The Mechanism And Design Of Underground Low-frequency Hydraulic Vibration Cementing Device

Vibration cementing is a new technology which used mechanical vibration, hydraulic or air pulse, hydraulic shock and other means generating vibration waves resulting in the casing, drilling fluids and cementing fluid to improve the quality of solid-well in the process of casing, cementing, replacing and waiting-on cementing. In this thesis, via the researching and analyzing the theory and tools developed home and abroad on vibration cementing, and got familiar with the direction of development at home and abroad vibration the cementing theory and tools developed. To deal with gas channeling in cementing control countermeasures, as vibration cementing tool to produce good results in foreign cementing gradually attracted the attention of experts at home and abroad. There are many experts and scholars to study the theory of vibration cementing tools developed and put into application in the field getting a good cementing effect. Practice has proved that vibration can improve cement strength, to improve the displacement efficiency, and eliminate the bubbles in the cement, the formation of intact cement ring and help to improve the bond strength of the interface, to shorten the time of waiting-on cementing, to prevent gas channeling in the process of cementing. This shows that using the exciter to produce vibration wave in the slurry is one of the effective measures to prevent gas channeling.Based on the research of large amounts of data at home and abroad, all in all, gas channeling can not be separated from the two necessary conditions for the channeling and channeling the flow of power. Obviously, channeling the flow of power from the pressure differential between layers, and channeling from the cement and formation, the casing combine to form a weak link in the good layer packer, cement rock body or cement stone with formation the connection between the casing interface. Relatively well annulus channeling theory, there are three:firstly, the interface bond theory; secondly weightlessness bridging doctrine; thirdly is the doctrine of the gel structure. But all of these theory, in which the fluid must be channel to complete channeling. Professor Gu Jun in China Geosciences University claimed that the root cause of the annular gas channeling cementing two interface seal the bond quality problems, although the hydrostatic pressure of the annulus is greater than the formation pore pressure, but the wellbore thermal change and pressure fluctuations in the formation of the interface micro-create channeling cracks and cake or death mud bypass channels or micro-channeling will continue to trap and gas formation. This is why logging data looks good seal the annulus to the real reason gas detected in the completion of several weeks or months after. This theory has been the recognized by many experts in the industry. Therefore, improving the cementing bond strength of the second surface of the strength of cement and cementing process is particularly important to ensure the quality of cementing of wells seem. For this vibration using the cementing device in the process of cementing, play the role of cement in the solidification process to prevent the occurrence of gas channeling with good results.Full investigation of the overview of the development at home and abroad vibration cementing device, commonly used in down-hole vibrating equipment just as such four kinds:electric, electromagnetic and electro-hydraulic, hydraulic pulse. Consideration the choice of vibration frequencies, some experts found that, when the vibration frequency is high, although removal of stubborn localized within the dense layer cake, but the stability of the shaft of the vibration wave will produce certain adverse effects. Espacially the frequency between0.5hertz to20hertz, the cementing quality will be better. And the higher the vibration frequency, vibration attenuation and faster propagation distance is shorter, but go against improving the quality of well cementing. Implementation, to control the lower frequency, but the tool is simple easy to install hydraulic pulse vibratory cementing device is an ideal choice.In the process of designation of this device, giving full consideration to the requirements of the cementing process, as much as possible the data closer to the site as a design reference data, the use of standard parts and commonly used materials for the choice of device components as much as possible, in the strength check, parts key parts stress analysis and using the inversion method to check the size of the parts, and ultimately getting a more reasonable design ideas, to map out the various components of the device parts drawing and assembly drawing of the overall. In this process of designation is just a process of testing and practice knowledge of drilling and mechanical designation. The designed device theoretically has a certain feasibility and play the complementary role for the improvement of the vibration cementing device.