Abstract: The effects of changes in ratios of n-alkane precipitants on the quantity of heavy organics precipitated at wellhead, separator and flowline during petroleum production was studied. Crude oils from three (3) wells at Sapele oil field, Niger Delta, Nigeria, were sampled. Gravimetric titration with single and corresponding binary mixtures of low molecular weight n-alkane precipitants (C5 and C6) at different ratios was used to generate the heavy organic precipitates. The results obtained from the 0:1, 1:3, 1:2, 1:1, 2:1, 3:1 and 1:0 ratios of C5:C6 binary mixtures of precipitants showed a consistent increase in the quantity of heavy organic precipitate at wellhead while the Separator recorded the least in all the three reservoirs. From the result obtained, it is important to closely monitor the operational pressure and temperature at the different locations of the production system and to ensure that the operational pressure and temperature at wellhead is higher than that of the flowline and that of flowline higher than the separator to prevent heavy organic precipitation and deposition.

Keywords: Precipitation, Heavy Organics, Precipitants, n-alkane, Crude oil, Ratios, Binary mixtures, Asphaltene.