An analysis of methods for determination of onsets of asphaltene phase separations

It is demonstrated that one may identify up to seven distinct phase transition points due to separations of heavy organics (saturates, resins and asphaltenes) from petroleum fluids. They include saturates-cloud point, saturates-pour point, asphaltene-precipitation onset (APO), asphaltene+resin-flocculation (colloid formation) onset (ARFO), asphaltene+resin-deposition onset (ARDO), asphaltene-micellization onset (AMO) and asphaltene-coacervation onset (ACO). The existing experimental methods for determination of the onsets of asphaltene phase separations/transitions are analyzed. It is demonstrated that these threshold-point measurement techniques are for various purposes, and they serve to measure onset of different phase separations due to changes in the conditions of a petroleum fluid under consideration.