Advances in rheology and flow assurance studies of waxy crude

Flow assurance is one of the core issues in safe and economical operation of waxy crude pipelines. Its essence lies in flow and heat transfer of the crude. In the past 10 years, the authors' team has achieved a lot of innovative results in aspects of waxy crude rheology, flow assurance assessment, and pipelining technologies on the basis of decades of studies. The rheological characteristics of waxy crude are much better understood, and a method for quantitatively simulating the effect of flow shear was developed based on some theoretical breakthroughs. Studies of the mechanism of waxy crude rheology have been deepened to the quantitative level. After successful development of efficient numerical-algorithms, accurate simulations have been achieved for various complex flow and heat transfer situations in waxy crude pipelining, and a reliability-based approach to flow assurance assessment has been set up. New pipelining technologies have been developed such as batching pour-point depressant-(PPD-) treated multiple-waxy-crudes, intermittent transport of waxy crudes through long-distance pipelines, and batching hot and cold crudes. By their application, a series of problems hindering safe, efficient and flexible operation of waxy crude pipelines were tackled, demonstrating that transportation technologies for waxy crude have advanced to a new and high level.