Influence of sand properties on sedimentation of heavy oil sands in submarine pipelines

Abstract

The presence of sand in submarine heavy oil pipelines may bring a series of problems to the pipelines and offshore processing platforms. As for the sedimentation of sands contained in the heavy oil transported by submarine pipelines, the feasibility of simulating the solid-liquid two-phase flow pattern and the sedimentation laws of sands with the OLGA software was studied, and with the submarine pipelines of an oil field as the study object, a model was established reasonably based on the actual data. On this basis, the influence of the size, volume fraction, repose angle and density of sands on the critical settling velocity and the maximum settling location in the pipelines was analyzed. The results indicate that: The critical settling velocity decreases at first and then increases with the increasing of the sand size. The critical settling velocity varies little at low sand volume fraction, while it is of positive correlation with the volume fraction and density, of sands when it is high. Further, the maximum settling location was negatively correlated with sand particle size and density but positively correlated with the repose angle. When the volume fraction of sands is less than 1%, the change of the maximum settling location is not obvious, but the influence of high sand volume fraction on the maximum settling location cannot be ignored. Generally, the study results are expected to provide reference for the reduction of safety risks of heavy oil transportation in submarine pipelines.

Keywords

• submarine pipelines
• highly-viscous crude oil
• sand particles
• sand sedimentation
• solid-liquid two-phase flow