This paper will provide the understanding for the preservation of assets from the effects of internal corrosion. A pre-screening for the mitigation of internal pipeline leaks at upstream and mid-stream pipeline facilities takes in consideration the internal safety aspects because of past leaks, elevation changes where liquids tend to collect in low spots or traps.
The primary goal in the screening process of large piping networks is to determine if corrosive environments exist while using a minimal amount of data to mitigate these leak risks to maintain production without reduction.
Let’s take a case with a network of approximately 1,000 gas production wells/pipelines in this study. Criteria were developed for mitigation and risk reduction strategies that includes inhibition, cleaning pigs, in-line-inspection (ILI) and repair. In addition, minimal time/information was required to apply the criteria utilizing a pattern recognition methodology conducted by an experienced corrosion engineer.
Once the pipelines of concern were identified as a threat (approximately 16%), the study then utilizes a multi-phase hydraulic simulator that integrates corrosion analysis from a comprehensive set of models to predict, identify and assess the location of highest likely risk and damage. The remaining 84% did not need any additional assessments using hydraulic simulation.
Key performance indicators (KPIs) were used to determine detrimental flow conditions. These indicators include predicted corrosion rates (influenced by total dissolved solids (TDS), flow regime, microbial induced corrosion, organic acids, temperature, glycol, etc.), remaining pipe life, water accumulation, etc.).
This type of study has been verified with other studies, but more importantly to actual field conditions. Assessing and locating internal corrosion has been a challenge with piping systems that have water hold up areas. This is because most monitoring tools are not located where the corrosion occurs. Typically, monitoring tools such as coupons or resistance probes are located at areas of accessibility rather than in required areas. In addition, these devices need to be placed where they will not impede the travel of cleaning pigs and other operational devices.