TEST METHODS FOR DETERMINING ASPHALTENE STABILITY IN CRUDE OILS

摘要

The high cost of remediating asphaltene deposition in crude oil production and processing has necessitated the development of test methods for determining the stability of asphaltenes in crude oils. In the current work, the stability of asphaltenes in crude oils of varying API gravity is predicted using the Oliensis Spot Test; two SARA-based tests; and a solvent titration method with NIR solids detection. The test methods are described in detail and experimental data from them presented. The experimental stability data were validated via correlation with data on the deposition histories of the oils. The effectiveness of the various tests as predictors of the stability of asphaltenes in oils is discussed. The Colloidal Instability Index and the solvent titration methods were found to predict a crude oil's propensity towards asphaltene precipitation better than both the Asphaltene-Resin ratio and the Oliensis Spot Test. For oils with low asphaltene content where most stability tests fail, live oil depressurization is proposed as the test for predicting the stability of asphaltenes.