Method for Separating Multi-Modal Acoustic Measurements for Evaluating Multilayer Structures

摘要

Techniques involve methods and systems for separating leaky-Lamb modes to evaluate cylindrically layered structures. Embodiments involve receiving acoustic cement evaluation data from one or more acoustic downhole tools used over a depth interval in a well having a casing. The acoustic cement evaluation data includes leaky-Lamb wave measurements measured from the acoustic downhole tools. Embodiments also involve determining an extensional mode component and a flexural mode component of the leaky-Lamb wave measurements and determining a flexural wave attenuation based on the flexural mode component of the leaky-Lamb wave measurement. In some embodiments, the extensional and flexural mode components can be determined using mode decomposition technique. Further, some embodiments involve constructing dictionaries for the extensional and flexural mode components and representing the leaky-Lamb wave measurement as a weighted sum based on the dictionaries and reconstruct a flexural wave attenuation based on the weighted sum.

主权项

1. A method comprising:
receiving acoustic cement evaluation data into a data processing system, wherein the acoustic cement evaluation data is obtained from one or more acoustic downhole tools used over a depth interval in a well having a casing, wherein the acoustic cement evaluation data comprises leaky-Lamb wave measurements measured from the one or more acoustic downhole tools; applying a mode decomposition technique on the leaky-Lamb wave measurements, wherein the mode decomposition technique comprises:
determining an extensional mode component of the leaky-Lamb wave measurements; anddetermining a flexural mode component of the leaky-Lamb wave measurement; and determining a flexural wave attenuation based on the flexural mode component of the leaky-Lamb wave measurement.