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All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Stability study of aqueous foams under high-temperature and high-pressure conditions relevant to Enhanced Geothermal Systems (EGS)

In Enhanced Geothermal System (EGS) hydraulic fracturing is carried out by injecting cold water into deep Hot Dry Rocks (HDR) under carefully controlled conditions to create new or reopen existing fractures. Water-based fracturing fluids demonstrate some challenges including immense quantity of water usage, water sensitivity of the formations, water blocking, and lack of proppant carrying capacity and transportation. Thus, an alternative is to use foam-based fracturing fluid which offers potential advantage over conventional water-based fracturing fluid such as minimum water usage, reduced wellbore damage, high proppant carrying capacity, and less environmental damage. However, foams are complex mixture of gaseous phase and liquid phase which are thermodynamically unstable at downhole conditions, and their stability can decrease over time due to liquid drainage, bubble coarsening, and coalescence. This paper shows laboratory experiments executed to study foam stability at high temperature (200°C) and high pressure (6.9MPa) conditions which simulates the geothermal environment. Foam stability was characterized by half-life of foam, which is defined as the time taken by the foam to decreases by 50% of its original height due to drainage. In this paper, two types of gaseous phases, nitrogen (N 2 ) and carbon dioxide (CO 2 ) were investigated. Also, based on successful practice of foam-based fracturing fluid in oil and gas industries, four surfactants, including Alpha olefin sulfonate (AOS), Sodium dodecyl sulfonate (SDS), Tergitol™ (NP – 40), and Cetyltrimethylammonium chloride (CTAC) at optimum concentration of 1wt.% were tested for best stability performance. In addition, different stabilizing agents including guar gum, bentonite clay, crosslinker, silicon dioxide nanoparticles (SiO 2 ), graphene oxide (GO) were also studied. Experimental results showed that N 2 foams were more stable than CO 2 foams. It was observed that foam half-life decreased with the increase in temperature. Among all the surfactants, AOS foams showed the most promising thermal stability at high temperatures. Moreover, with the addition of stabilizing agents, foam's half-life was enhanced. Stabilizing agents such as crosslinker and GO dispersion showed the most stable foams with half-life recorded at 20min and 17min, respectively, at 200°C and 6.9MPa. Finally, pressure also showed a positive effect on foam stability; with increased pressure, foam half-life was increased. Based on the experimental data, analytical models for the effect of temperature and pressure were developed, considering foam degradation is a first-order kinetic reaction that linearly depends on the foam drainage mechanism. The effect of temperature on foam half-life was studied as an exponential decay model. In this model, foam half-life is a function of drainage rate constant (D A ) and activation energy (E a ) of the foam system. The effect of pressure on foam half-life was found to obey a power-law model where an increase in pressure showed an increase in foam half-life. Furthermore, a linear relation was studied for the effect of pressure on foam activation energy and drainage rate. Then the combined effects of temperature and pressure were studied, which yielded an analytical model to predict the foam stabilities in terms of half-life for different foam compositions. In conclusion, this research indicates that with an appropriate selection of surfactants and stabilizing agents, it is possible to obtain stable foams, which could replace conventional water fracturing fluid under EGS conditions.

15 GEOTHERMAL ENERGY↗
DOE OSTI2023

A comparative investigation of the effect of gas type on foam strength and flow behavior in tight carbonates

Foam generation technique has been practically applied to overcome gas mobility issue during enhanced oil recovery (EOR) processes. Incorporated with the utilized gas, the capability of foaming agent to generate persistent foam determines the flow performance under reservoir conditions. Here, in this study, we first identified the surfactants with excellent phase behavior and foaming properties and, second, evaluated their bulk foam performance with different gases, including N 2 , CO 2 , and hydrocarbon gas (CH 4 ) under high-pressure and high-temperature conditions. In bulk, the foam generated with the high-density gas, i.e., CO 2 , exhibited the greatest foamability but the lowest foam stability. With amidoamine oxide-based surfactant, CH 4 -foam was found to be more stable than N 2 -foam, while the opposite was observed for sulfobetaine-based surfactant. The most effective surfactant was later used to perform flow experiments on two tight carbonate rocks, including Minnesota Norther Cream Buff and Edwards limestone, with permeabilities of ~0.8 and 16 mD, respectively. The core-flooding experiments showed that the optimum quality of CO 2 -foam was lower than that of N 2 - and CH 4 -foams. For a given flow rate and fixed foam quality, the steady-state strength followed the descending order of CH 4 -, N 2 -, and CO 2 -foam. However, in general, the difference in foam strength between N 2 - and CH 4 -foams was insignificant when the total flow rate was varied. We also found that the variation in rock permeability had a greater effect on the strength of the CO 2 -foam compared to those generated with N 2 and CH 4 . In the presence of oil, the shear-thinning behavior of all foams was found more prominent. The increase in oil saturation had a more adverse effect on the strength of N 2 - and CH 4 -foams, particularly in the higher permeability rock. The results indicated that the foam strength, which is key in the effectiveness of foam EOR applications, is greatly influenced by several factors such as gas density, gas solubility in water, the presence of oil, and rock permeability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1974

Application of advanced composites to helicopter airframe structures

The present work outlines a study whose objective was to assess the possible use of advanced composite materials to helicopter fuselage structure. The study used the CH-53D as a baseline design for comparison of composite with current conventional construction. Boron/epoxy and graphite/epoxy appeared to be the prime candidate materials for the major portion of the primary structure, while Kevlar-49/epoxy was the prime candidate material for secondary structure. A single-laminate shear-carrying skin combined with stringers and frames in an all-molded construction was considered the most promising concept for the airframe shell construction; foam-stabilized graphite/epoxy stringer was considered the prime concept for stringer construction. Shell construction and assembly concepts are discussed, and comparison of weight and material between current CH-53D airframe and the composite airframe shows that the latter may represent an 18% weight saving. Based on a fleet requirement of 600 vehicles, the operating cost for a fleet of helicopters constructed with the composite material airframe flying 500 hours a year per aircraft over a ten-year service life was calculated, indicating a $337,000 saving per helicopter.

Rich, M. J.↗
NASA NTRS2006

STS-121: Discovery Pre-Flight Crew News Briefing

The STS-121 crew is shown during this pre-flight news briefing. Steve Lindsey, Commander, begins with saying that they are only a few weeks from flight and the vehicle is in good shape. Mark Kelly, Pilot, is introduced by Lindsey and he discusses Kelly's main objective which is to direct the three spacewalks scheduled. Kelly introduces Mike Fossum, Mission Specialist. Kelly says that Fossum will be involved in three spacewalks. Fossum introduces Lisa Nowak, Mission Specialist, who is involved in robotics. Also Stephanie Wilson, Mission Specialist, will be involved in robotics. Piers Sellers, Mission Specialist, is introduced by Wilson, who is the lead spacewalker for this mission. Sellers then introduce Thomas Reiter, Mission Specialist, who is involved in spacewalks. The educational background of each crew member is given. Questions from the news media on the subjects of long term flights on the International Space Station, Ice frost ramp replacement, Orbiter Boom Sensor System (OBSS) stability, foam loss during STS-114 flight, duration of the mission, and mental preparation for test flights are addressed.

Source record↗
DOE OSTI2021

Optimum concentration of fly ash nanoparticles to stabilize CO 2 foams for aquifer and soil remediation

Contamination caused by non-aqueous phase liquids (NAPLs) in aquifers and soil is an important challenge that requires effective remediation techniques. One potential approach is through the use of CO 2 foams to displace NAPLs from permeable media. CO 2 foams generated only by surfactants are not stable enough for the efficient removal of NAPLs contamination. This shortcoming may be alleviated via the use of nanoparticles (NPs)-surfactant mixtures as a stabilizing agent. This work focuses on the evaluation of the optimum concentration of fly ash nanoparticles for stabilizing CO 2 foam with the combined action of the surfactant. The performance of this foam is evaluated in remediating a contaminated 41 mm × 36 mm surrogate permeable medium in a microfluidic device. Mixtures of fly ash, a by-product of coal-burning power plants, and alpha-olefin sulfonate (AOS) and lauramidopropyl betaine (LAPB) surfactants are used to generate stable foams. The results show that a 1000 mg/L AOS-LAPB surfactant solution along with 1000 mg/L of fly ash NPs produces the best performance. Formation of deposits in the matrix is observed. These deposits, which are more prominent at higher NP concentrations, appear to adversely affect displacement, displacement efficiency and remediation of the medium. This study demonstrates that using fly ash nanoparticles and optimizing their concentration can effectively stabilize CO 2 foams and improve the displacement efficiency for aquifer and soil remediation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Leakoff assessment of nanoparticle-stabilized CO 2 foams for fracturing applications

The leakoff of multiphase systems through porous media is a complicated process. In this study, we have designed an experimental setup that is used to assess the leakoff of the liquid and gas phase under pressurized conditions. The novelty of this study is that while most previous studies utilized fluid/gas in the aqueous phase, nanoparticles are introduced in this study, which formed a solid/fluid/gas multiphase system to boost foam performance and reduce leakoff. In the parametric experimental analysis, the effects of foam quality, core permeability, surfactant concentration, and polymer concentration on the dynamic and static leakoff rates of liquid and gas are evaluated. It was found that core permeability affects the leakoff of foam the most with a leakoff coefficient of up to 1.37015 $ft/\sqrt{min}$ for gas and up to 0.1056 $ft/\sqrt{min}$ for liquid under the experiment settings herein. The leakoff rate of gas is generally several magnitudes higher than that of the liquid. When CO 2 gas is present in the foam, the leakoff coefficient falls in the range between 0 and 1.37015 $ft/\sqrt{min}$ for gas, and between 0.0005 and 0.1056 $ft/\sqrt{min}$ for liquid. Finally, the methodology and results of this study shed light on the mechanistic understanding of the leakoff properties of multiphase systems and could be used to assist the design of foam fracturing for reservoir stimulation.

03 NATURAL GAS↗
DOE OSTI2025

Fatty acid foams for nonselective physical removal of microplastics from aqueous solutions

Microplastics (MPs) are pervasive environmental contaminants whose removal from water remains a major challenge due to their small size, chemical diversity, and dynamic surface properties arising from environmental aging/weathering. Here, we present a concept of foam-based separation method that physically traps MPs in the foam phase using microtubular assemblies of 12-hydroxystearic acid. These foams are stabilized by anisotropic fatty acid microtubules formed in the presence of ethanolamine, which jam within the foam channels and suppress fluid drainage thereby enhancing MP retention and foam stability. MPs of different sizes, polymer compositions (including polystyrene, polypropylene, polyethylene terephthalate, and polytetrafluoroethylene), and weathered states were retained in the foam phase without requiring chemical modification or relying on chemical interactions between the fatty acid and MPs. Thermally induced transition of the fatty acid microtubules into nanomicelles above the characteristic phase transition temperature (∼35 °C) enables controlled foam collapse and recovery of trapped MPs. The cumulative removal efficiency can exceed 85% through multiple foaming cycles, matching predictions from a probabilistic retention model. This work shows that foams can provide a simple platform to trap MPs, thus providing a new physical-removal strategy that does not rely on the particles’ chemistry.

Guillot, Kennedy A. [Louisiana State Univ., Baton ↗
DOE OSTI2022

Foam Fracturing Fluid Half-life Experimental Data

Foam thermal stability was studies at Temple University in collaboration with Oak Ridge National Lab (ORNL). The goal of this project is to explore thermally stable foams as hydrofracking fluid media for potential applications in enhanced geothermal system (EGS). Data generated from this project will allow researchers to explore foam as potential fracturing fluid. More than 800 data points on the half-life of foams are recorded in Excel files in the included archive resource (Half-life of Foams with Different Surfactants and Stabilizing Agents). The Excel file within each surfactant folder contains half-life data of the respective surfactant with different stabilizing agents, pressure, and temperature. The respective folders also contains Word files describing the details of the data included in the respective Excel sheet.

15 GEOTHERMAL ENERGY↗
DOE OSTI2020

A Pilot-Scale Evaluation of Natural Gas-Based Foam at Elevated Pressure and Temperature Conditions

Abstract Nitrogen (N2) and Carbon Dioxide (CO2) foams have been used as hydraulic fracturing fluids for several decades to reduce water usage and minimize damage in water-sensitive reservoirs. These foam treatments require gases to be liquefied and transported to site. An alternative approach would be to use natural gas (NG) that is readily available from nearby wells, pipelines, and processing facilities as the internal, gaseous phase to create a NG-based foam. Hydraulic fracturing with NG foam is a relatively inexpensive option, makes use of an abundant and often wasted resource, and may even provide production benefits in certain reservoirs. As part of an ongoing development project sponsored by the Department of Energy (DOE), the surface process to create NG foam is being developed and the properties of NG foam are being explored. This paper presents recent results from a rigorous pilot-scale demonstration of NG foam over a range of operating scenarios relevant to surface and bottomhole conditions with a variety of base-fluid mixtures. The Pilot-scale Foam Test Facility (PFTF) used in these investigations is first described. The PFTF is capable of generating foamed fluids at pressures up to 7,500 psig and at temperatures in excess of 300°F. Then, results from several investigations aimed at proving NG foam at conditions relevant to the field are presented. NG foam was characterized using rheology measurements and flow visualization techniques. Experiments were performed to investigate the texture and stability of NG foam generated by two different mixing methods: one using a custom designed tee to match mixing velocities in the field where the gas phase is jetted into the aqueous stream, and another to ensure comprehensive mixing for laboratory analysis. Parametric studies were conducted to explore the effects of flow rate, foam quality, and temperature on the stability of NG foam. Moreover, different fluid preparations were used to investigate the effect of base fluid and additive concentrations on the stability of NG foams. Additional laboratory studies that investigated foam stability with produced water and multicomponent NG mixtures are also reported. The NG foams explored in these investigations exhibited typical, shear-thinning behavior observed in rheological studies of N2- and CO2-based foams. The measured viscosity and observed stability indicate that NG foams are well suited for fracturing applications. Like other foams, NG foam exhibits sensitivity to operating temperature characterized by a decrease in apparent viscosity as temperature increases. Rapid foam breakdown was observed at significantly elevated temperatures exceeding 290°F. In addition to fluid characterization, these investigations also yielded several key lessons that should be applied to future field demonstrations of NG foam.

Beck, Griffin↗
NASA NTRS1994

Microgravity foam structure and rheology

Our long-range objective is to establish the fundamental interrelationship between the microscopic structure and dynamics of foams and their macroscopic stability and rheology. Foam structure and dynamics are to be measured directly and noninvasively through the use and development of novel multiple light scattering techniques such as diffusing-wave spectroscopy (DWS). Foam rheology is to be measured in a custom rheometer which allows simultaneous optical access for multiple light drainage of liquid from in between gas bubbles as the liquid:gas volume fraction in increased towards the rigidity-loss transition.

Durian, Douglas J.↗
DOE OSTI2021

Literature Data on Foam Fracturing Fluid

At the beginning of this project, the Temple team spent significant effort to collect data relevant to foam fracturing. More than 40 articles/reports were found in the open literature that reported the properties of aqueous foams under various testing conditions. The foam properties included viscosity and stability in terms of half-life, while were influenced by the foam quality, shear rate, temperature, pressure, as well as surfactants and additives used in making the foam base solutions. As a result, more than 1100 data points were collected, which are included in a master worksheet named "Literature data on Foam Fracturing Fluid". These data points are organized based on following parameters: 1. Literature source, including authors and publication year 2. Gaseous phase (e.g. CO2, N2) 3. Liquid phase (e.g. tap water, DI water, salt water) 4. Surfactants and their concentrations 6. Additives 7. Foam quality 8. Pressure 9. Temperature 10. Viscosity 11. Foam stability, which was characterized by its half-life: Half-life Foam study data base with data analysis was completed and a webpage is designed hosted on public server at https://surfactant-dashboard.herokuapp.com

15 GEOTHERMAL ENERGY↗
DOE OSTI2021

Additive Manufacturing of Porous Ceramics With Foaming Agent

The macro-porous ceramics has promising durability and thermal insulation performance. As porous ceramics find more and more applications across many industries, a cost-effective and scalable additive manufacturing technique for fabricating macro-porous ceramics is highly desirable. Herein, we reported a facile additive manufacturing approach to fabricate porous ceramics and control the printed porosity. Several printable ceramic inks were prepared, and the foaming agent was added to generate gaseous bubbles in the ink, followed by the direct ink writing and the ambient-pressure and room-temperature drying to create the three-dimensional geometries. In this work, a set of experimental studies were performed to optimize the printing quality. The results revealed the optimal process parameters for printing the foamed ceramic ink with a high spatial resolution and fine surface quality. Varying the concentration of the foaming agent enables the controllability of the structural porosity. The maximum porosity can reach 85%, with a crack-free internal porous structure. The tensile tests showed that the printed macro-porous ceramics possessed enhanced durability with the addition of fiber. With a high-fidelity three-dimensional (3D) printing process and the precise controllability of the porosity, we showed that the printed samples exhibited a remarkably low thermal conductivity and durable mechanical strength.

36 MATERIALS SCIENCE↗
NASA NTRS1996

Analysis and Tests of Reinforced Carbon-Epoxy/Foam-Core Sandwich Panels with Cutouts

The results of a study of a low-cost structurally efficient minimum-gage shear-panel design that can be used in light helicopters are presented. The shear-panel design is based on an integrally stiffened syntactic-foam stabilized-skin with an all-bias-ply tape construction for stabilized-skin concept with an all-bias-ply tape construction for the skins. This sandwich concept is an economical way to increase the panel bending stiffness weight penalty. The panels considered in the study were designed to be buckling resistant up to 100 lbs/in. of shear load and to have an ultimate strength of 300 lbs/in. The panel concept uses unidirectional carbon-epoxy tape on a syntactic adhesive as a stiffener that is co-cured with the skin and is an effective concept for improving panel buckling strength. The panel concept also uses pultruded carbon-epoxy rods embedded in a syntactic adhesive and over-wrapped with a bias-ply carbon-epoxy tape to form a reinforcing beam which is an effective method for redistributing load around rectangular cutout. The buckling strength of the reinforced panels is 83 to 90 percent of the predicted buckling strength based on a linear buckling analysis. The maximum experimental deflection exceeds the maximum deflection predicted by a nonlinear analysis by approximately one panel thickness. The failure strength of the reinforced panels was two and a half to seven times of the buckling strength. This efficient shear-panel design concept exceeds the required ultimate strength requirement of 300 lbs/in by more than 100 percent.

Baker, Donald J.↗
DOE OSTI2023

Methane foam performance in oil-wet unconsolidated porous media: A systematic experimental investigation at reservoir conditions

Methane foam performance was systematically evaluated using high-pressure and high-temperature experiments performed on oil-wet proppant packs. The sensitivities of foam performance to various key factors, including surfactant concentration, foam quality, total injection rate, salinity, operating pressure, and initial oil saturation were examined. The results showed that even though the foamability and foam strength in oil-wet proppant packs were adversely affected by wettability and presence of oil, the steady-state pressure drops across the proppant packs were insensitive to the quantity of oil initially present. The presence of oil above the critical oil saturation impeded the onset of foam generation. This suggested that the foamability of surfactants depends on the synergetic effects of surfactant’s ionic nature and foam parameters, such as foam quality and total injection rate, on their ability to reduce the oil saturation to a threshold value below which favorable bubble generation sites could be created. It was observed that, for low injection rate, anionic surfactant was ineffective at low salinity conditions, while amphoteric agent performed well at all salinities. Additionally, an increase in salinity resulted in enhanced pressure drop across the proppant packs for both anionic and amphoteric surfactants. Further, the results also established that too high operating pressures are somewhat detrimental to the foam strength and stability, irrespective of the ionic nature of foaming agents and the wettability of the porous medium. For the anionic surfactant, the increase in the total flow rate was found to mitigate the adverse effects of low salt concentration and operating pressure. Results from quality-sensitivity foam tests identified two regions for the foam behavior, named low-quality and high-quality regimes, separated by the transition foam quality. Finally, we discuss the implications of the results for the design and effective implementation of enhanced oil recovery (EOR) schemes that deploy hydrocarbon-based foams.

02 PETROLEUM↗
DOE OSTI2021

The preparation and properties of polyurethane foams reinforced with bamboo fiber sources in China

Abstract Polyurethane (PU) foams reinforced with bamboo fiber sources in China, i.e. , bamboo fiber, bamboo α -cellulose fiber, and bamboo nanocellulose fiber, were prepared and their physico-mechanical properties were analyzed in this work. The bamboo fiber sources and PU foams were characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), Thermal gravimetric analysis (TGA) and universal compression testing. The results indicated that the hydroxyl groups on the fiber surfaces were enhanced by removing non-celluloses in the preparation of α -cellulose and nanocellulose. With the addition of small particle size α -cellulose and nanocellulose, the cell sizes of PU foams were reduced due to more nucleating agents being introduced. The FTIR spectra confirmed that the bamboo fiber sources were involved in the foaming reaction. The PU foams with bamboo fiber sources had a higher thermal stability than neat foam, and they were satisfactory enough to be used as insulation. PU foams reinforced with 5% bamboo fiber, 3% α -cellulose fiber and 3% nanocellulose fiber had better physico-mechanical performance than other foams. The reinforcement performance of 3% bamboo α -cellulose fiber on PU foam was comparable with that of high-cost nanocellulose. Accordingly, bamboo α -cellulose fiber was demonstrated to be a promising candidate to reinforce PU foam, which could be used in the reinforcement of foam insulation.

Qiu, Chongpeng↗
DOE OSTI2022

Tailorable thermoplastic insulation foam composites enabled by porous-shell hollow glass spheres and expandable thermoplastic microspheres

Here we report a simple and commercially viable strategy to produce thermoplastic composite foams using synergistic foaming approaches – incorporating porous-shell hollow-interior glass spheres (PHGS) as a filler and utilizing expandable thermoplastic microspheres (EMS) as a physical blowing agent – for thermal insulation applications. The EMS in these composites ensure formation of highly porous, low-density foam while the PHGSs provide low thermal conductivity and lightweight mechanical reinforcement. Through systematic optimization of the PHGS and EMS loadings, a lightweight, and robust insulation with thermal resistivity greater than 27.7 m·K/W (R/in. > 4) is achieved. Notably, the fabricated foams also demonstrated comparable compressive strength than some commercial thermoplastic insulating materials. Through optimization of PHGS and EMS concentrations, results indicated similar thermal performance characteristics at varying foam densities, while higher loadings of both components lead to reduced insulation performance and weak mechanical stability of the foams. The results obtained, when coupled with the potential scalability and tailor ability of the overall process towards targeted insulation performance, not only endows competitiveness with current commercial thermoplastic insulating materials but also offers great promise for the development of unique thermoplastic composite foams for a variety of insulation systems.

36 MATERIALS SCIENCE↗