Microbiologically Influenced Corrosion (MIC) is one of the most damaging forms of corrosion. Microorganisms naturally present in the reservoir or introduced to it by contaminated injection water can travel through the network and find their way to the pipeline. An oil production field was protected from microorganisms by treating its water injection system with nitrate. The nitrate treatment was deactivated in 2017 where the SRB population has increased dramatically over the years. This was evident by an increase in the H2S levels detected in the associated gas and the water injection system as a result of SRB metabolic activities. Pipeline-D, which is considered the backbone of this field, suffered from severe internal corrosion. A comprehensive corrosion risk assessment was conducted to identify causal factors of the severe corrosion and provide remedial measures for Pipeline-D that led to $7.5 MM cost avoidance.
Pipeline-D was built in 1997 and was used to transport crude to Gas-Oil Separation Plant-1 (GOSP-1). The pipeline continued operating until it was subjected to intermittent shutdown in 2009 when GOSP-2 was built. As part of the project, 900 meters were added to connect Pipeline-D to GOSP-2. In addition, more trunklines were connected to Pipeline-D. A 12 o'clock connection to GOSP-1 was kept to supply the facility with additional associated gas, which is used as blanketing gas and flare gas. Both of these functions are very important for plant process safety. Figure 1 shows the oil simplified piping network layout.
Although the pipeline has been subject to low rates at different years of its service, caused by either demands or switching from GOSP-1 to GOSP-2, its asset payback value and criticality are still significant despite its age. The pipeline's significance was and will always be prevalent by being a major transporter of crude to GOSP-2 with more than 40% of the field's total production.
