Integrity Management of Hydrocarbon Vessel in Sour Environment-Role of UT/Phased Array and FFS Evaluation

摘要

Uninterrupted operation is the need of any oil and gas production facility. Over a period of time, some of the oilfields turned from sweet to sour production (presence of H2S in crude oil and gas). Most of the facilities were designed and installed prior to the publication of NACE MR 0175 (published in 1975) and NACE 0284 (published in 1984). These facilities are still in operation under sour conditions and hence necessary measures had to be taken for continuing these facilities in operation. In this paper, the authors share their experiences in monitoring the service-induced damages due to sour service using ultrasonic techniques including manual ultrasonic testing (MUT), advanced UT phased array, etc. The service of one HP gas scrubber in one of the operating facilities was prolonged for 10 more years, since the initial detection of mid-wall damages. The equipment was closely monitored at regular intervals. A fitness-for-service (FFS) assessment was carried out based on the data collected from the UT monitoring and was subsequently declared unfit for further service. In the intervening period, the company procured a new gas scrubber for installation, thus maximizing the run length and minimizing production loss.