Asphaltenes are the n-pentane or n-heptane insoluble fractions of crude oil that remain in solution under reservoir temperature and pressure conditions. They are destabilized and start to precipitate when the pressure, temperature and/or composition changes occur during primary production. The precipitated asphaltene particles will then grow in size and may start to deposit onto the product...

Abstract In this paper, the effect of asphalt deposition inhibitors coal tar, bromohexadecylpyridine and sodium oleate on viscosity reduction asphaltene crude oil was investigated. The results show that tar has a better inhibitory asphaltenes in oil. is best when addition amount 0.5%. Compared with blank, content reduced from 24.47% to 9.42%. cationic surfactant have good synergistic effect, by...

In this work, the precipitation and re-dissolution of asphaltenes were studied for an Iranian relatively heavy crude oil. A series of experiments were designed and carried out to quantitatively examine the reversibility of asphaltenes precipitation upon the change in the solvent concentration along with the temperature. n-Heptane was used as the precipitant, and a temperature range of 30 to...

asphaltenes are the n-pentane or n-heptane insoluble fractions of crude oil that remain in solution under reservoir temperature and pressure conditions. they are destabilized and start to precipitate when the pressure, temperature and/or composition changes occur during primary production. the precipitated asphaltene particles will then grow in size and may start to deposit onto the production ...

When oil is mixed with light alkanes, asphaltenes can precipitate out of oil solutions in a multistep process that involves the formation of nano and colloidal scale particles, the aggregation of asphaltene colloids, and their eventual sedimentation. Amphiphilic dispersants can greatly affect this process. The mechanism of the dispersant action in colloidal asphaltene suspensions in heptane has...

Asphaltenes constitute the heaviest fraction of the aromatic group in crude oil. Aggregation and precipitation of asphaltenes during petroleum processing costs the petroleum industry billions of dollars each year due to downtime and production inefficiencies. Asphaltene aggregation proceeds via a hierarchical self-assembly process that is well-described by the Yen-Mullins model. Nevertheless, t...

A pre®iously described molecular-thermodynamic framework, based on colloid theory, is used to correlate experimental asphaltene-precipitation data at high-temperature and pressure conditions. In this framework, asphaltenes and resins are represented by pseudopure components, and all other components in a crude oil are presented by a continuous medium that affects ®an der Waals attractions among...