Microbiologically Induced Corrosion (MIC) | Materials And Corrosion Control

Damage Description

·         Microbes require water to thrive

·         Sulfate-reducing bacteria (SRB) is the most common in oil industry and reduce the sulfate to the corrosive H₂S, which again reacts with steel to form iron sulfides.

·         H₂S is generated in aqueous environments, and is patent in stagnant or low-flow conditions that allow and/or promote the growth of microorganisms.

·         Observed as localized corrosion (pitting) under deposits

·         Compromises the integrity, safety, and reliability of piping or vessels.

Affected Materials

Control Methodology

·         Maintain flow velocities above minimum levels.

·         Minimize low flow or stagnant zones to avoid solid deposits.

·         Systems that are not designed for water containment should be kept clean and dry.

·         Empty hydrotest water as soon as possible. Blow dry and prevent moisture intrusion

·         catholically protecting underground structures

·         Maintain coatings

·         Prevent oxygen incursion.

·         Ensure good housekeeping and follow maintenance procedures

Monitoring Techniques

·         Establish bacteria monitoring program to be taken in a regular basis in order to obtain useful baseline data and assess long term trends.

·         Install flush coupons for evidence of fouling coinciding with MIC damage.

·         Periodic UV surveillance.

Inspection Frequency

·         Lab analyses on a weekly basis to detect and quantify MIC

KPIs

Reference Resources (Standards/GIs/BPs)

·         SABP-A-018

·         SABP-A-019

·         ASTM A123

·         API RP 571