A major oil and gas company faced a dilemma on a recent offshore pipeline rehabilitation project in the Gulf of Mexico. Saltwater and H2S corrosion had taken their toll on an existing steel pipeline.
Because outright replacement of the steel pipe was prohibitively costly and time-consuming, the company was considering a pull-through solution on a particularly challenging three-mile section.
Unfortunately, the application required a flexible pipe that could accommodate 150°F and 1,000 psi of pressure. To achieve those temperature and pressure ratings, the diameter and weight of the pipe would make the pull-through a difficult process. There was also a tight bending radius on two risers that would require pipe customization.
After evaluating a number of suppliers, the company selected Polyflow, which recommended 4-inch OD, 1000-psi PPS-lined Thermoflex Plus. This product has consistently proven itself as an effective and affordable solution for pipeline rehabilitation projects, including numerous offshore projects. Highly resistant to corrosion and erosion, it offers ultralow permeation to brine, H2S, CO2, CH4, and water vapor. With a unique, five-layer design, Thermoflex can accommodate pressures of up to 2,000 psi and temperatures of up to 180° F, making it ideal for oil and gas applications.
Due to the product’s low-friction coefficient, Thermoflex could also achieve flow rates comparable to those of much larger-diameter pipes, which meant a smaller pipe and lower weight relative to the competitor offerings. Moreover, Polyflow was able to provide certification training for the deployment and installation procedures—something else competitors couldn’t offer.
Upon deployment, workers were able to quickly pull the Thermoflex through the flooded 4-inch host pipeline at approximately 50 feet per minute—three miles were finished in a little over 5 hours. For connections, a Duplex 2205 stainless-steel coupling with Inconel fittings was used, as it was ideal for the corrosive environment and did not increase the diameter of the pipe.
Deployment went smoothly with no safety issues. After passing the hydrotest, both lines were performing to specifications. Had the company elected to install a new steel pipeline, the project would not only have far exceeded the budget on material and labor, but would have also required new permitting and a great deal of dive work.
Because of its success, Thermoflex is being considered as a solution for additional offshore rehabilitation projects.