Crude oils containing large quantities of waxes, and in situations where sudden temperature drops occur, a crystalline network can be formed, generating flow difficulties in production, transfer and offloading lines. Despite the scientific and economic importance of this phenomenon, correlations between the behavior of petroleum in relation to its pour point are scarce in the literature. In this work, nine crude oil samples were characterized regarding density, water content, wax fraction (one-and two-dimensional chromatography), pour point, yield stress and wax appearance temperature. The results showed that the storage conditions and oil characteristics had a strong influence on the pour point. Yield stress was influenced by initial temperature of the sample, cooling rate and shear rate during cooling. Finally, the content of aromatic compounds in oil with low concentration of n-alkanes can contribute to increase the pour point.
During the drilling and completion of oil wells, the drilling fluid flowing down the annulus can invade the rock formation, possibly causing irreversible damage to the reservoir. One of the main functions of these fluids is to form a film with low permeability on the borehole wall to prevent invasion of filtrate in the rock formation. Polymeric additives are increasingly used to control these infiltrations. Recent studies have shown the potential of using microspheres made of poly(methyl methacrylate-co-vinyl acetate) (PMMA-co-PVAc) with dimensions compatible with the size of the formation pores. In this study, PMMA and PMMAco-PVAc polymers were synthesized by suspension polymerization, producing in the presence or absence of porogenic agents. The particles porosities influence the glass transition temperature, surface roughness and apparent density. The results also demonstrate that less rigid spheres with pores in their structure form a more efficient barrier against filtration to the rock formation. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44484.
Abstract.1 Aphrons were produced using nonionic surfactants by applying a differential pressure. Bubble size distribution was obtained from optical microscopy using FIJI-ImageJ2 program. The aim of this work was to correlate surfactants structures with aphrons properties (density and viscosity), size distribution and the number of bubbles. API fluid loss tests were based on standard proceedings specifications for water-based drilling fluids of Petrobras/Brazil. The structure of the nonionic surfactants showed a great influence on the fluid properties and the performance of the fluid contributing with a filtrate reduction up to 31% with the systems that were presented between 1088 and 1850 bubbles with diameters ranging from 33 to 104µm. These systems were produced by poly(ethylene oxide) with 7 ethylene oxide units, a poly(ethylene oxide)-b-poly(propylene oxide) with 6 ethylene oxide units and 3 propylene oxide units.
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