Asphaltenes are high molecular weight, polar and paramagnetic hydrocarbons responsible for significant blockages and downtime. Often, chemical programs are used to manage fouling but it may prove difficult to determine the effectiveness and that makes optimization challenging. A newly introduced surveillance technique measures the total amount of asphaltene by quantifying its paramagnetic signature and that technology was considered attractive for offshore. Commissioning of the sensor for its first ever offshore operation was non-trivial and required an integrated partnership between the operator and sensor provider, with particular emphasis on data integration, component qualification and ease of maintenance.

A review of a few GOM oils established that, as had been previously seen in the Middle East, the paramagnetic signature consistently correlated with asphaltene content. This gave confidence to use the signature as a potential input for offshore production decisions. One new challenge for the offshore analysis, however, was that multiple wells on the seabed were commingled to two risers coming to the surface and the asphaltene sensor was plumbed to only one of those risers. To meet this challenge, it proved very beneficial to be able to integrate the asphaltene data with other real-time data traditionally available to the operator, such as well alignments. The integrated results were then viewable on a dedicated vendor dashboard as well as on the operator’s SEEQ dashboard.

A systematic sampling program was launched so that SARA data could be used to compare against the real-time data. The range of experiments to date include evaluating effectiveness of long-term solvent soaks, monitoring for change in baseline due to changes in chemicals or changes in subsea configuration and observing elative differences in asphaltene content influenced by continuous chemical treatments and the asphaltene stability of fluids from zonal production.