Investigation on the effects of concentration and paraffin type on the rheological behavior of model oils

by Vanessa Guersoni, Charlie Van Der Geest, Antonio Carlos Bannwart, Ivanei Ferreira Pinheiro, presented at Rio Oil & Gas 2022, September 2022.

Abstract

The intrinsic characteristics of crude oils, combined with the pressure and low temperature of the seabed, can lead to flow assurance problems, compromising production. The low temperature causes a decrease in the wax solubility, eventually reaching the wax appearance temperature (WAT). Precipitated crystals can cause deposition on the tube walls and can affect production as they increase the pressure drop, decreasing flow during production. Depending on molecular weight, molecular structure and carbon number distribution, waxes can be called macrocrystalline and microcrystalline. Macrocrystalline wax mainly has a carbon number distribution of approximately C20 to C40 and has a linear molecular structure, so hydrocarbons tend to form large plates. Microcrystalline wax generally has chains with carbon numbers between C30 to C70 and its crystals tend to form smaller crystals. In the present work, the impact on gel strength was evaluated as a function of wax type (macrostructure and microstructure), wax concentration and applied shear rate. Understanding these impacts makes it possible to improve the models of wax deposition and, consequently,
the methods of preventing and mitigating the phenomenon.

 

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