Stufy On The Influence Laws Of Vibration On Performance Of The Cement Slurry And Stone Dissertation

Vibration cementing is one of the most effective techniques to improve the cementing quality.The performance of cement slurry and the bond contiditions of the cement sheath between two interfaces will be improved when the vibration wave acts on the casing string and fluid in the annulus.Therefore,on the one hand,domestic and overseas institutes of scientific research have focused on the design of cementing processes,devices and application,there are still many gaps about the study on vibration experimental evaluations;On the other hand,perceptions on the influence laws of vibration on the perfarmence of the cement slurry and stone have not yet reached an agreement.As a result,development of this technology would be restricted.So this paper studied the influence laws of vibration on the performance of the cement slurry and stone by means of laboratory experiment and numerical simulation,and obtained the following research results:(1)Inventing an experimental platform to vibrate cement slurry mechanically by investigating the literature on vibration cementing at home and abroad.Through the orthogonal experiments,it was found that vibration has a better effect to increase the strength of the conventional density of cement stone,obtained the best combination of vibration parameters.And the performance of cement stone is more sensitive to shifts of the frequency and amplitude.Evenutally,the microscopic analysis verified that vibration is very positive to improve the microstructure of cement stone.(2)Testing the influence laws of vibration with different frequency on the traditional performance of cement slurry.The results show that vibration can promote the hardening process of cement slurry and shorten significantly the transition time of the development of the static gel strength and setting time of the cement slurry,and the rheological and pumpable properties were improved extremely.At the same time,inventing a new type of cement stone mold to explore the best position of the vibration which is in a certain range between the excitation and distal end.(3)Calculating the influence laws of vibration on the filling ratio of cement particles through the discrete element method.The results showed that effect of the vibration parameters on the particle filling ratio is basically consistent with the experimental results.Especially,the filling ratio of particles under the horizontal vibration is about 3 times the vertical vibration.In the simulation scheme,the filling ratio of the accumulation of different size and shape particles were increased by 40.22% and 8.33% respectively.(4)Calculating the propagation laws of the vibration wave along the axial direction of the casing string by means of the finite element analysis.The results showed that the amplitude of the bottom of the casing string decreases as frequency and casing wall thichness increase,and increases as the excitation force increases.At the same time,the attenuation coefficient is introduced to analyze the attenuation characteristics of the vibration wave.The attenuation rate of the vibration wave decreases as the frequency and the wall thichness of vibration increase,and increases as the excitation force increases.