Asphaltene precipitation in crude oils: Theory and experiments

The precipitation of asphaltenes in two Mexican crude oils was measured using a combination of high‐pressure isothermal expansion and atmospheric titration with n‐alkanes. Experiments were carried out from the live‐ and tank‐oil type of samples of the same crude oils. For the oils investigated, compositional data, precipitation phase diagrams, and bubble point pressures are reported. A theoretical study for these systems was performed using the statistical association fluid theory for potentials of variable range (SAFT‐VR) equation of state (EOS) in the framework of the McMillan–Mayer theory. By matching a single titration curve or two precipitation onset points with this EOS, a good prediction of asphaltene precipitation over wide temperature, pressure, and composition intervals is obtained.