Six residua from different crude oils were evaluated for composition and carbon residue forming tendencies. The whole residua were evaluated for elemental composition, trace metals content, carbon residue, and specific gravity. Each residuum was deasphaltened in heptane, and the heptane-soluble materials were separated into saturate, aromatic, and polar fractions on activated silica gel. The asphaltenes were evaluated for elemental composition, trace metals content, molecular weight, and carbon residue, The relationship between carbon residues and features of the asphaltenes was studied, and a correlation of contributing features was developed. The asphaltenes were further separated into four fractions according to apparent molecular size by preparative size exclusion chromatography (SEC). The preparative size exclusion chromatographic fractions from the asphaltenes were evaluated for sulfur content, molecular weight, and trace metals content, Material balances showed that the data obtained on the fractions account for the data obtained on the original material. This indicates that the contributions of the properties of the fractions can be studied and related to properties of the whole material.