What is colloidal instability index?
The colloidal instability index (CII) is one approach to determine the instability of heavy oil which is based on the chemical composition of crude oil [6].
How to test for asphaltenes?
Some of the older but more popular methods for determining the stability of asphaltenes are the Asphaltene–Resin ratio and the Oliensis Spot Test. Newer tests include solvent titration with solids detection and the Colloidal Instability Index (CII).
Is bitumen an asphaltene?
Bitumen (asphalt) is the highest-boiling point, heaviest and most polar fraction from the vacuum distillation of crude oil. Bitumen is composed of asphaltene and maltene. The heavy insoluble asphaltene molecules give bitumen its body and softening point while the maltenes are oily and make asphalt flexible.
What are asphaltenes in crude oil?
Asphaltenes are the crude oil component with the highest molecular weight. They are conditionally defined as fractions insoluble in pentane or heptane; their presence in heavy oil provides its high viscosity. Therefore, the removal of asphaltene is one of the most efficient methods for the reduction of oil viscosity.
What is Sara analysis of crude oil?
Saturate, Aromatic, Resin and Asphaltene (SARA) is an analysis method that divides crude oil components according to their polarizability and polarity. The saturate fraction consists of nonpolar material including linear, branched, and cyclic saturated hydrocarbons (paraffins).
Is crude oil stable?
The stability of crude oil is related to the saturation solubility of asphaltenes. By testing the CII value of the crude oil in its current state and the CII value of the dissolved asphaltenes in its saturated state, we were able to propose a new way to judge the oil stability.
What is the effect of increase of the asphaltene content in coker feed?
The higher asphaltene content also means that the change in viscosity of the coke drum liquid will be more pronounced and frequent which will move the surface dynamics towards more stable foam propagation.
What is asphaltenes in fuel?
Asphaltenes are formed when diesel fuel is heated under high pressure as it passes through today’s high pressure fuel injection systems. These systems operate at about 30,000 PSI (pounds per square inch) which is about six times the pressure of the previous conventional fuel injection systems.
What is asphaltene used for?
Asphaltenes in the form of asphalt or bitumen products from oil refineries are used as paving materials on roads, shingles for roofs, and waterproof coatings on building foundations.
What is asphaltene content?
Asphaltenes are complex, highly aromatic compounds with a high-molecular weight that usually contain sulphur, nitrogen, and oxygen as well as metals such as vanadium, nickel, and iron.
How do you treat asphaltene?
Because the solubility of asphaltene increases with an increase in aromatic contents, solvents such as xylene and toluene commonly are used to dissolve asphaltene deposits in both the wellbore and formation.
What is Sara bitumen?
Saturate, Aromatic, Resin and Asphaltene (SARA) is an analysis method that divides crude oil components according to their polarizability and polarity.
What is the stability index of Asphaltene?
Asphaltene stability index. (ρ oi − ρ ob) > 0.025, system is unstable (ρ oi − ρ ob) < 0.025, system is stable where ρ oi = oil density at initial reservoir pressure, gm/cm 3 and ρ ob = oil density at bubble-point pressure, gm/cm 3. For the crude oil of Example 6-1 and from Table 6-1:
Are asphaltenes more stable or unstable than crude oils?
For BMCI values lower than 9, asphaltenes are highly susceptible to precipitate, whereas when having values higher than 11, asphaltenes are stable. Values among 9 and 11 are considered as boundary ones and the crude oils are equally likely to be stable or unstable.
When do asphaltenes become a problem?
Asphaltenes only become a problem during production when they are unstable. Asphaltene stability is a function of the ratio of asphaltenes to stabilizing factors in the crude such as aromatics and resins. The factor having the biggest impact on asphaltene stability is pressure.
Does the colloidal instability index predict asphaltene precipitation in crude oil?
The Colloidal Instability Index and the solvent titration method were found to predict a crude oil’s propensity towards asphaltene precipitation better than both the Asphaltene–Resin ratio and the Oliensis Spot Test.