Structural optimization of downhole float valve via computational fluid dynamics

The internal parts of currently used float valve have serious erosion and unstable performance situations. If the drilling float valve fails, it will take a long time to deal with accidents and increase the risk of drilling operations. To solve this problem, we use the computational fluid dynamics method (CFD) to analyze the flow field structure of common downhole float valve, including the velocity field, turbulence intensity field, and wall shear stress field. The study found that: the flow field is quite disordered near the sealing surface of valve core, as well as near the spring and the opening parts of lower seat. Meanwhile, strong vortexes have been generated. This is a good corresponding relationship between the CFD simulation and the erosion (location and extent) in real float valve. This indicates that the CFD method can be used for optimization of existing float valve. On this basis, we present the optimal design, and use CFD method to analyze the new design. The analysis results show that the optimized design has not high velocity region, simultaneously, disturbance and vortex phenomenon of the flow field are significantly reduced and even disappeared. Its flow field distribution is more reasonable, which can reduce the factors causing erosion and performance failure. Therefore, we can infer that the new float valve has better anti-erosion performance and working stability.