Yang Siqi, Fan Jianchun, Zhao Nan, Yang Jiakun, Xu Changfeng, Lu Junan, Zou Guanggui, Wang Jianjun, Dai Siwei, Zhou Binchao
State Key Laboratory of Oil and Gas Equipment, CNPC Tubular Goods Research Institute, Xi'an, 710076, China.
Key Laboratory of Oil and Gas Safety and Emergency Technology, China University of Petroleum, Beijing, 102249, China.
Heliyon. 2024 Aug 14;10(16):e36341. doi: 10.1016/j.heliyon.2024.e36341. eCollection 2024 Aug 30.
In field hydraulic fracturing operation of shale gas development, the high pressure and large displacement liquid-particle two-phase fracturing fluid can be forced to change direction many times through high-pressure double-elbow, and be transported from the outlet pipeline of the fracturing pump to the main pipeline. The high-pressure double-elbow is prone to be affected by erosion wear and Fluid-Structure Interaction (FSI), resulting in perforation and fracture, posing a potential safety threat to field operation. In this study, we conducted the erosion wear experiments on 35CrMo steel used for high-pressure double-elbow in shale-gas fracturing. The erosion rates under different impact angles and flow velocities were obtained, and proposed a novel model of erosion prediction for high-pressure double-elbow. Then the numerical investigation was employed to conduct a comprehensive analysis of erosion wear, structural stress and deformation by the coupling of Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA). The effects of structural parameters such as connection straight pipe length, pipe inner diameter and fluid turning direction were discussed. The results indicate that with the increase of connection straight pipe length, the flow erosion decreases first then varies little, and the deformation gradually increases. Slight erosion wear but large structural stress and deformation in major inner diameter pipe. And the minimum degree of erosion and flow-induced deformation present with the fluid turning direction of double-elbow as 0°. The study can provide references for the design, installation and detection of high-pressure double-elbow and ensure safety in the process of shale gas fracturing.
在页岩气开发的现场水力压裂作业中，高压大排量液固两相压裂液可通过高压双弯头多次被迫改变方向，并从压裂泵的出口管道输送至主管线。高压双弯头容易受到冲蚀磨损和流固耦合作用（FSI）的影响，导致穿孔和破裂，对现场作业构成潜在安全威胁。在本研究中，我们对用于页岩气压裂高压双弯头的35CrMo钢进行了冲蚀磨损实验。获得了不同冲击角度和流速下的冲蚀速率，并提出了一种针对高压双弯头的新型冲蚀预测模型。然后采用数值研究方法，通过计算流体动力学（CFD）和有限元分析（FEA）的耦合，对冲蚀磨损、结构应力和变形进行综合分析。讨论了连接直管长度、管道内径和流体转向等结构参数的影响。结果表明，随着连接直管长度的增加，流动冲蚀先减小后变化不大，而变形逐渐增大。主管径管道冲蚀磨损轻微，但结构应力和变形较大。当双弯头的流体转向角度为0°时，冲蚀和流动诱导变形程度最小。该研究可为高压双弯头的设计、安装和检测提供参考，并确保页岩气压裂过程中的安全。
