caa a22 4500 605466890 CHVBK 20210128100309.0 cr unu---uuuuu 210128e20150201xx s 000 0 eng 10.1007/s00397-014-0812-0 doi (NATIONALLICENCE)springer-10.1007/s00397-014-0812-0 Influence of the initial cooling temperature on the gelation and yield stress of waxy crude oils [Elektronische Daten] [Diogo Andrade, Ana da Cruz, Admilson Franco, Cezar Negrão] One of the major problems in waxy crude oil production and transportation is oil gelation that takes place within pipelines as a result of wax crystallization at low temperatures. In such cases, the pressure needed to restart the oil flow in subsea pipelines can be much larger than the usual steady-state pressure, as the temperature in such environment can be as low as 4°C. The literature has shown that not only the temperature itself but also the fluid shear and thermal histories have significant influence on the yield stress of waxy crude oils. This paper investigates the effect of the initial cooling temperature on the waxy crude oil viscosity, gelation temperature, and yield stress. In order to accomplish that, rheological tests were carried out under static and dynamic cooling conditions. The results show that there is a critical range for the initial cooling temperature that provides maximum values for viscosity, gelation temperature, and yield stress. In other words, the highest values of those properties are observed when the cooling started within this temperature range. The effect of a thermal pretreatment usually used to remove light ends was also investigated. In spite of not changing the initial temperature critical range, the yield stress was slightly affected by the thermal treatment. It is worth noting that the yield stress varies from approximately zero to hundreds after dynamic cooling or to thousands after static cooling within the tested range of the initial cooling temperatures. Springer-Verlag Berlin Heidelberg, 2014 Waxy crude oil nationallicence Rheometry nationallicence Initial cooling temperature nationallicence Gelation nationallicence Yield stress nationallicence Andrade Diogo Research Center for Rheology and Non-Newtonian Fluids—CERNN, Postgraduate Program in Mechanical and Materials Engineering—PPGEM, Federal University of Technology-Paraná—UTFPR, Av. Sete de Setembro 3165, 80230-901, Curitiba, PR, Brazil aut da Cruz Ana Research Center for Rheology and Non-Newtonian Fluids—CERNN, Postgraduate Program in Mechanical and Materials Engineering—PPGEM, Federal University of Technology-Paraná—UTFPR, Av. Sete de Setembro 3165, 80230-901, Curitiba, PR, Brazil aut Franco Admilson Research Center for Rheology and Non-Newtonian Fluids—CERNN, Postgraduate Program in Mechanical and Materials Engineering—PPGEM, Federal University of Technology-Paraná—UTFPR, Av. Sete de Setembro 3165, 80230-901, Curitiba, PR, Brazil aut Negrão Cezar Research Center for Rheology and Non-Newtonian Fluids—CERNN, Postgraduate Program in Mechanical and Materials Engineering—PPGEM, Federal University of Technology-Paraná—UTFPR, Av. Sete de Setembro 3165, 80230-901, Curitiba, PR, Brazil aut Rheologica Acta Springer Berlin Heidelberg 54/2(2015-02-01), 149-157 0035-4511 54:2<149 2015 54 397 https://doi.org/10.1007/s00397-014-0812-0 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00397-014-0812-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Andrade Diogo Research Center for Rheology and Non-Newtonian Fluids—CERNN, Postgraduate Program in Mechanical and Materials Engineering—PPGEM, Federal University of Technology-Paraná—UTFPR, Av. Sete de Setembro 3165, 80230-901, Curitiba, PR, Brazil aut NATIONALLICENCE 700 1- da Cruz Ana Research Center for Rheology and Non-Newtonian Fluids—CERNN, Postgraduate Program in Mechanical and Materials Engineering—PPGEM, Federal University of Technology-Paraná—UTFPR, Av. Sete de Setembro 3165, 80230-901, Curitiba, PR, Brazil aut NATIONALLICENCE 700 1- Franco Admilson Research Center for Rheology and Non-Newtonian Fluids—CERNN, Postgraduate Program in Mechanical and Materials Engineering—PPGEM, Federal University of Technology-Paraná—UTFPR, Av. Sete de Setembro 3165, 80230-901, Curitiba, PR, Brazil aut NATIONALLICENCE 700 1- Negrão Cezar Research Center for Rheology and Non-Newtonian Fluids—CERNN, Postgraduate Program in Mechanical and Materials Engineering—PPGEM, Federal University of Technology-Paraná—UTFPR, Av. Sete de Setembro 3165, 80230-901, Curitiba, PR, Brazil aut NATIONALLICENCE 773 0- Rheologica Acta Springer Berlin Heidelberg 54/2(2015-02-01), 149-157 0035-4511 54:2<149 2015 54 397