Asphaltenes are tenacious
ingredients in heavy crude oil which can plug or 'gum' up downhole or
surface equipment. Typically, Asphaltenes exists with Paraffins to
provide two times the problem. Asphaltenes are held in suspension
by Resins which act similar to a suspension.
Control of asphaltenes is
visualized by the following picture:
The untreated (far right -
clear liquid with large black particles) has dissolved almost no
asphaltene. To the opposite extreme, the far left test tube has
completely prevented asphaltene from precipitating out of solution and
is completely dispersed in solution.
A line treated with an
asphaltene dispersant prevents asphaltene from precipitating out of
Dispersant physically removes the paraffin from the equipment. With
the asphaltene removed, more produced fluids are able to flow down the
Further research is being
performed to chemically treat or chemically modify the metal matrix to
lower the adhesion properties of production string metals. This is
in the field of metallurgical chemistry.
Organic molecules which have an aromatic and naphthalene ring containing
sulphur, nitrogen and oxygen molecules are called asphaltenes.
This portion of crude oil is in the hydrocarbon portion of crude oil and
is not soluble in chemicals such as hexane.
Asphaltenes remain in
solution within the hydrocarbons by resin molecules which stabilize
asphaltenes. This stability is highly dependant on the ratio of
resins to asphatlene molecules.
Asphaltenes can precipitate
due to 1) a pressure drop, 2) acids, 3) Carbon Dioxide, 4) turbulent
flow, 5) injected condensate, and 6) incompatible crude mixing.
Eugene for more information.