scholarly journals Influence of Surfactant Structure on the Stability of Water-in-Oil Emulsions under High-Temperature High-Salinity Conditions

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Abdelhalim I. A. Mohamed ◽  
Abdullah S. Sultan ◽  
Ibnelwaleed A. Hussein ◽  
Ghaithan A. Al-Muntasheri

Emulsified water-in-oil (W/O) systems are extensively used in the oil industry for water control and acid stimulation. Emulsifiers are commonly utilized to emulsify a water-soluble material to form W/O emulsion. The selection of a particular surfactant for such jobs is critical and certainly expensive. In this work, the impact of surfactant structure on the stability of W/O emulsions is investigated using the hydrophilic-lipophilic balance (HLB) of the surfactant. Different commercial surfactants were evaluated for use as emulsifiers for W/O systems at high-temperature (up to 120°C) high-salinity (221,673 ppm) HTHS conditions. Diverse surfactants were examined including ethoxylates, polyethylene glycols, fluorinated surfactants, and amides. Both commercial Diesel and waste oil are used for the oleic phase to prepare the emulsified system. Waste oil has shown higher stability (less separation) in comparison with Diesel. This work has successfully identified stable emulsified W/O systems that can tolerate HTHS environments using HLB approach. Amine Acetate family shows higher stability in comparison with Glycol Ether family and at even lower concentration. New insights into structure-surfactant stability relationship, beyond the HLB approach, are provided for surfactant selection.

2018 ◽  
Vol 160 ◽  
pp. 302-312 ◽  
Author(s):  
Abdelhalim I.A. Mohamed ◽  
Ibnelwaleed A. Hussein ◽  
Abdullah S. Sultan ◽  
Ghaithan A. Al-Muntasheri

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1967
Author(s):  
Bianca Enaru ◽  
Georgiana Drețcanu ◽  
Teodora Daria Pop ◽  
Andreea Stǎnilǎ ◽  
Zorița Diaconeasa

Anthocyanins are secondary metabolites and water-soluble pigments belonging to the phenolic group, with important functions in nature such as seed dispersal, pollination and development of plant organs. In addition to these important roles in plant life, anthocyanins are also used as natural pigments in various industries, due to the color palette they can produce from red to blue and purple. In addition, recent research has reported that anthocyanins have important antioxidant, anticancer, anti-inflammatory and antimicrobial properties, which can be used in the chemoprevention of various diseases such as diabetes, obesity and even cancer. However, anthocyanins have a major disadvantage, namely their low stability. Thus, their stability is influenced by a number of factors such as pH, light, temperature, co-pigmentation, sulfites, ascorbic acid, oxygen and enzymes. As such, this review aims at summarizing the effects of these factors on the stability of anthocyanins and their degradation. From this point of view, it is very important to be precisely aware of the impact that each parameter has on the stability of anthocyanins, in order to minimize their negative action and subsequently potentiate their beneficial health effects.


2021 ◽  
Vol 11 (4) ◽  
pp. 1905-1913
Author(s):  
Tagwa A. Musa ◽  
Ahmed F. Ibrahim ◽  
Hisham A. Nasr-El-Din ◽  
Anas. M. Hassan

AbstractChemical enhanced oil recovery (EOR) processes are usually used as additives for hydrocarbon production due to its simplicity and relatively reasonable additional production costs. Polymer flooding uses polymer solutions to increase oil recovery by decreasing the water/oil mobility ratio by increasing the viscosity of the displacing water. The commonly used synthetic water-soluble polymer in EOR application is partially hydrolyzed polyacrylamide (HPAM). However, synthetic polymers in general are not attractive because of high cost, environmental concerns, limitation in high temperature, and high-salinity environment. Guar gum is an environmentally friendly natural water-soluble polymer available in large quantities in many countries and widely used in various applications in the oil and gas industry especially in drilling fluids and hydraulic fracturing operations; however, very limited studies investigated on guar as a polymer for EOR and no any study investigated on its uses in high-temperature and high -salinity reservoirs. The objective of this study is to confirm the use of guar gum as a natural polymer for EOR applications in sandstone reservoirs and investigate its applicability for high-temperature and high-salinity reservoirs. The study experimentally investigated rheological characteristics of a natural polymer obtained from guar gum with consideration of high temperature (up to 210 °F) and high salinity (up to 20% NaCl) and tested the guar solution as EOR polymer. The results of this study show that the guar solution can be used as an environmentally friendly polymer to enhance oil recovery. Based on the results, it can be concluded that guar gum shows shear-thinning behavior and strongly susceptible to microbial degradation but also shows a very good properties stability in high temperature and salinity, where in low shear rate case, about 100 cp viscosity can be achieved at 210 °F for polymer prepared in deionized water. Guar polymer shows good viscosity in the presence of 20% NaCl where the viscosity is acceptable for temperature less than 190 °F. Also, the flooding experiment shows that the recovery factor can be increased by 16%.


2019 ◽  
Vol 201 (16) ◽  
Author(s):  
Joshua D. Quinn ◽  
Eric H. Weening ◽  
Taryn A. Miner ◽  
Virginia L. Miller

ABSTRACTPsaA, the subunit of the fimbria originally referred to as the “pH 6 antigen,” is required for full virulence ofYersinia pestisduring bubonic plague. The expression ofpsaAis dependent upon specific environmental signals, and while the signals (high temperature and acidic pH) are defined, the mechanisms underlying this regulation remain unclear. In the closely related speciesYersinia pseudotuberculosis,psaAtranscription requires two regulatory genes,psaEandpsaF, and it is speculated that posttranscriptional regulation of PsaE and/or PsaF contributes to the regulation ofpsaAtranscription. Few studies have examined the regulation ofpsaAexpression inY. pestis, and prior to this work, the roles ofpsaEandpsaFinY. pestishad not been defined. The data presented here show that bothpsaEandpsaFare required forpsaAtranscription inY. pestisand that the impact of temperature and pH is mediated through discrete posttranscriptional effects on PsaE and PsaF. By generating antibodies that recognize endogenous PsaE and PsaF, we determined that the levels of both proteins are impacted by temperature and pH. High temperature is required forpsaEandpsaFtranslation via discrete mechanisms mediated by the mRNA 5′ untranslated region (UTR) upstream of each gene. Additionally, levels of PsaE and PsaF are impacted by pH. We show that PsaF enhances the stability of PsaE, and thus, both PsaE and PsaF are required forpsaAtranscription. Our data indicate that the environmental signals (temperature and pH) impact the expression ofpsaAby affecting the translation ofpsaEandpsaFand the stability of PsaE and PsaF.IMPORTANCEY. pestisis a Gram-negative bacterial pathogen that causes bubonic plague. As a vector-borne pathogen,Y. pestisfluctuates between an arthropod vector (flea) and mammalian host. As such,Y. pestismust recognize environmental signals encountered within each host environment and respond by appropriately regulating gene expression. PsaA is a keyY. pestismammalian virulence determinant that forms fimbriae. Our work provides evidence thatY. pestisutilizes multiple posttranscriptional mechanisms to regulate the levels of two PsaA regulatory proteins in response to both temperature and pH. This study offers insight into mechanisms that bacteria utilize to sense environmental cues and regulate the expression of determinants required for mammalian disease.


2014 ◽  
Vol 68 (9) ◽  
Author(s):  
Paul Vanderauwera ◽  
Dorine Wambeke

AbstractBio-oil resulting from the pyrolysis of lignocellulose is a complex mixture of polar low molecular mass oxygenated compounds of various functionalities and non-polar high molecular mass lignin derivatives. Several approaches to the upgrading of bio-oil are currently in progress. This study investigates the valorisation of crude bio-oil using physical and chemical methods. The effects of methanol addition on some properties of the bio-oil are investigated. Stable bio-oil/diesel oil emulsions are produced by the addition of surfactants with a hydrophilic-lipophilic balance value of 5–6. An alternative approach towards the upgrading of bio-oil is the hydrotreatment of the water-soluble fraction of bio-oil. Two-stage hydroprocessing with noble-metal catalysts Ru/C and Pt/C increases the intrinsic hydrogen content of the water-soluble fraction. The results show that the thermally unstable components including sugars, ketones and aldehydes are readily converted to diols and alcohols at pressures of 5 MPa. These observations can be explained by a set of reaction pathways for the compounds identified.


Resources ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 75
Author(s):  
Sina Rezaei Gomari ◽  
Kamal Elyasi Gomari ◽  
Meez Islam ◽  
David Hughes

Tertiary recovery is directly dependent on the alteration in wettability and interfacial tension (IFT), hence releasing the trapped oil from rock pore spaces. Bio-surfactant water flooding to mobilise residual oil in reservoirs is a new and developing prospect that can be used more often in future due to its environmentally friendly nature and economic advantages. In this work, the impact of rhamnolipids as water soluble bio-surfactant solutions on the interfacial activities of saline water and the wettability of carbonate rock are studied at elevated temperature. The effectiveness of the bio-surfactant as a rock wettability modifier is analysed in the presence of different salinities, in particular SO42− ions. The reason for the focus on SO42− is its high affinity towards calcite surfaces, and hence its ability to intervene strongly on bio-surfactant performance. To achieve the objectives of this study, the oil-wet calcite samples at elevated temperature were put through a washing process that included bio-surfactant solutions in seawater at various concentrations of sodium sulphate ions, where the measurement of the contact angles of each sample after treatment and the IFT between the oil model and the washing solutions were taken. The obtained results illustrated that bio-surfactants (rhamnolipids) with incremental concentrations of SO42− ions in sea water (up to three times higher than the original ion concentration) can lower the IFT, and assessed changing the rocks towards greater water-wettability. This study reveals that the alteration of SO42− ions had a greater impact on the wettability alteration, whereas rhamnolipids were better at reducing the IFT between the oil phase and the aqueous phase. This study also looked at temperatures of 50 °C and 70 °C, which demonstrated undesired influences on the wettability and IFT. Bio-surfactants at high temperature showed less interfacial activity, thus indicating that rhamnolipids are not active at high temperatures, while the addition of SO42− shows a continuous decrease in the contact angle and IFT measurements at high temperature.


2018 ◽  
Vol 15 (30) ◽  
pp. 380-386
Author(s):  
Y. V. SAVINYKH ◽  
L. D. LANG

Polymer flooding is technologically simple and highly effective method of enhanced oil recovery. The method is based on adding a small amount of polymer in conventional water flooding of oil reservoirs. The increase in viscosity and the reduction of the mobility of injected water are to equalize the displacement front by slowing the moving of water in the highly permeable zones and restricting the formation of water finger. These factors help to increase the sweep efficiency and oil-water displacement efficiency during flooding. Polymer flooding has been used successfully in clastic and carbonate reservoirs, as well as in low-permeability reservoirs such as a fractured basement. However, most of the current polymer gel used for control water flows are decayed by a high content of ions Ca2+ and Mg2+ in formation water or in injected water. Similarly, polymer gels lose their stability at high reservoir temperature (above 70°C). Developing water-soluble polymer, which does not change their rheological properties under high salinity and high temperature (over 100°C), is very important when producing offshore, where sea water is commonly used for flooding (high salinity of 30-40 g/L).


Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1765
Author(s):  
Mohamed Adel Alzaabi ◽  
Juan Manuel Leon ◽  
Arne Skauge ◽  
Shehadeh Masalmeh

Polymer flooding has gained much interest within the oil industry in the past few decades as one of the most successful chemical enhanced oil recovery (CEOR) methods. The injectivity of polymer solutions in porous media is a key factor in polymer flooding projects. The main challenge that faces prediction of polymer injectivity in field applications is the inherent non-Newtonian behavior of polymer solutions. Polymer in situ rheology in porous media may exhibit complex behavior that encompasses shear thickening at high flow rates in addition to the typical shear thinning at low rates. This shear-dependent behavior is usually measured in lab core flood experiments. However, data from field applications are usually limited to the well bottom-hole pressure (BHP) as the sole source of information. In this paper, we analyze BHP data from field polymer injectivity test conducted in a Middle Eastern heterogeneous carbonate reservoir characterized by high-temperature and high-salinity (HTHS) conditions. The analysis involved incorporating available data to build a single-well model to simulate the injectivity test. Several generic sensitivities were tested to investigate the impact of stepwise variation in injection flow rate and polymer concentration. Polymer injection was reflected in a non-linear increase in pressure with injection, and longer transient behavior toward steady state. The results differ from water injection which have linear pressure response to rate variation, and quick stabilization of pressure after rate change. The best match of the polymer injection was obtained with complex rheology, that means the combined shear thickening at high rate near the well and moving through apparent Newtonian and shear thinning at low rate.


2014 ◽  
Vol 633-634 ◽  
pp. 537-540 ◽  
Author(s):  
Prakorn Kittipoomwong ◽  
Monpilai Narasingha

Effects of sorbitol derivative surfactants on the stability of pyrolysis oil emulsion prepared from plastic waste were experimentally investigated. The water-pyrolysis oil mixture emulsified by Sorbitan monooleate (Span 80) surfactant is more stable than the water-in-oil emulsions prepared by other Sorbitol derivative surfactants which have lower hydrophilic-lipophilic balance (HLB) numbers. The Span 80 concentration of 1.5% by volume was found to produce the most stable emulsion and the smallest average water droplet. This optimal surfactant concentration is the same as critical micelle concentration.


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