks, which in turn, impacts the structural and residual trapping during CO2 geo-sequestration. In this context, we have experimentally measured advancing and receding contact angles for brine-CO2-mica system (surface roughness ∼12nm) at different pressures (0.1MPa, 5MPa, 7MPa, 10MPa, 15MPa, 20MPa), temperatures (308K, 323K, and 343K), and salinities (0wt%, 5wt%, 10wt%, 20wt% and 30wt% NaCl). For the same experimental matrix, CO2-brine interfacial tensions have also been measured using the pendant drop technique. The results indicate that both advancing and receding contact angles increase with pressure and salinity, but decrease with temperature. On the contrary, CO2-brine interfacial tension decrease with pressure and increase with temperature. At 20MPa and 308K, the advancing angle is measured...

Water Resources Research, 2015

ABSTRACT We review the literature data published on the topic of CO2 wettability of storage and s... more ABSTRACT We review the literature data published on the topic of CO2 wettability of storage and seal rocks. We first introduce the concept of wettability and explain why it is important in the context of carbon geo-sequestration (CGS) projects, and review how it is measured. This is done to raise awareness of this parameter in the CGS community, which, as we show later on in this text, may have a dramatic impact on structural and residual trapping of CO2. These two trapping mechanisms would be severely and negatively affected in case of CO2-wet storage and/or seal rock.Overall, at the current state-of-the-art, a substantial amount of work has been completed, and we find that: sandstone and limestone, plus pure minerals such as quartz, calcite, feldspar and mica are strongly water wet in a CO2-water system.oil-wet limestone, oil-wet quartz or coal is intermediate-wet or CO2-wet in a CO2-water system.the contact angle alone is insufficient for predicting capillary pressures in reservoir or seal rocks.the current contact angle data has a large uncertainty.solid theoretical understanding on a molecular level of rock-CO2-brine interactions is currently limited.in an ideal scenario all seal and storage rocks in CGS formations are tested for their CO2-wettability.achieving representative subsurface conditions (especially in terms of the rock surface) in the laboratory is of key importance but also very challenging.

Journal of Colloid and Interface Science, 2016

Energy Procedia, 2014

We report experimental results for acoustic response measurements conducted during injection of s... more We report experimental results for acoustic response measurements conducted during injection of supercritical carbon dioxide into a brine saturated sandstone plug. We measured P-and S-wave velocities (V p , V s ) as a function of effective stress and CO 2 saturation in a sandstone plug. We demonstrate that Gassmann's fluid substitution procedure matches the experimental results well for this sample. A 3.5% reduction of P-wave velocity after injection of two pore volumes of CO 2 into brine-saturated sample was measured. We conclude that measurement of V p can be used to estimate CO 2 saturations in rock. In addition, x-ray computer tomography (CT) images were acquired at reservoir conditions with a resolution of 33 μm, which provided more detailed information about CO 2 saturations and distributions in the rock. It is envisaged that these techniques (seismic and CT) can be combined in the future to enable a more holistic understanding of how fluid-fluid displacement processes are coupled with the acoustic response characteristics of the rock.