THE ELASTO-VISCOPLASTIC-TIME-DEPENDENT NATURE OF WAXY CRUDE OILS

B. A. Tarcha, B. P. P. Forte, E. J. Soares, R. L. Thompson

Abstract


Production in reservoirs located in deep and ultra-deep water that contain waxy crude oils faces a huge obstacle imposed by the low temperatures of the environment. When the waxy crude oil is subjected to a temperature below the Gelation Temperature, as in the case investigated in the present work, it exhibits a variety of non-Newtonian features: elasticity, plasticity, viscous effects, and time-dependency, which renders to this material a highly complex behavior. A crucial feature that is frequently ignored when the determination of the yield stress is being carried out is the timedependency nature of these materials. We demonstrate that this character has a significant impact on the measurement of the yield stress and, therefore, values obtained from a protocol that neglects time-dependency can be substantially different from a more careful procedure.

Keywords


waxy crude oils; re-start problem; yield stress measurement; time-dependent material

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DOI: http://dx.doi.org/10.5380/reterm.v13i2.62088

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Revista da Engenharia Térmica. ISSN: 1676-1790