Petroleum sulfonates obtained from heavy vacuum gas oil (HVGO) were characterized by negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry [(−) ESI FT-ICR MS] to better understand the chemical nature of their surface-active components. Electrospray ionization (ESI) analysis showed that sulfonates contain mainly O3S, O3S2, O4S, and NO3S classes, which means that the sulfonation reaction does not occur selectively for aromatic hydrocarbon (HC) class compounds because it also reacts with N, S, and O heteroatom classes. Because sulfonates were separated by solubility into lipophilic and hydrophilic categories, it was confirmed that the same classes compose hydrophilic and lipophilic sulfonates. Moreover, this procedure revealed that lipophilic sulfonate extracts contain organic acids (O2 class) that are related to the total acid number of the starting HVGO. However, selective isolation of the surface-active species using the “wet-silica” procedure allowed for detection that these compounds have a non-surface-active character because they do not interact with the water phase. The new structural information disclosed about petroleum sulfonates and their raw materials might encourage further studies on the rational design and synthesis of novel petroleum surfactants with the desired properties for industrial applications, such as chemical enhanced oil recovery (CEOR).

A n efficient method for preparing petroleum sulfonates is described in this article. Petroleum sulfonates were prepared from five different refinery cuts and characterized by infrarred and ultra-violet spectroscopy. Their hydrophilic-lipophilic relative afinity was assessed by performing phase behavior scans. The prepared surfactants were evaluated in formulations for Chemical Enhanced Oil Recovery (CEOR), showing that, under the evaluation conditions, the solubilization ratios increase with the structural similarity between the crude oil and the surfactant molecules. It was confirmed that, when used as secondary surfactants, the petroleum sulfonates here prepared allow to achieve relatively high solubilization parameters. ABSTRACT PREPARACIÓN DE SULFONATOS DE PETRÓLEO Y EVALUACIÓN PARA RECOBRO QUÍMICO MEJORADO EN CAMPOS DE PETRÓLEO COLOMBIANOS 56N o presente trabalho é descrito um método eficiente para a preparação de sulfonatos de petróleo. Os sulfonatos de petróleo são preparados a partir de cinco cortes de refinaria diferentes e são caracterizados por espectroscopia de infravermelho e ultravioleta. Sua afinidade relativa hidrófilica lipófilica foi avaliada mediante a realização de comportamentos de fase. Os tensoativos preparados foram avaliados em formulações para Recuperação Química Melhorada demonstrando que, sob as condições de avaliação, as relações de solubilização aumentam com a semelhança estrutural que existe entre o petróleo cru e as moléculas do surfactante utilizado. Confirma-se que, quando são utilizados como surfactantes secundários, os sulfonatos de petróleo aqui preparados permitem atingir parâmetros de solubilização relativamente elevados. E n el presente trabajo se describe un método eficiente para la preparación de sulfonatos de petróleo. Los sulfonatos de petróleo se prepararon a partir de cinco cortes de refinería diferentes y se caracterizaron por espectroscopía de infrarrojo y ultravioleta. Su afinidad relativa hidrófilica lipófilica se evaluó mediante la realización de comportamientos de fase. Los tensoactivos preparados se evaluaron en formulaciones para Recobro Químico Mejorado demostrando que, bajo las condiciones de evaluación, las relaciones de solubilización aumentan con la similitud estructural que existe entre el petróleo crudo y las moléculas del surfactante utilizado. Se confirma que, cuando se utilizan como surfactantes secundarios, los sulfonatos de petróleo aquí preparados permiten alcanzar parámetros de solubilización relativamente elevados.Palabras clave: Surfactantes, Sulfonación, Síntesis química, Reacción de sulfonación, Recobro mejorado de petróleo, Caracterización, Espectroscopia infrarroja, Espectroscopia de luz ultravioleta.Palavras-chave: Surfactante, Sulfonação, Síntese química, Reação de sulfonação, Recuperação melhorada de petróleo, Caracterização, Espectropia de infravermelho, Espectropia de luz ultravioleta.

In the present work, petroleum sulfonates were obtained from three atmospheric residues (ARs) and characterized by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry [(−) ESI FT-ICR MS], looking for an approach to establish a relationship between molecular composition and interfacial activity for chemical enhanced oil recovery (CEOR) formulations. From the correlation of the (−) ESI FT-ICR MS data and the interfacial tension measurements, it was possible to infer that the composition and some characteristics, such as aromatic and/or naphthenic condensation, must be taken into account to understand the performance of petroleum sulfonates. Obtained sulfonates contained mainly O3S, NO3S, O3S2, and O4S compounds, but the relative abundance of each class depended directly upon the chemical composition of the raw AR. Both carbon number (CN) and double bound equivalent (DBE) distributions of the main classes provided a way to explain the lipophilicity and interfacial activity of the sulfonates. This information can be useful to establish the initial characteristics desired in ARs to produce petroleum sulfonates with appropriate capabilities for CEOR applications.

Oil recovery by water injection is the most extended technology in the world for additional recovery, however, formation heterogeneity can turn it into highly inefficient and expensive by channeling injected water. This work presents a chemical option that allows controlling the channeling of important amounts of injection water in specific layers, or portions of layers, which is the main explanation for low efficiency in many secondary oil recovery processes. The core of the stages presented here is using partially hydrolyzed polyacrylamide (HPAM) cross linked with a metallic ion (Cr+3), which, at high concentrations in the injection water (5000 – 20000 ppm), generates a rigid gel in the reservoir that forces the injected water to enter into the formation through upswept zones. The use of the stages presented here is a process that involves from experimental evaluation for the specific reservoir to the field monitoring, and going through a strict control during the well intervention, being this last step an innovation for this kind of treatments. This paper presents field cases that show positive results, besides the details of design, application and monitoring.

even chemical products with different chemical properties were evaluated as post-fracturing treatments to remove the polymer retained in the pore system of the fracture and adjacent rock after hydraulic fracturing. Three of those chemical products were used for the first time to degrade the polymer in fracturing fluids. All laboratory tests were conducted under the Unit K-1 Chichimene oil-field conditions -located in Eastern Colombia, and operated by Ecopetrol S.A.Fluid-fluid and fluid-rock compatibility tests were performed. In order to evaluate the capacity of the post-fracturing treatments to degrade the polymer in the fracturing fluid, a new methodology for polymer quantification was implemented. The chemical and thermal stability of the post-fracturing treatments was assessed trough coreflooding experiments. Finally, the evaluations of the effectiveness of the post-fracturing treatments were performed and assessed with coreflooding experiments using fractured rocks as porous media.The coreflooding results showed that the post-fracturing treatments evaluated promoted the recovery of about 40% of the total polymer retained in the porous system, and improved the retained permeability in values between 50 and 180%. The best obtained results came from the first-time usage of chemical products as post-fracturing treatments.