Abstract

The abrupt shutdown of the Joint Operations (JO) production facilities led to a deviation from normal shutdown standard operating procedures such as draining and purging of the corrosive production fluids. Consequently, the ensuing deterioration, as a result of corrosion and other associated damage mechanisms, is bound to increase the integrity threats to JO equipment and therefore, negatively impact the restart of operation. The main anticipated damage mechanisms such as microbiologically influenced corrosion (MIC) and under deposit corrosion (UDC) are likely to manifest in the form of pinhole leaks, leading to increased incidence of loss of containment and subsequent negative Environmental, Health and Safety (EHS) consequences. This paper explores different mitigations that were utilized in maintaining the integrity of the JO equipment, including chemical preservation, the use of risk based assessment for the optimization of the chemical preservation methodology and subsequently, the use of enhanced preservation as a long-term preservation approach.

The chemical methodology relied on the use of corrosion inhibitor and biocide coupled with extensive chemical and corrosion monitoring key performance indicators, which were utilized to determine the treatment efficacy. An improved risk-based approach of the chemical methodology, using an integrated inspection, chemical and monitoring data was subsequently devised, leading to the identification and subsequent risk-ranking of susceptible equipment. These equipment were subjected to an increased and targeted chemical preservation retreatment frequency. A realization that the chemical preservation efficacy will diminish with time, alongside the desire to effectively assure the long-term integrity of the equipment, spurred the development of an enhanced preservation methodology. This typically involved equipment desludging, inspection and/or repair, if necessary. The enhanced preservation methodology utilized a qualitative assessment, where criticality and prioritization of equipment were based on number of factors such as; production handling, equipment integrity, impact on startup, redundancy, and environment risk etc. These alongside samples of the post-inspection findings of the equipment will be highlighted and discussed

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