No abstract

It is well known that oil recovery processes can be increased by surfactant solution injections in the reservoir. However, the high adsorption of this type of compounds on the reservoirs rocks surface is one of the factors that have been preventing the Enhanced Oil Recovery (EOR) development and the economicity of the process. This work presents the synthesis of cross‐linked polystyrene nanoparticles (PSNP) and their evaluation as surfactant carriers, able to percolate through the reservoirs pores and to deliver it at the water/oil interface. The nanoparticles were synthesized by emulsion polymerization of styrene and divinylbenzene in the presence of nonylphenol ethoxylate‐10 (NF‐10EO) or sodium dodecyl sulphate. Photon Correlation Spectroscopy and Interfacial Tension results gave support to the initial supposition that the nanoparticles would swell when in contact with the oil phase, releasing the surfactant at the interface. The nanoparticles obtained with NF‐10EO were able to reduce the water/oil interfacial tension to values that were similar to the ones obtained with the aqueous solution of NF‐10EO. The results suggest that the PSNP have a great potential to be used as surfactant carriers in EOR. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43789.

The presence of acidic compounds as naphthenic acids in crude oil causes several problems for the petroleum industry, including corrosion in both upstream and downstream production processes. Based on this scenario, the main objective of this work was to investigate the removal of the acidic compound from two Brazilian heavy oils by adsorption processes using six potential adsorbents: powdered shale, activated carbon, bentonite, silica gel, powdered sandstone and powdered wood. These raw materials were previously characterized by conventional and surface analysis techniques, which show that they offer a good surface area and thermal stability. To evaluate the removal efficiency at the molecular level, the crude oil samples and the filtered oils were analyzed by negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry [ESI (-) FTICR MS]. The O 2 class, which is related to the relatively high acidity of the samples, was the most abundant in both crude oil samples, moreover, this class was more retained by adsorbents. Silica gel, activated carbon and bentonite were the best adsorbents of acidic compounds from the tested oils, in agreement with their markedly higher surface area and porous volume. Additionally, a chromatographic analysis was performed and showed no changes in the oil profile.

Biosurfactants and waterfl ooding have been widely reported thus far for enhancing oil production. Nevertheless, there is a lack of literature to explore enhanced oil recovered methods effects on its chemical composition. The aim of this work is to investigate the effects of a biosurfactant produced by Bacillus safensis and brine injection on the recovered petroleum composition, and their implications for geochemical interpretation. Original and oils recovered from displacement tests were analyzed by gas chromatography and ultra-high-resolution mass spectrometry, emphasizing saturated and aromatic biomarkers and basic and acidic polar compounds. Geochemical parameters based on some saturated compounds were subtly affected by the recovery methods, showing their reliable applicability in geochemical studies. Contrarily, parameters based on some aromatic compounds were more affected by biosurfactant fl ooding, mostly the low molecular weight compounds. Thus, these aromatic parameters should be applied with caution after such methods. The distribution of basic and acidic polar compounds can also be modifi ed affecting the geochemical interpretation. In the case of the basic ones, the biosurfactant greatly infl uenced the N class species with favorable loss of lower aromaticity compounds. In addition to water solubilization, the compositional changes described in this study can be related to fractionation due to adsorption on reservoir rocks.