Simulation Of Well Logging Piezoelectric Transducer And The Wellbore-formation Wave Field Calculation Based On Finite Element Method

Firstly, starting from the implementation of the piezoelectric effect, utilize Abaqus to achieve the piezoelectric coupling. And Then simulate a radially vibrating cylindrical piezoelectric transducer, extracting its eigenfrequency and analysing the specific effect of geometry size for the eigenfrequency. Afterward,we discuss the actual vibration of the transducer surface and analyze its surface parameters of vibration magnitude.Secondly, we use the acoustic contact element for coupling the radially vibrating cylindrical piezoelectric transducer(solid media) and water(fluid medium) together, which actually complete that the outer layer is fluid-structure coupling and for the transducer itself is piezoelectric coupling. This is theoretical method and finite difference method which cannot complete. And calculate the time-domain waveforms with transient voltage and different center frequency voltages, analyze the actual acoustic pressure magnitude of the transducer surface with different center frequency voltages.Preliminary reach a conclusion that using 2k Hz to 14 k Hz center frequency cosine envelope curve as loading voltage waveforms and siting 500 V as the voltage value, the actual acoustic pressure magnitude of transducer surface at 1mm is from 2 ′ 102 Pa to 4 ′ 104 Pa.Thirdly, making use of infinite element can initially solve the problem aroused by the return wave that is caused by artificial truncation. And exploratory using Abaqus to calculate the wellbore and the formation wave field with point acoustic source effect, by comparison with the theoretical solution, verify the correctness of finite element calculation., which indirectly illustrates that Abaqus has some applicability in the wellbore and the layer wave field calculation.Finally, the innovative use of finite element is to calculate the wellbore and the formation wave field aroused by a real log transducer, which represent a complete simulation of the actual logging process. And calculate the actual logging process wave fields with 500 V transient voltage and 500 V center frequency 4khz cosine wave voltage, and receive clear formation compressional wave, formation shear wave and Stoneley wave, which basically verify that the actual logging process simulation is correct.