oa Assessment of the Variation of the Fluid Properties and the Tar Formation by Investigating the Asphalthene Fraction

Asphaltene rich hydrocarbon fluids often present strong variation of their composition and characteristics within a same reservoir. Sometimes, tar mat can be present. Understanding the origin and the logic of the variation of fluid properties and of the tar formation is a challenging issue because fluid properties variation as well as the tar mat formation can be due to many factors: gravity segregation, fluid loading history, biodegradation, water washing, gas striping, liquid-liquid separation, asphaltene precipitation etc. The analysis of the driving forces leading compositional and properties variation is challenging. Many potential explanations are possible and often none can be easily proven or refuted.