The bulk fuel passed. The tank bottom did not.
A major offshore operator was changing fuel filters every 2 days to 1 week, and two other additive programs had already been tried with only minor effect. Lamurindo's diagnosis went past the bulk fuel sample and found the real source sitting at the bottom of the tank.
Two additives were already in use. Neither one fixed it.
The operator's offshore fuel system was blocking filters on a cycle as short as every 2 days, never longer than a week. Two other fuel additives had already been trialed to solve it, and both delivered only a minor improvement, not the sustained fix the operation needed.
Lamurindo's first step was diagnostic, not dosing. A fuel sample was tested for Filter Blocking Tendency (FBT) per ASTM D2068, the industry method for predicting how much a fuel will foul a filter. The bulk fuel came back at an FBT of 2.36, elevated enough to explain frequent blocking on its own.
Based on that result, Lamurindo recommended its additive. Lab testing brought the bulk fuel FBT down to 1.35, a clear improvement, and enough to justify moving the additive from the lab into a field trial on the actual system.
The field trial found a worse problem than the lab sample showed.
A bulk fuel sample can pass while the tank keeps failing the filter.
Frequent blocking was already a cost problem
Filters changing every 2 days to 1 week meant constant intervention, consumable spend, and downtime risk before the trial even started.
Two prior additives had already underdelivered
The operator had already spent on two other treatment programs with only minor effect, so the next recommendation had to be verified, not assumed.
The real contamination was hiding at the tank bottom
A bulk fuel result of FBT 1.35 would have looked like a success on its own, while settled sludge at the tank bottom, FBT 6.08, kept feeding the filters.
Offshore filter changes carry outsized risk
Every additional filter change offshore adds manhours, waste handling, and exposure in a working platform environment, not a simple onshore swap.
Test where the sludge actually settles, then treat it.
After the encouraging lab result on bulk fuel, Lamurindo pushed the diagnosis further in the field trial and sampled fuel from the tank bottom, where sludge is most likely to settle. That sample returned an FBT of 6.08, far worse than the bulk fuel result and a strong candidate explanation for why two earlier additives had failed to solve the problem.
Treatment continued through the trial period targeting that tank-bottom contamination directly. FBT at the tank bottom came down to 1.68, and the operational result followed: filter life extended out to 2 months, up from a cycle that had been running as short as every 2 days.
Finding the contamination mattered as much as treating it.
The headline number is filter life going from a matter of days to 2 months. The part that made it repeatable was testing the tank bottom separately from the bulk fuel, so the treatment addressed where the problem actually was.
Still swapping filters every few days after trying an additive?
Lamurindo tests bulk fuel and tank-bottom fuel separately, so the treatment addresses the actual source of contamination, not just what shows up in a routine sample.