Asphaltenes deposition is associated with several detrimental effects on oil production, paramount
among these being production deferment and integrity issues. The current paper presents an
investigation of asphaltenes risk assessment and mitigation strategies using a dynamic flow test method.
It includes a study of the key parameters that influence observation of asphaltenes deposition in the
laboratory and how laboratory testing methodologies can be designed to match more closely the
processes occurring in the field.
In these dynamic tests, dead crude oil is co-injected with n-heptane through a capillary and an inline filter,
allowing assessment of both deposition and precipitation in a single test. The method is able to assess
deposition tendency and rank asphaltenes inhibitor chemicals under flowing conditions and at more field representative temperature and pressure, and with much lower volume fractions of n-heptane than
required for conventional asphaltenes laboratory tests.
Fluid dynamics is recognised to play a key role in the extent of asphaltenes deposition and is often most
severe under low-shear conditions because erosive forces can reduce or eliminate deposition at higher
shear. Using the dynamic flow test method with capillaries of differing internal diameter, we investigate
the factors that either promote or suppress deposition, and determine certain boundary conditions where
deposition is inhibited under the influence of increasing shear.
The dynamic method is also used to evaluate the effectiveness of asphaltenes inhibitor chemicals against
both precipitation and deposition, thus demonstrating that this approach provides much more relevant
chemical-performance data than conventional test approaches, and may even elucidate why chemicals
selected using non-dynamic methods often perform indifferently in the field or sometimes fail to perform
completely.