Establishment of Wax Deposition Index from Saturates, Aromatics, Resins, Asphaltenes Analysis

Abstract

Saturates, aromatics, resins, asphaltenes (SARA) analysis is one method of characterizing crude oils. It is versatile because it can apply to many components of the crude oil. SARA analysis furnishes one with the composition of any crude and ultimately gives an idea of the potential of the crude oil to precipitate and deposit wax. This analysis method usually breaks crude oil down into four components (saturates, aromatics, resins and asphaltenes) according their solubility and polarity. SARA analysis results are always reported in terms of these four components and may not easily be understood by most decision makers at a glance without some explanation from laboratory analysts. Most importantly SARA analysis plays a vital role in providing information on whether or not a particular crude oil is waxy, a role that is not always obvious. Wax deposition index (WDI) bridges this gap by providing a single number from SARA analysis that captures the waxing potential of the crude as well as the degree of the waxicity. In this study, WDI was tested using a wide variety of SARA results from across the globe and has been found to be consistent. WDI could therefore be combined with other methods to determine the frequency of wax removal operations.

Keywords: SARA analysis, wax deposition index, waxicity