For the problem of erosion-corrosion in oil pipeline system, used ANSYS FLUENT software, by changed the inlet velocity, the particle mass flow rate and the particle diameter, conducted numerical simulation for flow field distribution and severe erosion area of 90° elbow pipe. The results show that: with the increase of inlet velocity, the pipe erosion rate increases gradually; with the increase of particle diameter, the pipe erosion rate decreases; with the increase of particle mass flow rate, the pipe erosion rate increases linearly; and there have interaction between the three erosion factors of inlet velocity, particle mass flow rate and particle diameter.

Pipeline crossing structure was very easy to be affected by the settlement of soil along the river, and effective preventive measures should be adopted to effectively prevent the damage to the crossing structure. The finite element model of pipeline crossing structure and soil interaction was established, and the stress change of pipeline span structure with the fixed bracket was established. It was found that the fixed bracket could effectively reduce the stress value of the pipeline when the span structure was affected by the settlement of soil mass, and the installation position of the fixing bracket was more prominent to reduce the stress value of the pipeline span structure. The results could provide a theoretical basis for the safety construction of pipeline crossing structure.

      The ice blocking could happen during the process of conveying products oil in the pipeline, because of the low temperature in north China in winter. The pipeline occurred ice blocking, not only oil transport was affected but also unnecessary damage of production was caused, and the potential safety hazard could exist when it became serious. Based on thenumerical simulation software FLUENT, the flow field distribution was calculated around the single and multiple ice blocks in products pipeline which were in different height. The research results showed that increasing with the height of the ice wall, the pressure difference of front and back produced nonlinear changes, the pressure distribution regularities of multiple ice also produced nonlinear changes. In the aspect of velocity, the velocity variation degree of front and back the ice block was relatively stable, but the velocity change process around the ice block was more obviously and layered effect was better, the speed distribution regularities of multiple ice blocks were similar to that of the single ice blocks.