Research On Hydraulic Shock Vibration Cementing Tool

The vibration cementing can enhance the displacement efficiency and bond strength at the first and second interfaces. This paper mainly study the mechanisms of vibration cementing based on external excited oscillation. Taking the outlet pulse pressure increase value in the external excited oscillation cavity as the target considered object, the orthogonal numerical simulation for the flow field in the cavity and annular has been conducted and the influences of the cavity structure parameters and the fluid characteristic parameters on the outlet pulse pressure increase value analyzed. The results are as following:(1) The vibration cementing tool can substantially increase the instantaneous velocity and pressure at the outlet of bottom casing and the produced pulsating pressure act the annulus fluid and enhance the cementing displacement efficiency.(2) The produced pulsating pressure decreases with the increase of distance from the bottom and the farthest propagation distance of the pulsating pressure is proportional to the initial pulse pressure at the bottom.(3) The numerical simulation for the flow field in the cavity indicates that the uniform flow will produce a strong oscillation after it through the vibration cementing tool and a pulse pressure with the amplitude0.7MPa is formed.(4) The main affecting factors for the outlet pulse pressure increase value in the external excited oscillation cavity are the ratio of the inlet diameter to the outlet diameter r and the inlet capacity Q. When r=1.5, the pulse pressure increase value is the largest. With the increase of inlet capacity Q, pulse pressure increases significantly, while the percentage of which changes not obviously.(5) The structure parameters of vibration cementing tool have been optimized base on the analysis of affecting factors for its cementing effectiveness.The theory and simulation analysis above indicates that the designed vibration cementing tool based on external excited oscillation can improve the cementing quality effectively.