Organic precipitates in oil production of a Venezuelan oil field

A very light crude oil is being produced in an oil field in Venezuela. Such oils are susceptible to asphaltene precipitation as the reservoir pressure decreases during production. An asphaltene deposit has been found in the t ubing of one of the wens and in the bottom sediment of the tanks on site. D ead oil samples from the well head of seven different producers in the fiel d were analyzed by three different companies. The laboratory results coveri ng the following aspects of different solvents show significant differences : asphaltene content, asphaltene/resin ratio, molecular mass of the precipi tated asphaltenes, flocculation point, Vanadium/nickel ratio, precipitated asphaltenes, and the Hildebrand parameter. Using different consistency chec ks and establishing correlations among the results, the analysis of one lab is strongly favored against the others. The analytical results are discuss ed in detail, including the correlation between asphaltenes and the well si tuation regarding perforation depth and the phase behavior of the produced oil.