Aspects of Selective WELD and HAZ Attack in CO2 Containing Production Environments

Abstract

Abstract An investigation was performed to assist in selecting materials and welding requirements during the design phase of oil and gas development projects. The objective was to eliminate selective weld attack for new subsea pipelines. Historically, the oil industry has experienced failures caused by selective weld attack in offshore production equipment. These failures have occurred in both platform process equipment and subsea flowlines. The results of this investigation and field trials show that use of alloyed weld filler metal prevents this problem. Increasing preheat improves corrosion resistance, in certain parent metal/weld metal combinations that are susceptible. Carbon manganese steels welded with a nominally 1% nickel filler metal can provide acceptable performance, thus eliminating the requirement for a more expensive pipeline base metal.