Bio. for George J. HirasakiB.S. Chemical Engineering (1963) Lamar UniversityPh.D. Chemical Engineering (1967) Rice UniversityGeorge Hirasaki is the A.J. Hartsook Professor Emeritus in the Department of Chemical and Biomolecular Engineering at Rice University. He graduated with a B.S. from Lamar University in 1963 and with a Ph.D. from Rice University in 1967. He was employed by Shell Development and Shell Oil Companies from 1967 to 1993. He joined the Rice faculty in 1993 as Professor.George received the Ralph Budd Award for the best PhD in Engineering at Rice in 1967. He was inducted into the National Academy of Engineering in 1991. He is a charter member of The Academy of Medicine, Engineering Phone: (713) 348-5416 Address: MS 362 Rice University 6100 Main St. Houston, TX 77005
Journal of Chemical & Engineering Data, Jun 21, 2016
The design of surfactants for stabilizing CO2-in-water (brine) (C/W) foams at high temperature is... more The design of surfactants for stabilizing CO2-in-water (brine) (C/W) foams at high temperature is challenging given the low density (solvent strength) of CO2, limited surfactant solubility in brine, and a lack of knowledge of the interfacial and rheological properties. Herein, the tail length of trimethylammonium cationic surfactants was optimized to provide the desired phase behavior and interfacial properties for formation and stabilization of the C/W foams. The headgroup was properly balanced with a C12–14 hydrocarbon tail to achieve aqueous solubility in 22% total dissolved solids (TDS) brine up to 393 K (120 °C) along with high surfactant adsorption (area/surfactant molecule of 154 A2) at the CO2–water (C–W) interface which reduced the interfacial tension from ∼40 mN/m to ∼6 mN/m. For C12–14N(CH3)3Cl, these properties enabled stabilization of a C/W foam with an apparent viscosity of 14 mPa·s at 393 K in both a crushed calcium carbonate packed bed (75 μm2 or 76 Darcy) and a capillary tube downstream o...
Over the last few years, more than 40 partitioning interwell tracer tests (PITTs) have been condu... more Over the last few years, more than 40 partitioning interwell tracer tests (PITTs) have been conducted at many different sites to measure nonaqueous phase liquid (NAPL) saturations in the subsurface. While the main goal of these PITTs was to estimate the NAPL volume in the subsurface, some were specifically conducted to assess the performance of remedial actions involving NAPL removal. In this paper, we present a quantitative approach to assess the performance of remedial actions to recover NAPL that can be used to assess any NAPL removal technology. It combines the use of PITTs (to estimate the NAPL volume in the swept pore volume between injection and extraction wells of a test area) with the use of several cores to determine the vertical NAPL distribution in the subsurface. We illustrate the effectiveness of such an approach by assessing the performance of a surfactant/foam flood conducted at Hill Air Force Base, UT, to remove a TCE-rich NAPL from alluvium with permeability contrasts as high as one order of magnitude. In addition, we compare the NAPL volumes determined by the PITTs with volumes estimated through geostatistical interpolation of aquifer sediment core data collected with a vertical frequency of 5-10 cm and a lateral borehole spacing of 0.15 m. We demonstrate the use of several innovations including the explicit estimation of not only the errors associated with NAPL volumes and saturations derived from PITTs but also the heterogeneity of the aquifer sediments based upon permeability estimates. Most importantly, we demonstrate the reliability of the
A surfactant/foam process is described for the remediation of aquifers contaminated with dense no... more A surfactant/foam process is described for the remediation of aquifers contaminated with dense nonaqueous phase liquid (DNAPL). Foam is used for mobility control to displace DNAPL from low permeability sands that are often unswept during a remediation process. Introduction An area where the technology developed for enhanced oil recovery can be applied to environmental remediation is the application of surfactant to remove nonaqueous phase liquid (NAPL) from aquifers. NAPL can be of two types, those which are less dense than water, called light nonaqueous phase liquid (LNAPL) and those which are more dense than water, called dense nonaqueous phase liquid (DNAPL). We concentrate on DNAPL because there are fewer viable alternatives to surfactant remediation. DNAPL will tend to migrate to the lowest accessible point in the aquifer and to enter lower permeability sediments if the capillary pressure becomes large enough. The challenge is to remove DNAPL from local depressions along the base of an aquifer and from low permeability layers in the presence of higher permeability layers. An approach to improve the sweep efficiency of a displacement process is to use mobility control so that the injected fluid is less mobile than the resident fluids. The common method of mobility control for surfactant flooding is through the generation of an inherently viscous microemulsion phase and through the addition of a polymer. However, Lawson and Reisberg introduced the concept of injecting gas with the surfactant solution to generate an in situ foam for mobility control. This approach has not been as popular because the mobility of foam is not as predictable as with polymers. However, much has been learned about the mobility of foam since that time and some publications on the use of foam for mobility control of surfactant flooding have appeared. Also foam has the potential of selectively reducing the mobility more in higher permeability layers in contact with lower permeability layers. Site Characterization The location for a field test of the surfactant/foam process for aquifer remediation is Hill Air Force Base near Ogden, Utah. This base has been the test site of many remediation technologies during 1996. The Operable Unit 2 (OU2) is a waste disposal site where unlined earthen trenches were used from 1967 to 1975 for the disposal of spent liquid degreasing solvents (primarily trichloroethylene). OU2 is currently being treated by "pump and treat" where the DNAPL and ground water are pumped out and the organic material removed by sedimentation and steam stripping. However, pump and treat treatment alone would have to continue for a very long time because of the low solubility of the contaminants in water and the large volume of DNAPL existing in pools and as a residual saturation. A surfactant flood without mobility control was conducted successfully by INTERA and the University of Texas at a site adjacent to where the surfactant/foam is to be tested. A steam flood test in an adjacent site is planned in the near future. Aquifer structure A structure map of the base of the unconfined aquifer is shown in Fig. 1. The aquifer consists of coarse-grained, unconsolidated sediments of recent alluvium and/or Provo Formation. It is about 50 ft thick and the water table is about 25 ft below ground level. The aquifer is underlain by more than 100 ft of the clay dominated Alpine Formation. This formation will be called the "aquitard". The structure of the aquitard and the water table helps to keep the aquifer confined in a trough or channel. Fig. 2 is a cross section along the long axis of the channel. The disposal trenches were located somewhere near the southern end of this cross-section. P. 471
ABSTRACT We demonstrate the use of foam to divert flow from high permeable to low permeable regio... more ABSTRACT We demonstrate the use of foam to divert flow from high permeable to low permeable regions in a PDMS heterogeneous porous microfluidic system. Foam is generated using a flow-focusing microfluidic device with co-flowing gas and aqueous surfactant streams. Foam quality (gas fraction) is modulated by adjusting the flow rate of the aqueous surfactant solution while keeping the gas inlet pressure fixed. The foam is then injected into an aqueous-solution filled heterogeneous porous media containing a high and low permeable region and sweep of the saturated aqueous phase is monitored. Compared with 100% gas injection, surfactant-stabilized foam is shown to effectively improve the sweep of the aqueous fluid in both high and low permeable regions of the porous micromodel. The best performance of foam on fluid diversion is observed in the lamella-separated foam regime, where the presence of foam can enhance gas saturation in the low permeable region up to 45.1% at the time of gas breakthrough. The presented results are useful in understanding and designing foam injection in porous underground formations for aquifer remediation and enhanced oil recovery processes.
Journal of Surfactants and Detergents, Jan 22, 2023
Nonionic surfactants are increasingly being applied in oil recovery processes due to their stabil... more Nonionic surfactants are increasingly being applied in oil recovery processes due to their stability and low adsorption onto mineral surfaces. However, these surfactants lead to the production of emulsified oil that is extremely stable and difficult to separate by conventional methods. This research characterizes the stability of crude oil mixed with a nonionic surfactant, L24–22, in a brine solution. When subjected to gravity separation, a middle oil‐rich and bottom water‐rich emulsion are generated for various water–oil ratios. Thermal treatments can effectively break oil‐rich emulsions, but the bottom water layer remains contaminated with micron‐sized crude oil droplets. A magnetic nanoparticle treatment is shown to demulsify the crude oil emulsions, dropping the total organic carbon (TOC) in the water layer from 1470 to 30 ppm.
Journal of Chemical & Engineering Data, Jun 21, 2016
The design of surfactants for stabilizing CO2-in-water (brine) (C/W) foams at high temperature is... more The design of surfactants for stabilizing CO2-in-water (brine) (C/W) foams at high temperature is challenging given the low density (solvent strength) of CO2, limited surfactant solubility in brine, and a lack of knowledge of the interfacial and rheological properties. Herein, the tail length of trimethylammonium cationic surfactants was optimized to provide the desired phase behavior and interfacial properties for formation and stabilization of the C/W foams. The headgroup was properly balanced with a C12–14 hydrocarbon tail to achieve aqueous solubility in 22% total dissolved solids (TDS) brine up to 393 K (120 °C) along with high surfactant adsorption (area/surfactant molecule of 154 A2) at the CO2–water (C–W) interface which reduced the interfacial tension from ∼40 mN/m to ∼6 mN/m. For C12–14N(CH3)3Cl, these properties enabled stabilization of a C/W foam with an apparent viscosity of 14 mPa·s at 393 K in both a crushed calcium carbonate packed bed (75 μm2 or 76 Darcy) and a capillary tube downstream o...
Over the last few years, more than 40 partitioning interwell tracer tests (PITTs) have been condu... more Over the last few years, more than 40 partitioning interwell tracer tests (PITTs) have been conducted at many different sites to measure nonaqueous phase liquid (NAPL) saturations in the subsurface. While the main goal of these PITTs was to estimate the NAPL volume in the subsurface, some were specifically conducted to assess the performance of remedial actions involving NAPL removal. In this paper, we present a quantitative approach to assess the performance of remedial actions to recover NAPL that can be used to assess any NAPL removal technology. It combines the use of PITTs (to estimate the NAPL volume in the swept pore volume between injection and extraction wells of a test area) with the use of several cores to determine the vertical NAPL distribution in the subsurface. We illustrate the effectiveness of such an approach by assessing the performance of a surfactant/foam flood conducted at Hill Air Force Base, UT, to remove a TCE-rich NAPL from alluvium with permeability contrasts as high as one order of magnitude. In addition, we compare the NAPL volumes determined by the PITTs with volumes estimated through geostatistical interpolation of aquifer sediment core data collected with a vertical frequency of 5-10 cm and a lateral borehole spacing of 0.15 m. We demonstrate the use of several innovations including the explicit estimation of not only the errors associated with NAPL volumes and saturations derived from PITTs but also the heterogeneity of the aquifer sediments based upon permeability estimates. Most importantly, we demonstrate the reliability of the
A surfactant/foam process is described for the remediation of aquifers contaminated with dense no... more A surfactant/foam process is described for the remediation of aquifers contaminated with dense nonaqueous phase liquid (DNAPL). Foam is used for mobility control to displace DNAPL from low permeability sands that are often unswept during a remediation process. Introduction An area where the technology developed for enhanced oil recovery can be applied to environmental remediation is the application of surfactant to remove nonaqueous phase liquid (NAPL) from aquifers. NAPL can be of two types, those which are less dense than water, called light nonaqueous phase liquid (LNAPL) and those which are more dense than water, called dense nonaqueous phase liquid (DNAPL). We concentrate on DNAPL because there are fewer viable alternatives to surfactant remediation. DNAPL will tend to migrate to the lowest accessible point in the aquifer and to enter lower permeability sediments if the capillary pressure becomes large enough. The challenge is to remove DNAPL from local depressions along the base of an aquifer and from low permeability layers in the presence of higher permeability layers. An approach to improve the sweep efficiency of a displacement process is to use mobility control so that the injected fluid is less mobile than the resident fluids. The common method of mobility control for surfactant flooding is through the generation of an inherently viscous microemulsion phase and through the addition of a polymer. However, Lawson and Reisberg introduced the concept of injecting gas with the surfactant solution to generate an in situ foam for mobility control. This approach has not been as popular because the mobility of foam is not as predictable as with polymers. However, much has been learned about the mobility of foam since that time and some publications on the use of foam for mobility control of surfactant flooding have appeared. Also foam has the potential of selectively reducing the mobility more in higher permeability layers in contact with lower permeability layers. Site Characterization The location for a field test of the surfactant/foam process for aquifer remediation is Hill Air Force Base near Ogden, Utah. This base has been the test site of many remediation technologies during 1996. The Operable Unit 2 (OU2) is a waste disposal site where unlined earthen trenches were used from 1967 to 1975 for the disposal of spent liquid degreasing solvents (primarily trichloroethylene). OU2 is currently being treated by "pump and treat" where the DNAPL and ground water are pumped out and the organic material removed by sedimentation and steam stripping. However, pump and treat treatment alone would have to continue for a very long time because of the low solubility of the contaminants in water and the large volume of DNAPL existing in pools and as a residual saturation. A surfactant flood without mobility control was conducted successfully by INTERA and the University of Texas at a site adjacent to where the surfactant/foam is to be tested. A steam flood test in an adjacent site is planned in the near future. Aquifer structure A structure map of the base of the unconfined aquifer is shown in Fig. 1. The aquifer consists of coarse-grained, unconsolidated sediments of recent alluvium and/or Provo Formation. It is about 50 ft thick and the water table is about 25 ft below ground level. The aquifer is underlain by more than 100 ft of the clay dominated Alpine Formation. This formation will be called the "aquitard". The structure of the aquitard and the water table helps to keep the aquifer confined in a trough or channel. Fig. 2 is a cross section along the long axis of the channel. The disposal trenches were located somewhere near the southern end of this cross-section. P. 471
ABSTRACT We demonstrate the use of foam to divert flow from high permeable to low permeable regio... more ABSTRACT We demonstrate the use of foam to divert flow from high permeable to low permeable regions in a PDMS heterogeneous porous microfluidic system. Foam is generated using a flow-focusing microfluidic device with co-flowing gas and aqueous surfactant streams. Foam quality (gas fraction) is modulated by adjusting the flow rate of the aqueous surfactant solution while keeping the gas inlet pressure fixed. The foam is then injected into an aqueous-solution filled heterogeneous porous media containing a high and low permeable region and sweep of the saturated aqueous phase is monitored. Compared with 100% gas injection, surfactant-stabilized foam is shown to effectively improve the sweep of the aqueous fluid in both high and low permeable regions of the porous micromodel. The best performance of foam on fluid diversion is observed in the lamella-separated foam regime, where the presence of foam can enhance gas saturation in the low permeable region up to 45.1% at the time of gas breakthrough. The presented results are useful in understanding and designing foam injection in porous underground formations for aquifer remediation and enhanced oil recovery processes.
Journal of Surfactants and Detergents, Jan 22, 2023
Nonionic surfactants are increasingly being applied in oil recovery processes due to their stabil... more Nonionic surfactants are increasingly being applied in oil recovery processes due to their stability and low adsorption onto mineral surfaces. However, these surfactants lead to the production of emulsified oil that is extremely stable and difficult to separate by conventional methods. This research characterizes the stability of crude oil mixed with a nonionic surfactant, L24–22, in a brine solution. When subjected to gravity separation, a middle oil‐rich and bottom water‐rich emulsion are generated for various water–oil ratios. Thermal treatments can effectively break oil‐rich emulsions, but the bottom water layer remains contaminated with micron‐sized crude oil droplets. A magnetic nanoparticle treatment is shown to demulsify the crude oil emulsions, dropping the total organic carbon (TOC) in the water layer from 1470 to 30 ppm.
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