Protecting from H2S Damage – Expanding the Knowledge

Abstract

This paper will present an update on the operational benefits of utilizing anti-cracking inhibitors in sour wells. Multiple papers have shared the details of a Joint Industry Project which resulted in a one-size-fits-all fatigue derating factor by the service supplier. In recent years, additional testing has challenged that practice and a greater variety of improved derating factors are utilized in fatigue tracking software. The testing process of exposing samples to sour conditions for 72 hours and conducting bend fatigue testing post exposure remains the method used in this paper. The process updated the JIP practice of one-time coating of the sample with the addition of an anti-cracking inhibitor to the sour fluid. This update more closely replicates real-world operations. In addition, there was a greater focus on the test sample size, stress and strain to reduce fatigue testing time and reduce the effects of any outgassing leading to a more accurate and repeatable test. A comparison of three typical test methods will be presented: non-inhibited sour tests by the original equipment manufacturer, inhibited field specific partial pressure testing by an operator and globally applicable inhibited testing conducted at the maximum apparatus test level by a service provider. Comparison of prior anti-cracking inhibitor and a North Sea approved inhibitor results will be detailed. The practice for conducting the tests with a high yield material and extending the results to a lower grade material with similar chemistry will be detailed. Note that the results of separate tests conducted on the pipe body and bias welds will be compared and detailed. A brief summary of the service providers record of global sour pipe operations will illustrate these practices have proved suitable in the field. The updated practices and procedures for sour testing have not been shared in prior papers. The improved pipe life will assist the industry with efficient and safe operational planning in sour wells. Finally extending pipe life will reduce the amount of raw steel required for operations and ultimately reducing carbon dioxide emissions, a global challenge from which we can all benefit.