E2-a1 - Coupling of elastic waves and voltage waveforms in monopole ALWD: role of piezoelectricity and acoustic propagation
- Event
- 2025 ICU PADERBORN - 9th International Congress on Ultrasonics
2025-09-21 - 2025-09-25
Paderborn - Band
- Lectures
- Chapter
- E2-a - Coupled acoustic/elastic/electromagnetic waves
- Author(s)
- C. Zhang, Z. Chen, W. Guan - Harbin Institude of Technology, Harbin (China)
- Pages
- 283 - 286
- DOI
- 10.5162/Ultrasonic2025/E2-a1
- ISBN
- 978-3-910600-08-9
- Price
- free
Abstract
Acoustic Logging While Drilling (ALWD) acoustic measurement, characterized by combining drilling and logging operations, is widely used to obtain elastic parameters of formation surrounding the borehole. Most published simulated monopole acoustic LWD waveforms are typically represented by acoustic pressure. However, these pressure waveforms do not match the voltage waveforms recorded experimentally. To investigate this discrepancy, we employed the finite element method to comprehensively calculate both the piezoelectric effects of transducers and acoustic wave propagation, obtaining voltage waveforms and mechanical waveforms. Quantitative comparisons between mechanical and voltage waveforms reveal that the output voltage does not represent pressure signals alone but rather constitutes a combination of multiple mechanical signals. Based on piezoelectric equations and the structure of piezoelectric transducers used in this study, we systematically investigated the coupled effects of four mechanical quantities on output voltage: radial strain and axial stress (reflecting formation information), as well as acoustic pressure and radial displacement in borehole fluid (indicating interference effects from measurement tools). Further analysis explores the respective contributions of these four mechanical quantities to different wave groups. This research provides valuable insights for understanding the coupling mechanisms between elastic waves in logging applications.