Abstract
This paper describes joining systems for internally-coated tubular goods used in the petroleum industry. These joining systems permit the internal coating to be continuous throughout the joining connection and the body of the pipe to control internal corrosion. A typical threaded connection used for tubing is described with an example of proper coating application in the threaded area to provide a reliable barrier against corrosion damage of the threads. Line pipe joining systems that are described includes threaded, grooved, welded and interference fit systems that are available for use in the petroleum industry. These joining systems allow internally-coated line pipe to be installed without damaging the coating in the connection. Important factors that were considered in selecting a joining system are cost, availability, performance, coating system selected and speed of installation. The performance was measured by testing the joining systems and evaluating results of cyclic pressure testing, quick burst pressure testing and flow testing. The coating systems were also selected by using results of performance testing that used an autoclave and flow test. Field installation practices that include field handling the coated line pipe, fittings for tie-ins, subs for bends and transition fittings for terminal connections, welder qualification, crossing foreign lines, field wrapping the connection and hydrostatic testing the finished pipeline are also discussed.
