Prebending Coiled Tubing and Its Fatigue Life Prediction

摘要

Sand management strategies become an important study to be performed as part of multiphase flow assurance assessments during oil and gas project life and especially for subsea multiphase flow network. This paper presents experimental works to investigate the sand transport characteristics and identify the sand minimum transport condition (MTC) in sand-water and sand-air-water flows in a horizontal and + 5 deg inclined pipelines. The used sand volume fraction, C_v, ranged from 1.61 × 10~(-5) up to 5.38 × 10~(-4). The sand minimum transport velocity in single-phase water flow was obtained visually and then compared with that calculated by previous correlations for slurry transport. It was found that in sand-water flow, the pipeline inclination had negligible effect on the minimum sand transport velocity. However, the transport characteristics of sand particles were found changed significantly by changing the pipe inclination, which could result in the change of air-water flow regime. It was observed that sand particles transport more efficiently in terrain slug than stratified wavy flow in +5 deg inclined pipes. The sand transport and settling boundary for different air-water flow regimes were generated for horizontal and+5 deg inclined pipeline.