Abstract
An increasing incidence of amorphous deposits in both production and water injection systems is causing considerable problems for offshore fields. The amorphous deposits are typically comprised of both organic (biological or hydrocarbon) and inorganic material and can differ considerably in composition.
System deposits of this nature have been previously characterised as ‘Schmoo’ and within our company the descriptive, but non-specific term ‘Black Sticky Stuff’ has been coined. The challenge with use of this terminology is that it makes accurate description of deposits from different systems difficult and does not allow similar materials to be easily categorised.
This paper describes the work undertaken to better understand the composition of samples taken from different systems, both production and injection. Systematic analysis has led to the development of a classification matrix for deposits related to their major components. From the classification, improved knowledge has been gained to enable increased consistency of removal or preventive methods.
Some initial observations are made on an unusual form of deposit - being either a product of, or promoting corrosion - being encountered in water injection systems. The material is causing concern with regard to system integrity and intervention in injection wells. Work to define the root cause, and develop removal methods of this type of deposit is presented.
