1. A method for characterizing petroleum fluid in a reservoir traversed by at least one wellbore, the method comprising: (a) at a plurality of measurements stations within the at least one wellbore, acquiring at least one fluid sample at the respective measurement station and performing downhole fluid analysis of the fluid sample to measure properties of the fluid sample, the properties including concentration of a plurality of high molecular weight components; (b) for each given one of a plurality of class-types corresponding to different subsets of a predetermined set of high molecular weight components, using a model that predicts concentration of the high molecular weight components of the given class-type for said plurality of measurement stations; (c) comparing the predicted concentrations of the high molecular weight components for the plurality of class-types as derived in (b) with corresponding concentrations measured by the downhole fluid analysis in (a) for said plurality of measurement stations to identify the best matching class-type; (d) in the event that the best-matching class type identified in (c) corresponds to at least one predetermined asphaltene component, evaluating asphaltene stability in the petroleum fluid of the reservoir at a given depth in the reservoir using equilibrium criteria involving an oil rich phase and an asphaltene rich phase of respective components of the petroleum fluid at the given depth; and (e) using the results of (d) for reservoir analysis.