Novel transmitter transducer for acoustic logging while drilling. (May 2022)

• Record Type: Journal Article
• Authors: Fu, Xin; Gou, Yang
• Is Part Of: Applied acoustics. Volume 193(2022)
• Publication Date: 2022-05
• Subjects: Piezoelectric transducer -- Acoustic logging while drilling -- Numerical simulation -- Sound field and well experiments; Acoustical engineering -- Periodicals; Periodicals; 620.2
• DOI: 10.1016/j.apacoust.2022.108752
• Languages: English
• ISSNs: 0003-682X

Abstract

Highlights: Further, we believe that this paper will be of interest to the readership of your journal because the improvements in transducer design are fundamentally acoustic in nature. Readers with an interest in acoustic and borderline ultrasonic transducers will find this research of interest even if they are not actively pursuing oil exploration. Abstract: In this paper, a new transmitter transducer for an acoustic logging while drilling (ALWD) tool is proposed. The piezoelectric ceramic is cut into two parts based on conventional transducers, and a buffer material is set in the middle. Thus, the radial vibration displacement of the new transducer is larger at the resonant frequency, whereas the longitudinal coupling vibration is significantly reduced. Although conventional transducers have a simple structure, they have large longitudinal vibration displacements, which directly cause strong drill collar waves. These collar waves negatively affect the measurement of formation signals. In this study, the differences in admittance and vibration displacement distribution between a conventional transducer and the new transducer are compared using COMSOL simulation. Finite element simulation results show that the transducer employing soft epoxy resin with a height of 6 mm as the filling material is the most effective. The real axis integral method is used to verify that the longitudinal vibration of the transducer causes strong drill collar waves. Then, sound field and well field experiments are conducted on actual transducers. The experimental results show that the emission voltage response of the new ALWD transducer designed in this study can reach 140 dB, which is 6.22% higher than that of a conventional transducer; moreover, the output voltage increased by 52.81%, directivity improved by 67.82%, and drill collar wave interference decreased by 66%. Therefore, the new transducer can improve the detection performance of ALWD instruments and provide a reference for the design of other transducers.