Determination of hydrocarbons volumetric fractions by a HP 5890A gas chromatograph

Abstract

Miscible displacements of waterflood residual oil in packed glass beads were carried out. In the experiments, n-hexane was used as solvent to miscibly displaced and recover n-octane, n-decane or mixture of broth. A gas chromatograph model HP 5890A was employed to determine the produced hydrocarbons volumetric compositions. Samples injection were done manually by 1 uL syringe. Flame Ionization Detector (FID) with helium and hydrogen as carrier gas was used. The gas chromatograph integrator was Shimadzu C-R3A. Initially samples of known volumetric fractions of n-hexane, n-octane and n-decane were prepared. These were injected into the gas chromatograph and the respective peak areas were obtained. The known volumetric frations versus the peak areas obtained from the chromatograms were plotted for each component. These standard curve were later used to determine the volumetric fractions of the produced fluids from the miscible displacements. The reproducibility of the systems was checked four times and found very satisfactory. More than one hundred samples containing mixtures of n-hexane, n-octane and n-decane were analysed. The volume of samples range from 6.0mL to 12 mL. The volumetric fractions and hence the recovery efficiency of the miscible displacements were successfully obtained.