通径式喷砂器伞键流场仿真与防冲蚀设计

Flow Field Simulation and Anti-erosion Design of Umbrella Key in Sand Blasting Device

低渗透致密油藏在水力压裂施工中需要大排量和长时间的作业,往往导致压裂管柱冲刷磨损严重而使其强度降低。伞键作为冲刷磨损最为严重的部位,其抗冲蚀性能决定了整套管柱的抗冲蚀能力。为此,以通径式喷砂器伞槽滑套为研究对象,采用有限元软件建立了流场仿真模型,研究了混砂液在伞槽内部的流场分布规律,找到伞键发生冲蚀的原因,并对其进行改进设计。在其内部增加挡板结构,使其内部流场发生改变,进而降低了伞键的冲蚀。优化设计后,伞键冲蚀率密度降低为原结构的1%,冲蚀质量降低了90.31%,使伞键在压裂施工全程具备导向功能,键尖得到有效保护。研究结果可为压裂管柱及工具的设计提供理论依据。

Large-displacement and long-duration hydraulic fracturing operation usually applied in the low permeability tight reservoirs often leads to serious fracturing string erosion and strength decrease. As the most serious erosion component,the performance of the umbrella key determines the erosion resistance of the entire fracturing string. In view of this,taking the umbrella key sliding sleeve of full bore sandblasting device as study object,the finite element model of umbrella key numerical simulation has been established by considering the internal structure of the umbrella key. Through the analysis of the flow field,the distribution of the internal fluid and the solid particles has been attained. The reason of umbrella key erosion is found to be caused by the direct impact of the solid particles on the surface of the umbrella key due to its internal geometry. Through structure modification of the umbrella key by adding the internal baffle structure to change the internal flow field,the erosion of the umbrella key has been reduced. After optimization design,the umbrella key erosion rate density has been reduced to 1% of the original structure,and the mass erosion has been reduced by 90. 31%,which greatly improves the erosion resistance of the umbrella key and ensures long operation time.