The Duoline Flush System is an extension and natural progression to the successful Duoline DL System, which has been used in thousands of onshore and offshore wells worldwide over the past 10 years. Using the same component material with an enhanced internal geometry, Duoline is now able to offer an increased through bore while still maintaining all the benefits of the original Duoline DL Ring System. Duoline Flush is a glass-reinforced-epoxy lining system that, when installed into carbon-steel casing and tubing, protects the base material from corrosion from materials that may be present in the well fluid. Reservoir cleanup with hydrochloric acid at concentrations up to 28% can be accommodated to ensure good flow rates. Duoline Flush may be installed into threaded oil-country tubular goods, either new or used, within most connection options. The Duoline Flush System uses the patented FL-Ring system that permits lining of shoulder-to-shoulder premium connections without affecting the geometry and performance of the connections. The system can be installed into a wide range of bore diameters and weights. Duoline can accommodate interventions with both coiled tubing and wireline; procedures are already available for this operation.