A UK offshore 8" condensate pipeline had an extensive wax blockage that could not be removed, causing a significant production outage. The decision was taken to replace the affected section with a 23km bypass.
In order to protect both saturation divers and environment, it was critical to thoroughly clean the line and to prevent any hydrocarbon discharges. SANCCUS was called in to tackle this challenge.
2 hot stabs were installed on either side of the blockage area as per the diagram and 2" downlines were connected to the Diver Support Vessel (DSV).
Aqualink Gel, J-Clean 1 and Pipesurf 10 were pumped from the DSV through the hot stabs 1 and then 4 to clean and deoil the line.
Glycostat Gel were injected through the hot stabs 2 and then 3 to form a 300m long environmental barrier on each end of the blockage.
Cut out the pipeline section containing the blockage and replaced it with a bypass.
Approx. 1100m3 (6918 bbls) of hydrocarbon was efficiently treated to <30ppm oil in water target by using minimal volumes of SANCCUS proprietary cleaning gels. The environmental gel barrier enabled the divers to safely cut out the affected section of pipeline in prior to the installation of bypass.
Returned water samples showed clear and rapid deoiling and recovered subsea spool had no traces of hydrocarbons as per the photos.
SANCCUS gel technology enabled an effective and rapid execution that have significantly reduced the DSV time and costs without compromising diver safety and environmental responsibility.
The operation was a great success and has set the benchmark for future subsea and pipeline operations where pure mechanical approaches cannot deliver the desired result. It is believed to be the largest environmental barrier used in the saturation diving and the ROV industry for a subsea pipeline to date.
We know from years of experience that no two jobs are identical. We will work closely with you to provide the appropriate gel and/or gel pig combined with reliable technical advice and support to give you the best possible outcome. Get in touch with us for a tailored information pack.
