Compositional changes of diamondoid distributions caused by simulated evaporative fractionation

We simulate and observe the effects of vertical migration on diamondoid composition for a single-phase fluid. A SGS Mini-PVT™ phase behavior cell was used to simulate upward migration of a condensate through multi-stacked reservoirs. PVT cell pressure was reduced from 4000 psi to 1000 psi in 1000 psi increments. At each pressure reduction step, the liquid phase of the condensate dropped out and samples were collected of both the liquid and gas phases. The liquid hydrocarbons were analyzed using GC and GC-MS to evaluate phase fractionation effects. The absolute and relative concentrations of diamondoids indicate that measurable compositional changes accompany simulated vertical migration.