Dissolution of solid deposits and asphaltenes isolated from crude oil production facilities

Solid deposits that precipitate in oil production facilities are extremely complex materials. The most insoluble asphaltene fractions, inorganic species, very, large alkanes, and insoluble hydrocarbon species often contribute to their formation. In this work, five dissolution techniques were explored to investigate their dissolution in organic solvents. Three of the approaches were based on common laboratory hardware designed for temperature and mixing control. The fourth was suited for operation at high pressure and temperature, enabling us to investigate the effect of these parameters on the dissolution process. The last approach was suited to carry out kinetic dissolution studies, using gravimetric and spectrophotometric. quantitation techniques. A practical dissolution technique was selected among the five described above in order to perform routine analysis. Deposits solubility mappings are described, which combine solubility of solids in solvents of known aromatic contents plus the solids composition. Analysis of the information provided by these maps allows us to understand the behavior of each sample, as well as the selection of the appropriate treatment for deposit removal. Temperature was found to be the physical parameter that influences the most the dissolution phenomenon. Aromatic hydrocarbon content was a key chemical property of solvent mixtures that enhance their dissolving power, when applied to very insoluble materials. High asphaltene fraction aromaticity was observed to impair their solubility, being the determined dissolution kinetics inversely proportional to this property. Also, high asphaltene aromaticity values were found to correlate with high density and low H/C ratios.