Asphaltene precipitates in oil production wells

At the beginning of production in a southern German oil field, flow blockage was observed during file initial stage of production from the oil wells. The hindrance was caused by the precipitation of asphaltenes in the proximity of the borehole and in the tubings. The precipitates were of solid, "dry" consistency and resulted in total damage to flow. On the basis of residue samples from the wells, a number of physical and chemical analyses were performed, and the results were compared with those from studies on other asphaltenic precipitates. Among other items, the fraction of aromatic compounds in the organic scales from operations definitely differed from the data published in the literature. In order to dissolve the precipitates and thus eliminate the damage, various organic solvents and industrial solvent mixtures were examined. The kinetics of the dissolution process in operational samples are described and discussed in detail. The laboratory results were subsequently applied in preparing a stimulation concept which takes into account the specific asphaltene problems in this field. The stimulation measures were implemented several times in two wells. Eruptive production was subsequently resumed in these wells. The production from the wells was adjusted in such a way that the conditions for asphaltene deposition are effectively suppressed for several years. The long-term success of the treatment tons also supported by modifying the production strategy. The process of optimising production is also explained and discussed in detail from a reservoir engineering standpoint.