The Use of MP-ICDA ICPM to Evaluate Design Implications for a New Kuwait Crude Oil Pipeline

This paper discusses how internal corrosion predictive modeling (ICPM) was used to model theoretical flow scenarios in the 20 in × 30.25 km crude oil pipeline (CR195) to determine the best course of action for future pipeline integrity. The client had proposed the addition of heavy oil to CR195, which was flowing conventional oil. The MP-ICDA methodology (excluding Step 3 Detailed Examination) was used to determine the potential consequential impact of commingling heavy oil with conventional oil in comparison to flowing conventional oil alone. The conventional oil had both a very high CO₂ and water content. The heavy crude oil had a lower corrosivity than the conventional crude oil. This paper describes the methodologies and sensitivity analyses performed to capture the nuances associated with each sensitivity analysis on an accurate basis. The modeling led to operational conclusions regarding the impacts associated with commingling. For both scenarios, recommendations were made to lower the corrosivity and ensure pipeline integrity going forward, including performing verification digs after MP-ICDA was completed.

The Kuwait Oil Company ⁽¹⁾ subject CR195 pipeline was commissioned in 2018 for transporting crude oil from the Ratqa Main Manifold to the Ratqa Midpoint Manifold over a distance of 30.2 km (18.7 mi). CR195 was constructed from Schedule 30 (12.7 mm or 0.5 in wall thickness) 508 mm (20 in) API ⁽²⁾ 5L X-52 (Sour Service) carbon steel pipe externally coated with three-layer high density polyethylene (HDPE).¹ No internal coating or corrosion inhibitor were used at the time of assessment.²

After it was proposed to commingle heavy crude into the conventional crude flowing through the CR195 pipeline, the Kuwaiti oil producer decided to perform Multiphase Flow Internal Corrosion Direct Assessment (MP-ICDA) (i.e., NACE SP0116-2016).³ The purpose of this MP-ICDA was to assess the pipeline up to the time of the assessment and forecast two different "what-if" scenarios to determine the impact of commingling heavy and conventional crude on the long-term integrity of the pipeline. When the MP-ICDA protocol was completed, what occurred, the action plan and causes of corrosion in the future were clear. The complete MP-ICDA process consists of: Pre-Assessment (PreA), Indirect Inspection (IDi), Detailed Examination (DEx) and Post-Assessment (PoA). Due to the main concern of the ICDA being forecasting, no DEx was performed for CR195, although an ILI or DEx was recommended afterwards. Hence, this paper reviews the partially completed theoretical 3-step (out of 4 steps) ICDA process performed by Broadsword Corrosion Engineering Ltd. ⁽³⁾ and Allied Engineers ⁽⁴⁾ for the Kuwaiti producer.