Mitigation Techniques for Foaming Engine Oil
Engine oil foaming presents a significant challenge in modern combustion systems, with foam volumes often reaching 150-200 mL under standard test conditions and persisting for 30-45 seconds. This phenomenon impairs lubrication effectiveness by reducing oil film strength, disrupting heat transfer at critical interfaces, and creating vapor barriers that prevent adequate surface wetting across engine components.
The fundamental challenge lies in balancing foam suppression with the preservation of other critical lubricant properties—particularly detergency, wear protection, and high-temperature stability.
This page brings together solutions from recent research—including polyalkylsiloxane antifoam formulations with precise silicon concentration control, non-silicone poly(acrylate) copolymers with tailored molecular weights, and room-temperature cured silicone integration techniques. These and other approaches allow engineers to address foaming concerns while maintaining the overall performance profile required in modern high-stress engine environments.
1. Lubricating Oil Composition with Low Molecular Weight Silicon Compounds and Polyalkylsiloxane Antifoam
AFTON CHEMICAL CORP, 2025
Lubricating oil for spark-ignition engines that maintains low foaming and aeration while also providing good low-speed pre-ignition (LSPI) performance. The oil contains a low level of silicon from a polyalkylsiloxane antifoam polymer, as well as higher levels of silicon from silicon-containing compounds like trisiloxanes and silanes with molecular weights under 650. This composition allows reducing foaming and aeration compared to higher molecular weight silicon compounds. It also enables passing LSPI tests.
2. Method for Evaluating Dispersing Capacity of Lubricating Compositions Using Lacunarity Analysis of Carbonaceous Particulate Dispersions
ENI SPA, 2025
A method for assessing the dispersing capacity of lubricating compositions and additives for internal combustion engines, comprising preparing a dispersion of carbonaceous particulate in the lubricating composition, analyzing the dispersion by optical microscopy, and calculating the degree of dispersion based on lacunarity. The method enables preliminary assessment of lubricating compositions and additives without engine testing, allowing for cost-effective selection of promising candidates for further evaluation.
3. Poly(Acrylate) Polymer Antifoam Composition with Solubility and Surface Tension Monomers
THE LUBRIZOL CORP, 2024
Antifoam compositions for diesel fuels comprising poly(acrylate) polymers prepared by polymerizing a combination of solubility monomers and surface tension monomers, particularly those comprising C1-C4 alkyl esters of (meth)acrylic acid and C5-C12 alkyl esters of (meth)acrylic acid. The poly(acrylate) polymers exhibit improved antifoam performance compared to conventional silicon-based antifoams, and are particularly effective in reducing foam generation during fuel fill-ups.
4. Effects and Mechanisms of Dilute-Foam Dispersion System on Enhanced Oil Recovery from Pore-Scale to Core-Scale
Xiuyu Wang, Rui Shen, Yuanyuan Gao - MDPI AG, 2024
The dilute-foam dispersion system improves oil recovery by reducing interfacial tension between oil and water, altering wettability, and diverting displaced fluids by plugging larger pores. An optimized foaming system is obtained by formability evaluation experiments, in which the half-life for drainage and foaming volume by different types and concentrations of surfactants are analyzed, followed by the addition of partially hydrolyzed polyacrylamide (HPAM) with varied concentrations to enhance the foam stability. Using COMSOL Multiphysics 5.6 software, the Jamin effect and plugging mechanism of the watergas dispersion system in narrow pore throats were simulated. This dispersion system is applied to assist CO2 huff-n-puff in a low-permeability core, combined with the online NMR method, to investigate its effects on enhanced oil recovery from the pore scale. Core-flooding experiments with double-pipe parallel cores are then performed to check the effect and mechanism of this dilute-foam dispersion system (DFDS) on enhanced oil recovery from the core scale. Results show that foam gen... Read More
5. Effect of Oil Polarity on Surfactant Foam Properties at Bulk and Macroscopic Scale
Alvin Balakirisnan, Mohd Zaidi Jaafar, Akhmal Sidek - SPE, 2024
Abstract Recent studies on oil-foam interaction using different types of oil were limited to the aspect of alkane chain length, density and viscosity of crude oil. However, oil polarity toward foam stability to predict the significant variable of the foam half-life and its evaluation in macroscopic oil displacement is still elusive in literature. In this study, the effect of oil polarity on foam properties at bulk and macroscopic scales was investigated. The effect of electrolytes on surfactant foam stability was studied. Subsequently, the foam stability in the presence of polar and non-polar oil was determined. Thereafter, the macroscopic oil displacement efficiency of surfactant foam was evaluated. Finally, a multivariate linear regression analysis was used to predict the significant variable of the foam half-life. The results indicate that cocamidopropyl betaine (CAPB) foam had better stability under the influence of oil polarity, with a half-life decrease of 8% in hexane oil compared to 86% by sodium dodecyl sulfate (SDS). Moreover, SDS foam flooding recovered 10% additional oil ... Read More
6. An experimental study of foam-oil interactions for nonionic-based binary surfactant systems under high salinity conditions
Ayomikun Bello, Anastasia Ivanova, Denis Bakulin - Springer Science and Business Media LLC, 2024
Abstract A key factor affecting foam stability is the interaction of foam with oil in the reservoir. This work investigates how different types of oil influence the stability of foams generated with binary surfactant systems under a high salinity condition. Foam was generated with binary surfactant systems, one composed of a zwitterionic and a nonionic surfactant, and the other composed of an anionic and a nonionic surfactant. Our results showed that the binary surfactant foams investigated are more tolerant under high salinity conditions and in the presence of oil. This was visually observed in our microscopic analysis and was further attributed to an increase in apparent viscosity achieved with binary surfactant systems, compared to single surfactant foams. To understand the influence of oil on foam stability, we performed a mechanistic study to investigate how these oils interact with foams generated with binary surfactants, focusing on their applicability under high salinity conditions. The generation and stability of foam are linked to the ability of the surfactant system to sol... Read More
7. Lubricating Oil Composition with Fischer-Tropsch Base Oil and Polyalkylene Glycol for Viscosity Stability
SHELL USA INC, 2024
A lubricating oil composition for axles that maintains viscosity stability across a wide temperature range, comprising a Fischer-Tropsch derived base oil and a polyalkylene glycol high-viscosity component. The composition provides effective lubrication at both low and high temperatures, with the Fischer-Tropsch derived base oil providing low-temperature lubricity and the polyalkylene glycol component providing high-temperature wear protection. The composition also includes anti-foam additives that maintain their effectiveness across the temperature range, particularly a non-ionic surfactant-based anti-foam that provides excellent foaming results in both two-phase and single-phase states.
8. Influence of typical liquid fuels on foam properties of critical components of environmentally friendly aqueous film-forming foams
Jiaqing Zhang, Fengju Shang, Xin Liu - Elsevier BV, 2024
In this study, the influence mechanism of typical fuels (oils) on the foam properties of mixture of hydrocarbon and fluorocarbon surfactants was investigated. A mixed solution was prepared based on a nonionic hydrocarbon surfactant (APG-0810) and a zwitterionic C6 fluorocarbon surfactant (short-chain). The effect of different oils (heptane, kerosene, diesel, and transformer oil) on the physical property parameters, foamability, oil resistivity of foam and single vertical liquid film of the mixture are systematically investigated. Results indicate that the viscosity of mixture increases, but the conductivity, surface activity, and initial foam height decreases with addition of the four oils. The drainage and volume decay of the foam are accelerated by the presence of oils. In addition, the presence of oils accelerates liquid film thinning through affecting drainage, especially for the oil with higher density, water solubility, and volatility. The four oils showed different effect on foam properties due to the difference in nature and emulsification of them. Among them, the foam proper... Read More
9. Expansion process of foamed bitumen considering surface energy
Zhiqiang Cheng, Ruilin Wang, Xuekai Gao - Informa UK Limited, 2024
Bitumen, sourced from different crude oils, exhibits distinct foaming properties that significantly influence the performance of foamed bitumen mixtures. This research investigates the relationship between the expansion ratio of foamed bitumen and its surface energy. A theoretical analysis was conducted on a single bitumen bubble to explore the equilibrium between internal steam work and surface energy during expansion. This led to a unique formula linking the bitumen bubble's expansion ratio to its surface energy. The validity of this formula was confirmed through empirical measurements of four different bitumens. Results reveal a significant exponential relationship between the expansion ratio of a single bituminous bubble and the bitumen surface energy. This correlation, supported by experimental data from four bitumen samples, suggests that bitumens with lower surface energy enhance foaming performance.
10. Experimental study on the effect of formulation and hydrodynamic variables on non‐aqueous foams stability
Alexis Cova‐Bonillo, Rayda Patiño-Camino, José Danglad‐Flores - Wiley, 2024
Abstract This study investigated the factors affecting the foamability and stability of nonaqueous foams. The researchers systematically varied the formulation (surfactant and alcohol type and concentration) and flow parameters (viscosity and gas flow rate). A custom setup with an 80 cm temperaturecontrolled glass column was used for foam generation. Among the tested nonionic surfactants type sorbitan esters, the Span 80 (liquid W/O emulsifier and O/W emulsion stabilizer) produced the most voluminous foams. Interestingly, increasing surfactant concentration improved foamability but decreased foam stability. Similar trends were observed with the oil fraction and temperature (which affects viscosity). Higher viscosity led to more stable but less foamy structures. The study also explored the effect of different alcohols (ethanol to n decanol) at varying flow rates. While all alcohols generated some foam at lower flow rates (200 mL/min N 2 ), the effect diminished at higher flow rates. Additionally, foam stability and volume decreased with longer alcohol chains. These findings provid... Read More
11. Impact of Surfactant Concentration on Chemical-Assisted Methane Flooding in Foamy Oil Reservoirs
Sheng-jun Tian, Xingmin Li, Xiao-xing Shi - Springer Nature Singapore, 2024
The primary recovery factor of extra-heavy oils with foamy oil flow characteristic is only 812%. In previous studies, an approach of chemical-assisted methane flooding to enhance recovery in foamy oil reservoirs after primary depletion was proposed. The approach includes injecting viscosity reducer naphtha, methane and surfactant solution slugs sequentially to recreate foamy oil flow in situ. This study further investigated the effect of the surfactant concentration on the process through indoor experiments. Extra-heavy crude oil sample with typical foamy oil features, taken from Venezuela Heavy-Oil-Belt, was adopted during the experiments. To begin with, 16 groups of interfacial tension test between oil added with surfactant solution of different concentration and methane were conducted. Afterwards, 6 groups of foam stabilization test were conducted to record the foam volume and the half-life period under different surfactant concentrations. Finally, 3 groups of 2D visualized micro-flow experiments were conducted to investigate the surfactant concentration effect on the generation ... Read More
12. Influence of Mixing Speed on Demulsification Effect of Enhanced Foam Flooding Produced Fluid
Jin Zhang, Yuanyuan Wang, Guo-na Wang - Springer Nature Singapore, 2024
With the continuous improvement of the exploitation degree of oil fields, most of the domestic oil fields have entered the tertiary production stage. As a relatively mature oil production technology in the tertiary oil production stage, enhanced foam flooding technology is widely used in all oil fields. At the end of 2014, a combined station of an oil field began to carry out the production test of nitrogen foam drive. With the increase of the number of measure wells and the implementation of strengthening nitrogen bubble foam drive, the emulsion strength of the produced fluid entering the combined station gradually changed, and the difficulty of dehydration increased. Specifically, the water content at the outlet of the two-phase separator fluctuates seriously, the crude oil dehydration temperature rises, and the energy consumption increases; Due to the high degree of emulsification of the produced liquid, it is more difficult to dewater the crude oil, and the demulsifier needs to be adjusted repeatedly; The water content of crude oil is difficult to meet the standard, and it has oc... Read More
13. A non‐ionic green surfactant extracted from the <i>Anabasis setifera</i> plant for improving bulk properties of <scp>CO<sub>2</sub></scp>‐foam in the process of enhanced oil recovery from carbonate reservoirs
Iman Nowrouzi, Amir H. Mohammadi, Abbas Khaksar Manshad - Wiley, 2024
Abstract Foam, as a gasinliquid colloid, has a higher appearance viscosity than the one of both gas and liquid that form it. Adjusting the mobility ratio of the injected fluidoil system and increasing gas diffusion in the foam injection process increase oil production. With these properties, foam as an injection fluid in fractured reservoirs has a major effect on oil production from the matrixes and prevents premature production of injection fluid. Surfactants are common foaming agents in injection water. Saponins are known as plantderived surfactants for forming stable foam. This feature, along with its cheap price and availability, can make them candidates for enhanced oil recovery (EOR) by the foam injection method. However, the utilization of CO 2 as the gaseous phase in foam introduces additional machanisms of CO 2 injection to the oil recovery operations. In this assessment, a nonionic green surfactant derived from the Anabasis setifera plant was used as a foaming agent, while CO 2 served as the gas phase. A series of surface tension tests in CO 2 environment were performe... Read More
14. Bubble size and foamability: role of surfactants and hydrodynamic conditions
Slavka Tcholakova, B. Petkova - Elsevier BV, 2024
The primary objective of this review is to consolidate our current understanding of the factors controlling the foamability of surfactant solutions under hydrodynamic conditions realized in various laboratory tests. In particular, two regimes of foam generation are considered: at low surfactant concentrations where the coalescence between the bubbles plays a crucial role, and a high surfactant concentration range where the hydrodynamic conditions are much more important for the final outcome of foaming. The review discusses the role of surfactant concentration, dynamic surface coverage, and surface forces acting between film surfaces for the foam generated in the surfactant-poor regime. Additionally, the interplay between the hydrodynamic conditions and the viscosity of the formed foams in the surfactant-rich regime is also discussed.
15. Stability Analysis of Anionic-CO<sub>2</sub>-Soluble Surfactant Di-(2-ethylhexyl) Sodium Sulfosuccinate-Assisted Oily Foam Based on Statistical Analysis of Bubble Dynamic Characteristics
Tianhan Xu, Jian Wang, Yuhao Lu - American Chemical Society (ACS), 2023
Currently, oily foam stability in CO2 injection for heavy oil recovery exhibits inadequacies that considerably constrain its extensive application. Some scholars have conducted research demonstrating that CO2-soluble surfactants can assist in inducing heavy oil to form oil-based foams (oily foam). In this study, stability tests for the oily foam were conducted at different surfactant concentrations using a visualized PVT cell. Oily foam stability was assessed by calculating the comprehensive foam index (S) and analyzing the bubble images. The research indicates that AOT can effectively reduce the interfacial tension between oil and gas. At a concentration of 0.1 wt % AOT, the interfacial tension can be effectively reduced from 1.75 to 1.14 mN/m. The concentration of 0.3 wt % AOT represents a turning point, with an S of 16 101.7 mLmin. Beyond this concentration, the increase in S becomes less pronounced. As the concentration of CO2-soluble surfactant is increased from 0.1 to 0.5 wt %, the average bubble radius decreases from 2.74 to 0.43 mm, while the number of bubbles per unit area ... Read More
16. Stability and interfacial rheology of oil-based foam with polydimethylsiloxane and natural rubber
Huanxin Wang, Zhidong Chang, Wenli Luo - Informa UK Limited, 2023
Oil-based foam has become a research hotspot in petroleum industry, whose stability plays a key role in the application. The employment of oil-based foam prevents the damage to water-sensitive reservoir. This paper focuses on the stabilization of oil-based foam by improving the viscoelasticity of foam film and the effect study of polymer-surfactant. The Polydimethylsiloxane (PDMS) and Natural rubber (NR) are employed to stabilize oil-based foam, and the comprehensive properties of foam which created by air flow method are evaluated by FCI. Besides, the behavior of interfacial adsorption foam film is analyzed through rheological study and molecular dynamics (MD) simulation. According to the results, the oil-based foam volume increases to 150 mL and the half-life time is extended to 140 s with the combination of NR and PDMS. It is ascribed that the synergistic effect of NR and PDMS molecules. The NR molecules, which are stretched and crimped corresponding to the change of external force, begin to move toward the interface after blending with PDMS to improve the viscoelasticity of the f... Read More
17. Anionic–zwitterionic viscoelastic surfactant strengthened air foams for heterogeneous reservoirs
Zhe Li, Yingqi He, Wanli Kang - AIP Publishing, 2023
Foam flooding technology can effectively enhance oil recovery (EOR) and has conformance control in heterogeneous reservoirs. However, the stability of foam migrating through porous media is still a challenge with individual surfactant. Herein, we developed viscoelastic surfactant (VES) via the synergisms of anionic (sodium dodecyl sulfate, SDS) and zwitterionic (erucamidopropyl hydroxysulfobetaine, EHSB) surfactants to strengthen the air foams stability. First, the VES formulation was optimized by investigating the initial foaming volume (V0), drainage half-life (td), and foam half-life (tf) for VES solutions. Then, the oilwater interfacial tension (IFT) and emulsification of the optimum VES system were systematically studied. Particularly, emphasizes were placed on the anti-gas channeling ability, EOR performance, and mechanisms using the core-flooding and microfluidic experiments. The results showed that the V0, td, tf of air forms could be greatly improved to 400 ml, 56.6 min, and 36 h, respectively, with 0.3 wt. % SDS:EHSB at mass ratio of 1:1.3. This was attributed to the syner... Read More
18. Revolutionizing Foam Physics: A Cutting-Edge Drainage Equation Model for Wet Foam
Ahmad M. Al-Qararah - Canadian Center of Science and Education, 2023
Foam physics is a field of study that scientists and researchers are interested in due to the vast range of uses, e.g. foam-foamed materials, oil extraction, and food processing. This study proposes a new equation for the drainage of wet foam that could add to the science of foam. To improve our comprehension of the intricate behaviour of wet foam, this model expands on a theoretical derivation. The usage of a bubble size formula that was proposed using the experimental data is one of the model&#39;s distinguishing characteristics. The size of foam bubbles can be predicted using this formula more precisely. A thorough derivation of the theoretical model is provided in the paper. Finally, this work presents a novel wet foam drainage model that has the potential to enhance the field of foam physics. The results of this work have important implications for industries. Therefore, more study is needed for developing a two dimensional drainage equation.
19. Lubricating Oil Composition with Silicone-Based Anti-Foaming Agent and Specified Silicon Concentration
IDEMITSU KOSAN CO LTD, 2023
A lubricating oil composition that balances long-term anti-foaming performance with detergency, comprising a base oil and a silicone-based anti-foaming agent. The composition contains 50-4000 ppb silicon by mass, a range that enables both effective anti-foaming and satisfactory detergency.
20. Integrity Investigation of Macroscopic and Microscopic Properties of Non-Aqueous Foams for Enhanced Oil Recovery
Yibo Li, Tianshuang He, Jinzhou Zhao - IPTC, 2023
Abstract Foam flooding is a crucial enhanced oil recovery technique for profile control during the oil displacement process. The stability of the foam is the key factor for the success of foam flooding, but typical aqueous foams generally lose their stability in the presence of hydrocarbons because of their low oil tolerance. Non-aqueous foams possess outstanding stability in the presence of hydrocarbons as a result of their unique properties. However, few studies have been conducted on the stabilization mechanisms of non-aqueous foams in the presence of hydrocarbons. In this study, comparative experiments were performed to investigate differences in the stabilization mechanism between aqueous and non-aqueous foams. The results showed that a non-aqueous foam had excellent oil tolerance in a bulk foaming test. Then, the stabilization mechanisms of foams were investigated in terms of surface dilatational viscoelasticity and liquid film thinning. For a non-aqueous foam system, the maximum viscoelastic modulus of 55 mN/m occurred at a surfactant concentration of 5.0 wt%, which indicated ... Read More
Get Full Report
Access our comprehensive collection of 72 documents related to this technology