Evaluation and implementation of High Density Polyethylene liner: Alternative of solution to corrosion-wear problems in flowlines

Abstract

Failure mechanisms of CO2 corrosion and abrasive wear by production sand have reduced the service life of flowlines and collector lines in Casabe’s mature field located in the middle Magdalena River Valley Basin of Colombia’s Antioquia department, which has required a timely and effective solution. In this work, laboratory tests set to conditions of Casabe’s production fluid were performed to assess abrasive wear and CO2 corrosion resistance on pipeline sections of both HDPE (High Density Polyethylene) and carbon steel API 5L grade X65.  The results obtained showed that resistance of HDPE to abrasive wear and CO2 corrosion of HDPE is significant, being three times higher as compared with carbon steel. Additionally, material properties of HDPE remained constant in contrast to performance of carbon steel over time tests. This result is due to the toughness and chemical resistance of HDPE.  Based on these results, a field trial was implemented to pilot-scale for evaluating the performance of HDPE liner in a collector line with a service life between 6 to 9 months, which collect fluids of different flowlines from producing wells.  After 12 months in service, the field trial of the liner assessed through visual inspection and DSC tests revealed that HDPE liner exposed at multiphasic fluid conditions with production sand remained stable without evidence of swelling, blistering, softening or changes in its geometry associated with liquid hydrocarbon absorption in its physical structure. This was also evidenced in the results of melting temperature and crystallinity obtained from DSC tests before and after exposure to field conditions. Moreover, pilot tests with HDPE lining after six years of service still operate successfully.