Shell is developing an offshore gas-condensate field in Asia-pacific. Sand is expected to be co-produced during the life of this project due to minimal downhole sand control, which combined with high gas flow rate pose a significant threat to the integrity of the subsea hardware due to erosion. A Computational Fluid Dynamics (CFD) based erosion study has been carried out to identify the location of erosion hotspots and erosion rates in the piping of the subsea X-mas tree, well Jumper and Manifold. The study has been used to either determine Inconel 625 clad thickness to be provided on the inner wall of the piping or modify the design of the piping to bring the erosion within acceptable limits. The CFD models have been validated using experiments in controlled environment. Through this study, the risk of potential erosive failure of the piping in the subsea hardware, leading to loss of containment has been greatly reduced.
In literature, CFD based erosion modeling has been used and validated on simple geometries (elbow, target tee, ID reduction etc). In this work, erosion in the entire piping which is a combination of such simple entities has been calculated in an integrated manner.
The results show that the required cladding varies between 3mm and 10 mm. The knowledge about erosion acquired in the past through experimental and modeling exercises, has been utilized to create a technique to do assessment and management of sand erosion in the subsea hardware.
This integrated modeling approach provides insights about the behavior of sand particles in complex piping geometries, which can help design the piping, especially at locations of change in flow direction. The CFD model has also been used to determine the best location to place the IED (Intrusive Erosion Device) in the piping to monitor erosion during operation.
