大型压裂施工中超级13Cr油管冲蚀规律研究

Research on Erosion Law of Super 13Cr Tubing during Large-scale Fracturing

大规模压裂施工过程中,油管受到高速携砂压裂液冲蚀而导致壁厚变薄,增加了后续施工和生产安全风险。为研究大规模压裂施工对超级13Cr油管的冲蚀影响,利用喷射式冲蚀实验装置模拟压裂施工过程中冲蚀环境,研究了超级13Cr油管冲蚀速率与压裂液冲击角度、喷射流速、含砂量之间的关系。研究结果表明超级13Cr油管冲蚀速率随冲击角度增加先增大后减小,在30°时冲蚀速率最大,材料损伤在冲击角度较低时以微切削为主,在冲击角度较高时以挤压锻打脱落为主。冲蚀速率随着压裂液流速和含砂量增加而增大,冲蚀速率与喷射流速之间呈幂函数关系。依据实验数据建立了冲蚀速率计算模型,能够预测在不同施工排量、注入量条件下超级13Cr油管压裂冲蚀后油管壁厚损失,可为压裂施工参数设计和后期管柱安全评价提供重要参考。

In the process of large-scale fracturing,the tubing is eroded by high-speed sand-carrying fracturing fluid,which results in thinner wall thickness.It increases the risk of the operation follow up and produc-tion safety.In order to research the impact of large-scale fracturing on super 13Cr tubing erosion,the jet erosion experimental unit is used to simulate the erosion environment during fracturing operation,and the relationship between the super 13Cr tubing erosion rate and the angle impacted by the fracturing fluid,jet velocity and sand content is studied.The results show that the erosion rate of the super 13Cr tubing increases first and then decreases with the increase of impact angle,and reaches the maximum at 30°.When the impact angle is low,the material is damaged as micro-cutting mainly;and when the impact angle is high,the material mainly falls off by extrusion forging.The erosion rate increases with the increase of flow rate of the fracturing fluid and sand content,and the relationship between the erosion rate and jet velocity is power function.Calculation model of erosion rate is established based on the experimental data,which can predict the wall thickness loss after the fracturing erosion on the super 13Cr tubing under the conditions of various dis-charge and injection rates,which may provide an important reference for fracturing parameter design and later string safety evaluation.