Advanced Paraffin Dispersant Improves Oil Flow to FPSO | SLB

Advanced paraffin dispersant improves oil flow to FPSO

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Ivory Coast, Africa, Offshore

Injection of a proprietary paraffin dispersant reduced the pressure drop across a subsea flowline and stopped production decline. It also eliminated the need for steam flushing the separator on the FPSO, enhancing safety and increasing uptime.

A customer operating an oil field offshore Ivory Coast was encountering paraffin deposition in the production flowline between a wellhead tower and the FPSO. Despite the wax inhibitor program in place, wax particles were found in the lower chambers of the test separator vessels, and a wax pad was forming at the oil/water interface. Increased pressure drop (ΔP) across the flowline also indicated wax buildup.

Schematic of 2 wellhead towers producing to an FPSO, which exports to an onshore terminal.
Paraffin wax buildup in the pipeline between a wellhead tower and FPSO as well as in the separator was challenging production.

Following a system review that included sampling the interface and debris collected from the vessels, SLB recommended its proprietary paraffin dispersant PI-7259. Laboratory solvency tests performed on a deposit sample indicated that the selected product was the optimal choice. To trial the solution, the dispersant was injected at the wellhead tower at a dose rate of 300 ppm to prevent paraffin wax deposits in the flowline and allied downstream equipment.

An average 22% reduction was observed in the ΔP between the tower and FPSO, and steam flushing of the test separator was required less frequently. Pleased with the results, the operator initiated long-term injection of PI-7259. Daily operations have improved, with significant reduction in wax deposits aboard the FPSO. The operator also decided to start injecting the paraffin dispersant at a second wellhead tower supplying the FPSO after a wax-producing well was identified there. This measure has further reduced the likelihood of process shutdown and eliminated steam flushing, thereby enhancing safety and uptime.

Graphs show reduced pressure drop across subsea flowline after injecting paraffin dispersant PI-7259
Following steady injection of the paraffin dispersant PI-7259, pressure drop across the pipeline between wellhead tower 1 and the FPSO reduced from an average of 161 psi to 126 psi.
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