Mechanisms for lowering of interfacial tension in alkali/acidic oil systems 2. Theoretical studies

Rudin, Jeff; Wasan, Darsh T.

doi:10.1016/0166-6622(92)80149-v

Cited by 79 publications

(48 citation statements)

References 19 publications

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“…They suggested that the un-ionized acid contributed to the lowering of the dynamic IFT through adsorbing simultaneously at the oil/water interface with ionized acid and added surfactant. Similar suggestions were also advocated to explain the dynamic IFT behavior in added surfactant/alkali/acidic oil systems (17,18). In these studies, the authors proposed that the un-ionized acid species indeed play a dominant role in affecting the IFT and the plausible mechanism by which added surfactant aids in the reduction of the IFT is the formation of mixed micelles.…”

Section: Resultsmentioning

confidence: 91%

Novel surfactants for ultralow interfacial tension in a wide range of surfactant concentration and temperature

Aoudia

Al-Shibli

Al-Kasimi

et al. 2006

J Surfact & Detergents

115

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This work investigates the possibility of injecting dilute aqueous solutions of novel surfactants into the Yibal field (Sultanate of Oman). This was accomplished through an experimental protocol based on the following criteria: (i) compatibility of the surfactants with the high-saline reservoir water (~200 g/L); (ii) low interfacial tension (IFT) between crude oil and reservoir water (less than 10 -2 mN m -1 ); and (iii) maintaining the low IFT behavior during the entire surfactant flooding. Novel surfactants selected in this study consist of a series of ether sulfonates and an amphoteric surfactant (6-105). These surfactants were found to be compatible with reservoir water up to 0.1% surfactant concentration, whereas 6-105 and 7-58 showed compatibility within the full range of surfactant concentration investigated (0.001-0.5%). All surfactant systems displayed dynamic IFT behavior, in which ultralow transient minima were observed in the range 10 -4 -10 -3 mN m -1 , followed by an increase in the IFT to equilibrium values in the range 10 -3 -10 -1 mN m -1 . The results also showed that with respect to concentration (0.05-0.5 %) and temperature (45-80°C), AES-205 and 7-58 surfactants exhibit a wide range of applicability, with the IFT remaining below 10 -2 mN m -1 , as required for substantial residual oil recovery. In addition, ultralow IFT were obtained at surfactant concentrations as low as 0.001%, making the use of these surfactants in enhanced oil recovery extremely cost-effective.Paper no. S1524 in JSD 9, 287-293 (Qtr. 3, 2006). KEY WORDS: Compatibility, dynamic interfacial tension, surfactants, ultralow transient interfacial tension.Approximately 60% of the original oil in place (OOIP) will remain in an average oil reservoir after primary and secondary (water flooding in most cases) production. The residual oil is trapped in the reservoir pore structures by capillary forces and cannot be recovered by conventional means. Among the non-conventional techniques (known as enhanced oil recovery [EOR]) used to enhance oil production, surfactant flooding is one of the most appealing methods to enhance oil recovery from depleted reservoirs. In this technique, surfactants are added to the oil/water system to reduce the interfacial tension (IFT) from about 20-30 mN m -1 to less than 10 -2 mN m -1 (1,2). This seems to be a very simple method for recovering residual oil from reservoirs. However, from a technical point of view, there are some adverse conditions that prevent this technique from being successful in the field. The environment of an oil reservoir is often such that surfactants cannot generate this considerable reduction in surface tension as simply as described. One crucial aspect is that the water in these reservoirs is very salty (up to 200 g/L)-salinities above the solubility limits of most conventional surfactants used in EOR. Clearly, the compatibility of surfactants with reservoir brine is essential to avoid plugging of the porous medium, especially in reservoirs of low permeability. The other importa...

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Section: Resultsmentioning

confidence: 91%

Novel surfactants for ultralow interfacial tension in a wide range of surfactant concentration and temperature

Aoudia

Al-Shibli

Al-Kasimi

et al. 2006

J Surfact & Detergents

115

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“…As moléculas menores dissolvem-se na fase aquosa (pH ~ 5) e as maiores, no óleo, enquanto os homólogos dissolvem na fase aquosa (pH > 10). 34,[36][37][38] A presença de sais alcalinos, junto com o pH, deve ser responsável pelas sensíveis variações na estabilidade das emulsões de frações contendo ácidos naftênicos. [39][40][41][42] Os ácidos naftênicos presentes em asfaltenos formam um sistema difícil de analisar por técnicas espectroscópicas, já que a banda de absorção registrada tem um valor comum à de compósito.…”

Section: Propriedades Dos áCidos Naftênicosunclassified

“…36,38,40 A estabilização das emulsões água/óleo causa problemas na entrada e saída dos separadores. Os sais metálicos pouco solúveis em água, como os de Ca e Mg, acumulam-se na interface, como nucleação, formando aglomerados de partículas, que são responsáveis por frequentes interrupções operacionais nos processos de separação.…”

Section: Propriedades Dos áCidos Naftênicosunclassified

Ácidos naftênicos no petróleo

Gruber¹,

Damasceno²,

Caramão³

et al. 2012

Quím. Nova

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Recebido em 22/7/11; aceito em 5/2/12; publicado na web em 15/5/12 NAPHTHENIC ACIDS IN PETROLEUM. Brazilian petroleum is known by its high acidity due to the presence of acidic constituents, especially naphthenic acids (NA). The total characterization of the NA in petrochemical samples has been receiving special attention in research and comprises an analytical challenge, mainly due to the complexity of their mixtures. Gas chromatography with mass detector (GC/MS) is the technique of analysis more used, but recently comprehensive two-dimensional gas chromatography (GC × GC) has been used, due to its high resolution, peak capacity and sensitivity. The goal of this article is to discuss the techniques for sample preparation and analysis of NA in petroleum.Keywords: petrochemicals samples; naphthenic acids; characterization of the NA. INTRODUÇÃONos últimos anos grande parte das reservas de petróleo descobertas em território brasileiro consiste de óleo pesado de baixo grau API (<20º), alta viscosidade e elevada acidez total. 1 A Empresa de Petróleo Brasileiro S/A, PETROBRAS, visando viabilizar a comercialização do petróleo vem investindo em programas de pesquisa e desenvolvimento, tais como, PRAVAP (Programa de Recuperação Avançada de Petróleo), PROTER (Programa de Tecnologias Estratégicas de Refino) e PROPES (Programa Tecnológico de Óleos Pesados).As fontes de óleo cru na América do Sul, incluindo o petróleo brasileiro, estão entre as mais ácidas do mundo.2,3 Tal acidez é responsabilizada por muitas dificuldades na utilização desta matéria-prima nas refinarias e no aproveitamento de seus resíduos.Os ácidos naftênicos (AN) são encontrados, predominantemente, em óleos imaturos, biodegradados, em óleos pesados e águas residuá-rias geradas no processo de extração do betume.4,5 Sua importância é salientada em geoquímica, aplicações comerciais, aspectos ambientais e corrosão. [2][3][4][5][6] O termo naftênico, correspondente a compostos cíclicos saturados, é usado para todos os tipos de ácidos encontrados em petróleos, mesmo os saturados lineares e os ramificados. 2,5,7 Os ácidos carboxílicos presentes no petróleo representam um grande problema para o refino e craqueamento do mesmo, devido ao seu efeito corrosivo em linhas de transferência de massa e calor, nas seções de entrada e refluxo de colunas (à pressão atmosférica e a vácuo) e nos condensadores das unidades de destilação das refinarias. 5 De forma geral, determina-se o teor de ácidos através da titulação com KOH, obtendo-se então o índice ou número de acidez naftênica. Este índice pode ser indicativo de atividade corrosiva da amostra, contudo, nada acrescenta quanto à qualidade do petróleo e à natureza dos ácidos presentes. Para caracterizar estes ácidos, é necessário extraí-los e analisá-los de forma individual. 2,5 O petróleo é constituído de uma mistura complexa de hidrocarbonetos com quantidade bastante significativa de isômeros, além destes, apresenta compostos contendo nitrogênio, oxigênio e enxofre, que dificultam as etapas de extração, isolamento e caract...

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“…Interestingly, the addition of surfactant did not always lower the interfacial tension and the effect of added surfactant depended on the alkali concentration [6]. Rudin et al [7,8] investigated both equilibrium and DIT in surfactant-alkali-acidic oil and suggested that the unionized organic acid species play a dominant role in affecting the DIT and that the formation of added surfactant-ionized acid mixed film at the oilwater interface is the key mechanism in the DIT reduction. Chatterjee et al [9] showed that the addition of surfactant to the alkaline solution resulted in an increase in the minimum dynamic interfacial tension (DIT min ) at surfactant concentration above its CMC.…”

Section: Introductionmentioning

confidence: 97%

Novel Alkyl Ether Sulfonates for High Salinity Reservoir: Effect of Concentration on Transient Ultralow Interfacial Tension at the Oil–Water Interface

Aoudia

Al-Harthi

Al-Maamari

et al. 2010

J Surfact & Detergents

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The effect of surfactant concentration on the occurrence and detection of transient ultralow interfacial tension (IFT) between crude oil and formation water at 75°C has been investigated using a series of novel sodium alkyl ether sulfonates having various increasing molecular weights and degrees of ethoxylation. All surfactant systems displayed dynamic interfacial tension (DIT). Transient ultralow DIT (DIT min ) were detected only within an intermediate surfactant concentration. This behavior was attributed to an implicit concentration-related length scale required for the added surfactant to diffuse from the bulk phase to the freshly prepared oil-water interface. In the high surfactant concentration range, this length scale is relatively short and results in an instantaneous (and undetectable) occurrence of DIT mim in a relatively very short time scale, well beyond the detection limit of the spinning drop tensiometer (*2-3 min). Interestingly, DIT min were detected only in systems above the surfactant's critical micelle concentration, suggesting that DIT min occurs as a result of the diffusion (subsequent to the adsorption) of the oil acidic species from the interface to the bulk phase to form mixed micelles with the added surfactant.Measurements of DITs in the presence of decane showed no evidence for DIT min , confirming the general belief that DIT min is indeed due to the interaction of the added surfactant with the oil acidic components. Finally, the effect of surfactant concentration on the equilibrium IFT (c eq ) showed evidence for relatively low values (*10 -2 mNm -1 ) for some surfactant systems.

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Mechanisms for lowering of interfacial tension in alkali/acidic oil systems 2. Theoretical studies

Cited by 79 publications

References 19 publications

Novel surfactants for ultralow interfacial tension in a wide range of surfactant concentration and temperature

Novel surfactants for ultralow interfacial tension in a wide range of surfactant concentration and temperature

Ácidos naftênicos no petróleo

Novel Alkyl Ether Sulfonates for High Salinity Reservoir: Effect of Concentration on Transient Ultralow Interfacial Tension at the Oil–Water Interface

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